1 /*
2 * Copyright (c) 1999, 2022, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2015, 2022 SAP SE. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 // no precompiled headers
27 #include "jvm.h"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/icBuffer.hpp"
30 #include "code/vtableStubs.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "compiler/disassembler.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "jvmtifiles/jvmti.h"
35 #include "logging/log.hpp"
36 #include "logging/logStream.hpp"
37 #include "memory/allocation.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "os_linux.inline.hpp"
40 #include "os_posix.inline.hpp"
41 #include "os_share_linux.hpp"
42 #include "osContainer_linux.hpp"
43 #include "prims/jniFastGetField.hpp"
44 #include "prims/jvm_misc.hpp"
45 #include "runtime/arguments.hpp"
46 #include "runtime/atomic.hpp"
47 #include "runtime/globals.hpp"
48 #include "runtime/globals_extension.hpp"
49 #include "runtime/interfaceSupport.inline.hpp"
50 #include "runtime/init.hpp"
51 #include "runtime/java.hpp"
52 #include "runtime/javaCalls.hpp"
53 #include "runtime/mutexLocker.hpp"
54 #include "runtime/objectMonitor.hpp"
55 #include "runtime/osThread.hpp"
56 #include "runtime/perfMemory.hpp"
57 #include "runtime/sharedRuntime.hpp"
58 #include "runtime/statSampler.hpp"
59 #include "runtime/stubRoutines.hpp"
60 #include "runtime/thread.inline.hpp"
61 #include "runtime/threadCritical.hpp"
62 #include "runtime/threadSMR.hpp"
63 #include "runtime/timer.hpp"
64 #include "runtime/vm_version.hpp"
65 #include "signals_posix.hpp"
66 #include "semaphore_posix.hpp"
67 #include "services/memTracker.hpp"
68 #include "services/runtimeService.hpp"
69 #include "utilities/align.hpp"
70 #include "utilities/decoder.hpp"
71 #include "utilities/defaultStream.hpp"
72 #include "utilities/events.hpp"
73 #include "utilities/elfFile.hpp"
74 #include "utilities/growableArray.hpp"
75 #include "utilities/macros.hpp"
76 #include "utilities/powerOfTwo.hpp"
77 #include "utilities/vmError.hpp"
78
79 // put OS-includes here
80 # include <sys/types.h>
81 # include <sys/mman.h>
82 # include <sys/stat.h>
83 # include <sys/select.h>
84 # include <pthread.h>
85 # include <signal.h>
86 # include <endian.h>
87 # include <errno.h>
88 # include <dlfcn.h>
89 # include <stdio.h>
90 # include <unistd.h>
91 # include <sys/resource.h>
92 # include <pthread.h>
93 # include <sys/stat.h>
94 # include <sys/time.h>
95 # include <sys/times.h>
96 # include <sys/utsname.h>
97 # include <sys/socket.h>
98 # include <pwd.h>
99 # include <poll.h>
100 # include <fcntl.h>
101 # include <string.h>
102 # include <syscall.h>
103 # include <sys/sysinfo.h>
104 # include <sys/ipc.h>
105 # include <sys/shm.h>
106 # include <link.h>
107 # include <stdint.h>
108 # include <inttypes.h>
109 # include <sys/ioctl.h>
110 # include <linux/elf-em.h>
111 #ifdef __GLIBC__
112 # include <malloc.h>
113 #endif
114
115 #ifndef _GNU_SOURCE
116 #define _GNU_SOURCE
117 #include <sched.h>
118 #undef _GNU_SOURCE
119 #else
120 #include <sched.h>
121 #endif
122
123 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
124 // getrusage() is prepared to handle the associated failure.
125 #ifndef RUSAGE_THREAD
126 #define RUSAGE_THREAD (1) /* only the calling thread */
127 #endif
128
129 #define MAX_PATH (2 * K)
130
131 #define MAX_SECS 100000000
132
133 // for timer info max values which include all bits
134 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
135
136 #ifdef MUSL_LIBC
137 // dlvsym is not a part of POSIX
138 // and musl libc doesn't implement it.
139 static void *dlvsym(void *handle,
140 const char *symbol,
141 const char *version) {
142 // load the latest version of symbol
143 return dlsym(handle, symbol);
144 }
145 #endif
146
147 enum CoredumpFilterBit {
148 FILE_BACKED_PVT_BIT = 1 << 2,
149 FILE_BACKED_SHARED_BIT = 1 << 3,
150 LARGEPAGES_BIT = 1 << 6,
151 DAX_SHARED_BIT = 1 << 8
152 };
153
154 ////////////////////////////////////////////////////////////////////////////////
155 // global variables
156 julong os::Linux::_physical_memory = 0;
157
158 address os::Linux::_initial_thread_stack_bottom = NULL;
159 uintptr_t os::Linux::_initial_thread_stack_size = 0;
160
161 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
162 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
163 pthread_t os::Linux::_main_thread;
164 int os::Linux::_page_size = -1;
165 bool os::Linux::_supports_fast_thread_cpu_time = false;
166 const char * os::Linux::_libc_version = NULL;
167 const char * os::Linux::_libpthread_version = NULL;
168 size_t os::Linux::_default_large_page_size = 0;
169
170 #ifdef __GLIBC__
171 os::Linux::mallinfo_func_t os::Linux::_mallinfo = NULL;
172 os::Linux::mallinfo2_func_t os::Linux::_mallinfo2 = NULL;
173 #endif // __GLIBC__
174
175 static jlong initial_time_count=0;
176
177 static int clock_tics_per_sec = 100;
178
179 // If the VM might have been created on the primordial thread, we need to resolve the
180 // primordial thread stack bounds and check if the current thread might be the
181 // primordial thread in places. If we know that the primordial thread is never used,
182 // such as when the VM was created by one of the standard java launchers, we can
183 // avoid this
184 static bool suppress_primordial_thread_resolution = false;
185
186 // utility functions
187
188 julong os::available_memory() {
189 return Linux::available_memory();
190 }
191
192 julong os::Linux::available_memory() {
193 // values in struct sysinfo are "unsigned long"
194 struct sysinfo si;
195 julong avail_mem;
196
197 if (OSContainer::is_containerized()) {
198 jlong mem_limit = OSContainer::memory_limit_in_bytes();
199 jlong mem_usage;
200 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) {
201 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage);
202 }
203 if (mem_limit > 0 && mem_usage > 0) {
204 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0;
205 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem);
206 return avail_mem;
207 }
208 }
209
210 sysinfo(&si);
211 avail_mem = (julong)si.freeram * si.mem_unit;
212 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem);
213 return avail_mem;
214 }
215
216 julong os::physical_memory() {
217 jlong phys_mem = 0;
218 if (OSContainer::is_containerized()) {
219 jlong mem_limit;
220 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) {
221 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit);
222 return mem_limit;
223 }
224 }
225
226 phys_mem = Linux::physical_memory();
227 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem);
228 return phys_mem;
229 }
230
231 static uint64_t initial_total_ticks = 0;
232 static uint64_t initial_steal_ticks = 0;
233 static bool has_initial_tick_info = false;
234
235 static void next_line(FILE *f) {
236 int c;
237 do {
238 c = fgetc(f);
239 } while (c != '\n' && c != EOF);
240 }
241
242 bool os::Linux::get_tick_information(CPUPerfTicks* pticks, int which_logical_cpu) {
243 FILE* fh;
244 uint64_t userTicks, niceTicks, systemTicks, idleTicks;
245 // since at least kernel 2.6 : iowait: time waiting for I/O to complete
246 // irq: time servicing interrupts; softirq: time servicing softirqs
247 uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0;
248 // steal (since kernel 2.6.11): time spent in other OS when running in a virtualized environment
249 uint64_t stealTicks = 0;
250 // guest (since kernel 2.6.24): time spent running a virtual CPU for guest OS under the
251 // control of the Linux kernel
252 uint64_t guestNiceTicks = 0;
253 int logical_cpu = -1;
254 const int required_tickinfo_count = (which_logical_cpu == -1) ? 4 : 5;
255 int n;
256
257 memset(pticks, 0, sizeof(CPUPerfTicks));
258
259 if ((fh = fopen("/proc/stat", "r")) == NULL) {
260 return false;
261 }
262
263 if (which_logical_cpu == -1) {
264 n = fscanf(fh, "cpu " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
265 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
266 UINT64_FORMAT " " UINT64_FORMAT " ",
267 &userTicks, &niceTicks, &systemTicks, &idleTicks,
268 &iowTicks, &irqTicks, &sirqTicks,
269 &stealTicks, &guestNiceTicks);
270 } else {
271 // Move to next line
272 next_line(fh);
273
274 // find the line for requested cpu faster to just iterate linefeeds?
275 for (int i = 0; i < which_logical_cpu; i++) {
276 next_line(fh);
277 }
278
279 n = fscanf(fh, "cpu%u " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
280 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
281 UINT64_FORMAT " " UINT64_FORMAT " ",
282 &logical_cpu, &userTicks, &niceTicks,
283 &systemTicks, &idleTicks, &iowTicks, &irqTicks, &sirqTicks,
284 &stealTicks, &guestNiceTicks);
285 }
286
287 fclose(fh);
288 if (n < required_tickinfo_count || logical_cpu != which_logical_cpu) {
289 return false;
290 }
291 pticks->used = userTicks + niceTicks;
292 pticks->usedKernel = systemTicks + irqTicks + sirqTicks;
293 pticks->total = userTicks + niceTicks + systemTicks + idleTicks +
294 iowTicks + irqTicks + sirqTicks + stealTicks + guestNiceTicks;
295
296 if (n > required_tickinfo_count + 3) {
297 pticks->steal = stealTicks;
298 pticks->has_steal_ticks = true;
299 } else {
300 pticks->steal = 0;
301 pticks->has_steal_ticks = false;
302 }
303
304 return true;
305 }
306
307 // Return true if user is running as root.
308
309 bool os::have_special_privileges() {
310 static bool init = false;
311 static bool privileges = false;
312 if (!init) {
313 privileges = (getuid() != geteuid()) || (getgid() != getegid());
314 init = true;
315 }
316 return privileges;
317 }
318
319
320 #ifndef SYS_gettid
321 // i386: 224, ia64: 1105, amd64: 186, sparc: 143
322 #ifdef __ia64__
323 #define SYS_gettid 1105
324 #else
325 #ifdef __i386__
326 #define SYS_gettid 224
327 #else
328 #ifdef __amd64__
329 #define SYS_gettid 186
330 #else
331 #ifdef __sparc__
332 #define SYS_gettid 143
333 #else
334 #error define gettid for the arch
335 #endif
336 #endif
337 #endif
338 #endif
339 #endif
340
341
342 // pid_t gettid()
343 //
344 // Returns the kernel thread id of the currently running thread. Kernel
345 // thread id is used to access /proc.
346 pid_t os::Linux::gettid() {
347 int rslt = syscall(SYS_gettid);
348 assert(rslt != -1, "must be."); // old linuxthreads implementation?
349 return (pid_t)rslt;
350 }
351
352 // Returns the amount of swap currently configured, in bytes.
353 // This can change at any time.
354 julong os::Linux::host_swap() {
355 struct sysinfo si;
356 sysinfo(&si);
357 return (julong)si.totalswap;
358 }
359
360 // Most versions of linux have a bug where the number of processors are
361 // determined by looking at the /proc file system. In a chroot environment,
362 // the system call returns 1.
363 static bool unsafe_chroot_detected = false;
364 static const char *unstable_chroot_error = "/proc file system not found.\n"
365 "Java may be unstable running multithreaded in a chroot "
366 "environment on Linux when /proc filesystem is not mounted.";
367
368 void os::Linux::initialize_system_info() {
369 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
370 if (processor_count() == 1) {
371 pid_t pid = os::Linux::gettid();
372 char fname[32];
373 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
374 FILE *fp = fopen(fname, "r");
375 if (fp == NULL) {
376 unsafe_chroot_detected = true;
377 } else {
378 fclose(fp);
379 }
380 }
381 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
382 assert(processor_count() > 0, "linux error");
383 }
384
385 void os::init_system_properties_values() {
386 // The next steps are taken in the product version:
387 //
388 // Obtain the JAVA_HOME value from the location of libjvm.so.
389 // This library should be located at:
390 // <JAVA_HOME>/lib/{client|server}/libjvm.so.
391 //
392 // If "/jre/lib/" appears at the right place in the path, then we
393 // assume libjvm.so is installed in a JDK and we use this path.
394 //
395 // Otherwise exit with message: "Could not create the Java virtual machine."
396 //
397 // The following extra steps are taken in the debugging version:
398 //
399 // If "/jre/lib/" does NOT appear at the right place in the path
400 // instead of exit check for $JAVA_HOME environment variable.
401 //
402 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
403 // then we append a fake suffix "hotspot/libjvm.so" to this path so
404 // it looks like libjvm.so is installed there
405 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
406 //
407 // Otherwise exit.
408 //
409 // Important note: if the location of libjvm.so changes this
410 // code needs to be changed accordingly.
411
412 // See ld(1):
413 // The linker uses the following search paths to locate required
414 // shared libraries:
415 // 1: ...
416 // ...
417 // 7: The default directories, normally /lib and /usr/lib.
418 #ifndef OVERRIDE_LIBPATH
419 #if defined(_LP64)
420 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
421 #else
422 #define DEFAULT_LIBPATH "/lib:/usr/lib"
423 #endif
424 #else
425 #define DEFAULT_LIBPATH OVERRIDE_LIBPATH
426 #endif
427
428 // Base path of extensions installed on the system.
429 #define SYS_EXT_DIR "/usr/java/packages"
430 #define EXTENSIONS_DIR "/lib/ext"
431
432 // Buffer that fits several sprintfs.
433 // Note that the space for the colon and the trailing null are provided
434 // by the nulls included by the sizeof operator.
435 const size_t bufsize =
436 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
437 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
438 char *buf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
439
440 // sysclasspath, java_home, dll_dir
441 {
442 char *pslash;
443 os::jvm_path(buf, bufsize);
444
445 // Found the full path to libjvm.so.
446 // Now cut the path to <java_home>/jre if we can.
447 pslash = strrchr(buf, '/');
448 if (pslash != NULL) {
449 *pslash = '\0'; // Get rid of /libjvm.so.
450 }
451 pslash = strrchr(buf, '/');
452 if (pslash != NULL) {
453 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
454 }
455 Arguments::set_dll_dir(buf);
456
457 if (pslash != NULL) {
458 pslash = strrchr(buf, '/');
459 if (pslash != NULL) {
460 *pslash = '\0'; // Get rid of /lib.
461 }
462 }
463 Arguments::set_java_home(buf);
464 if (!set_boot_path('/', ':')) {
465 vm_exit_during_initialization("Failed setting boot class path.", NULL);
466 }
467 }
468
469 // Where to look for native libraries.
470 //
471 // Note: Due to a legacy implementation, most of the library path
472 // is set in the launcher. This was to accomodate linking restrictions
473 // on legacy Linux implementations (which are no longer supported).
474 // Eventually, all the library path setting will be done here.
475 //
476 // However, to prevent the proliferation of improperly built native
477 // libraries, the new path component /usr/java/packages is added here.
478 // Eventually, all the library path setting will be done here.
479 {
480 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
481 // should always exist (until the legacy problem cited above is
482 // addressed).
483 const char *v = ::getenv("LD_LIBRARY_PATH");
484 const char *v_colon = ":";
485 if (v == NULL) { v = ""; v_colon = ""; }
486 // That's +1 for the colon and +1 for the trailing '\0'.
487 char *ld_library_path = NEW_C_HEAP_ARRAY(char,
488 strlen(v) + 1 +
489 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1,
490 mtInternal);
491 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon);
492 Arguments::set_library_path(ld_library_path);
493 FREE_C_HEAP_ARRAY(char, ld_library_path);
494 }
495
496 // Extensions directories.
497 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
498 Arguments::set_ext_dirs(buf);
499
500 FREE_C_HEAP_ARRAY(char, buf);
501
502 #undef DEFAULT_LIBPATH
503 #undef SYS_EXT_DIR
504 #undef EXTENSIONS_DIR
505 }
506
507 ////////////////////////////////////////////////////////////////////////////////
508 // breakpoint support
509
510 void os::breakpoint() {
511 BREAKPOINT;
512 }
513
514 extern "C" void breakpoint() {
515 // use debugger to set breakpoint here
516 }
517
518 //////////////////////////////////////////////////////////////////////////////
519 // detecting pthread library
520
521 void os::Linux::libpthread_init() {
522 // Save glibc and pthread version strings.
523 #if !defined(_CS_GNU_LIBC_VERSION) || \
524 !defined(_CS_GNU_LIBPTHREAD_VERSION)
525 #error "glibc too old (< 2.3.2)"
526 #endif
527
528 #ifdef MUSL_LIBC
529 // confstr() from musl libc returns EINVAL for
530 // _CS_GNU_LIBC_VERSION and _CS_GNU_LIBPTHREAD_VERSION
531 os::Linux::set_libc_version("musl - unknown");
532 os::Linux::set_libpthread_version("musl - unknown");
533 #else
534 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
535 assert(n > 0, "cannot retrieve glibc version");
536 char *str = (char *)malloc(n, mtInternal);
537 confstr(_CS_GNU_LIBC_VERSION, str, n);
538 os::Linux::set_libc_version(str);
539
540 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
541 assert(n > 0, "cannot retrieve pthread version");
542 str = (char *)malloc(n, mtInternal);
543 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
544 os::Linux::set_libpthread_version(str);
545 #endif
546 }
547
548 /////////////////////////////////////////////////////////////////////////////
549 // thread stack expansion
550
551 // os::Linux::manually_expand_stack() takes care of expanding the thread
552 // stack. Note that this is normally not needed: pthread stacks allocate
553 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
554 // committed. Therefore it is not necessary to expand the stack manually.
555 //
556 // Manually expanding the stack was historically needed on LinuxThreads
557 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
558 // it is kept to deal with very rare corner cases:
559 //
560 // For one, user may run the VM on an own implementation of threads
561 // whose stacks are - like the old LinuxThreads - implemented using
562 // mmap(MAP_GROWSDOWN).
563 //
564 // Also, this coding may be needed if the VM is running on the primordial
565 // thread. Normally we avoid running on the primordial thread; however,
566 // user may still invoke the VM on the primordial thread.
567 //
568 // The following historical comment describes the details about running
569 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
570
571
572 // Force Linux kernel to expand current thread stack. If "bottom" is close
573 // to the stack guard, caller should block all signals.
574 //
575 // MAP_GROWSDOWN:
576 // A special mmap() flag that is used to implement thread stacks. It tells
577 // kernel that the memory region should extend downwards when needed. This
578 // allows early versions of LinuxThreads to only mmap the first few pages
579 // when creating a new thread. Linux kernel will automatically expand thread
580 // stack as needed (on page faults).
581 //
582 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
583 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
584 // region, it's hard to tell if the fault is due to a legitimate stack
585 // access or because of reading/writing non-exist memory (e.g. buffer
586 // overrun). As a rule, if the fault happens below current stack pointer,
587 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
588 // application (see Linux kernel fault.c).
589 //
590 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
591 // stack overflow detection.
592 //
593 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
594 // not use MAP_GROWSDOWN.
595 //
596 // To get around the problem and allow stack banging on Linux, we need to
597 // manually expand thread stack after receiving the SIGSEGV.
598 //
599 // There are two ways to expand thread stack to address "bottom", we used
600 // both of them in JVM before 1.5:
601 // 1. adjust stack pointer first so that it is below "bottom", and then
602 // touch "bottom"
603 // 2. mmap() the page in question
604 //
605 // Now alternate signal stack is gone, it's harder to use 2. For instance,
606 // if current sp is already near the lower end of page 101, and we need to
607 // call mmap() to map page 100, it is possible that part of the mmap() frame
608 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
609 // That will destroy the mmap() frame and cause VM to crash.
610 //
611 // The following code works by adjusting sp first, then accessing the "bottom"
612 // page to force a page fault. Linux kernel will then automatically expand the
613 // stack mapping.
614 //
615 // _expand_stack_to() assumes its frame size is less than page size, which
616 // should always be true if the function is not inlined.
617
618 static void NOINLINE _expand_stack_to(address bottom) {
619 address sp;
620 size_t size;
621 volatile char *p;
622
623 // Adjust bottom to point to the largest address within the same page, it
624 // gives us a one-page buffer if alloca() allocates slightly more memory.
625 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size());
626 bottom += os::Linux::page_size() - 1;
627
628 // sp might be slightly above current stack pointer; if that's the case, we
629 // will alloca() a little more space than necessary, which is OK. Don't use
630 // os::current_stack_pointer(), as its result can be slightly below current
631 // stack pointer, causing us to not alloca enough to reach "bottom".
632 sp = (address)&sp;
633
634 if (sp > bottom) {
635 size = sp - bottom;
636 p = (volatile char *)alloca(size);
637 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
638 p[0] = '\0';
639 }
640 }
641
642 void os::Linux::expand_stack_to(address bottom) {
643 _expand_stack_to(bottom);
644 }
645
646 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
647 assert(t!=NULL, "just checking");
648 assert(t->osthread()->expanding_stack(), "expand should be set");
649
650 if (t->is_in_usable_stack(addr)) {
651 sigset_t mask_all, old_sigset;
652 sigfillset(&mask_all);
653 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
654 _expand_stack_to(addr);
655 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
656 return true;
657 }
658 return false;
659 }
660
661 //////////////////////////////////////////////////////////////////////////////
662 // create new thread
663
664 // Thread start routine for all newly created threads
665 static void *thread_native_entry(Thread *thread) {
666
667 thread->record_stack_base_and_size();
668
669 #ifndef __GLIBC__
670 // Try to randomize the cache line index of hot stack frames.
671 // This helps when threads of the same stack traces evict each other's
672 // cache lines. The threads can be either from the same JVM instance, or
673 // from different JVM instances. The benefit is especially true for
674 // processors with hyperthreading technology.
675 // This code is not needed anymore in glibc because it has MULTI_PAGE_ALIASING
676 // and we did not see any degradation in performance without `alloca()`.
677 static int counter = 0;
678 int pid = os::current_process_id();
679 int random = ((pid ^ counter++) & 7) * 128;
680 void *stackmem = alloca(random != 0 ? random : 1); // ensure we allocate > 0
681 // Ensure the alloca result is used in a way that prevents the compiler from eliding it.
682 *(char *)stackmem = 1;
683 #endif
684
685 thread->initialize_thread_current();
686
687 OSThread* osthread = thread->osthread();
688 Monitor* sync = osthread->startThread_lock();
689
690 osthread->set_thread_id(os::current_thread_id());
691
692 if (UseNUMA) {
693 int lgrp_id = os::numa_get_group_id();
694 if (lgrp_id != -1) {
695 thread->set_lgrp_id(lgrp_id);
696 }
697 }
698 // initialize signal mask for this thread
699 PosixSignals::hotspot_sigmask(thread);
700
701 // initialize floating point control register
702 os::Linux::init_thread_fpu_state();
703
704 // handshaking with parent thread
705 {
706 MutexLocker ml(sync, Mutex::_no_safepoint_check_flag);
707
708 // notify parent thread
709 osthread->set_state(INITIALIZED);
710 sync->notify_all();
711
712 // wait until os::start_thread()
713 while (osthread->get_state() == INITIALIZED) {
714 sync->wait_without_safepoint_check();
715 }
716 }
717
718 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
719 os::current_thread_id(), (uintx) pthread_self());
720
721 assert(osthread->pthread_id() != 0, "pthread_id was not set as expected");
722
723 // call one more level start routine
724 thread->call_run();
725
726 // Note: at this point the thread object may already have deleted itself.
727 // Prevent dereferencing it from here on out.
728 thread = NULL;
729
730 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
731 os::current_thread_id(), (uintx) pthread_self());
732
733 return 0;
734 }
735
736 // On Linux, glibc places static TLS blocks (for __thread variables) on
737 // the thread stack. This decreases the stack size actually available
738 // to threads.
739 //
740 // For large static TLS sizes, this may cause threads to malfunction due
741 // to insufficient stack space. This is a well-known issue in glibc:
742 // http://sourceware.org/bugzilla/show_bug.cgi?id=11787.
743 //
744 // As a workaround, we call a private but assumed-stable glibc function,
745 // __pthread_get_minstack() to obtain the minstack size and derive the
746 // static TLS size from it. We then increase the user requested stack
747 // size by this TLS size.
748 //
749 // Due to compatibility concerns, this size adjustment is opt-in and
750 // controlled via AdjustStackSizeForTLS.
751 typedef size_t (*GetMinStack)(const pthread_attr_t *attr);
752
753 GetMinStack _get_minstack_func = NULL;
754
755 static void get_minstack_init() {
756 _get_minstack_func =
757 (GetMinStack)dlsym(RTLD_DEFAULT, "__pthread_get_minstack");
758 log_info(os, thread)("Lookup of __pthread_get_minstack %s",
759 _get_minstack_func == NULL ? "failed" : "succeeded");
760 }
761
762 // Returns the size of the static TLS area glibc puts on thread stacks.
763 // The value is cached on first use, which occurs when the first thread
764 // is created during VM initialization.
765 static size_t get_static_tls_area_size(const pthread_attr_t *attr) {
766 size_t tls_size = 0;
767 if (_get_minstack_func != NULL) {
768 // Obtain the pthread minstack size by calling __pthread_get_minstack.
769 size_t minstack_size = _get_minstack_func(attr);
770
771 // Remove non-TLS area size included in minstack size returned
772 // by __pthread_get_minstack() to get the static TLS size.
773 // In glibc before 2.27, minstack size includes guard_size.
774 // In glibc 2.27 and later, guard_size is automatically added
775 // to the stack size by pthread_create and is no longer included
776 // in minstack size. In both cases, the guard_size is taken into
777 // account, so there is no need to adjust the result for that.
778 //
779 // Although __pthread_get_minstack() is a private glibc function,
780 // it is expected to have a stable behavior across future glibc
781 // versions while glibc still allocates the static TLS blocks off
782 // the stack. Following is glibc 2.28 __pthread_get_minstack():
783 //
784 // size_t
785 // __pthread_get_minstack (const pthread_attr_t *attr)
786 // {
787 // return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN;
788 // }
789 //
790 //
791 // The following 'minstack_size > os::vm_page_size() + PTHREAD_STACK_MIN'
792 // if check is done for precaution.
793 if (minstack_size > (size_t)os::vm_page_size() + PTHREAD_STACK_MIN) {
794 tls_size = minstack_size - os::vm_page_size() - PTHREAD_STACK_MIN;
795 }
796 }
797
798 log_info(os, thread)("Stack size adjustment for TLS is " SIZE_FORMAT,
799 tls_size);
800 return tls_size;
801 }
802
803 bool os::create_thread(Thread* thread, ThreadType thr_type,
804 size_t req_stack_size) {
805 assert(thread->osthread() == NULL, "caller responsible");
806
807 // Allocate the OSThread object
808 OSThread* osthread = new OSThread(NULL, NULL);
809 if (osthread == NULL) {
810 return false;
811 }
812
813 // set the correct thread state
814 osthread->set_thread_type(thr_type);
815
816 // Initial state is ALLOCATED but not INITIALIZED
817 osthread->set_state(ALLOCATED);
818
819 thread->set_osthread(osthread);
820
821 // init thread attributes
822 pthread_attr_t attr;
823 pthread_attr_init(&attr);
824 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
825
826 // Calculate stack size if it's not specified by caller.
827 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
828 // In glibc versions prior to 2.7 the guard size mechanism
829 // is not implemented properly. The posix standard requires adding
830 // the size of the guard pages to the stack size, instead Linux
831 // takes the space out of 'stacksize'. Thus we adapt the requested
832 // stack_size by the size of the guard pages to mimick proper
833 // behaviour. However, be careful not to end up with a size
834 // of zero due to overflow. Don't add the guard page in that case.
835 size_t guard_size = os::Linux::default_guard_size(thr_type);
836 // Configure glibc guard page. Must happen before calling
837 // get_static_tls_area_size(), which uses the guard_size.
838 pthread_attr_setguardsize(&attr, guard_size);
839
840 size_t stack_adjust_size = 0;
841 if (AdjustStackSizeForTLS) {
842 // Adjust the stack_size for on-stack TLS - see get_static_tls_area_size().
843 stack_adjust_size += get_static_tls_area_size(&attr);
844 } else {
845 stack_adjust_size += guard_size;
846 }
847
848 stack_adjust_size = align_up(stack_adjust_size, os::vm_page_size());
849 if (stack_size <= SIZE_MAX - stack_adjust_size) {
850 stack_size += stack_adjust_size;
851 }
852 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned");
853
854 int status = pthread_attr_setstacksize(&attr, stack_size);
855 if (status != 0) {
856 // pthread_attr_setstacksize() function can fail
857 // if the stack size exceeds a system-imposed limit.
858 assert_status(status == EINVAL, status, "pthread_attr_setstacksize");
859 log_warning(os, thread)("The %sthread stack size specified is invalid: " SIZE_FORMAT "k",
860 (thr_type == compiler_thread) ? "compiler " : ((thr_type == java_thread) ? "" : "VM "),
861 stack_size / K);
862 thread->set_osthread(NULL);
863 delete osthread;
864 return false;
865 }
866
867 ThreadState state;
868
869 {
870 ResourceMark rm;
871 pthread_t tid;
872 int ret = 0;
873 int limit = 3;
874 do {
875 ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
876 } while (ret == EAGAIN && limit-- > 0);
877
878 char buf[64];
879 if (ret == 0) {
880 log_info(os, thread)("Thread \"%s\" started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
881 thread->name(), (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
882 } else {
883 log_warning(os, thread)("Failed to start thread \"%s\" - pthread_create failed (%s) for attributes: %s.",
884 thread->name(), os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
885 // Log some OS information which might explain why creating the thread failed.
886 log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads());
887 LogStream st(Log(os, thread)::info());
888 os::Posix::print_rlimit_info(&st);
889 os::print_memory_info(&st);
890 os::Linux::print_proc_sys_info(&st);
891 os::Linux::print_container_info(&st);
892 }
893
894 pthread_attr_destroy(&attr);
895
896 if (ret != 0) {
897 // Need to clean up stuff we've allocated so far
898 thread->set_osthread(NULL);
899 delete osthread;
900 return false;
901 }
902
903 // Store pthread info into the OSThread
904 osthread->set_pthread_id(tid);
905
906 // Wait until child thread is either initialized or aborted
907 {
908 Monitor* sync_with_child = osthread->startThread_lock();
909 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
910 while ((state = osthread->get_state()) == ALLOCATED) {
911 sync_with_child->wait_without_safepoint_check();
912 }
913 }
914 }
915
916 // The thread is returned suspended (in state INITIALIZED),
917 // and is started higher up in the call chain
918 assert(state == INITIALIZED, "race condition");
919 return true;
920 }
921
922 /////////////////////////////////////////////////////////////////////////////
923 // attach existing thread
924
925 // bootstrap the main thread
926 bool os::create_main_thread(JavaThread* thread) {
927 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
928 return create_attached_thread(thread);
929 }
930
931 bool os::create_attached_thread(JavaThread* thread) {
932 #ifdef ASSERT
933 thread->verify_not_published();
934 #endif
935
936 // Allocate the OSThread object
937 OSThread* osthread = new OSThread(NULL, NULL);
938
939 if (osthread == NULL) {
940 return false;
941 }
942
943 // Store pthread info into the OSThread
944 osthread->set_thread_id(os::Linux::gettid());
945 osthread->set_pthread_id(::pthread_self());
946
947 // initialize floating point control register
948 os::Linux::init_thread_fpu_state();
949
950 // Initial thread state is RUNNABLE
951 osthread->set_state(RUNNABLE);
952
953 thread->set_osthread(osthread);
954
955 if (UseNUMA) {
956 int lgrp_id = os::numa_get_group_id();
957 if (lgrp_id != -1) {
958 thread->set_lgrp_id(lgrp_id);
959 }
960 }
961
962 if (os::is_primordial_thread()) {
963 // If current thread is primordial thread, its stack is mapped on demand,
964 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
965 // the entire stack region to avoid SEGV in stack banging.
966 // It is also useful to get around the heap-stack-gap problem on SuSE
967 // kernel (see 4821821 for details). We first expand stack to the top
968 // of yellow zone, then enable stack yellow zone (order is significant,
969 // enabling yellow zone first will crash JVM on SuSE Linux), so there
970 // is no gap between the last two virtual memory regions.
971
972 StackOverflow* overflow_state = thread->stack_overflow_state();
973 address addr = overflow_state->stack_reserved_zone_base();
974 assert(addr != NULL, "initialization problem?");
975 assert(overflow_state->stack_available(addr) > 0, "stack guard should not be enabled");
976
977 osthread->set_expanding_stack();
978 os::Linux::manually_expand_stack(thread, addr);
979 osthread->clear_expanding_stack();
980 }
981
982 // initialize signal mask for this thread
983 // and save the caller's signal mask
984 PosixSignals::hotspot_sigmask(thread);
985
986 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT
987 ", stack: " PTR_FORMAT " - " PTR_FORMAT " (" SIZE_FORMAT "K) ).",
988 os::current_thread_id(), (uintx) pthread_self(),
989 p2i(thread->stack_base()), p2i(thread->stack_end()), thread->stack_size());
990
991 return true;
992 }
993
994 void os::pd_start_thread(Thread* thread) {
995 OSThread * osthread = thread->osthread();
996 assert(osthread->get_state() != INITIALIZED, "just checking");
997 Monitor* sync_with_child = osthread->startThread_lock();
998 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
999 sync_with_child->notify();
1000 }
1001
1002 // Free Linux resources related to the OSThread
1003 void os::free_thread(OSThread* osthread) {
1004 assert(osthread != NULL, "osthread not set");
1005
1006 // We are told to free resources of the argument thread,
1007 // but we can only really operate on the current thread.
1008 assert(Thread::current()->osthread() == osthread,
1009 "os::free_thread but not current thread");
1010
1011 #ifdef ASSERT
1012 sigset_t current;
1013 sigemptyset(¤t);
1014 pthread_sigmask(SIG_SETMASK, NULL, ¤t);
1015 assert(!sigismember(¤t, PosixSignals::SR_signum), "SR signal should not be blocked!");
1016 #endif
1017
1018 // Restore caller's signal mask
1019 sigset_t sigmask = osthread->caller_sigmask();
1020 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1021
1022 delete osthread;
1023 }
1024
1025 //////////////////////////////////////////////////////////////////////////////
1026 // primordial thread
1027
1028 // Check if current thread is the primordial thread, similar to Solaris thr_main.
1029 bool os::is_primordial_thread(void) {
1030 if (suppress_primordial_thread_resolution) {
1031 return false;
1032 }
1033 char dummy;
1034 // If called before init complete, thread stack bottom will be null.
1035 // Can be called if fatal error occurs before initialization.
1036 if (os::Linux::initial_thread_stack_bottom() == NULL) return false;
1037 assert(os::Linux::initial_thread_stack_bottom() != NULL &&
1038 os::Linux::initial_thread_stack_size() != 0,
1039 "os::init did not locate primordial thread's stack region");
1040 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() &&
1041 (address)&dummy < os::Linux::initial_thread_stack_bottom() +
1042 os::Linux::initial_thread_stack_size()) {
1043 return true;
1044 } else {
1045 return false;
1046 }
1047 }
1048
1049 // Find the virtual memory area that contains addr
1050 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1051 FILE *fp = fopen("/proc/self/maps", "r");
1052 if (fp) {
1053 address low, high;
1054 while (!feof(fp)) {
1055 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1056 if (low <= addr && addr < high) {
1057 if (vma_low) *vma_low = low;
1058 if (vma_high) *vma_high = high;
1059 fclose(fp);
1060 return true;
1061 }
1062 }
1063 for (;;) {
1064 int ch = fgetc(fp);
1065 if (ch == EOF || ch == (int)'\n') break;
1066 }
1067 }
1068 fclose(fp);
1069 }
1070 return false;
1071 }
1072
1073 // Locate primordial thread stack. This special handling of primordial thread stack
1074 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1075 // bogus value for the primordial process thread. While the launcher has created
1076 // the VM in a new thread since JDK 6, we still have to allow for the use of the
1077 // JNI invocation API from a primordial thread.
1078 void os::Linux::capture_initial_stack(size_t max_size) {
1079
1080 // max_size is either 0 (which means accept OS default for thread stacks) or
1081 // a user-specified value known to be at least the minimum needed. If we
1082 // are actually on the primordial thread we can make it appear that we have a
1083 // smaller max_size stack by inserting the guard pages at that location. But we
1084 // cannot do anything to emulate a larger stack than what has been provided by
1085 // the OS or threading library. In fact if we try to use a stack greater than
1086 // what is set by rlimit then we will crash the hosting process.
1087
1088 // Maximum stack size is the easy part, get it from RLIMIT_STACK.
1089 // If this is "unlimited" then it will be a huge value.
1090 struct rlimit rlim;
1091 getrlimit(RLIMIT_STACK, &rlim);
1092 size_t stack_size = rlim.rlim_cur;
1093
1094 // 6308388: a bug in ld.so will relocate its own .data section to the
1095 // lower end of primordial stack; reduce ulimit -s value a little bit
1096 // so we won't install guard page on ld.so's data section.
1097 // But ensure we don't underflow the stack size - allow 1 page spare
1098 if (stack_size >= (size_t)(3 * page_size())) {
1099 stack_size -= 2 * page_size();
1100 }
1101
1102 // Try to figure out where the stack base (top) is. This is harder.
1103 //
1104 // When an application is started, glibc saves the initial stack pointer in
1105 // a global variable "__libc_stack_end", which is then used by system
1106 // libraries. __libc_stack_end should be pretty close to stack top. The
1107 // variable is available since the very early days. However, because it is
1108 // a private interface, it could disappear in the future.
1109 //
1110 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1111 // to __libc_stack_end, it is very close to stack top, but isn't the real
1112 // stack top. Note that /proc may not exist if VM is running as a chroot
1113 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1114 // /proc/<pid>/stat could change in the future (though unlikely).
1115 //
1116 // We try __libc_stack_end first. If that doesn't work, look for
1117 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1118 // as a hint, which should work well in most cases.
1119
1120 uintptr_t stack_start;
1121
1122 // try __libc_stack_end first
1123 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1124 if (p && *p) {
1125 stack_start = *p;
1126 } else {
1127 // see if we can get the start_stack field from /proc/self/stat
1128 FILE *fp;
1129 int pid;
1130 char state;
1131 int ppid;
1132 int pgrp;
1133 int session;
1134 int nr;
1135 int tpgrp;
1136 unsigned long flags;
1137 unsigned long minflt;
1138 unsigned long cminflt;
1139 unsigned long majflt;
1140 unsigned long cmajflt;
1141 unsigned long utime;
1142 unsigned long stime;
1143 long cutime;
1144 long cstime;
1145 long prio;
1146 long nice;
1147 long junk;
1148 long it_real;
1149 uintptr_t start;
1150 uintptr_t vsize;
1151 intptr_t rss;
1152 uintptr_t rsslim;
1153 uintptr_t scodes;
1154 uintptr_t ecode;
1155 int i;
1156
1157 // Figure what the primordial thread stack base is. Code is inspired
1158 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1159 // followed by command name surrounded by parentheses, state, etc.
1160 char stat[2048];
1161 int statlen;
1162
1163 fp = fopen("/proc/self/stat", "r");
1164 if (fp) {
1165 statlen = fread(stat, 1, 2047, fp);
1166 stat[statlen] = '\0';
1167 fclose(fp);
1168
1169 // Skip pid and the command string. Note that we could be dealing with
1170 // weird command names, e.g. user could decide to rename java launcher
1171 // to "java 1.4.2 :)", then the stat file would look like
1172 // 1234 (java 1.4.2 :)) R ... ...
1173 // We don't really need to know the command string, just find the last
1174 // occurrence of ")" and then start parsing from there. See bug 4726580.
1175 char * s = strrchr(stat, ')');
1176
1177 i = 0;
1178 if (s) {
1179 // Skip blank chars
1180 do { s++; } while (s && isspace(*s));
1181
1182 #define _UFM UINTX_FORMAT
1183 #define _DFM INTX_FORMAT
1184
1185 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1186 // 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8
1187 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM,
1188 &state, // 3 %c
1189 &ppid, // 4 %d
1190 &pgrp, // 5 %d
1191 &session, // 6 %d
1192 &nr, // 7 %d
1193 &tpgrp, // 8 %d
1194 &flags, // 9 %lu
1195 &minflt, // 10 %lu
1196 &cminflt, // 11 %lu
1197 &majflt, // 12 %lu
1198 &cmajflt, // 13 %lu
1199 &utime, // 14 %lu
1200 &stime, // 15 %lu
1201 &cutime, // 16 %ld
1202 &cstime, // 17 %ld
1203 &prio, // 18 %ld
1204 &nice, // 19 %ld
1205 &junk, // 20 %ld
1206 &it_real, // 21 %ld
1207 &start, // 22 UINTX_FORMAT
1208 &vsize, // 23 UINTX_FORMAT
1209 &rss, // 24 INTX_FORMAT
1210 &rsslim, // 25 UINTX_FORMAT
1211 &scodes, // 26 UINTX_FORMAT
1212 &ecode, // 27 UINTX_FORMAT
1213 &stack_start); // 28 UINTX_FORMAT
1214 }
1215
1216 #undef _UFM
1217 #undef _DFM
1218
1219 if (i != 28 - 2) {
1220 assert(false, "Bad conversion from /proc/self/stat");
1221 // product mode - assume we are the primordial thread, good luck in the
1222 // embedded case.
1223 warning("Can't detect primordial thread stack location - bad conversion");
1224 stack_start = (uintptr_t) &rlim;
1225 }
1226 } else {
1227 // For some reason we can't open /proc/self/stat (for example, running on
1228 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1229 // most cases, so don't abort:
1230 warning("Can't detect primordial thread stack location - no /proc/self/stat");
1231 stack_start = (uintptr_t) &rlim;
1232 }
1233 }
1234
1235 // Now we have a pointer (stack_start) very close to the stack top, the
1236 // next thing to do is to figure out the exact location of stack top. We
1237 // can find out the virtual memory area that contains stack_start by
1238 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1239 // and its upper limit is the real stack top. (again, this would fail if
1240 // running inside chroot, because /proc may not exist.)
1241
1242 uintptr_t stack_top;
1243 address low, high;
1244 if (find_vma((address)stack_start, &low, &high)) {
1245 // success, "high" is the true stack top. (ignore "low", because initial
1246 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1247 stack_top = (uintptr_t)high;
1248 } else {
1249 // failed, likely because /proc/self/maps does not exist
1250 warning("Can't detect primordial thread stack location - find_vma failed");
1251 // best effort: stack_start is normally within a few pages below the real
1252 // stack top, use it as stack top, and reduce stack size so we won't put
1253 // guard page outside stack.
1254 stack_top = stack_start;
1255 stack_size -= 16 * page_size();
1256 }
1257
1258 // stack_top could be partially down the page so align it
1259 stack_top = align_up(stack_top, page_size());
1260
1261 // Allowed stack value is minimum of max_size and what we derived from rlimit
1262 if (max_size > 0) {
1263 _initial_thread_stack_size = MIN2(max_size, stack_size);
1264 } else {
1265 // Accept the rlimit max, but if stack is unlimited then it will be huge, so
1266 // clamp it at 8MB as we do on Solaris
1267 _initial_thread_stack_size = MIN2(stack_size, 8*M);
1268 }
1269 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size());
1270 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1271
1272 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
1273
1274 if (log_is_enabled(Info, os, thread)) {
1275 // See if we seem to be on primordial process thread
1276 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) &&
1277 uintptr_t(&rlim) < stack_top;
1278
1279 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: "
1280 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT,
1281 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K,
1282 stack_top, intptr_t(_initial_thread_stack_bottom));
1283 }
1284 }
1285
1286 ////////////////////////////////////////////////////////////////////////////////
1287 // time support
1288
1289 // Time since start-up in seconds to a fine granularity.
1290 double os::elapsedTime() {
1291 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1292 }
1293
1294 jlong os::elapsed_counter() {
1295 return javaTimeNanos() - initial_time_count;
1296 }
1297
1298 jlong os::elapsed_frequency() {
1299 return NANOSECS_PER_SEC; // nanosecond resolution
1300 }
1301
1302 bool os::supports_vtime() { return true; }
1303
1304 double os::elapsedVTime() {
1305 struct rusage usage;
1306 int retval = getrusage(RUSAGE_THREAD, &usage);
1307 if (retval == 0) {
1308 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000);
1309 } else {
1310 // better than nothing, but not much
1311 return elapsedTime();
1312 }
1313 }
1314
1315 void os::Linux::fast_thread_clock_init() {
1316 if (!UseLinuxPosixThreadCPUClocks) {
1317 return;
1318 }
1319 clockid_t clockid;
1320 struct timespec tp;
1321 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1322 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1323
1324 // Switch to using fast clocks for thread cpu time if
1325 // the clock_getres() returns 0 error code.
1326 // Note, that some kernels may support the current thread
1327 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1328 // returned by the pthread_getcpuclockid().
1329 // If the fast Posix clocks are supported then the clock_getres()
1330 // must return at least tp.tv_sec == 0 which means a resolution
1331 // better than 1 sec. This is extra check for reliability.
1332
1333 if (pthread_getcpuclockid_func &&
1334 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1335 clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1336 _supports_fast_thread_cpu_time = true;
1337 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1338 }
1339 }
1340
1341 // Return the real, user, and system times in seconds from an
1342 // arbitrary fixed point in the past.
1343 bool os::getTimesSecs(double* process_real_time,
1344 double* process_user_time,
1345 double* process_system_time) {
1346 struct tms ticks;
1347 clock_t real_ticks = times(&ticks);
1348
1349 if (real_ticks == (clock_t) (-1)) {
1350 return false;
1351 } else {
1352 double ticks_per_second = (double) clock_tics_per_sec;
1353 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1354 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1355 *process_real_time = ((double) real_ticks) / ticks_per_second;
1356
1357 return true;
1358 }
1359 }
1360
1361
1362 char * os::local_time_string(char *buf, size_t buflen) {
1363 struct tm t;
1364 time_t long_time;
1365 time(&long_time);
1366 localtime_r(&long_time, &t);
1367 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1368 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1369 t.tm_hour, t.tm_min, t.tm_sec);
1370 return buf;
1371 }
1372
1373 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1374 return localtime_r(clock, res);
1375 }
1376
1377 // thread_id is kernel thread id (similar to Solaris LWP id)
1378 intx os::current_thread_id() { return os::Linux::gettid(); }
1379 int os::current_process_id() {
1380 return ::getpid();
1381 }
1382
1383 // DLL functions
1384
1385 const char* os::dll_file_extension() { return ".so"; }
1386
1387 // This must be hard coded because it's the system's temporary
1388 // directory not the java application's temp directory, ala java.io.tmpdir.
1389 const char* os::get_temp_directory() { return "/tmp"; }
1390
1391 static bool file_exists(const char* filename) {
1392 struct stat statbuf;
1393 if (filename == NULL || strlen(filename) == 0) {
1394 return false;
1395 }
1396 return os::stat(filename, &statbuf) == 0;
1397 }
1398
1399 // check if addr is inside libjvm.so
1400 bool os::address_is_in_vm(address addr) {
1401 static address libjvm_base_addr;
1402 Dl_info dlinfo;
1403
1404 if (libjvm_base_addr == NULL) {
1405 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1406 libjvm_base_addr = (address)dlinfo.dli_fbase;
1407 }
1408 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1409 }
1410
1411 if (dladdr((void *)addr, &dlinfo) != 0) {
1412 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1413 }
1414
1415 return false;
1416 }
1417
1418 bool os::dll_address_to_function_name(address addr, char *buf,
1419 int buflen, int *offset,
1420 bool demangle) {
1421 // buf is not optional, but offset is optional
1422 assert(buf != NULL, "sanity check");
1423
1424 Dl_info dlinfo;
1425
1426 if (dladdr((void*)addr, &dlinfo) != 0) {
1427 // see if we have a matching symbol
1428 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1429 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1430 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1431 }
1432 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1433 return true;
1434 }
1435 // no matching symbol so try for just file info
1436 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1437 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1438 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1439 return true;
1440 }
1441 }
1442 }
1443
1444 buf[0] = '\0';
1445 if (offset != NULL) *offset = -1;
1446 return false;
1447 }
1448
1449 struct _address_to_library_name {
1450 address addr; // input : memory address
1451 size_t buflen; // size of fname
1452 char* fname; // output: library name
1453 address base; // library base addr
1454 };
1455
1456 static int address_to_library_name_callback(struct dl_phdr_info *info,
1457 size_t size, void *data) {
1458 int i;
1459 bool found = false;
1460 address libbase = NULL;
1461 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1462
1463 // iterate through all loadable segments
1464 for (i = 0; i < info->dlpi_phnum; i++) {
1465 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1466 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1467 // base address of a library is the lowest address of its loaded
1468 // segments.
1469 if (libbase == NULL || libbase > segbase) {
1470 libbase = segbase;
1471 }
1472 // see if 'addr' is within current segment
1473 if (segbase <= d->addr &&
1474 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1475 found = true;
1476 }
1477 }
1478 }
1479
1480 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1481 // so dll_address_to_library_name() can fall through to use dladdr() which
1482 // can figure out executable name from argv[0].
1483 if (found && info->dlpi_name && info->dlpi_name[0]) {
1484 d->base = libbase;
1485 if (d->fname) {
1486 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1487 }
1488 return 1;
1489 }
1490 return 0;
1491 }
1492
1493 bool os::dll_address_to_library_name(address addr, char* buf,
1494 int buflen, int* offset) {
1495 // buf is not optional, but offset is optional
1496 assert(buf != NULL, "sanity check");
1497
1498 Dl_info dlinfo;
1499 struct _address_to_library_name data;
1500
1501 // There is a bug in old glibc dladdr() implementation that it could resolve
1502 // to wrong library name if the .so file has a base address != NULL. Here
1503 // we iterate through the program headers of all loaded libraries to find
1504 // out which library 'addr' really belongs to. This workaround can be
1505 // removed once the minimum requirement for glibc is moved to 2.3.x.
1506 data.addr = addr;
1507 data.fname = buf;
1508 data.buflen = buflen;
1509 data.base = NULL;
1510 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1511
1512 if (rslt) {
1513 // buf already contains library name
1514 if (offset) *offset = addr - data.base;
1515 return true;
1516 }
1517 if (dladdr((void*)addr, &dlinfo) != 0) {
1518 if (dlinfo.dli_fname != NULL) {
1519 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1520 }
1521 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1522 *offset = addr - (address)dlinfo.dli_fbase;
1523 }
1524 return true;
1525 }
1526
1527 buf[0] = '\0';
1528 if (offset) *offset = -1;
1529 return false;
1530 }
1531
1532 // Loads .dll/.so and
1533 // in case of error it checks if .dll/.so was built for the
1534 // same architecture as Hotspot is running on
1535
1536
1537 // Remember the stack's state. The Linux dynamic linker will change
1538 // the stack to 'executable' at most once, so we must safepoint only once.
1539 bool os::Linux::_stack_is_executable = false;
1540
1541 // VM operation that loads a library. This is necessary if stack protection
1542 // of the Java stacks can be lost during loading the library. If we
1543 // do not stop the Java threads, they can stack overflow before the stacks
1544 // are protected again.
1545 class VM_LinuxDllLoad: public VM_Operation {
1546 private:
1547 const char *_filename;
1548 char *_ebuf;
1549 int _ebuflen;
1550 void *_lib;
1551 public:
1552 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1553 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1554 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1555 void doit() {
1556 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1557 os::Linux::_stack_is_executable = true;
1558 }
1559 void* loaded_library() { return _lib; }
1560 };
1561
1562 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1563 void * result = NULL;
1564 bool load_attempted = false;
1565
1566 log_info(os)("attempting shared library load of %s", filename);
1567
1568 // Check whether the library to load might change execution rights
1569 // of the stack. If they are changed, the protection of the stack
1570 // guard pages will be lost. We need a safepoint to fix this.
1571 //
1572 // See Linux man page execstack(8) for more info.
1573 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1574 if (!ElfFile::specifies_noexecstack(filename)) {
1575 if (!is_init_completed()) {
1576 os::Linux::_stack_is_executable = true;
1577 // This is OK - No Java threads have been created yet, and hence no
1578 // stack guard pages to fix.
1579 //
1580 // Dynamic loader will make all stacks executable after
1581 // this function returns, and will not do that again.
1582 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet.");
1583 } else {
1584 warning("You have loaded library %s which might have disabled stack guard. "
1585 "The VM will try to fix the stack guard now.\n"
1586 "It's highly recommended that you fix the library with "
1587 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1588 filename);
1589
1590 JavaThread *jt = JavaThread::current();
1591 if (jt->thread_state() != _thread_in_native) {
1592 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1593 // that requires ExecStack. Cannot enter safe point. Let's give up.
1594 warning("Unable to fix stack guard. Giving up.");
1595 } else {
1596 if (!LoadExecStackDllInVMThread) {
1597 // This is for the case where the DLL has an static
1598 // constructor function that executes JNI code. We cannot
1599 // load such DLLs in the VMThread.
1600 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1601 }
1602
1603 ThreadInVMfromNative tiv(jt);
1604 debug_only(VMNativeEntryWrapper vew;)
1605
1606 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1607 VMThread::execute(&op);
1608 if (LoadExecStackDllInVMThread) {
1609 result = op.loaded_library();
1610 }
1611 load_attempted = true;
1612 }
1613 }
1614 }
1615 }
1616
1617 if (!load_attempted) {
1618 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1619 }
1620
1621 if (result != NULL) {
1622 // Successful loading
1623 return result;
1624 }
1625
1626 Elf32_Ehdr elf_head;
1627 int diag_msg_max_length=ebuflen-strlen(ebuf);
1628 char* diag_msg_buf=ebuf+strlen(ebuf);
1629
1630 if (diag_msg_max_length==0) {
1631 // No more space in ebuf for additional diagnostics message
1632 return NULL;
1633 }
1634
1635
1636 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1637
1638 if (file_descriptor < 0) {
1639 // Can't open library, report dlerror() message
1640 return NULL;
1641 }
1642
1643 bool failed_to_read_elf_head=
1644 (sizeof(elf_head)!=
1645 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1646
1647 ::close(file_descriptor);
1648 if (failed_to_read_elf_head) {
1649 // file i/o error - report dlerror() msg
1650 return NULL;
1651 }
1652
1653 if (elf_head.e_ident[EI_DATA] != LITTLE_ENDIAN_ONLY(ELFDATA2LSB) BIG_ENDIAN_ONLY(ELFDATA2MSB)) {
1654 // handle invalid/out of range endianness values
1655 if (elf_head.e_ident[EI_DATA] == 0 || elf_head.e_ident[EI_DATA] > 2) {
1656 return NULL;
1657 }
1658
1659 #if defined(VM_LITTLE_ENDIAN)
1660 // VM is LE, shared object BE
1661 elf_head.e_machine = be16toh(elf_head.e_machine);
1662 #else
1663 // VM is BE, shared object LE
1664 elf_head.e_machine = le16toh(elf_head.e_machine);
1665 #endif
1666 }
1667
1668 typedef struct {
1669 Elf32_Half code; // Actual value as defined in elf.h
1670 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1671 unsigned char elf_class; // 32 or 64 bit
1672 unsigned char endianness; // MSB or LSB
1673 char* name; // String representation
1674 } arch_t;
1675
1676 #ifndef EM_AARCH64
1677 #define EM_AARCH64 183 /* ARM AARCH64 */
1678 #endif
1679 #ifndef EM_RISCV
1680 #define EM_RISCV 243 /* RISC-V */
1681 #endif
1682 #ifndef EM_LOONGARCH
1683 #define EM_LOONGARCH 258 /* LoongArch */
1684 #endif
1685
1686 static const arch_t arch_array[]={
1687 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1688 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1689 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1690 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1691 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1692 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1693 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1694 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1695 #if defined(VM_LITTLE_ENDIAN)
1696 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"},
1697 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"},
1698 #else
1699 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1700 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"},
1701 #endif
1702 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1703 // we only support 64 bit z architecture
1704 {EM_S390, EM_S390, ELFCLASS64, ELFDATA2MSB, (char*)"IBM System/390"},
1705 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1706 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1707 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1708 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1709 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
1710 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
1711 {EM_RISCV, EM_RISCV, ELFCLASS64, ELFDATA2LSB, (char*)"RISC-V"},
1712 {EM_LOONGARCH, EM_LOONGARCH, ELFCLASS64, ELFDATA2LSB, (char*)"LoongArch"},
1713 };
1714
1715 #if (defined IA32)
1716 static Elf32_Half running_arch_code=EM_386;
1717 #elif (defined AMD64) || (defined X32)
1718 static Elf32_Half running_arch_code=EM_X86_64;
1719 #elif (defined IA64)
1720 static Elf32_Half running_arch_code=EM_IA_64;
1721 #elif (defined __sparc) && (defined _LP64)
1722 static Elf32_Half running_arch_code=EM_SPARCV9;
1723 #elif (defined __sparc) && (!defined _LP64)
1724 static Elf32_Half running_arch_code=EM_SPARC;
1725 #elif (defined __powerpc64__)
1726 static Elf32_Half running_arch_code=EM_PPC64;
1727 #elif (defined __powerpc__)
1728 static Elf32_Half running_arch_code=EM_PPC;
1729 #elif (defined AARCH64)
1730 static Elf32_Half running_arch_code=EM_AARCH64;
1731 #elif (defined ARM)
1732 static Elf32_Half running_arch_code=EM_ARM;
1733 #elif (defined S390)
1734 static Elf32_Half running_arch_code=EM_S390;
1735 #elif (defined ALPHA)
1736 static Elf32_Half running_arch_code=EM_ALPHA;
1737 #elif (defined MIPSEL)
1738 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1739 #elif (defined PARISC)
1740 static Elf32_Half running_arch_code=EM_PARISC;
1741 #elif (defined MIPS)
1742 static Elf32_Half running_arch_code=EM_MIPS;
1743 #elif (defined M68K)
1744 static Elf32_Half running_arch_code=EM_68K;
1745 #elif (defined SH)
1746 static Elf32_Half running_arch_code=EM_SH;
1747 #elif (defined RISCV)
1748 static Elf32_Half running_arch_code=EM_RISCV;
1749 #elif (defined LOONGARCH)
1750 static Elf32_Half running_arch_code=EM_LOONGARCH;
1751 #else
1752 #error Method os::dll_load requires that one of following is defined:\
1753 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, LOONGARCH, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, RISCV, S390, SH, __sparc
1754 #endif
1755
1756 // Identify compatibility class for VM's architecture and library's architecture
1757 // Obtain string descriptions for architectures
1758
1759 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1760 int running_arch_index=-1;
1761
1762 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1763 if (running_arch_code == arch_array[i].code) {
1764 running_arch_index = i;
1765 }
1766 if (lib_arch.code == arch_array[i].code) {
1767 lib_arch.compat_class = arch_array[i].compat_class;
1768 lib_arch.name = arch_array[i].name;
1769 }
1770 }
1771
1772 assert(running_arch_index != -1,
1773 "Didn't find running architecture code (running_arch_code) in arch_array");
1774 if (running_arch_index == -1) {
1775 // Even though running architecture detection failed
1776 // we may still continue with reporting dlerror() message
1777 return NULL;
1778 }
1779
1780 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1781 if (lib_arch.name != NULL) {
1782 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1783 " (Possible cause: can't load %s .so on a %s platform)",
1784 lib_arch.name, arch_array[running_arch_index].name);
1785 } else {
1786 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1787 " (Possible cause: can't load this .so (machine code=0x%x) on a %s platform)",
1788 lib_arch.code, arch_array[running_arch_index].name);
1789 }
1790 return NULL;
1791 }
1792
1793 if (lib_arch.endianness != arch_array[running_arch_index].endianness) {
1794 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: endianness mismatch)");
1795 return NULL;
1796 }
1797
1798 // ELF file class/capacity : 0 - invalid, 1 - 32bit, 2 - 64bit
1799 if (lib_arch.elf_class > 2 || lib_arch.elf_class < 1) {
1800 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: invalid ELF file class)");
1801 return NULL;
1802 }
1803
1804 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1805 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1806 " (Possible cause: architecture word width mismatch, can't load %d-bit .so on a %d-bit platform)",
1807 (int) lib_arch.elf_class * 32, arch_array[running_arch_index].elf_class * 32);
1808 return NULL;
1809 }
1810
1811 return NULL;
1812 }
1813
1814 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1815 int ebuflen) {
1816 void * result = ::dlopen(filename, RTLD_LAZY);
1817 if (result == NULL) {
1818 const char* error_report = ::dlerror();
1819 if (error_report == NULL) {
1820 error_report = "dlerror returned no error description";
1821 }
1822 if (ebuf != NULL && ebuflen > 0) {
1823 ::strncpy(ebuf, error_report, ebuflen-1);
1824 ebuf[ebuflen-1]='\0';
1825 }
1826 Events::log_dll_message(NULL, "Loading shared library %s failed, %s", filename, error_report);
1827 log_info(os)("shared library load of %s failed, %s", filename, error_report);
1828 } else {
1829 Events::log_dll_message(NULL, "Loaded shared library %s", filename);
1830 log_info(os)("shared library load of %s was successful", filename);
1831 }
1832 return result;
1833 }
1834
1835 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
1836 int ebuflen) {
1837 void * result = NULL;
1838 if (LoadExecStackDllInVMThread) {
1839 result = dlopen_helper(filename, ebuf, ebuflen);
1840 }
1841
1842 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
1843 // library that requires an executable stack, or which does not have this
1844 // stack attribute set, dlopen changes the stack attribute to executable. The
1845 // read protection of the guard pages gets lost.
1846 //
1847 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
1848 // may have been queued at the same time.
1849
1850 if (!_stack_is_executable) {
1851 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
1852 StackOverflow* overflow_state = jt->stack_overflow_state();
1853 if (!overflow_state->stack_guard_zone_unused() && // Stack not yet fully initialized
1854 overflow_state->stack_guards_enabled()) { // No pending stack overflow exceptions
1855 if (!os::guard_memory((char *)jt->stack_end(), StackOverflow::stack_guard_zone_size())) {
1856 warning("Attempt to reguard stack yellow zone failed.");
1857 }
1858 }
1859 }
1860 }
1861
1862 return result;
1863 }
1864
1865 const char* os::Linux::dll_path(void* lib) {
1866 struct link_map *lmap;
1867 const char* l_path = NULL;
1868 assert(lib != NULL, "dll_path parameter must not be NULL");
1869
1870 int res_dli = ::dlinfo(lib, RTLD_DI_LINKMAP, &lmap);
1871 if (res_dli == 0) {
1872 l_path = lmap->l_name;
1873 }
1874 return l_path;
1875 }
1876
1877 static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) {
1878 int fd = ::open(filename, O_RDONLY);
1879 if (fd == -1) {
1880 return false;
1881 }
1882
1883 if (hdr != NULL) {
1884 st->print_cr("%s", hdr);
1885 }
1886
1887 char buf[33];
1888 int bytes;
1889 buf[32] = '\0';
1890 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
1891 st->print_raw(buf, bytes);
1892 }
1893
1894 ::close(fd);
1895
1896 return true;
1897 }
1898
1899 static void _print_ascii_file_h(const char* header, const char* filename, outputStream* st, bool same_line = true) {
1900 st->print("%s:%c", header, same_line ? ' ' : '\n');
1901 if (!_print_ascii_file(filename, st)) {
1902 st->print_cr("<Not Available>");
1903 }
1904 }
1905
1906 void os::print_dll_info(outputStream *st) {
1907 st->print_cr("Dynamic libraries:");
1908
1909 char fname[32];
1910 pid_t pid = os::Linux::gettid();
1911
1912 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
1913
1914 if (!_print_ascii_file(fname, st)) {
1915 st->print_cr("Can not get library information for pid = %d", pid);
1916 }
1917 }
1918
1919 struct loaded_modules_info_param {
1920 os::LoadedModulesCallbackFunc callback;
1921 void *param;
1922 };
1923
1924 static int dl_iterate_callback(struct dl_phdr_info *info, size_t size, void *data) {
1925 if ((info->dlpi_name == NULL) || (*info->dlpi_name == '\0')) {
1926 return 0;
1927 }
1928
1929 struct loaded_modules_info_param *callback_param = reinterpret_cast<struct loaded_modules_info_param *>(data);
1930 address base = NULL;
1931 address top = NULL;
1932 for (int idx = 0; idx < info->dlpi_phnum; idx++) {
1933 const ElfW(Phdr) *phdr = info->dlpi_phdr + idx;
1934 if (phdr->p_type == PT_LOAD) {
1935 address raw_phdr_base = reinterpret_cast<address>(info->dlpi_addr + phdr->p_vaddr);
1936
1937 address phdr_base = align_down(raw_phdr_base, phdr->p_align);
1938 if ((base == NULL) || (base > phdr_base)) {
1939 base = phdr_base;
1940 }
1941
1942 address phdr_top = align_up(raw_phdr_base + phdr->p_memsz, phdr->p_align);
1943 if ((top == NULL) || (top < phdr_top)) {
1944 top = phdr_top;
1945 }
1946 }
1947 }
1948
1949 return callback_param->callback(info->dlpi_name, base, top, callback_param->param);
1950 }
1951
1952 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
1953 struct loaded_modules_info_param callback_param = {callback, param};
1954 return dl_iterate_phdr(&dl_iterate_callback, &callback_param);
1955 }
1956
1957 void os::print_os_info_brief(outputStream* st) {
1958 os::Linux::print_distro_info(st);
1959
1960 os::Posix::print_uname_info(st);
1961
1962 os::Linux::print_libversion_info(st);
1963
1964 }
1965
1966 void os::print_os_info(outputStream* st) {
1967 st->print_cr("OS:");
1968
1969 os::Linux::print_distro_info(st);
1970
1971 os::Posix::print_uname_info(st);
1972
1973 os::Linux::print_uptime_info(st);
1974
1975 // Print warning if unsafe chroot environment detected
1976 if (unsafe_chroot_detected) {
1977 st->print_cr("WARNING!! %s", unstable_chroot_error);
1978 }
1979
1980 os::Linux::print_libversion_info(st);
1981
1982 os::Posix::print_rlimit_info(st);
1983
1984 os::Posix::print_load_average(st);
1985 st->cr();
1986
1987 os::Linux::print_system_memory_info(st);
1988 st->cr();
1989
1990 os::Linux::print_process_memory_info(st);
1991 st->cr();
1992
1993 os::Linux::print_proc_sys_info(st);
1994 st->cr();
1995
1996 if (os::Linux::print_ld_preload_file(st)) {
1997 st->cr();
1998 }
1999
2000 if (os::Linux::print_container_info(st)) {
2001 st->cr();
2002 }
2003
2004 VM_Version::print_platform_virtualization_info(st);
2005
2006 os::Linux::print_steal_info(st);
2007 }
2008
2009 // Try to identify popular distros.
2010 // Most Linux distributions have a /etc/XXX-release file, which contains
2011 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2012 // file that also contains the OS version string. Some have more than one
2013 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2014 // /etc/redhat-release.), so the order is important.
2015 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2016 // their own specific XXX-release file as well as a redhat-release file.
2017 // Because of this the XXX-release file needs to be searched for before the
2018 // redhat-release file.
2019 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
2020 // search for redhat-release / SuSE-release needs to be before lsb-release.
2021 // Since the lsb-release file is the new standard it needs to be searched
2022 // before the older style release files.
2023 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2024 // next to last resort. The os-release file is a new standard that contains
2025 // distribution information and the system-release file seems to be an old
2026 // standard that has been replaced by the lsb-release and os-release files.
2027 // Searching for the debian_version file is the last resort. It contains
2028 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2029 // "Debian " is printed before the contents of the debian_version file.
2030
2031 const char* distro_files[] = {
2032 "/etc/oracle-release",
2033 "/etc/mandriva-release",
2034 "/etc/mandrake-release",
2035 "/etc/sun-release",
2036 "/etc/redhat-release",
2037 "/etc/SuSE-release",
2038 "/etc/lsb-release",
2039 "/etc/turbolinux-release",
2040 "/etc/gentoo-release",
2041 "/etc/ltib-release",
2042 "/etc/angstrom-version",
2043 "/etc/system-release",
2044 "/etc/os-release",
2045 NULL };
2046
2047 void os::Linux::print_distro_info(outputStream* st) {
2048 for (int i = 0;; i++) {
2049 const char* file = distro_files[i];
2050 if (file == NULL) {
2051 break; // done
2052 }
2053 // If file prints, we found it.
2054 if (_print_ascii_file(file, st)) {
2055 return;
2056 }
2057 }
2058
2059 if (file_exists("/etc/debian_version")) {
2060 st->print("Debian ");
2061 _print_ascii_file("/etc/debian_version", st);
2062 } else {
2063 st->print_cr("Linux");
2064 }
2065 }
2066
2067 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
2068 char buf[256];
2069 while (fgets(buf, sizeof(buf), fp)) {
2070 // Edit out extra stuff in expected format
2071 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
2072 char* ptr = strstr(buf, "\""); // the name is in quotes
2073 if (ptr != NULL) {
2074 ptr++; // go beyond first quote
2075 char* nl = strchr(ptr, '\"');
2076 if (nl != NULL) *nl = '\0';
2077 strncpy(distro, ptr, length);
2078 } else {
2079 ptr = strstr(buf, "=");
2080 ptr++; // go beyond equals then
2081 char* nl = strchr(ptr, '\n');
2082 if (nl != NULL) *nl = '\0';
2083 strncpy(distro, ptr, length);
2084 }
2085 return;
2086 } else if (get_first_line) {
2087 char* nl = strchr(buf, '\n');
2088 if (nl != NULL) *nl = '\0';
2089 strncpy(distro, buf, length);
2090 return;
2091 }
2092 }
2093 // print last line and close
2094 char* nl = strchr(buf, '\n');
2095 if (nl != NULL) *nl = '\0';
2096 strncpy(distro, buf, length);
2097 }
2098
2099 static void parse_os_info(char* distro, size_t length, const char* file) {
2100 FILE* fp = fopen(file, "r");
2101 if (fp != NULL) {
2102 // if suse format, print out first line
2103 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
2104 parse_os_info_helper(fp, distro, length, get_first_line);
2105 fclose(fp);
2106 }
2107 }
2108
2109 void os::get_summary_os_info(char* buf, size_t buflen) {
2110 for (int i = 0;; i++) {
2111 const char* file = distro_files[i];
2112 if (file == NULL) {
2113 break; // ran out of distro_files
2114 }
2115 if (file_exists(file)) {
2116 parse_os_info(buf, buflen, file);
2117 return;
2118 }
2119 }
2120 // special case for debian
2121 if (file_exists("/etc/debian_version")) {
2122 strncpy(buf, "Debian ", buflen);
2123 if (buflen > 7) {
2124 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2125 }
2126 } else {
2127 strncpy(buf, "Linux", buflen);
2128 }
2129 }
2130
2131 void os::Linux::print_libversion_info(outputStream* st) {
2132 // libc, pthread
2133 st->print("libc: ");
2134 st->print("%s ", os::Linux::libc_version());
2135 st->print("%s ", os::Linux::libpthread_version());
2136 st->cr();
2137 }
2138
2139 void os::Linux::print_proc_sys_info(outputStream* st) {
2140 _print_ascii_file_h("/proc/sys/kernel/threads-max (system-wide limit on the number of threads)",
2141 "/proc/sys/kernel/threads-max", st);
2142 _print_ascii_file_h("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have)",
2143 "/proc/sys/vm/max_map_count", st);
2144 _print_ascii_file_h("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers)",
2145 "/proc/sys/kernel/pid_max", st);
2146 }
2147
2148 void os::Linux::print_system_memory_info(outputStream* st) {
2149 _print_ascii_file_h("/proc/meminfo", "/proc/meminfo", st, false);
2150 st->cr();
2151
2152 // some information regarding THPs; for details see
2153 // https://www.kernel.org/doc/Documentation/vm/transhuge.txt
2154 _print_ascii_file_h("/sys/kernel/mm/transparent_hugepage/enabled",
2155 "/sys/kernel/mm/transparent_hugepage/enabled", st);
2156 _print_ascii_file_h("/sys/kernel/mm/transparent_hugepage/defrag (defrag/compaction efforts parameter)",
2157 "/sys/kernel/mm/transparent_hugepage/defrag", st);
2158 }
2159
2160 bool os::Linux::query_process_memory_info(os::Linux::meminfo_t* info) {
2161 FILE* f = ::fopen("/proc/self/status", "r");
2162 const int num_values = sizeof(os::Linux::meminfo_t) / sizeof(size_t);
2163 int num_found = 0;
2164 char buf[256];
2165 info->vmsize = info->vmpeak = info->vmrss = info->vmhwm = info->vmswap =
2166 info->rssanon = info->rssfile = info->rssshmem = -1;
2167 if (f != NULL) {
2168 while (::fgets(buf, sizeof(buf), f) != NULL && num_found < num_values) {
2169 if ( (info->vmsize == -1 && sscanf(buf, "VmSize: " SSIZE_FORMAT " kB", &info->vmsize) == 1) ||
2170 (info->vmpeak == -1 && sscanf(buf, "VmPeak: " SSIZE_FORMAT " kB", &info->vmpeak) == 1) ||
2171 (info->vmswap == -1 && sscanf(buf, "VmSwap: " SSIZE_FORMAT " kB", &info->vmswap) == 1) ||
2172 (info->vmhwm == -1 && sscanf(buf, "VmHWM: " SSIZE_FORMAT " kB", &info->vmhwm) == 1) ||
2173 (info->vmrss == -1 && sscanf(buf, "VmRSS: " SSIZE_FORMAT " kB", &info->vmrss) == 1) ||
2174 (info->rssanon == -1 && sscanf(buf, "RssAnon: " SSIZE_FORMAT " kB", &info->rssanon) == 1) || // Needs Linux 4.5
2175 (info->rssfile == -1 && sscanf(buf, "RssFile: " SSIZE_FORMAT " kB", &info->rssfile) == 1) || // Needs Linux 4.5
2176 (info->rssshmem == -1 && sscanf(buf, "RssShmem: " SSIZE_FORMAT " kB", &info->rssshmem) == 1) // Needs Linux 4.5
2177 )
2178 {
2179 num_found ++;
2180 }
2181 }
2182 fclose(f);
2183 return true;
2184 }
2185 return false;
2186 }
2187
2188 #ifdef __GLIBC__
2189 // For Glibc, print a one-liner with the malloc tunables.
2190 // Most important and popular is MALLOC_ARENA_MAX, but we are
2191 // thorough and print them all.
2192 static void print_glibc_malloc_tunables(outputStream* st) {
2193 static const char* var[] = {
2194 // the new variant
2195 "GLIBC_TUNABLES",
2196 // legacy variants
2197 "MALLOC_CHECK_", "MALLOC_TOP_PAD_", "MALLOC_PERTURB_",
2198 "MALLOC_MMAP_THRESHOLD_", "MALLOC_TRIM_THRESHOLD_",
2199 "MALLOC_MMAP_MAX_", "MALLOC_ARENA_TEST", "MALLOC_ARENA_MAX",
2200 NULL};
2201 st->print("glibc malloc tunables: ");
2202 bool printed = false;
2203 for (int i = 0; var[i] != NULL; i ++) {
2204 const char* const val = ::getenv(var[i]);
2205 if (val != NULL) {
2206 st->print("%s%s=%s", (printed ? ", " : ""), var[i], val);
2207 printed = true;
2208 }
2209 }
2210 if (!printed) {
2211 st->print("(default)");
2212 }
2213 }
2214 #endif // __GLIBC__
2215
2216 void os::Linux::print_process_memory_info(outputStream* st) {
2217
2218 st->print_cr("Process Memory:");
2219
2220 // Print virtual and resident set size; peak values; swap; and for
2221 // rss its components if the kernel is recent enough.
2222 meminfo_t info;
2223 if (query_process_memory_info(&info)) {
2224 st->print_cr("Virtual Size: " SSIZE_FORMAT "K (peak: " SSIZE_FORMAT "K)", info.vmsize, info.vmpeak);
2225 st->print("Resident Set Size: " SSIZE_FORMAT "K (peak: " SSIZE_FORMAT "K)", info.vmrss, info.vmhwm);
2226 if (info.rssanon != -1) { // requires kernel >= 4.5
2227 st->print(" (anon: " SSIZE_FORMAT "K, file: " SSIZE_FORMAT "K, shmem: " SSIZE_FORMAT "K)",
2228 info.rssanon, info.rssfile, info.rssshmem);
2229 }
2230 st->cr();
2231 if (info.vmswap != -1) { // requires kernel >= 2.6.34
2232 st->print_cr("Swapped out: " SSIZE_FORMAT "K", info.vmswap);
2233 }
2234 } else {
2235 st->print_cr("Could not open /proc/self/status to get process memory related information");
2236 }
2237
2238 // glibc only:
2239 // - Print outstanding allocations using mallinfo
2240 // - Print glibc tunables
2241 #ifdef __GLIBC__
2242 size_t total_allocated = 0;
2243 size_t free_retained = 0;
2244 bool might_have_wrapped = false;
2245 if (_mallinfo2 != NULL) {
2246 struct glibc_mallinfo2 mi = _mallinfo2();
2247 total_allocated = mi.uordblks + mi.hblkhd;
2248 free_retained = mi.fordblks;
2249 } else if (_mallinfo != NULL) {
2250 // mallinfo is an old API. Member names mean next to nothing and, beyond that, are 32-bit signed.
2251 // So for larger footprints the values may have wrapped around. We try to detect this here: if the
2252 // process whole resident set size is smaller than 4G, malloc footprint has to be less than that
2253 // and the numbers are reliable.
2254 struct glibc_mallinfo mi = _mallinfo();
2255 total_allocated = (size_t)(unsigned)mi.uordblks + (size_t)(unsigned)mi.hblkhd;
2256 free_retained = (size_t)(unsigned)mi.fordblks;
2257 // Since mallinfo members are int, glibc values may have wrapped. Warn about this.
2258 might_have_wrapped = (info.vmrss * K) > UINT_MAX && (info.vmrss * K) > (total_allocated + UINT_MAX);
2259 }
2260 if (_mallinfo2 != NULL || _mallinfo != NULL) {
2261 st->print_cr("C-Heap outstanding allocations: " SIZE_FORMAT "K, retained: " SIZE_FORMAT "K%s",
2262 total_allocated / K, free_retained / K,
2263 might_have_wrapped ? " (may have wrapped)" : "");
2264 }
2265 // Tunables
2266 print_glibc_malloc_tunables(st);
2267 st->cr();
2268 #endif
2269 }
2270
2271 bool os::Linux::print_ld_preload_file(outputStream* st) {
2272 return _print_ascii_file("/etc/ld.so.preload", st, "/etc/ld.so.preload:");
2273 }
2274
2275 void os::Linux::print_uptime_info(outputStream* st) {
2276 struct sysinfo sinfo;
2277 int ret = sysinfo(&sinfo);
2278 if (ret == 0) {
2279 os::print_dhm(st, "OS uptime:", (long) sinfo.uptime);
2280 }
2281 }
2282
2283 bool os::Linux::print_container_info(outputStream* st) {
2284 if (!OSContainer::is_containerized()) {
2285 st->print_cr("container information not found.");
2286 return false;
2287 }
2288
2289 st->print_cr("container (cgroup) information:");
2290
2291 const char *p_ct = OSContainer::container_type();
2292 st->print_cr("container_type: %s", p_ct != NULL ? p_ct : "not supported");
2293
2294 char *p = OSContainer::cpu_cpuset_cpus();
2295 st->print_cr("cpu_cpuset_cpus: %s", p != NULL ? p : "not supported");
2296 free(p);
2297
2298 p = OSContainer::cpu_cpuset_memory_nodes();
2299 st->print_cr("cpu_memory_nodes: %s", p != NULL ? p : "not supported");
2300 free(p);
2301
2302 int i = OSContainer::active_processor_count();
2303 st->print("active_processor_count: ");
2304 if (i > 0) {
2305 if (ActiveProcessorCount > 0) {
2306 st->print_cr("%d, but overridden by -XX:ActiveProcessorCount %d", i, ActiveProcessorCount);
2307 } else {
2308 st->print_cr("%d", i);
2309 }
2310 } else {
2311 st->print_cr("not supported");
2312 }
2313
2314 i = OSContainer::cpu_quota();
2315 st->print("cpu_quota: ");
2316 if (i > 0) {
2317 st->print_cr("%d", i);
2318 } else {
2319 st->print_cr("%s", i == OSCONTAINER_ERROR ? "not supported" : "no quota");
2320 }
2321
2322 i = OSContainer::cpu_period();
2323 st->print("cpu_period: ");
2324 if (i > 0) {
2325 st->print_cr("%d", i);
2326 } else {
2327 st->print_cr("%s", i == OSCONTAINER_ERROR ? "not supported" : "no period");
2328 }
2329
2330 i = OSContainer::cpu_shares();
2331 st->print("cpu_shares: ");
2332 if (i > 0) {
2333 st->print_cr("%d", i);
2334 } else {
2335 st->print_cr("%s", i == OSCONTAINER_ERROR ? "not supported" : "no shares");
2336 }
2337
2338 OSContainer::print_container_helper(st, OSContainer::memory_limit_in_bytes(), "memory_limit_in_bytes");
2339 OSContainer::print_container_helper(st, OSContainer::memory_and_swap_limit_in_bytes(), "memory_and_swap_limit_in_bytes");
2340 OSContainer::print_container_helper(st, OSContainer::memory_soft_limit_in_bytes(), "memory_soft_limit_in_bytes");
2341 OSContainer::print_container_helper(st, OSContainer::memory_usage_in_bytes(), "memory_usage_in_bytes");
2342 OSContainer::print_container_helper(st, OSContainer::memory_max_usage_in_bytes(), "memory_max_usage_in_bytes");
2343
2344 OSContainer::print_version_specific_info(st);
2345
2346 jlong j = OSContainer::pids_max();
2347 st->print("maximum number of tasks: ");
2348 if (j > 0) {
2349 st->print_cr(JLONG_FORMAT, j);
2350 } else {
2351 st->print_cr("%s", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2352 }
2353
2354 j = OSContainer::pids_current();
2355 st->print("current number of tasks: ");
2356 if (j > 0) {
2357 st->print_cr(JLONG_FORMAT, j);
2358 } else {
2359 if (j == OSCONTAINER_ERROR) {
2360 st->print_cr("not supported");
2361 }
2362 }
2363
2364 return true;
2365 }
2366
2367 void os::Linux::print_steal_info(outputStream* st) {
2368 if (has_initial_tick_info) {
2369 CPUPerfTicks pticks;
2370 bool res = os::Linux::get_tick_information(&pticks, -1);
2371
2372 if (res && pticks.has_steal_ticks) {
2373 uint64_t steal_ticks_difference = pticks.steal - initial_steal_ticks;
2374 uint64_t total_ticks_difference = pticks.total - initial_total_ticks;
2375 double steal_ticks_perc = 0.0;
2376 if (total_ticks_difference != 0) {
2377 steal_ticks_perc = (double) steal_ticks_difference / total_ticks_difference;
2378 }
2379 st->print_cr("Steal ticks since vm start: " UINT64_FORMAT, steal_ticks_difference);
2380 st->print_cr("Steal ticks percentage since vm start:%7.3f", steal_ticks_perc);
2381 }
2382 }
2383 }
2384
2385 void os::print_memory_info(outputStream* st) {
2386
2387 st->print("Memory:");
2388 st->print(" %dk page", os::vm_page_size()>>10);
2389
2390 // values in struct sysinfo are "unsigned long"
2391 struct sysinfo si;
2392 sysinfo(&si);
2393
2394 st->print(", physical " UINT64_FORMAT "k",
2395 os::physical_memory() >> 10);
2396 st->print("(" UINT64_FORMAT "k free)",
2397 os::available_memory() >> 10);
2398 st->print(", swap " UINT64_FORMAT "k",
2399 ((jlong)si.totalswap * si.mem_unit) >> 10);
2400 st->print("(" UINT64_FORMAT "k free)",
2401 ((jlong)si.freeswap * si.mem_unit) >> 10);
2402 st->cr();
2403 st->print("Page Sizes: ");
2404 _page_sizes.print_on(st);
2405 st->cr();
2406 }
2407
2408 // Print the first "model name" line and the first "flags" line
2409 // that we find and nothing more. We assume "model name" comes
2410 // before "flags" so if we find a second "model name", then the
2411 // "flags" field is considered missing.
2412 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2413 #if defined(IA32) || defined(AMD64)
2414 // Other platforms have less repetitive cpuinfo files
2415 FILE *fp = fopen("/proc/cpuinfo", "r");
2416 if (fp) {
2417 bool model_name_printed = false;
2418 while (!feof(fp)) {
2419 if (fgets(buf, buflen, fp)) {
2420 // Assume model name comes before flags
2421 if (strstr(buf, "model name") != NULL) {
2422 if (!model_name_printed) {
2423 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
2424 st->print_raw(buf);
2425 model_name_printed = true;
2426 } else {
2427 // model name printed but not flags? Odd, just return
2428 fclose(fp);
2429 return true;
2430 }
2431 }
2432 // print the flags line too
2433 if (strstr(buf, "flags") != NULL) {
2434 st->print_raw(buf);
2435 fclose(fp);
2436 return true;
2437 }
2438 }
2439 }
2440 fclose(fp);
2441 }
2442 #endif // x86 platforms
2443 return false;
2444 }
2445
2446 // additional information about CPU e.g. available frequency ranges
2447 static void print_sys_devices_cpu_info(outputStream* st, char* buf, size_t buflen) {
2448 _print_ascii_file_h("Online cpus", "/sys/devices/system/cpu/online", st);
2449 _print_ascii_file_h("Offline cpus", "/sys/devices/system/cpu/offline", st);
2450
2451 if (ExtensiveErrorReports) {
2452 // cache related info (cpu 0, should be similar for other CPUs)
2453 for (unsigned int i=0; i < 10; i++) { // handle max. 10 cache entries
2454 char hbuf_level[60];
2455 char hbuf_type[60];
2456 char hbuf_size[60];
2457 char hbuf_coherency_line_size[80];
2458 snprintf(hbuf_level, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/level", i);
2459 snprintf(hbuf_type, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/type", i);
2460 snprintf(hbuf_size, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/size", i);
2461 snprintf(hbuf_coherency_line_size, 80, "/sys/devices/system/cpu/cpu0/cache/index%u/coherency_line_size", i);
2462 if (file_exists(hbuf_level)) {
2463 _print_ascii_file_h("cache level", hbuf_level, st);
2464 _print_ascii_file_h("cache type", hbuf_type, st);
2465 _print_ascii_file_h("cache size", hbuf_size, st);
2466 _print_ascii_file_h("cache coherency line size", hbuf_coherency_line_size, st);
2467 }
2468 }
2469 }
2470
2471 // we miss the cpufreq entries on Power and s390x
2472 #if defined(IA32) || defined(AMD64)
2473 _print_ascii_file_h("BIOS frequency limitation", "/sys/devices/system/cpu/cpu0/cpufreq/bios_limit", st);
2474 _print_ascii_file_h("Frequency switch latency (ns)", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_transition_latency", st);
2475 _print_ascii_file_h("Available cpu frequencies", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies", st);
2476 // min and max should be in the Available range but still print them (not all info might be available for all kernels)
2477 if (ExtensiveErrorReports) {
2478 _print_ascii_file_h("Maximum cpu frequency", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq", st);
2479 _print_ascii_file_h("Minimum cpu frequency", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq", st);
2480 _print_ascii_file_h("Current cpu frequency", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq", st);
2481 }
2482 // governors are power schemes, see https://wiki.archlinux.org/index.php/CPU_frequency_scaling
2483 if (ExtensiveErrorReports) {
2484 _print_ascii_file_h("Available governors", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors", st);
2485 }
2486 _print_ascii_file_h("Current governor", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor", st);
2487 // Core performance boost, see https://www.kernel.org/doc/Documentation/cpu-freq/boost.txt
2488 // Raise operating frequency of some cores in a multi-core package if certain conditions apply, e.g.
2489 // whole chip is not fully utilized
2490 _print_ascii_file_h("Core performance/turbo boost", "/sys/devices/system/cpu/cpufreq/boost", st);
2491 #endif
2492 }
2493
2494 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2495 // Only print the model name if the platform provides this as a summary
2496 if (!print_model_name_and_flags(st, buf, buflen)) {
2497 _print_ascii_file_h("/proc/cpuinfo", "/proc/cpuinfo", st, false);
2498 }
2499 st->cr();
2500 print_sys_devices_cpu_info(st, buf, buflen);
2501 }
2502
2503 #if defined(AMD64) || defined(IA32) || defined(X32)
2504 const char* search_string = "model name";
2505 #elif defined(M68K)
2506 const char* search_string = "CPU";
2507 #elif defined(PPC64)
2508 const char* search_string = "cpu";
2509 #elif defined(S390)
2510 const char* search_string = "machine =";
2511 #elif defined(SPARC)
2512 const char* search_string = "cpu";
2513 #else
2514 const char* search_string = "Processor";
2515 #endif
2516
2517 // Parses the cpuinfo file for string representing the model name.
2518 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2519 FILE* fp = fopen("/proc/cpuinfo", "r");
2520 if (fp != NULL) {
2521 while (!feof(fp)) {
2522 char buf[256];
2523 if (fgets(buf, sizeof(buf), fp)) {
2524 char* start = strstr(buf, search_string);
2525 if (start != NULL) {
2526 char *ptr = start + strlen(search_string);
2527 char *end = buf + strlen(buf);
2528 while (ptr != end) {
2529 // skip whitespace and colon for the rest of the name.
2530 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2531 break;
2532 }
2533 ptr++;
2534 }
2535 if (ptr != end) {
2536 // reasonable string, get rid of newline and keep the rest
2537 char* nl = strchr(buf, '\n');
2538 if (nl != NULL) *nl = '\0';
2539 strncpy(cpuinfo, ptr, length);
2540 fclose(fp);
2541 return;
2542 }
2543 }
2544 }
2545 }
2546 fclose(fp);
2547 }
2548 // cpuinfo not found or parsing failed, just print generic string. The entire
2549 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2550 #if defined(AARCH64)
2551 strncpy(cpuinfo, "AArch64", length);
2552 #elif defined(AMD64)
2553 strncpy(cpuinfo, "x86_64", length);
2554 #elif defined(ARM) // Order wrt. AARCH64 is relevant!
2555 strncpy(cpuinfo, "ARM", length);
2556 #elif defined(IA32)
2557 strncpy(cpuinfo, "x86_32", length);
2558 #elif defined(IA64)
2559 strncpy(cpuinfo, "IA64", length);
2560 #elif defined(PPC)
2561 strncpy(cpuinfo, "PPC64", length);
2562 #elif defined(RISCV)2563 strncpy(cpuinfo, "RISCV64", length);
2564 #elif defined(S390)
2565 strncpy(cpuinfo, "S390", length);
2566 #elif defined(SPARC)
2567 strncpy(cpuinfo, "sparcv9", length);
2568 #elif defined(ZERO_LIBARCH)
2569 strncpy(cpuinfo, ZERO_LIBARCH, length);
2570 #else
2571 strncpy(cpuinfo, "unknown", length);
2572 #endif
2573 }
2574
2575 static char saved_jvm_path[MAXPATHLEN] = {0};
2576
2577 // Find the full path to the current module, libjvm.so
2578 void os::jvm_path(char *buf, jint buflen) {
2579 // Error checking.
2580 if (buflen < MAXPATHLEN) {
2581 assert(false, "must use a large-enough buffer");
2582 buf[0] = '\0';
2583 return;
2584 }
2585 // Lazy resolve the path to current module.
2586 if (saved_jvm_path[0] != 0) {
2587 strcpy(buf, saved_jvm_path);
2588 return;
2589 }
2590
2591 char dli_fname[MAXPATHLEN];
2592 dli_fname[0] = '\0';
2593 bool ret = dll_address_to_library_name(
2594 CAST_FROM_FN_PTR(address, os::jvm_path),
2595 dli_fname, sizeof(dli_fname), NULL);
2596 assert(ret, "cannot locate libjvm");
2597 char *rp = NULL;
2598 if (ret && dli_fname[0] != '\0') {
2599 rp = os::Posix::realpath(dli_fname, buf, buflen);
2600 }
2601 if (rp == NULL) {
2602 return;
2603 }
2604
2605 if (Arguments::sun_java_launcher_is_altjvm()) {
2606 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2607 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
2608 // If "/jre/lib/" appears at the right place in the string, then
2609 // assume we are installed in a JDK and we're done. Otherwise, check
2610 // for a JAVA_HOME environment variable and fix up the path so it
2611 // looks like libjvm.so is installed there (append a fake suffix
2612 // hotspot/libjvm.so).
2613 const char *p = buf + strlen(buf) - 1;
2614 for (int count = 0; p > buf && count < 5; ++count) {
2615 for (--p; p > buf && *p != '/'; --p)
2616 /* empty */ ;
2617 }
2618
2619 if (strncmp(p, "/jre/lib/", 9) != 0) {
2620 // Look for JAVA_HOME in the environment.
2621 char* java_home_var = ::getenv("JAVA_HOME");
2622 if (java_home_var != NULL && java_home_var[0] != 0) {
2623 char* jrelib_p;
2624 int len;
2625
2626 // Check the current module name "libjvm.so".
2627 p = strrchr(buf, '/');
2628 if (p == NULL) {
2629 return;
2630 }
2631 assert(strstr(p, "/libjvm") == p, "invalid library name");
2632
2633 rp = os::Posix::realpath(java_home_var, buf, buflen);
2634 if (rp == NULL) {
2635 return;
2636 }
2637
2638 // determine if this is a legacy image or modules image
2639 // modules image doesn't have "jre" subdirectory
2640 len = strlen(buf);
2641 assert(len < buflen, "Ran out of buffer room");
2642 jrelib_p = buf + len;
2643 snprintf(jrelib_p, buflen-len, "/jre/lib");
2644 if (0 != access(buf, F_OK)) {
2645 snprintf(jrelib_p, buflen-len, "/lib");
2646 }
2647
2648 if (0 == access(buf, F_OK)) {
2649 // Use current module name "libjvm.so"
2650 len = strlen(buf);
2651 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2652 } else {
2653 // Go back to path of .so
2654 rp = os::Posix::realpath(dli_fname, buf, buflen);
2655 if (rp == NULL) {
2656 return;
2657 }
2658 }
2659 }
2660 }
2661 }
2662
2663 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2664 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2665 }
2666
2667 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2668 // no prefix required, not even "_"
2669 }
2670
2671 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2672 // no suffix required
2673 }
2674
2675 ////////////////////////////////////////////////////////////////////////////////
2676 // Virtual Memory
2677
2678 int os::vm_page_size() {
2679 // Seems redundant as all get out
2680 assert(os::Linux::page_size() != -1, "must call os::init");
2681 return os::Linux::page_size();
2682 }
2683
2684 // Solaris allocates memory by pages.
2685 int os::vm_allocation_granularity() {
2686 assert(os::Linux::page_size() != -1, "must call os::init");
2687 return os::Linux::page_size();
2688 }
2689
2690 // Rationale behind this function:
2691 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2692 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2693 // samples for JITted code. Here we create private executable mapping over the code cache
2694 // and then we can use standard (well, almost, as mapping can change) way to provide
2695 // info for the reporting script by storing timestamp and location of symbol
2696 void linux_wrap_code(char* base, size_t size) {
2697 static volatile jint cnt = 0;
2698
2699 if (!UseOprofile) {
2700 return;
2701 }
2702
2703 char buf[PATH_MAX+1];
2704 int num = Atomic::add(&cnt, 1);
2705
2706 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2707 os::get_temp_directory(), os::current_process_id(), num);
2708 unlink(buf);
2709
2710 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2711
2712 if (fd != -1) {
2713 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2714 if (rv != (off_t)-1) {
2715 if (::write(fd, "", 1) == 1) {
2716 mmap(base, size,
2717 PROT_READ|PROT_WRITE|PROT_EXEC,
2718 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2719 }
2720 }
2721 ::close(fd);
2722 unlink(buf);
2723 }
2724 }
2725
2726 static bool recoverable_mmap_error(int err) {
2727 // See if the error is one we can let the caller handle. This
2728 // list of errno values comes from JBS-6843484. I can't find a
2729 // Linux man page that documents this specific set of errno
2730 // values so while this list currently matches Solaris, it may
2731 // change as we gain experience with this failure mode.
2732 switch (err) {
2733 case EBADF:
2734 case EINVAL:
2735 case ENOTSUP:
2736 // let the caller deal with these errors
2737 return true;
2738
2739 default:
2740 // Any remaining errors on this OS can cause our reserved mapping
2741 // to be lost. That can cause confusion where different data
2742 // structures think they have the same memory mapped. The worst
2743 // scenario is if both the VM and a library think they have the
2744 // same memory mapped.
2745 return false;
2746 }
2747 }
2748
2749 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2750 int err) {
2751 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2752 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2753 os::strerror(err), err);
2754 }
2755
2756 static void warn_fail_commit_memory(char* addr, size_t size,
2757 size_t alignment_hint, bool exec,
2758 int err) {
2759 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2760 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2761 alignment_hint, exec, os::strerror(err), err);
2762 }
2763
2764 // NOTE: Linux kernel does not really reserve the pages for us.
2765 // All it does is to check if there are enough free pages
2766 // left at the time of mmap(). This could be a potential
2767 // problem.
2768 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2769 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2770 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2771 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2772 if (res != (uintptr_t) MAP_FAILED) {
2773 if (UseNUMAInterleaving) {
2774 numa_make_global(addr, size);
2775 }
2776 return 0;
2777 }
2778
2779 int err = errno; // save errno from mmap() call above
2780
2781 if (!recoverable_mmap_error(err)) {
2782 warn_fail_commit_memory(addr, size, exec, err);
2783 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2784 }
2785
2786 return err;
2787 }
2788
2789 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2790 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2791 }
2792
2793 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2794 const char* mesg) {
2795 assert(mesg != NULL, "mesg must be specified");
2796 int err = os::Linux::commit_memory_impl(addr, size, exec);
2797 if (err != 0) {
2798 // the caller wants all commit errors to exit with the specified mesg:
2799 warn_fail_commit_memory(addr, size, exec, err);
2800 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2801 }
2802 }
2803
2804 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2805 #ifndef MAP_HUGETLB
2806 #define MAP_HUGETLB 0x40000
2807 #endif
2808
2809 // If mmap flags are set with MAP_HUGETLB and the system supports multiple
2810 // huge page sizes, flag bits [26:31] can be used to encode the log2 of the
2811 // desired huge page size. Otherwise, the system's default huge page size will be used.
2812 // See mmap(2) man page for more info (since Linux 3.8).
2813 // https://lwn.net/Articles/533499/
2814 #ifndef MAP_HUGE_SHIFT
2815 #define MAP_HUGE_SHIFT 26
2816 #endif
2817
2818 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2819 #ifndef MADV_HUGEPAGE
2820 #define MADV_HUGEPAGE 14
2821 #endif
2822
2823 int os::Linux::commit_memory_impl(char* addr, size_t size,
2824 size_t alignment_hint, bool exec) {
2825 int err = os::Linux::commit_memory_impl(addr, size, exec);
2826 if (err == 0) {
2827 realign_memory(addr, size, alignment_hint);
2828 }
2829 return err;
2830 }
2831
2832 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2833 bool exec) {
2834 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2835 }
2836
2837 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2838 size_t alignment_hint, bool exec,
2839 const char* mesg) {
2840 assert(mesg != NULL, "mesg must be specified");
2841 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2842 if (err != 0) {
2843 // the caller wants all commit errors to exit with the specified mesg:
2844 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2845 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2846 }
2847 }
2848
2849 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2850 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2851 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2852 // be supported or the memory may already be backed by huge pages.
2853 ::madvise(addr, bytes, MADV_HUGEPAGE);
2854 }
2855 }
2856
2857 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2858 // This method works by doing an mmap over an existing mmaping and effectively discarding
2859 // the existing pages. However it won't work for SHM-based large pages that cannot be
2860 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2861 // small pages on top of the SHM segment. This method always works for small pages, so we
2862 // allow that in any case.
2863 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2864 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2865 }
2866 }
2867
2868 void os::numa_make_global(char *addr, size_t bytes) {
2869 Linux::numa_interleave_memory(addr, bytes);
2870 }
2871
2872 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2873 // bind policy to MPOL_PREFERRED for the current thread.
2874 #define USE_MPOL_PREFERRED 0
2875
2876 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2877 // To make NUMA and large pages more robust when both enabled, we need to ease
2878 // the requirements on where the memory should be allocated. MPOL_BIND is the
2879 // default policy and it will force memory to be allocated on the specified
2880 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2881 // the specified node, but will not force it. Using this policy will prevent
2882 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2883 // free large pages.
2884 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2885 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2886 }
2887
2888 bool os::numa_topology_changed() { return false; }
2889
2890 size_t os::numa_get_groups_num() {
2891 // Return just the number of nodes in which it's possible to allocate memory
2892 // (in numa terminology, configured nodes).
2893 return Linux::numa_num_configured_nodes();
2894 }
2895
2896 int os::numa_get_group_id() {
2897 int cpu_id = Linux::sched_getcpu();
2898 if (cpu_id != -1) {
2899 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2900 if (lgrp_id != -1) {
2901 return lgrp_id;
2902 }
2903 }
2904 return 0;
2905 }
2906
2907 int os::numa_get_group_id_for_address(const void* address) {
2908 void** pages = const_cast<void**>(&address);
2909 int id = -1;
2910
2911 if (os::Linux::numa_move_pages(0, 1, pages, NULL, &id, 0) == -1) {
2912 return -1;
2913 }
2914 if (id < 0) {
2915 return -1;
2916 }
2917 return id;
2918 }
2919
2920 int os::Linux::get_existing_num_nodes() {
2921 int node;
2922 int highest_node_number = Linux::numa_max_node();
2923 int num_nodes = 0;
2924
2925 // Get the total number of nodes in the system including nodes without memory.
2926 for (node = 0; node <= highest_node_number; node++) {
2927 if (is_node_in_existing_nodes(node)) {
2928 num_nodes++;
2929 }
2930 }
2931 return num_nodes;
2932 }
2933
2934 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2935 int highest_node_number = Linux::numa_max_node();
2936 size_t i = 0;
2937
2938 // Map all node ids in which it is possible to allocate memory. Also nodes are
2939 // not always consecutively available, i.e. available from 0 to the highest
2940 // node number. If the nodes have been bound explicitly using numactl membind,
2941 // then allocate memory from those nodes only.
2942 for (int node = 0; node <= highest_node_number; node++) {
2943 if (Linux::is_node_in_bound_nodes((unsigned int)node)) {
2944 ids[i++] = node;
2945 }
2946 }
2947 return i;
2948 }
2949
2950 bool os::get_page_info(char *start, page_info* info) {
2951 return false;
2952 }
2953
2954 char *os::scan_pages(char *start, char* end, page_info* page_expected,
2955 page_info* page_found) {
2956 return end;
2957 }
2958
2959
2960 int os::Linux::sched_getcpu_syscall(void) {
2961 unsigned int cpu = 0;
2962 int retval = -1;
2963
2964 #if defined(IA32)
2965 #ifndef SYS_getcpu
2966 #define SYS_getcpu 318
2967 #endif
2968 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2969 #elif defined(AMD64)
2970 // Unfortunately we have to bring all these macros here from vsyscall.h
2971 // to be able to compile on old linuxes.
2972 #define __NR_vgetcpu 2
2973 #define VSYSCALL_START (-10UL << 20)
2974 #define VSYSCALL_SIZE 1024
2975 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2976 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2977 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2978 retval = vgetcpu(&cpu, NULL, NULL);
2979 #endif
2980
2981 return (retval == -1) ? retval : cpu;
2982 }
2983
2984 void os::Linux::sched_getcpu_init() {
2985 // sched_getcpu() should be in libc.
2986 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2987 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2988
2989 // If it's not, try a direct syscall.
2990 if (sched_getcpu() == -1) {
2991 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2992 (void*)&sched_getcpu_syscall));
2993 }
2994
2995 if (sched_getcpu() == -1) {
2996 vm_exit_during_initialization("getcpu(2) system call not supported by kernel");
2997 }
2998 }
2999
3000 // Something to do with the numa-aware allocator needs these symbols
3001 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
3002 extern "C" JNIEXPORT void numa_error(char *where) { }
3003
3004 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails
3005 // load symbol from base version instead.
3006 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
3007 void *f = dlvsym(handle, name, "libnuma_1.1");
3008 if (f == NULL) {
3009 f = dlsym(handle, name);
3010 }
3011 return f;
3012 }
3013
3014 // Handle request to load libnuma symbol version 1.2 (API v2) only.
3015 // Return NULL if the symbol is not defined in this particular version.
3016 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) {
3017 return dlvsym(handle, name, "libnuma_1.2");
3018 }
3019
3020 // Check numa dependent syscalls
3021 static bool numa_syscall_check() {
3022 // NUMA APIs depend on several syscalls. E.g., get_mempolicy is required for numa_get_membind and
3023 // numa_get_interleave_mask. But these dependent syscalls can be unsupported for various reasons.
3024 // Especially in dockers, get_mempolicy is not allowed with the default configuration. So it's necessary
3025 // to check whether the syscalls are available. Currently, only get_mempolicy is checked since checking
3026 // others like mbind would cause unexpected side effects.
3027 #ifdef SYS_get_mempolicy
3028 int dummy = 0;
3029 if (syscall(SYS_get_mempolicy, &dummy, NULL, 0, (void*)&dummy, 3) == -1) {
3030 return false;
3031 }
3032 #endif
3033
3034 return true;
3035 }
3036
3037 bool os::Linux::libnuma_init() {
3038 // Requires sched_getcpu() and numa dependent syscalls support
3039 if ((sched_getcpu() != -1) && numa_syscall_check()) {
3040 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
3041 if (handle != NULL) {
3042 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
3043 libnuma_dlsym(handle, "numa_node_to_cpus")));
3044 set_numa_node_to_cpus_v2(CAST_TO_FN_PTR(numa_node_to_cpus_v2_func_t,
3045 libnuma_v2_dlsym(handle, "numa_node_to_cpus")));
3046 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
3047 libnuma_dlsym(handle, "numa_max_node")));
3048 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t,
3049 libnuma_dlsym(handle, "numa_num_configured_nodes")));
3050 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
3051 libnuma_dlsym(handle, "numa_available")));
3052 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
3053 libnuma_dlsym(handle, "numa_tonode_memory")));
3054 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
3055 libnuma_dlsym(handle, "numa_interleave_memory")));
3056 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t,
3057 libnuma_v2_dlsym(handle, "numa_interleave_memory")));
3058 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
3059 libnuma_dlsym(handle, "numa_set_bind_policy")));
3060 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t,
3061 libnuma_dlsym(handle, "numa_bitmask_isbitset")));
3062 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t,
3063 libnuma_dlsym(handle, "numa_distance")));
3064 set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t,
3065 libnuma_v2_dlsym(handle, "numa_get_membind")));
3066 set_numa_get_interleave_mask(CAST_TO_FN_PTR(numa_get_interleave_mask_func_t,
3067 libnuma_v2_dlsym(handle, "numa_get_interleave_mask")));
3068 set_numa_move_pages(CAST_TO_FN_PTR(numa_move_pages_func_t,
3069 libnuma_dlsym(handle, "numa_move_pages")));
3070 set_numa_set_preferred(CAST_TO_FN_PTR(numa_set_preferred_func_t,
3071 libnuma_dlsym(handle, "numa_set_preferred")));
3072
3073 if (numa_available() != -1) {
3074 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
3075 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr"));
3076 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr"));
3077 set_numa_interleave_bitmask(_numa_get_interleave_mask());
3078 set_numa_membind_bitmask(_numa_get_membind());
3079 // Create an index -> node mapping, since nodes are not always consecutive
3080 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, mtInternal);
3081 rebuild_nindex_to_node_map();
3082 // Create a cpu -> node mapping
3083 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, mtInternal);
3084 rebuild_cpu_to_node_map();
3085 return true;
3086 }
3087 }
3088 }
3089 return false;
3090 }
3091
3092 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
3093 // Creating guard page is very expensive. Java thread has HotSpot
3094 // guard pages, only enable glibc guard page for non-Java threads.
3095 // (Remember: compiler thread is a Java thread, too!)
3096 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size());
3097 }
3098
3099 void os::Linux::rebuild_nindex_to_node_map() {
3100 int highest_node_number = Linux::numa_max_node();
3101
3102 nindex_to_node()->clear();
3103 for (int node = 0; node <= highest_node_number; node++) {
3104 if (Linux::is_node_in_existing_nodes(node)) {
3105 nindex_to_node()->append(node);
3106 }
3107 }
3108 }
3109
3110 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
3111 // The table is later used in get_node_by_cpu().
3112 void os::Linux::rebuild_cpu_to_node_map() {
3113 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
3114 // in libnuma (possible values are starting from 16,
3115 // and continuing up with every other power of 2, but less
3116 // than the maximum number of CPUs supported by kernel), and
3117 // is a subject to change (in libnuma version 2 the requirements
3118 // are more reasonable) we'll just hardcode the number they use
3119 // in the library.
3120 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
3121
3122 size_t cpu_num = processor_count();
3123 size_t cpu_map_size = NCPUS / BitsPerCLong;
3124 size_t cpu_map_valid_size =
3125 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
3126
3127 cpu_to_node()->clear();
3128 cpu_to_node()->at_grow(cpu_num - 1);
3129
3130 size_t node_num = get_existing_num_nodes();
3131
3132 int distance = 0;
3133 int closest_distance = INT_MAX;
3134 int closest_node = 0;
3135 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
3136 for (size_t i = 0; i < node_num; i++) {
3137 // Check if node is configured (not a memory-less node). If it is not, find
3138 // the closest configured node. Check also if node is bound, i.e. it's allowed
3139 // to allocate memory from the node. If it's not allowed, map cpus in that node
3140 // to the closest node from which memory allocation is allowed.
3141 if (!is_node_in_configured_nodes(nindex_to_node()->at(i)) ||
3142 !is_node_in_bound_nodes(nindex_to_node()->at(i))) {
3143 closest_distance = INT_MAX;
3144 // Check distance from all remaining nodes in the system. Ignore distance
3145 // from itself, from another non-configured node, and from another non-bound
3146 // node.
3147 for (size_t m = 0; m < node_num; m++) {
3148 if (m != i &&
3149 is_node_in_configured_nodes(nindex_to_node()->at(m)) &&
3150 is_node_in_bound_nodes(nindex_to_node()->at(m))) {
3151 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m));
3152 // If a closest node is found, update. There is always at least one
3153 // configured and bound node in the system so there is always at least
3154 // one node close.
3155 if (distance != 0 && distance < closest_distance) {
3156 closest_distance = distance;
3157 closest_node = nindex_to_node()->at(m);
3158 }
3159 }
3160 }
3161 } else {
3162 // Current node is already a configured node.
3163 closest_node = nindex_to_node()->at(i);
3164 }
3165
3166 // Get cpus from the original node and map them to the closest node. If node
3167 // is a configured node (not a memory-less node), then original node and
3168 // closest node are the same.
3169 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
3170 for (size_t j = 0; j < cpu_map_valid_size; j++) {
3171 if (cpu_map[j] != 0) {
3172 for (size_t k = 0; k < BitsPerCLong; k++) {
3173 if (cpu_map[j] & (1UL << k)) {
3174 int cpu_index = j * BitsPerCLong + k;
3175
3176 #ifndef PRODUCT
3177 if (UseDebuggerErgo1 && cpu_index >= (int)cpu_num) {
3178 // Some debuggers limit the processor count without
3179 // intercepting the NUMA APIs. Just fake the values.
3180 cpu_index = 0;
3181 }
3182 #endif
3183
3184 cpu_to_node()->at_put(cpu_index, closest_node);
3185 }
3186 }
3187 }
3188 }
3189 }
3190 }
3191 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
3192 }
3193
3194 int os::Linux::numa_node_to_cpus(int node, unsigned long *buffer, int bufferlen) {
3195 // use the latest version of numa_node_to_cpus if available
3196 if (_numa_node_to_cpus_v2 != NULL) {
3197
3198 // libnuma bitmask struct
3199 struct bitmask {
3200 unsigned long size; /* number of bits in the map */
3201 unsigned long *maskp;
3202 };
3203
3204 struct bitmask mask;
3205 mask.maskp = (unsigned long *)buffer;
3206 mask.size = bufferlen * 8;
3207 return _numa_node_to_cpus_v2(node, &mask);
3208 } else if (_numa_node_to_cpus != NULL) {
3209 return _numa_node_to_cpus(node, buffer, bufferlen);
3210 }
3211 return -1;
3212 }
3213
3214 int os::Linux::get_node_by_cpu(int cpu_id) {
3215 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
3216 return cpu_to_node()->at(cpu_id);
3217 }
3218 return -1;
3219 }
3220
3221 GrowableArray<int>* os::Linux::_cpu_to_node;
3222 GrowableArray<int>* os::Linux::_nindex_to_node;
3223 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
3224 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
3225 os::Linux::numa_node_to_cpus_v2_func_t os::Linux::_numa_node_to_cpus_v2;
3226 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
3227 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes;
3228 os::Linux::numa_available_func_t os::Linux::_numa_available;
3229 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
3230 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
3231 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2;
3232 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
3233 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset;
3234 os::Linux::numa_distance_func_t os::Linux::_numa_distance;
3235 os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind;
3236 os::Linux::numa_get_interleave_mask_func_t os::Linux::_numa_get_interleave_mask;
3237 os::Linux::numa_move_pages_func_t os::Linux::_numa_move_pages;
3238 os::Linux::numa_set_preferred_func_t os::Linux::_numa_set_preferred;
3239 os::Linux::NumaAllocationPolicy os::Linux::_current_numa_policy;
3240 unsigned long* os::Linux::_numa_all_nodes;
3241 struct bitmask* os::Linux::_numa_all_nodes_ptr;
3242 struct bitmask* os::Linux::_numa_nodes_ptr;
3243 struct bitmask* os::Linux::_numa_interleave_bitmask;
3244 struct bitmask* os::Linux::_numa_membind_bitmask;
3245
3246 bool os::pd_uncommit_memory(char* addr, size_t size, bool exec) {
3247 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
3248 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
3249 return res != (uintptr_t) MAP_FAILED;
3250 }
3251
3252 static address get_stack_commited_bottom(address bottom, size_t size) {
3253 address nbot = bottom;
3254 address ntop = bottom + size;
3255
3256 size_t page_sz = os::vm_page_size();
3257 unsigned pages = size / page_sz;
3258
3259 unsigned char vec[1];
3260 unsigned imin = 1, imax = pages + 1, imid;
3261 int mincore_return_value = 0;
3262
3263 assert(imin <= imax, "Unexpected page size");
3264
3265 while (imin < imax) {
3266 imid = (imax + imin) / 2;
3267 nbot = ntop - (imid * page_sz);
3268
3269 // Use a trick with mincore to check whether the page is mapped or not.
3270 // mincore sets vec to 1 if page resides in memory and to 0 if page
3271 // is swapped output but if page we are asking for is unmapped
3272 // it returns -1,ENOMEM
3273 mincore_return_value = mincore(nbot, page_sz, vec);
3274
3275 if (mincore_return_value == -1) {
3276 // Page is not mapped go up
3277 // to find first mapped page
3278 if (errno != EAGAIN) {
3279 assert(errno == ENOMEM, "Unexpected mincore errno");
3280 imax = imid;
3281 }
3282 } else {
3283 // Page is mapped go down
3284 // to find first not mapped page
3285 imin = imid + 1;
3286 }
3287 }
3288
3289 nbot = nbot + page_sz;
3290
3291 // Adjust stack bottom one page up if last checked page is not mapped
3292 if (mincore_return_value == -1) {
3293 nbot = nbot + page_sz;
3294 }
3295
3296 return nbot;
3297 }
3298
3299 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
3300 int mincore_return_value;
3301 const size_t stripe = 1024; // query this many pages each time
3302 unsigned char vec[stripe + 1];
3303 // set a guard
3304 vec[stripe] = 'X';
3305
3306 const size_t page_sz = os::vm_page_size();
3307 size_t pages = size / page_sz;
3308
3309 assert(is_aligned(start, page_sz), "Start address must be page aligned");
3310 assert(is_aligned(size, page_sz), "Size must be page aligned");
3311
3312 committed_start = NULL;
3313
3314 int loops = (pages + stripe - 1) / stripe;
3315 int committed_pages = 0;
3316 address loop_base = start;
3317 bool found_range = false;
3318
3319 for (int index = 0; index < loops && !found_range; index ++) {
3320 assert(pages > 0, "Nothing to do");
3321 int pages_to_query = (pages >= stripe) ? stripe : pages;
3322 pages -= pages_to_query;
3323
3324 // Get stable read
3325 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN);
3326
3327 // During shutdown, some memory goes away without properly notifying NMT,
3328 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object.
3329 // Bailout and return as not committed for now.
3330 if (mincore_return_value == -1 && errno == ENOMEM) {
3331 return false;
3332 }
3333
3334 assert(vec[stripe] == 'X', "overflow guard");
3335 assert(mincore_return_value == 0, "Range must be valid");
3336 // Process this stripe
3337 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) {
3338 if ((vec[vecIdx] & 0x01) == 0) { // not committed
3339 // End of current contiguous region
3340 if (committed_start != NULL) {
3341 found_range = true;
3342 break;
3343 }
3344 } else { // committed
3345 // Start of region
3346 if (committed_start == NULL) {
3347 committed_start = loop_base + page_sz * vecIdx;
3348 }
3349 committed_pages ++;
3350 }
3351 }
3352
3353 loop_base += pages_to_query * page_sz;
3354 }
3355
3356 if (committed_start != NULL) {
3357 assert(committed_pages > 0, "Must have committed region");
3358 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has");
3359 assert(committed_start >= start && committed_start < start + size, "Out of range");
3360 committed_size = page_sz * committed_pages;
3361 return true;
3362 } else {
3363 assert(committed_pages == 0, "Should not have committed region");
3364 return false;
3365 }
3366 }
3367
3368
3369 // Linux uses a growable mapping for the stack, and if the mapping for
3370 // the stack guard pages is not removed when we detach a thread the
3371 // stack cannot grow beyond the pages where the stack guard was
3372 // mapped. If at some point later in the process the stack expands to
3373 // that point, the Linux kernel cannot expand the stack any further
3374 // because the guard pages are in the way, and a segfault occurs.
3375 //
3376 // However, it's essential not to split the stack region by unmapping
3377 // a region (leaving a hole) that's already part of the stack mapping,
3378 // so if the stack mapping has already grown beyond the guard pages at
3379 // the time we create them, we have to truncate the stack mapping.
3380 // So, we need to know the extent of the stack mapping when
3381 // create_stack_guard_pages() is called.
3382
3383 // We only need this for stacks that are growable: at the time of
3384 // writing thread stacks don't use growable mappings (i.e. those
3385 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3386 // only applies to the main thread.
3387
3388 // If the (growable) stack mapping already extends beyond the point
3389 // where we're going to put our guard pages, truncate the mapping at
3390 // that point by munmap()ping it. This ensures that when we later
3391 // munmap() the guard pages we don't leave a hole in the stack
3392 // mapping. This only affects the main/primordial thread
3393
3394 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3395 if (os::is_primordial_thread()) {
3396 // As we manually grow stack up to bottom inside create_attached_thread(),
3397 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3398 // we don't need to do anything special.
3399 // Check it first, before calling heavy function.
3400 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3401 unsigned char vec[1];
3402
3403 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3404 // Fallback to slow path on all errors, including EAGAIN
3405 assert((uintptr_t)addr >= stack_extent,
3406 "Sanity: addr should be larger than extent, " PTR_FORMAT " >= " PTR_FORMAT,
3407 p2i(addr), stack_extent);
3408 stack_extent = (uintptr_t) get_stack_commited_bottom(
3409 os::Linux::initial_thread_stack_bottom(),
3410 (size_t)addr - stack_extent);
3411 }
3412
3413 if (stack_extent < (uintptr_t)addr) {
3414 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3415 }
3416 }
3417
3418 return os::commit_memory(addr, size, !ExecMem);
3419 }
3420
3421 // If this is a growable mapping, remove the guard pages entirely by
3422 // munmap()ping them. If not, just call uncommit_memory(). This only
3423 // affects the main/primordial thread, but guard against future OS changes.
3424 // It's safe to always unmap guard pages for primordial thread because we
3425 // always place it right after end of the mapped region.
3426
3427 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3428 uintptr_t stack_extent, stack_base;
3429
3430 if (os::is_primordial_thread()) {
3431 return ::munmap(addr, size) == 0;
3432 }
3433
3434 return os::uncommit_memory(addr, size);
3435 }
3436
3437 // 'requested_addr' is only treated as a hint, the return value may or
3438 // may not start from the requested address. Unlike Linux mmap(), this
3439 // function returns NULL to indicate failure.
3440 static char* anon_mmap(char* requested_addr, size_t bytes) {
3441 // MAP_FIXED is intentionally left out, to leave existing mappings intact.
3442 const int flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3443
3444 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3445 // touch an uncommitted page. Otherwise, the read/write might
3446 // succeed if we have enough swap space to back the physical page.
3447 char* addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, flags, -1, 0);
3448
3449 return addr == MAP_FAILED ? NULL : addr;
3450 }
3451
3452 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3453 // (req_addr != NULL) or with a given alignment.
3454 // - bytes shall be a multiple of alignment.
3455 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3456 // - alignment sets the alignment at which memory shall be allocated.
3457 // It must be a multiple of allocation granularity.
3458 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3459 // req_addr or NULL.
3460 static char* anon_mmap_aligned(char* req_addr, size_t bytes, size_t alignment) {
3461 size_t extra_size = bytes;
3462 if (req_addr == NULL && alignment > 0) {
3463 extra_size += alignment;
3464 }
3465
3466 char* start = anon_mmap(req_addr, extra_size);
3467 if (start != NULL) {
3468 if (req_addr != NULL) {
3469 if (start != req_addr) {
3470 ::munmap(start, extra_size);
3471 start = NULL;
3472 }
3473 } else {
3474 char* const start_aligned = align_up(start, alignment);
3475 char* const end_aligned = start_aligned + bytes;
3476 char* const end = start + extra_size;
3477 if (start_aligned > start) {
3478 ::munmap(start, start_aligned - start);
3479 }
3480 if (end_aligned < end) {
3481 ::munmap(end_aligned, end - end_aligned);
3482 }
3483 start = start_aligned;
3484 }
3485 }
3486 return start;
3487 }
3488
3489 static int anon_munmap(char * addr, size_t size) {
3490 return ::munmap(addr, size) == 0;
3491 }
3492
3493 char* os::pd_reserve_memory(size_t bytes, bool exec) {
3494 return anon_mmap(NULL, bytes);
3495 }
3496
3497 bool os::pd_release_memory(char* addr, size_t size) {
3498 return anon_munmap(addr, size);
3499 }
3500
3501 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3502 extern char* g_assert_poison; // assertion poison page address
3503 #endif
3504
3505 static bool linux_mprotect(char* addr, size_t size, int prot) {
3506 // Linux wants the mprotect address argument to be page aligned.
3507 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size());
3508
3509 // According to SUSv3, mprotect() should only be used with mappings
3510 // established by mmap(), and mmap() always maps whole pages. Unaligned
3511 // 'addr' likely indicates problem in the VM (e.g. trying to change
3512 // protection of malloc'ed or statically allocated memory). Check the
3513 // caller if you hit this assert.
3514 assert(addr == bottom, "sanity check");
3515
3516 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3517 // Don't log anything if we're executing in the poison page signal handling
3518 // context. It can lead to reentrant use of other parts of the VM code.
3519 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3520 if (addr != g_assert_poison)
3521 #endif
3522 Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with protection modes %x", p2i(bottom), p2i(bottom+size), prot);
3523 return ::mprotect(bottom, size, prot) == 0;
3524 }
3525
3526 // Set protections specified
3527 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3528 bool is_committed) {
3529 unsigned int p = 0;
3530 switch (prot) {
3531 case MEM_PROT_NONE: p = PROT_NONE; break;
3532 case MEM_PROT_READ: p = PROT_READ; break;
3533 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3534 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3535 default:
3536 ShouldNotReachHere();
3537 }
3538 // is_committed is unused.
3539 return linux_mprotect(addr, bytes, p);
3540 }
3541
3542 bool os::guard_memory(char* addr, size_t size) {
3543 return linux_mprotect(addr, size, PROT_NONE);
3544 }
3545
3546 bool os::unguard_memory(char* addr, size_t size) {
3547 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3548 }
3549
3550 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3551 size_t page_size) {
3552 bool result = false;
3553 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3554 MAP_ANONYMOUS|MAP_PRIVATE,
3555 -1, 0);
3556 if (p != MAP_FAILED) {
3557 void *aligned_p = align_up(p, page_size);
3558
3559 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3560
3561 munmap(p, page_size * 2);
3562 }
3563
3564 if (warn && !result) {
3565 warning("TransparentHugePages is not supported by the operating system.");
3566 }
3567
3568 return result;
3569 }
3570
3571 int os::Linux::hugetlbfs_page_size_flag(size_t page_size) {
3572 if (page_size != default_large_page_size()) {
3573 return (exact_log2(page_size) << MAP_HUGE_SHIFT);
3574 }
3575 return 0;
3576 }
3577
3578 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3579 // Include the page size flag to ensure we sanity check the correct page size.
3580 int flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_HUGETLB | hugetlbfs_page_size_flag(page_size);
3581 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, flags, -1, 0);
3582
3583 if (p != MAP_FAILED) {
3584 // Mapping succeeded, sanity check passed.
3585 munmap(p, page_size);
3586 return true;
3587 } else {
3588 log_info(pagesize)("Large page size (" SIZE_FORMAT "%s) failed sanity check, "
3589 "checking if smaller large page sizes are usable",
3590 byte_size_in_exact_unit(page_size),
3591 exact_unit_for_byte_size(page_size));
3592 for (size_t page_size_ = _page_sizes.next_smaller(page_size);
3593 page_size_ != (size_t)os::vm_page_size();
3594 page_size_ = _page_sizes.next_smaller(page_size_)) {
3595 flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_HUGETLB | hugetlbfs_page_size_flag(page_size_);
3596 p = mmap(NULL, page_size_, PROT_READ|PROT_WRITE, flags, -1, 0);
3597 if (p != MAP_FAILED) {
3598 // Mapping succeeded, sanity check passed.
3599 munmap(p, page_size_);
3600 log_info(pagesize)("Large page size (" SIZE_FORMAT "%s) passed sanity check",
3601 byte_size_in_exact_unit(page_size_),
3602 exact_unit_for_byte_size(page_size_));
3603 return true;
3604 }
3605 }
3606 }
3607
3608 if (warn) {
3609 warning("HugeTLBFS is not configured or not supported by the operating system.");
3610 }
3611
3612 return false;
3613 }
3614
3615 bool os::Linux::shm_hugetlbfs_sanity_check(bool warn, size_t page_size) {
3616 // Try to create a large shared memory segment.
3617 int shmid = shmget(IPC_PRIVATE, page_size, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3618 if (shmid == -1) {
3619 // Possible reasons for shmget failure:
3620 // 1. shmmax is too small for the request.
3621 // > check shmmax value: cat /proc/sys/kernel/shmmax
3622 // > increase shmmax value: echo "new_value" > /proc/sys/kernel/shmmax
3623 // 2. not enough large page memory.
3624 // > check available large pages: cat /proc/meminfo
3625 // > increase amount of large pages:
3626 // sysctl -w vm.nr_hugepages=new_value
3627 // > For more information regarding large pages please refer to:
3628 // https://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt
3629 if (warn) {
3630 warning("Large pages using UseSHM are not configured on this system.");
3631 }
3632 return false;
3633 }
3634 // Managed to create a segment, now delete it.
3635 shmctl(shmid, IPC_RMID, NULL);
3636 return true;
3637 }
3638
3639 // From the coredump_filter documentation:
3640 //
3641 // - (bit 0) anonymous private memory
3642 // - (bit 1) anonymous shared memory
3643 // - (bit 2) file-backed private memory
3644 // - (bit 3) file-backed shared memory
3645 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3646 // effective only if the bit 2 is cleared)
3647 // - (bit 5) hugetlb private memory
3648 // - (bit 6) hugetlb shared memory
3649 // - (bit 7) dax private memory
3650 // - (bit 8) dax shared memory
3651 //
3652 static void set_coredump_filter(CoredumpFilterBit bit) {
3653 FILE *f;
3654 long cdm;
3655
3656 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3657 return;
3658 }
3659
3660 if (fscanf(f, "%lx", &cdm) != 1) {
3661 fclose(f);
3662 return;
3663 }
3664
3665 long saved_cdm = cdm;
3666 rewind(f);
3667 cdm |= bit;
3668
3669 if (cdm != saved_cdm) {
3670 fprintf(f, "%#lx", cdm);
3671 }
3672
3673 fclose(f);
3674 }
3675
3676 // Large page support
3677
3678 static size_t _large_page_size = 0;
3679
3680 static size_t scan_default_large_page_size() {
3681 size_t default_large_page_size = 0;
3682
3683 // large_page_size on Linux is used to round up heap size. x86 uses either
3684 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3685 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3686 // page as large as 1G.
3687 //
3688 // Here we try to figure out page size by parsing /proc/meminfo and looking
3689 // for a line with the following format:
3690 // Hugepagesize: 2048 kB
3691 //
3692 // If we can't determine the value (e.g. /proc is not mounted, or the text
3693 // format has been changed), we'll set largest page size to 0
3694
3695 FILE *fp = fopen("/proc/meminfo", "r");
3696 if (fp) {
3697 while (!feof(fp)) {
3698 int x = 0;
3699 char buf[16];
3700 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3701 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3702 default_large_page_size = x * K;
3703 break;
3704 }
3705 } else {
3706 // skip to next line
3707 for (;;) {
3708 int ch = fgetc(fp);
3709 if (ch == EOF || ch == (int)'\n') break;
3710 }
3711 }
3712 }
3713 fclose(fp);
3714 }
3715
3716 return default_large_page_size;
3717 }
3718
3719 static os::PageSizes scan_multiple_page_support() {
3720 // Scan /sys/kernel/mm/hugepages
3721 // to discover the available page sizes
3722 const char* sys_hugepages = "/sys/kernel/mm/hugepages";
3723 os::PageSizes page_sizes;
3724
3725 DIR *dir = opendir(sys_hugepages);
3726
3727 struct dirent *entry;
3728 size_t page_size;
3729 while ((entry = readdir(dir)) != NULL) {
3730 if (entry->d_type == DT_DIR &&
3731 sscanf(entry->d_name, "hugepages-%zukB", &page_size) == 1) {
3732 // The kernel is using kB, hotspot uses bytes
3733 // Add each found Large Page Size to page_sizes
3734 page_sizes.add(page_size * K);
3735 }
3736 }
3737 closedir(dir);
3738
3739 LogTarget(Debug, pagesize) lt;
3740 if (lt.is_enabled()) {
3741 LogStream ls(lt);
3742 ls.print("Large Page sizes: ");
3743 page_sizes.print_on(&ls);
3744 }
3745
3746 return page_sizes;
3747 }
3748
3749 size_t os::Linux::default_large_page_size() {
3750 return _default_large_page_size;
3751 }
3752
3753 void warn_no_large_pages_configured() {
3754 if (!FLAG_IS_DEFAULT(UseLargePages)) {
3755 log_warning(pagesize)("UseLargePages disabled, no large pages configured and available on the system.");
3756 }
3757 }
3758
3759 bool os::Linux::setup_large_page_type(size_t page_size) {
3760 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3761 FLAG_IS_DEFAULT(UseSHM) &&
3762 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3763
3764 // The type of large pages has not been specified by the user.
3765
3766 // Try UseHugeTLBFS and then UseSHM.
3767 UseHugeTLBFS = UseSHM = true;
3768
3769 // Don't try UseTransparentHugePages since there are known
3770 // performance issues with it turned on. This might change in the future.
3771 UseTransparentHugePages = false;
3772 }
3773
3774 if (UseTransparentHugePages) {
3775 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3776 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3777 UseHugeTLBFS = false;
3778 UseSHM = false;
3779 return true;
3780 }
3781 UseTransparentHugePages = false;
3782 }
3783
3784 if (UseHugeTLBFS) {
3785 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3786 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3787 UseSHM = false;
3788 return true;
3789 }
3790 UseHugeTLBFS = false;
3791 }
3792
3793 if (UseSHM) {
3794 bool warn_on_failure = !FLAG_IS_DEFAULT(UseSHM);
3795 if (shm_hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3796 return true;
3797 }
3798 UseSHM = false;
3799 }
3800
3801 warn_no_large_pages_configured();
3802 return false;
3803 }
3804
3805 void os::large_page_init() {
3806 // 1) Handle the case where we do not want to use huge pages and hence
3807 // there is no need to scan the OS for related info
3808 if (!UseLargePages &&
3809 !UseTransparentHugePages &&
3810 !UseHugeTLBFS &&
3811 !UseSHM) {
3812 // Not using large pages.
3813 return;
3814 }
3815
3816 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3817 // The user explicitly turned off large pages.
3818 // Ignore the rest of the large pages flags.
3819 UseTransparentHugePages = false;
3820 UseHugeTLBFS = false;
3821 UseSHM = false;
3822 return;
3823 }
3824
3825 // 2) Scan OS info
3826 size_t default_large_page_size = scan_default_large_page_size();
3827 os::Linux::_default_large_page_size = default_large_page_size;
3828 if (default_large_page_size == 0) {
3829 // No large pages configured, return.
3830 warn_no_large_pages_configured();
3831 UseLargePages = false;
3832 UseTransparentHugePages = false;
3833 UseHugeTLBFS = false;
3834 UseSHM = false;
3835 return;
3836 }
3837 os::PageSizes all_large_pages = scan_multiple_page_support();
3838
3839 // 3) Consistency check and post-processing
3840
3841 // It is unclear if /sys/kernel/mm/hugepages/ and /proc/meminfo could disagree. Manually
3842 // re-add the default page size to the list of page sizes to be sure.
3843 all_large_pages.add(default_large_page_size);
3844
3845 // Check LargePageSizeInBytes matches an available page size and if so set _large_page_size
3846 // using LargePageSizeInBytes as the maximum allowed large page size. If LargePageSizeInBytes
3847 // doesn't match an available page size set _large_page_size to default_large_page_size
3848 // and use it as the maximum.
3849 if (FLAG_IS_DEFAULT(LargePageSizeInBytes) ||
3850 LargePageSizeInBytes == 0 ||
3851 LargePageSizeInBytes == default_large_page_size) {
3852 _large_page_size = default_large_page_size;
3853 log_info(pagesize)("Using the default large page size: " SIZE_FORMAT "%s",
3854 byte_size_in_exact_unit(_large_page_size),
3855 exact_unit_for_byte_size(_large_page_size));
3856 } else {
3857 if (all_large_pages.contains(LargePageSizeInBytes)) {
3858 _large_page_size = LargePageSizeInBytes;
3859 log_info(pagesize)("Overriding default large page size (" SIZE_FORMAT "%s) "
3860 "using LargePageSizeInBytes: " SIZE_FORMAT "%s",
3861 byte_size_in_exact_unit(default_large_page_size),
3862 exact_unit_for_byte_size(default_large_page_size),
3863 byte_size_in_exact_unit(_large_page_size),
3864 exact_unit_for_byte_size(_large_page_size));
3865 } else {
3866 _large_page_size = default_large_page_size;
3867 log_info(pagesize)("LargePageSizeInBytes is not a valid large page size (" SIZE_FORMAT "%s) "
3868 "using the default large page size: " SIZE_FORMAT "%s",
3869 byte_size_in_exact_unit(LargePageSizeInBytes),
3870 exact_unit_for_byte_size(LargePageSizeInBytes),
3871 byte_size_in_exact_unit(_large_page_size),
3872 exact_unit_for_byte_size(_large_page_size));
3873 }
3874 }
3875
3876 // Populate _page_sizes with large page sizes less than or equal to
3877 // _large_page_size.
3878 for (size_t page_size = _large_page_size; page_size != 0;
3879 page_size = all_large_pages.next_smaller(page_size)) {
3880 _page_sizes.add(page_size);
3881 }
3882
3883 LogTarget(Info, pagesize) lt;
3884 if (lt.is_enabled()) {
3885 LogStream ls(lt);
3886 ls.print("Usable page sizes: ");
3887 _page_sizes.print_on(&ls);
3888 }
3889
3890 // Now determine the type of large pages to use:
3891 UseLargePages = os::Linux::setup_large_page_type(_large_page_size);
3892
3893 set_coredump_filter(LARGEPAGES_BIT);
3894 }
3895
3896 #ifndef SHM_HUGETLB
3897 #define SHM_HUGETLB 04000
3898 #endif
3899
3900 #define shm_warning_format(format, ...) \
3901 do { \
3902 if (UseLargePages && \
3903 (!FLAG_IS_DEFAULT(UseLargePages) || \
3904 !FLAG_IS_DEFAULT(UseSHM) || \
3905 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3906 warning(format, __VA_ARGS__); \
3907 } \
3908 } while (0)
3909
3910 #define shm_warning(str) shm_warning_format("%s", str)
3911
3912 #define shm_warning_with_errno(str) \
3913 do { \
3914 int err = errno; \
3915 shm_warning_format(str " (error = %d)", err); \
3916 } while (0)
3917
3918 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3919 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment");
3920
3921 if (!is_aligned(alignment, SHMLBA)) {
3922 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3923 return NULL;
3924 }
3925
3926 // To ensure that we get 'alignment' aligned memory from shmat,
3927 // we pre-reserve aligned virtual memory and then attach to that.
3928
3929 char* pre_reserved_addr = anon_mmap_aligned(NULL /* req_addr */, bytes, alignment);
3930 if (pre_reserved_addr == NULL) {
3931 // Couldn't pre-reserve aligned memory.
3932 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3933 return NULL;
3934 }
3935
3936 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3937 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3938
3939 if ((intptr_t)addr == -1) {
3940 int err = errno;
3941 shm_warning_with_errno("Failed to attach shared memory.");
3942
3943 assert(err != EACCES, "Unexpected error");
3944 assert(err != EIDRM, "Unexpected error");
3945 assert(err != EINVAL, "Unexpected error");
3946
3947 // Since we don't know if the kernel unmapped the pre-reserved memory area
3948 // we can't unmap it, since that would potentially unmap memory that was
3949 // mapped from other threads.
3950 return NULL;
3951 }
3952
3953 return addr;
3954 }
3955
3956 static char* shmat_at_address(int shmid, char* req_addr) {
3957 if (!is_aligned(req_addr, SHMLBA)) {
3958 assert(false, "Requested address needs to be SHMLBA aligned");
3959 return NULL;
3960 }
3961
3962 char* addr = (char*)shmat(shmid, req_addr, 0);
3963
3964 if ((intptr_t)addr == -1) {
3965 shm_warning_with_errno("Failed to attach shared memory.");
3966 return NULL;
3967 }
3968
3969 return addr;
3970 }
3971
3972 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3973 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3974 if (req_addr != NULL) {
3975 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3976 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment");
3977 return shmat_at_address(shmid, req_addr);
3978 }
3979
3980 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3981 // return large page size aligned memory addresses when req_addr == NULL.
3982 // However, if the alignment is larger than the large page size, we have
3983 // to manually ensure that the memory returned is 'alignment' aligned.
3984 if (alignment > os::large_page_size()) {
3985 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3986 return shmat_with_alignment(shmid, bytes, alignment);
3987 } else {
3988 return shmat_at_address(shmid, NULL);
3989 }
3990 }
3991
3992 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
3993 char* req_addr, bool exec) {
3994 // "exec" is passed in but not used. Creating the shared image for
3995 // the code cache doesn't have an SHM_X executable permission to check.
3996 assert(UseLargePages && UseSHM, "only for SHM large pages");
3997 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
3998 assert(is_aligned(req_addr, alignment), "Unaligned address");
3999
4000 if (!is_aligned(bytes, os::large_page_size())) {
4001 return NULL; // Fallback to small pages.
4002 }
4003
4004 // Create a large shared memory region to attach to based on size.
4005 // Currently, size is the total size of the heap.
4006 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
4007 if (shmid == -1) {
4008 // Possible reasons for shmget failure:
4009 // 1. shmmax is too small for the request.
4010 // > check shmmax value: cat /proc/sys/kernel/shmmax
4011 // > increase shmmax value: echo "new_value" > /proc/sys/kernel/shmmax
4012 // 2. not enough large page memory.
4013 // > check available large pages: cat /proc/meminfo
4014 // > increase amount of large pages:
4015 // sysctl -w vm.nr_hugepages=new_value
4016 // > For more information regarding large pages please refer to:
4017 // https://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt
4018 // Note 1: different Linux may use different name for this property,
4019 // e.g. on Redhat AS-3 it is "hugetlb_pool".
4020 // Note 2: it's possible there's enough physical memory available but
4021 // they are so fragmented after a long run that they can't
4022 // coalesce into large pages. Try to reserve large pages when
4023 // the system is still "fresh".
4024 shm_warning_with_errno("Failed to reserve shared memory.");
4025 return NULL;
4026 }
4027
4028 // Attach to the region.
4029 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
4030
4031 // Remove shmid. If shmat() is successful, the actual shared memory segment
4032 // will be deleted when it's detached by shmdt() or when the process
4033 // terminates. If shmat() is not successful this will remove the shared
4034 // segment immediately.
4035 shmctl(shmid, IPC_RMID, NULL);
4036
4037 return addr;
4038 }
4039
4040 static void warn_on_commit_special_failure(char* req_addr, size_t bytes,
4041 size_t page_size, int error) {
4042 assert(error == ENOMEM, "Only expect to fail if no memory is available");
4043
4044 bool warn_on_failure = UseLargePages &&
4045 (!FLAG_IS_DEFAULT(UseLargePages) ||
4046 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
4047 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
4048
4049 if (warn_on_failure) {
4050 char msg[128];
4051 jio_snprintf(msg, sizeof(msg), "Failed to reserve and commit memory. req_addr: "
4052 PTR_FORMAT " bytes: " SIZE_FORMAT " page size: "
4053 SIZE_FORMAT " (errno = %d).",
4054 req_addr, bytes, page_size, error);
4055 warning("%s", msg);
4056 }
4057 }
4058
4059 bool os::Linux::commit_memory_special(size_t bytes,
4060 size_t page_size,
4061 char* req_addr,
4062 bool exec) {
4063 assert(UseLargePages && UseHugeTLBFS, "Should only get here when HugeTLBFS large pages are used");
4064 assert(is_aligned(bytes, page_size), "Unaligned size");
4065 assert(is_aligned(req_addr, page_size), "Unaligned address");
4066 assert(req_addr != NULL, "Must have a requested address for special mappings");
4067
4068 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
4069 int flags = MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED;
4070
4071 // For large pages additional flags are required.
4072 if (page_size > (size_t) os::vm_page_size()) {
4073 flags |= MAP_HUGETLB | hugetlbfs_page_size_flag(page_size);
4074 }
4075 char* addr = (char*)::mmap(req_addr, bytes, prot, flags, -1, 0);
4076
4077 if (addr == MAP_FAILED) {
4078 warn_on_commit_special_failure(req_addr, bytes, page_size, errno);
4079 return false;
4080 }
4081
4082 log_debug(pagesize)("Commit special mapping: " PTR_FORMAT ", size=" SIZE_FORMAT "%s, page size="
4083 SIZE_FORMAT "%s",
4084 p2i(addr), byte_size_in_exact_unit(bytes),
4085 exact_unit_for_byte_size(bytes),
4086 byte_size_in_exact_unit(page_size),
4087 exact_unit_for_byte_size(page_size));
4088 assert(is_aligned(addr, page_size), "Must be");
4089 return true;
4090 }
4091
4092 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
4093 size_t alignment,
4094 size_t page_size,
4095 char* req_addr,
4096 bool exec) {
4097 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
4098 assert(is_aligned(req_addr, alignment), "Must be");
4099 assert(is_aligned(req_addr, page_size), "Must be");
4100 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be");
4101 assert(_page_sizes.contains(page_size), "Must be a valid page size");
4102 assert(page_size > (size_t)os::vm_page_size(), "Must be a large page size");
4103 assert(bytes >= page_size, "Shouldn't allocate large pages for small sizes");
4104
4105 // We only end up here when at least 1 large page can be used.
4106 // If the size is not a multiple of the large page size, we
4107 // will mix the type of pages used, but in a decending order.
4108 // Start off by reserving a range of the given size that is
4109 // properly aligned. At this point no pages are committed. If
4110 // a requested address is given it will be used and it must be
4111 // aligned to both the large page size and the given alignment.
4112 // The larger of the two will be used.
4113 size_t required_alignment = MAX(page_size, alignment);
4114 char* const aligned_start = anon_mmap_aligned(req_addr, bytes, required_alignment);
4115 if (aligned_start == NULL) {
4116 return NULL;
4117 }
4118
4119 // First commit using large pages.
4120 size_t large_bytes = align_down(bytes, page_size);
4121 bool large_committed = commit_memory_special(large_bytes, page_size, aligned_start, exec);
4122
4123 if (large_committed && bytes == large_bytes) {
4124 // The size was large page aligned so no additional work is
4125 // needed even if the commit failed.
4126 return aligned_start;
4127 }
4128
4129 // The requested size requires some small pages as well.
4130 char* small_start = aligned_start + large_bytes;
4131 size_t small_size = bytes - large_bytes;
4132 if (!large_committed) {
4133 // Failed to commit large pages, so we need to unmap the
4134 // reminder of the orinal reservation.
4135 ::munmap(small_start, small_size);
4136 return NULL;
4137 }
4138
4139 // Commit the remaining bytes using small pages.
4140 bool small_committed = commit_memory_special(small_size, os::vm_page_size(), small_start, exec);
4141 if (!small_committed) {
4142 // Failed to commit the remaining size, need to unmap
4143 // the large pages part of the reservation.
4144 ::munmap(aligned_start, large_bytes);
4145 return NULL;
4146 }
4147 return aligned_start;
4148 }
4149
4150 char* os::pd_reserve_memory_special(size_t bytes, size_t alignment, size_t page_size,
4151 char* req_addr, bool exec) {
4152 assert(UseLargePages, "only for large pages");
4153
4154 char* addr;
4155 if (UseSHM) {
4156 // No support for using specific page sizes with SHM.
4157 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
4158 } else {
4159 assert(UseHugeTLBFS, "must be");
4160 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, page_size, req_addr, exec);
4161 }
4162
4163 if (addr != NULL) {
4164 if (UseNUMAInterleaving) {
4165 numa_make_global(addr, bytes);
4166 }
4167 }
4168
4169 return addr;
4170 }
4171
4172 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
4173 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
4174 return shmdt(base) == 0;
4175 }
4176
4177 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
4178 return pd_release_memory(base, bytes);
4179 }
4180
4181 bool os::pd_release_memory_special(char* base, size_t bytes) {
4182 assert(UseLargePages, "only for large pages");
4183 bool res;
4184
4185 if (UseSHM) {
4186 res = os::Linux::release_memory_special_shm(base, bytes);
4187 } else {
4188 assert(UseHugeTLBFS, "must be");
4189 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
4190 }
4191 return res;
4192 }
4193
4194 size_t os::large_page_size() {
4195 return _large_page_size;
4196 }
4197
4198 // With SysV SHM the entire memory region must be allocated as shared
4199 // memory.
4200 // HugeTLBFS allows application to commit large page memory on demand.
4201 // However, when committing memory with HugeTLBFS fails, the region
4202 // that was supposed to be committed will lose the old reservation
4203 // and allow other threads to steal that memory region. Because of this
4204 // behavior we can't commit HugeTLBFS memory.
4205 bool os::can_commit_large_page_memory() {
4206 return UseTransparentHugePages;
4207 }
4208
4209 bool os::can_execute_large_page_memory() {
4210 return UseTransparentHugePages || UseHugeTLBFS;
4211 }
4212
4213 char* os::pd_attempt_map_memory_to_file_at(char* requested_addr, size_t bytes, int file_desc) {
4214 assert(file_desc >= 0, "file_desc is not valid");
4215 char* result = pd_attempt_reserve_memory_at(requested_addr, bytes, !ExecMem);
4216 if (result != NULL) {
4217 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) {
4218 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
4219 }
4220 }
4221 return result;
4222 }
4223
4224 // Reserve memory at an arbitrary address, only if that area is
4225 // available (and not reserved for something else).
4226
4227 char* os::pd_attempt_reserve_memory_at(char* requested_addr, size_t bytes, bool exec) {
4228 // Assert only that the size is a multiple of the page size, since
4229 // that's all that mmap requires, and since that's all we really know
4230 // about at this low abstraction level. If we need higher alignment,
4231 // we can either pass an alignment to this method or verify alignment
4232 // in one of the methods further up the call chain. See bug 5044738.
4233 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
4234
4235 // Repeatedly allocate blocks until the block is allocated at the
4236 // right spot.
4237
4238 // Linux mmap allows caller to pass an address as hint; give it a try first,
4239 // if kernel honors the hint then we can return immediately.
4240 char * addr = anon_mmap(requested_addr, bytes);
4241 if (addr == requested_addr) {
4242 return requested_addr;
4243 }
4244
4245 if (addr != NULL) {
4246 // mmap() is successful but it fails to reserve at the requested address
4247 anon_munmap(addr, bytes);
4248 }
4249
4250 return NULL;
4251 }
4252
4253 // Used to convert frequent JVM_Yield() to nops
4254 bool os::dont_yield() {
4255 return DontYieldALot;
4256 }
4257
4258 // Linux CFS scheduler (since 2.6.23) does not guarantee sched_yield(2) will
4259 // actually give up the CPU. Since skip buddy (v2.6.28):
4260 //
4261 // * Sets the yielding task as skip buddy for current CPU's run queue.
4262 // * Picks next from run queue, if empty, picks a skip buddy (can be the yielding task).
4263 // * Clears skip buddies for this run queue (yielding task no longer a skip buddy).
4264 //
4265 // An alternative is calling os::naked_short_nanosleep with a small number to avoid
4266 // getting re-scheduled immediately.
4267 //
4268 void os::naked_yield() {
4269 sched_yield();
4270 }
4271
4272 ////////////////////////////////////////////////////////////////////////////////
4273 // thread priority support
4274
4275 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
4276 // only supports dynamic priority, static priority must be zero. For real-time
4277 // applications, Linux supports SCHED_RR which allows static priority (1-99).
4278 // However, for large multi-threaded applications, SCHED_RR is not only slower
4279 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
4280 // of 5 runs - Sep 2005).
4281 //
4282 // The following code actually changes the niceness of kernel-thread/LWP. It
4283 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
4284 // not the entire user process, and user level threads are 1:1 mapped to kernel
4285 // threads. It has always been the case, but could change in the future. For
4286 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
4287 // It is only used when ThreadPriorityPolicy=1 and may require system level permission
4288 // (e.g., root privilege or CAP_SYS_NICE capability).
4289
4290 int os::java_to_os_priority[CriticalPriority + 1] = {
4291 19, // 0 Entry should never be used
4292
4293 4, // 1 MinPriority
4294 3, // 2
4295 2, // 3
4296
4297 1, // 4
4298 0, // 5 NormPriority
4299 -1, // 6
4300
4301 -2, // 7
4302 -3, // 8
4303 -4, // 9 NearMaxPriority
4304
4305 -5, // 10 MaxPriority
4306
4307 -5 // 11 CriticalPriority
4308 };
4309
4310 static int prio_init() {
4311 if (ThreadPriorityPolicy == 1) {
4312 if (geteuid() != 0) {
4313 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy) && !FLAG_IS_JIMAGE_RESOURCE(ThreadPriorityPolicy)) {
4314 warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \
4315 "e.g., being the root user. If the necessary permission is not " \
4316 "possessed, changes to priority will be silently ignored.");
4317 }
4318 }
4319 }
4320 if (UseCriticalJavaThreadPriority) {
4321 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
4322 }
4323 return 0;
4324 }
4325
4326 OSReturn os::set_native_priority(Thread* thread, int newpri) {
4327 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
4328
4329 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
4330 return (ret == 0) ? OS_OK : OS_ERR;
4331 }
4332
4333 OSReturn os::get_native_priority(const Thread* const thread,
4334 int *priority_ptr) {
4335 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
4336 *priority_ptr = java_to_os_priority[NormPriority];
4337 return OS_OK;
4338 }
4339
4340 errno = 0;
4341 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
4342 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
4343 }
4344
4345 // This is the fastest way to get thread cpu time on Linux.
4346 // Returns cpu time (user+sys) for any thread, not only for current.
4347 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4348 // It might work on 2.6.10+ with a special kernel/glibc patch.
4349 // For reference, please, see IEEE Std 1003.1-2004:
4350 // http://www.unix.org/single_unix_specification
4351
4352 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4353 struct timespec tp;
4354 int status = clock_gettime(clockid, &tp);
4355 assert(status == 0, "clock_gettime error: %s", os::strerror(errno));
4356 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4357 }
4358
4359 // Determine if the vmid is the parent pid for a child in a PID namespace.
4360 // Return the namespace pid if so, otherwise -1.
4361 int os::Linux::get_namespace_pid(int vmid) {
4362 char fname[24];
4363 int retpid = -1;
4364
4365 snprintf(fname, sizeof(fname), "/proc/%d/status", vmid);
4366 FILE *fp = fopen(fname, "r");
4367
4368 if (fp) {
4369 int pid, nspid;
4370 int ret;
4371 while (!feof(fp) && !ferror(fp)) {
4372 ret = fscanf(fp, "NSpid: %d %d", &pid, &nspid);
4373 if (ret == 1) {
4374 break;
4375 }
4376 if (ret == 2) {
4377 retpid = nspid;
4378 break;
4379 }
4380 for (;;) {
4381 int ch = fgetc(fp);
4382 if (ch == EOF || ch == (int)'\n') break;
4383 }
4384 }
4385 fclose(fp);
4386 }
4387 return retpid;
4388 }
4389
4390 extern void report_error(char* file_name, int line_no, char* title,
4391 char* format, ...);
4392
4393 // Some linux distributions (notably: Alpine Linux) include the
4394 // grsecurity in the kernel. Of particular interest from a JVM perspective
4395 // is PaX (https://pax.grsecurity.net/), which adds some security features
4396 // related to page attributes. Specifically, the MPROTECT PaX functionality
4397 // (https://pax.grsecurity.net/docs/mprotect.txt) prevents dynamic
4398 // code generation by disallowing a (previously) writable page to be
4399 // marked as executable. This is, of course, exactly what HotSpot does
4400 // for both JIT compiled method, as well as for stubs, adapters, etc.
4401 //
4402 // Instead of crashing "lazily" when trying to make a page executable,
4403 // this code probes for the presence of PaX and reports the failure
4404 // eagerly.
4405 static void check_pax(void) {
4406 // Zero doesn't generate code dynamically, so no need to perform the PaX check
4407 #ifndef ZERO
4408 size_t size = os::Linux::page_size();
4409
4410 void* p = ::mmap(NULL, size, PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4411 if (p == MAP_FAILED) {
4412 log_debug(os)("os_linux.cpp: check_pax: mmap failed (%s)" , os::strerror(errno));
4413 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "failed to allocate memory for PaX check.");
4414 }
4415
4416 int res = ::mprotect(p, size, PROT_WRITE|PROT_EXEC);
4417 if (res == -1) {
4418 log_debug(os)("os_linux.cpp: check_pax: mprotect failed (%s)" , os::strerror(errno));
4419 vm_exit_during_initialization(
4420 "Failed to mark memory page as executable - check if grsecurity/PaX is enabled");
4421 }
4422
4423 ::munmap(p, size);
4424 #endif
4425 }
4426
4427 // this is called _before_ most of the global arguments have been parsed
4428 void os::init(void) {
4429 char dummy; // used to get a guess on initial stack address
4430
4431 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4432
4433 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4434 if (Linux::page_size() == -1) {
4435 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
4436 os::strerror(errno));
4437 }
4438 _page_sizes.add(Linux::page_size());
4439
4440 Linux::initialize_system_info();
4441
4442 #ifdef __GLIBC__
4443 Linux::_mallinfo = CAST_TO_FN_PTR(Linux::mallinfo_func_t, dlsym(RTLD_DEFAULT, "mallinfo"));
4444 Linux::_mallinfo2 = CAST_TO_FN_PTR(Linux::mallinfo2_func_t, dlsym(RTLD_DEFAULT, "mallinfo2"));
4445 #endif // __GLIBC__
4446
4447 os::Linux::CPUPerfTicks pticks;
4448 bool res = os::Linux::get_tick_information(&pticks, -1);
4449
4450 if (res && pticks.has_steal_ticks) {
4451 has_initial_tick_info = true;
4452 initial_total_ticks = pticks.total;
4453 initial_steal_ticks = pticks.steal;
4454 }
4455
4456 // _main_thread points to the thread that created/loaded the JVM.
4457 Linux::_main_thread = pthread_self();
4458
4459 // retrieve entry point for pthread_setname_np
4460 Linux::_pthread_setname_np =
4461 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
4462
4463 check_pax();
4464
4465 os::Posix::init();
4466
4467 initial_time_count = javaTimeNanos();
4468 }
4469
4470 // To install functions for atexit system call
4471 extern "C" {
4472 static void perfMemory_exit_helper() {
4473 perfMemory_exit();
4474 }
4475 }
4476
4477 void os::pd_init_container_support() {
4478 OSContainer::init();
4479 }
4480
4481 void os::Linux::numa_init() {
4482
4483 // Java can be invoked as
4484 // 1. Without numactl and heap will be allocated/configured on all nodes as
4485 // per the system policy.
4486 // 2. With numactl --interleave:
4487 // Use numa_get_interleave_mask(v2) API to get nodes bitmask. The same
4488 // API for membind case bitmask is reset.
4489 // Interleave is only hint and Kernel can fallback to other nodes if
4490 // no memory is available on the target nodes.
4491 // 3. With numactl --membind:
4492 // Use numa_get_membind(v2) API to get nodes bitmask. The same API for
4493 // interleave case returns bitmask of all nodes.
4494 // numa_all_nodes_ptr holds bitmask of all nodes.
4495 // numa_get_interleave_mask(v2) and numa_get_membind(v2) APIs returns correct
4496 // bitmask when externally configured to run on all or fewer nodes.
4497
4498 if (!Linux::libnuma_init()) {
4499 FLAG_SET_ERGO(UseNUMA, false);
4500 FLAG_SET_ERGO(UseNUMAInterleaving, false); // Also depends on libnuma.
4501 } else {
4502 if ((Linux::numa_max_node() < 1) || Linux::is_bound_to_single_node()) {
4503 // If there's only one node (they start from 0) or if the process
4504 // is bound explicitly to a single node using membind, disable NUMA
4505 UseNUMA = false;
4506 } else {
4507 LogTarget(Info,os) log;
4508 LogStream ls(log);
4509
4510 Linux::set_configured_numa_policy(Linux::identify_numa_policy());
4511
4512 struct bitmask* bmp = Linux::_numa_membind_bitmask;
4513 const char* numa_mode = "membind";
4514
4515 if (Linux::is_running_in_interleave_mode()) {
4516 bmp = Linux::_numa_interleave_bitmask;
4517 numa_mode = "interleave";
4518 }
4519
4520 ls.print("UseNUMA is enabled and invoked in '%s' mode."
4521 " Heap will be configured using NUMA memory nodes:", numa_mode);
4522
4523 for (int node = 0; node <= Linux::numa_max_node(); node++) {
4524 if (Linux::_numa_bitmask_isbitset(bmp, node)) {
4525 ls.print(" %d", node);
4526 }
4527 }
4528 }
4529 }
4530
4531 // When NUMA requested, not-NUMA-aware allocations default to interleaving.
4532 if (UseNUMA && !UseNUMAInterleaving) {
4533 FLAG_SET_ERGO_IF_DEFAULT(UseNUMAInterleaving, true);
4534 }
4535
4536 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
4537 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
4538 // we can make the adaptive lgrp chunk resizing work. If the user specified both
4539 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn
4540 // and disable adaptive resizing.
4541 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
4542 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, "
4543 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
4544 UseAdaptiveSizePolicy = false;
4545 UseAdaptiveNUMAChunkSizing = false;
4546 }
4547 }
4548 }
4549
4550 // this is called _after_ the global arguments have been parsed
4551 jint os::init_2(void) {
4552
4553 // This could be set after os::Posix::init() but all platforms
4554 // have to set it the same so we have to mirror Solaris.
4555 DEBUG_ONLY(os::set_mutex_init_done();)
4556
4557 os::Posix::init_2();
4558
4559 Linux::fast_thread_clock_init();
4560
4561 if (PosixSignals::init() == JNI_ERR) {
4562 return JNI_ERR;
4563 }
4564
4565 if (AdjustStackSizeForTLS) {
4566 get_minstack_init();
4567 }
4568
4569 // Check and sets minimum stack sizes against command line options
4570 if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
4571 return JNI_ERR;
4572 }
4573
4574 #if defined(IA32) && !defined(ZERO)
4575 // Need to ensure we've determined the process's initial stack to
4576 // perform the workaround
4577 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4578 workaround_expand_exec_shield_cs_limit();
4579 #else
4580 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher();
4581 if (!suppress_primordial_thread_resolution) {
4582 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4583 }
4584 #endif
4585
4586 Linux::libpthread_init();
4587 Linux::sched_getcpu_init();
4588 log_info(os)("HotSpot is running with %s, %s",
4589 Linux::libc_version(), Linux::libpthread_version());
4590
4591 if (UseNUMA || UseNUMAInterleaving) {
4592 Linux::numa_init();
4593 }
4594
4595 if (MaxFDLimit) {
4596 // set the number of file descriptors to max. print out error
4597 // if getrlimit/setrlimit fails but continue regardless.
4598 struct rlimit nbr_files;
4599 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4600 if (status != 0) {
4601 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
4602 } else {
4603 nbr_files.rlim_cur = nbr_files.rlim_max;
4604 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4605 if (status != 0) {
4606 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
4607 }
4608 }
4609 }
4610
4611 // at-exit methods are called in the reverse order of their registration.
4612 // atexit functions are called on return from main or as a result of a
4613 // call to exit(3C). There can be only 32 of these functions registered
4614 // and atexit() does not set errno.
4615
4616 if (PerfAllowAtExitRegistration) {
4617 // only register atexit functions if PerfAllowAtExitRegistration is set.
4618 // atexit functions can be delayed until process exit time, which
4619 // can be problematic for embedded VM situations. Embedded VMs should
4620 // call DestroyJavaVM() to assure that VM resources are released.
4621
4622 // note: perfMemory_exit_helper atexit function may be removed in
4623 // the future if the appropriate cleanup code can be added to the
4624 // VM_Exit VMOperation's doit method.
4625 if (atexit(perfMemory_exit_helper) != 0) {
4626 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
4627 }
4628 }
4629
4630 // initialize thread priority policy
4631 prio_init();
4632
4633 if (!FLAG_IS_DEFAULT(AllocateHeapAt)) {
4634 set_coredump_filter(DAX_SHARED_BIT);
4635 }
4636
4637 if (DumpPrivateMappingsInCore) {
4638 set_coredump_filter(FILE_BACKED_PVT_BIT);
4639 }
4640
4641 if (DumpSharedMappingsInCore) {
4642 set_coredump_filter(FILE_BACKED_SHARED_BIT);
4643 }
4644
4645 if (DumpPerfMapAtExit && FLAG_IS_DEFAULT(UseCodeCacheFlushing)) {
4646 // Disable code cache flushing to ensure the map file written at
4647 // exit contains all nmethods generated during execution.
4648 FLAG_SET_DEFAULT(UseCodeCacheFlushing, false);
4649 }
4650
4651 return JNI_OK;
4652 }
4653
4654 // older glibc versions don't have this macro (which expands to
4655 // an optimized bit-counting function) so we have to roll our own
4656 #ifndef CPU_COUNT
4657
4658 static int _cpu_count(const cpu_set_t* cpus) {
4659 int count = 0;
4660 // only look up to the number of configured processors
4661 for (int i = 0; i < os::processor_count(); i++) {
4662 if (CPU_ISSET(i, cpus)) {
4663 count++;
4664 }
4665 }
4666 return count;
4667 }
4668
4669 #define CPU_COUNT(cpus) _cpu_count(cpus)
4670
4671 #endif // CPU_COUNT
4672
4673 // Get the current number of available processors for this process.
4674 // This value can change at any time during a process's lifetime.
4675 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
4676 // If it appears there may be more than 1024 processors then we do a
4677 // dynamic check - see 6515172 for details.
4678 // If anything goes wrong we fallback to returning the number of online
4679 // processors - which can be greater than the number available to the process.
4680 static int get_active_processor_count() {
4681 // Note: keep this function, with its CPU_xx macros, *outside* the os namespace (see JDK-8289477).
4682 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
4683 cpu_set_t* cpus_p = &cpus;
4684 int cpus_size = sizeof(cpu_set_t);
4685
4686 int configured_cpus = os::processor_count(); // upper bound on available cpus
4687 int cpu_count = 0;
4688
4689 // old build platforms may not support dynamic cpu sets
4690 #ifdef CPU_ALLOC
4691
4692 // To enable easy testing of the dynamic path on different platforms we
4693 // introduce a diagnostic flag: UseCpuAllocPath
4694 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
4695 // kernel may use a mask bigger than cpu_set_t
4696 log_trace(os)("active_processor_count: using dynamic path %s"
4697 "- configured processors: %d",
4698 UseCpuAllocPath ? "(forced) " : "",
4699 configured_cpus);
4700 cpus_p = CPU_ALLOC(configured_cpus);
4701 if (cpus_p != NULL) {
4702 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
4703 // zero it just to be safe
4704 CPU_ZERO_S(cpus_size, cpus_p);
4705 }
4706 else {
4707 // failed to allocate so fallback to online cpus
4708 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4709 log_trace(os)("active_processor_count: "
4710 "CPU_ALLOC failed (%s) - using "
4711 "online processor count: %d",
4712 os::strerror(errno), online_cpus);
4713 return online_cpus;
4714 }
4715 }
4716 else {
4717 log_trace(os)("active_processor_count: using static path - configured processors: %d",
4718 configured_cpus);
4719 }
4720 #else // CPU_ALLOC
4721 // these stubs won't be executed
4722 #define CPU_COUNT_S(size, cpus) -1
4723 #define CPU_FREE(cpus)
4724
4725 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
4726 configured_cpus);
4727 #endif // CPU_ALLOC
4728
4729 // pid 0 means the current thread - which we have to assume represents the process
4730 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
4731 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
4732 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
4733 }
4734 else {
4735 cpu_count = CPU_COUNT(cpus_p);
4736 }
4737 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
4738 }
4739 else {
4740 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
4741 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
4742 "which may exceed available processors", os::strerror(errno), cpu_count);
4743 }
4744
4745 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
4746 CPU_FREE(cpus_p);
4747 }
4748
4749 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check");
4750 return cpu_count;
4751 }
4752
4753 int os::Linux::active_processor_count() {
4754 return get_active_processor_count();
4755 }
4756
4757 // Determine the active processor count from one of
4758 // three different sources:
4759 //
4760 // 1. User option -XX:ActiveProcessorCount
4761 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN)
4762 // 3. extracted from cgroup cpu subsystem (shares and quotas)
4763 //
4764 // Option 1, if specified, will always override.
4765 // If the cgroup subsystem is active and configured, we
4766 // will return the min of the cgroup and option 2 results.
4767 // This is required since tools, such as numactl, that
4768 // alter cpu affinity do not update cgroup subsystem
4769 // cpuset configuration files.
4770 int os::active_processor_count() {
4771 // User has overridden the number of active processors
4772 if (ActiveProcessorCount > 0) {
4773 log_trace(os)("active_processor_count: "
4774 "active processor count set by user : %d",
4775 ActiveProcessorCount);
4776 return ActiveProcessorCount;
4777 }
4778
4779 int active_cpus;
4780 if (OSContainer::is_containerized()) {
4781 active_cpus = OSContainer::active_processor_count();
4782 log_trace(os)("active_processor_count: determined by OSContainer: %d",
4783 active_cpus);
4784 } else {
4785 active_cpus = os::Linux::active_processor_count();
4786 }
4787
4788 return active_cpus;
4789 }
4790
4791 static bool should_warn_invalid_processor_id() {
4792 if (os::processor_count() == 1) {
4793 // Don't warn if we only have one processor
4794 return false;
4795 }
4796
4797 static volatile int warn_once = 1;
4798
4799 if (Atomic::load(&warn_once) == 0 ||
4800 Atomic::xchg(&warn_once, 0) == 0) {
4801 // Don't warn more than once
4802 return false;
4803 }
4804
4805 return true;
4806 }
4807
4808 uint os::processor_id() {
4809 const int id = Linux::sched_getcpu();
4810
4811 if (id < processor_count()) {
4812 return (uint)id;
4813 }
4814
4815 // Some environments (e.g. openvz containers and the rr debugger) incorrectly
4816 // report a processor id that is higher than the number of processors available.
4817 // This is problematic, for example, when implementing CPU-local data structures,
4818 // where the processor id is used to index into an array of length processor_count().
4819 // If this happens we return 0 here. This is is safe since we always have at least
4820 // one processor, but it's not optimal for performance if we're actually executing
4821 // in an environment with more than one processor.
4822 if (should_warn_invalid_processor_id()) {
4823 log_warning(os)("Invalid processor id reported by the operating system "
4824 "(got processor id %d, valid processor id range is 0-%d)",
4825 id, processor_count() - 1);
4826 log_warning(os)("Falling back to assuming processor id is 0. "
4827 "This could have a negative impact on performance.");
4828 }
4829
4830 return 0;
4831 }
4832
4833 void os::set_native_thread_name(const char *name) {
4834 if (Linux::_pthread_setname_np) {
4835 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
4836 snprintf(buf, sizeof(buf), "%s", name);
4837 buf[sizeof(buf) - 1] = '\0';
4838 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
4839 // ERANGE should not happen; all other errors should just be ignored.
4840 assert(rc != ERANGE, "pthread_setname_np failed");
4841 }
4842 }
4843
4844 bool os::bind_to_processor(uint processor_id) {
4845 // Not yet implemented.
4846 return false;
4847 }
4848
4849 ////////////////////////////////////////////////////////////////////////////////
4850 // debug support
4851
4852 bool os::find(address addr, outputStream* st) {
4853 Dl_info dlinfo;
4854 memset(&dlinfo, 0, sizeof(dlinfo));
4855 if (dladdr(addr, &dlinfo) != 0) {
4856 st->print(PTR_FORMAT ": ", p2i(addr));
4857 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
4858 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
4859 p2i(addr) - p2i(dlinfo.dli_saddr));
4860 } else if (dlinfo.dli_fbase != NULL) {
4861 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
4862 } else {
4863 st->print("<absolute address>");
4864 }
4865 if (dlinfo.dli_fname != NULL) {
4866 st->print(" in %s", dlinfo.dli_fname);
4867 }
4868 if (dlinfo.dli_fbase != NULL) {
4869 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
4870 }
4871 st->cr();
4872
4873 if (Verbose) {
4874 // decode some bytes around the PC
4875 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
4876 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
4877 address lowest = (address) dlinfo.dli_sname;
4878 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4879 if (begin < lowest) begin = lowest;
4880 Dl_info dlinfo2;
4881 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
4882 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
4883 end = (address) dlinfo2.dli_saddr;
4884 }
4885 Disassembler::decode(begin, end, st);
4886 }
4887 return true;
4888 }
4889 return false;
4890 }
4891
4892 ////////////////////////////////////////////////////////////////////////////////
4893 // misc
4894
4895 // This does not do anything on Linux. This is basically a hook for being
4896 // able to use structured exception handling (thread-local exception filters)
4897 // on, e.g., Win32.
4898 void
4899 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
4900 JavaCallArguments* args, JavaThread* thread) {
4901 f(value, method, args, thread);
4902 }
4903
4904 // This code originates from JDK's sysOpen and open64_w
4905 // from src/solaris/hpi/src/system_md.c
4906
4907 int os::open(const char *path, int oflag, int mode) {
4908 if (strlen(path) > MAX_PATH - 1) {
4909 errno = ENAMETOOLONG;
4910 return -1;
4911 }
4912
4913 // All file descriptors that are opened in the Java process and not
4914 // specifically destined for a subprocess should have the close-on-exec
4915 // flag set. If we don't set it, then careless 3rd party native code
4916 // might fork and exec without closing all appropriate file descriptors
4917 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
4918 // turn might:
4919 //
4920 // - cause end-of-file to fail to be detected on some file
4921 // descriptors, resulting in mysterious hangs, or
4922 //
4923 // - might cause an fopen in the subprocess to fail on a system
4924 // suffering from bug 1085341.
4925 //
4926 // (Yes, the default setting of the close-on-exec flag is a Unix
4927 // design flaw)
4928 //
4929 // See:
4930 // 1085341: 32-bit stdio routines should support file descriptors >255
4931 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
4932 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
4933 //
4934 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
4935 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
4936 // because it saves a system call and removes a small window where the flag
4937 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
4938 // and we fall back to using FD_CLOEXEC (see below).
4939 #ifdef O_CLOEXEC
4940 oflag |= O_CLOEXEC;
4941 #endif
4942
4943 int fd = ::open64(path, oflag, mode);
4944 if (fd == -1) return -1;
4945
4946 //If the open succeeded, the file might still be a directory
4947 {
4948 struct stat64 buf64;
4949 int ret = ::fstat64(fd, &buf64);
4950 int st_mode = buf64.st_mode;
4951
4952 if (ret != -1) {
4953 if ((st_mode & S_IFMT) == S_IFDIR) {
4954 errno = EISDIR;
4955 ::close(fd);
4956 return -1;
4957 }
4958 } else {
4959 ::close(fd);
4960 return -1;
4961 }
4962 }
4963
4964 #ifdef FD_CLOEXEC
4965 // Validate that the use of the O_CLOEXEC flag on open above worked.
4966 // With recent kernels, we will perform this check exactly once.
4967 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
4968 if (!O_CLOEXEC_is_known_to_work) {
4969 int flags = ::fcntl(fd, F_GETFD);
4970 if (flags != -1) {
4971 if ((flags & FD_CLOEXEC) != 0)
4972 O_CLOEXEC_is_known_to_work = 1;
4973 else
4974 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
4975 }
4976 }
4977 #endif
4978
4979 return fd;
4980 }
4981
4982
4983 // create binary file, rewriting existing file if required
4984 int os::create_binary_file(const char* path, bool rewrite_existing) {
4985 int oflags = O_WRONLY | O_CREAT;
4986 oflags |= rewrite_existing ? O_TRUNC : O_EXCL;
4987 return ::open64(path, oflags, S_IREAD | S_IWRITE);
4988 }
4989
4990 // return current position of file pointer
4991 jlong os::current_file_offset(int fd) {
4992 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
4993 }
4994
4995 // move file pointer to the specified offset
4996 jlong os::seek_to_file_offset(int fd, jlong offset) {
4997 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
4998 }
4999
5000 // This code originates from JDK's sysAvailable
5001 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5002
5003 int os::available(int fd, jlong *bytes) {
5004 jlong cur, end;
5005 int mode;
5006 struct stat64 buf64;
5007
5008 if (::fstat64(fd, &buf64) >= 0) {
5009 mode = buf64.st_mode;
5010 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5011 int n;
5012 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5013 *bytes = n;
5014 return 1;
5015 }
5016 }
5017 }
5018 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5019 return 0;
5020 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5021 return 0;
5022 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5023 return 0;
5024 }
5025 *bytes = end - cur;
5026 return 1;
5027 }
5028
5029 // Map a block of memory.
5030 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5031 char *addr, size_t bytes, bool read_only,
5032 bool allow_exec) {
5033 int prot;
5034 int flags = MAP_PRIVATE;
5035
5036 if (read_only) {
5037 prot = PROT_READ;
5038 } else {
5039 prot = PROT_READ | PROT_WRITE;
5040 }
5041
5042 if (allow_exec) {
5043 prot |= PROT_EXEC;
5044 }
5045
5046 if (addr != NULL) {
5047 flags |= MAP_FIXED;
5048 }
5049
5050 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5051 fd, file_offset);
5052 if (mapped_address == MAP_FAILED) {
5053 return NULL;
5054 }
5055 return mapped_address;
5056 }
5057
5058
5059 // Remap a block of memory.
5060 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5061 char *addr, size_t bytes, bool read_only,
5062 bool allow_exec) {
5063 // same as map_memory() on this OS
5064 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5065 allow_exec);
5066 }
5067
5068
5069 // Unmap a block of memory.
5070 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5071 return munmap(addr, bytes) == 0;
5072 }
5073
5074 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5075
5076 static jlong fast_cpu_time(Thread *thread) {
5077 clockid_t clockid;
5078 int rc = os::Linux::pthread_getcpuclockid(thread->osthread()->pthread_id(),
5079 &clockid);
5080 if (rc == 0) {
5081 return os::Linux::fast_thread_cpu_time(clockid);
5082 } else {
5083 // It's possible to encounter a terminated native thread that failed
5084 // to detach itself from the VM - which should result in ESRCH.
5085 assert_status(rc == ESRCH, rc, "pthread_getcpuclockid failed");
5086 return -1;
5087 }
5088 }
5089
5090 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5091 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5092 // of a thread.
5093 //
5094 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5095 // the fast estimate available on the platform.
5096
5097 jlong os::current_thread_cpu_time() {
5098 if (os::Linux::supports_fast_thread_cpu_time()) {
5099 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5100 } else {
5101 // return user + sys since the cost is the same
5102 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5103 }
5104 }
5105
5106 jlong os::thread_cpu_time(Thread* thread) {
5107 // consistent with what current_thread_cpu_time() returns
5108 if (os::Linux::supports_fast_thread_cpu_time()) {
5109 return fast_cpu_time(thread);
5110 } else {
5111 return slow_thread_cpu_time(thread, true /* user + sys */);
5112 }
5113 }
5114
5115 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5116 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5117 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5118 } else {
5119 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5120 }
5121 }
5122
5123 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5124 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5125 return fast_cpu_time(thread);
5126 } else {
5127 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5128 }
5129 }
5130
5131 // -1 on error.
5132 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5133 pid_t tid = thread->osthread()->thread_id();
5134 char *s;
5135 char stat[2048];
5136 int statlen;
5137 char proc_name[64];
5138 int count;
5139 long sys_time, user_time;
5140 char cdummy;
5141 int idummy;
5142 long ldummy;
5143 FILE *fp;
5144
5145 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5146 fp = fopen(proc_name, "r");
5147 if (fp == NULL) return -1;
5148 statlen = fread(stat, 1, 2047, fp);
5149 stat[statlen] = '\0';
5150 fclose(fp);
5151
5152 // Skip pid and the command string. Note that we could be dealing with
5153 // weird command names, e.g. user could decide to rename java launcher
5154 // to "java 1.4.2 :)", then the stat file would look like
5155 // 1234 (java 1.4.2 :)) R ... ...
5156 // We don't really need to know the command string, just find the last
5157 // occurrence of ")" and then start parsing from there. See bug 4726580.
5158 s = strrchr(stat, ')');
5159 if (s == NULL) return -1;
5160
5161 // Skip blank chars
5162 do { s++; } while (s && isspace(*s));
5163
5164 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5165 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5166 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5167 &user_time, &sys_time);
5168 if (count != 13) return -1;
5169 if (user_sys_cpu_time) {
5170 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5171 } else {
5172 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5173 }
5174 }
5175
5176 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5177 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5178 info_ptr->may_skip_backward = false; // elapsed time not wall time
5179 info_ptr->may_skip_forward = false; // elapsed time not wall time
5180 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5181 }
5182
5183 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5184 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5185 info_ptr->may_skip_backward = false; // elapsed time not wall time
5186 info_ptr->may_skip_forward = false; // elapsed time not wall time
5187 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5188 }
5189
5190 bool os::is_thread_cpu_time_supported() {
5191 return true;
5192 }
5193
5194 // System loadavg support. Returns -1 if load average cannot be obtained.
5195 // Linux doesn't yet have a (official) notion of processor sets,
5196 // so just return the system wide load average.
5197 int os::loadavg(double loadavg[], int nelem) {
5198 return ::getloadavg(loadavg, nelem);
5199 }
5200
5201 void os::pause() {
5202 char filename[MAX_PATH];
5203 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5204 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5205 } else {
5206 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5207 }
5208
5209 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5210 if (fd != -1) {
5211 struct stat buf;
5212 ::close(fd);
5213 while (::stat(filename, &buf) == 0) {
5214 (void)::poll(NULL, 0, 100);
5215 }
5216 } else {
5217 jio_fprintf(stderr,
5218 "Could not open pause file '%s', continuing immediately.\n", filename);
5219 }
5220 }
5221
5222 // Get the default path to the core file
5223 // Returns the length of the string
5224 int os::get_core_path(char* buffer, size_t bufferSize) {
5225 /*
5226 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
5227 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
5228 */
5229 const int core_pattern_len = 129;
5230 char core_pattern[core_pattern_len] = {0};
5231
5232 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
5233 if (core_pattern_file == -1) {
5234 return -1;
5235 }
5236
5237 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
5238 ::close(core_pattern_file);
5239 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
5240 return -1;
5241 }
5242 if (core_pattern[ret-1] == '\n') {
5243 core_pattern[ret-1] = '\0';
5244 } else {
5245 core_pattern[ret] = '\0';
5246 }
5247
5248 // Replace the %p in the core pattern with the process id. NOTE: we do this
5249 // only if the pattern doesn't start with "|", and we support only one %p in
5250 // the pattern.
5251 char *pid_pos = strstr(core_pattern, "%p");
5252 const char* tail = (pid_pos != NULL) ? (pid_pos + 2) : ""; // skip over the "%p"
5253 int written;
5254
5255 if (core_pattern[0] == '/') {
5256 if (pid_pos != NULL) {
5257 *pid_pos = '\0';
5258 written = jio_snprintf(buffer, bufferSize, "%s%d%s", core_pattern,
5259 current_process_id(), tail);
5260 } else {
5261 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
5262 }
5263 } else {
5264 char cwd[PATH_MAX];
5265
5266 const char* p = get_current_directory(cwd, PATH_MAX);
5267 if (p == NULL) {
5268 return -1;
5269 }
5270
5271 if (core_pattern[0] == '|') {
5272 written = jio_snprintf(buffer, bufferSize,
5273 "\"%s\" (or dumping to %s/core.%d)",
5274 &core_pattern[1], p, current_process_id());
5275 } else if (pid_pos != NULL) {
5276 *pid_pos = '\0';
5277 written = jio_snprintf(buffer, bufferSize, "%s/%s%d%s", p, core_pattern,
5278 current_process_id(), tail);
5279 } else {
5280 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
5281 }
5282 }
5283
5284 if (written < 0) {
5285 return -1;
5286 }
5287
5288 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
5289 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
5290
5291 if (core_uses_pid_file != -1) {
5292 char core_uses_pid = 0;
5293 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
5294 ::close(core_uses_pid_file);
5295
5296 if (core_uses_pid == '1') {
5297 jio_snprintf(buffer + written, bufferSize - written,
5298 ".%d", current_process_id());
5299 }
5300 }
5301 }
5302
5303 return strlen(buffer);
5304 }
5305
5306 bool os::start_debugging(char *buf, int buflen) {
5307 int len = (int)strlen(buf);
5308 char *p = &buf[len];
5309
5310 jio_snprintf(p, buflen-len,
5311 "\n\n"
5312 "Do you want to debug the problem?\n\n"
5313 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
5314 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
5315 "Otherwise, press RETURN to abort...",
5316 os::current_process_id(), os::current_process_id(),
5317 os::current_thread_id(), os::current_thread_id());
5318
5319 bool yes = os::message_box("Unexpected Error", buf);
5320
5321 if (yes) {
5322 // yes, user asked VM to launch debugger
5323 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
5324 os::current_process_id(), os::current_process_id());
5325
5326 os::fork_and_exec(buf);
5327 yes = false;
5328 }
5329 return yes;
5330 }
5331
5332
5333 // Java/Compiler thread:
5334 //
5335 // Low memory addresses
5336 // P0 +------------------------+
5337 // | |\ Java thread created by VM does not have glibc
5338 // | glibc guard page | - guard page, attached Java thread usually has
5339 // | |/ 1 glibc guard page.
5340 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
5341 // | |\
5342 // | HotSpot Guard Pages | - red, yellow and reserved pages
5343 // | |/
5344 // +------------------------+ StackOverflow::stack_reserved_zone_base()
5345 // | |\
5346 // | Normal Stack | -
5347 // | |/
5348 // P2 +------------------------+ Thread::stack_base()
5349 //
5350 // Non-Java thread:
5351 //
5352 // Low memory addresses
5353 // P0 +------------------------+
5354 // | |\
5355 // | glibc guard page | - usually 1 page
5356 // | |/
5357 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
5358 // | |\
5359 // | Normal Stack | -
5360 // | |/
5361 // P2 +------------------------+ Thread::stack_base()
5362 //
5363 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size
5364 // returned from pthread_attr_getstack().
5365 // ** Due to NPTL implementation error, linux takes the glibc guard page out
5366 // of the stack size given in pthread_attr. We work around this for
5367 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.)
5368 //
5369 #ifndef ZERO
5370 static void current_stack_region(address * bottom, size_t * size) {
5371 if (os::is_primordial_thread()) {
5372 // primordial thread needs special handling because pthread_getattr_np()
5373 // may return bogus value.
5374 *bottom = os::Linux::initial_thread_stack_bottom();
5375 *size = os::Linux::initial_thread_stack_size();
5376 } else {
5377 pthread_attr_t attr;
5378
5379 int rslt = pthread_getattr_np(pthread_self(), &attr);
5380
5381 // JVM needs to know exact stack location, abort if it fails
5382 if (rslt != 0) {
5383 if (rslt == ENOMEM) {
5384 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
5385 } else {
5386 fatal("pthread_getattr_np failed with error = %d", rslt);
5387 }
5388 }
5389
5390 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
5391 fatal("Cannot locate current stack attributes!");
5392 }
5393
5394 // Work around NPTL stack guard error.
5395 size_t guard_size = 0;
5396 rslt = pthread_attr_getguardsize(&attr, &guard_size);
5397 if (rslt != 0) {
5398 fatal("pthread_attr_getguardsize failed with error = %d", rslt);
5399 }
5400 *bottom += guard_size;
5401 *size -= guard_size;
5402
5403 pthread_attr_destroy(&attr);
5404
5405 }
5406 assert(os::current_stack_pointer() >= *bottom &&
5407 os::current_stack_pointer() < *bottom + *size, "just checking");
5408 }
5409
5410 address os::current_stack_base() {
5411 address bottom;
5412 size_t size;
5413 current_stack_region(&bottom, &size);
5414 return (bottom + size);
5415 }
5416
5417 size_t os::current_stack_size() {
5418 // This stack size includes the usable stack and HotSpot guard pages
5419 // (for the threads that have Hotspot guard pages).
5420 address bottom;
5421 size_t size;
5422 current_stack_region(&bottom, &size);
5423 return size;
5424 }
5425 #endif
5426
5427 static inline struct timespec get_mtime(const char* filename) {
5428 struct stat st;
5429 int ret = os::stat(filename, &st);
5430 assert(ret == 0, "failed to stat() file '%s': %s", filename, os::strerror(errno));
5431 return st.st_mtim;
5432 }
5433
5434 int os::compare_file_modified_times(const char* file1, const char* file2) {
5435 struct timespec filetime1 = get_mtime(file1);
5436 struct timespec filetime2 = get_mtime(file2);
5437 int diff = filetime1.tv_sec - filetime2.tv_sec;
5438 if (diff == 0) {
5439 return filetime1.tv_nsec - filetime2.tv_nsec;
5440 }
5441 return diff;
5442 }
5443
5444 bool os::supports_map_sync() {
5445 return true;
5446 }
5447
5448 void os::print_memory_mappings(char* addr, size_t bytes, outputStream* st) {
5449 // Note: all ranges are "[..)"
5450 unsigned long long start = (unsigned long long)addr;
5451 unsigned long long end = start + bytes;
5452 FILE* f = ::fopen("/proc/self/maps", "r");
5453 int num_found = 0;
5454 if (f != NULL) {
5455 st->print_cr("Range [%llx-%llx) contains: ", start, end);
5456 char line[512];
5457 while(fgets(line, sizeof(line), f) == line) {
5458 unsigned long long segment_start = 0;
5459 unsigned long long segment_end = 0;
5460 if (::sscanf(line, "%llx-%llx", &segment_start, &segment_end) == 2) {
5461 // Lets print out every range which touches ours.
5462 if (segment_start < end && segment_end > start) {
5463 num_found ++;
5464 st->print("%s", line); // line includes \n
5465 }
5466 }
5467 }
5468 ::fclose(f);
5469 if (num_found == 0) {
5470 st->print_cr("nothing.");
5471 }
5472 st->cr();
5473 }
5474 }
--- EOF ---