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