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 }