1 /* 2 * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 // no precompiled headers 26 #include "jvm.h" 27 #include "classfile/classLoader.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "code/icBuffer.hpp" 31 #include "code/vtableStubs.hpp" 32 #include "compiler/compileBroker.hpp" 33 #include "compiler/disassembler.hpp" 34 #include "interpreter/interpreter.hpp" 35 #include "logging/log.hpp" 36 #include "logging/logStream.hpp" 37 #include "memory/allocation.inline.hpp" 38 #include "memory/filemap.hpp" 39 #include "oops/oop.inline.hpp" 40 #include "os_linux.inline.hpp" 41 #include "os_posix.inline.hpp" 42 #include "os_share_linux.hpp" 43 #include "osContainer_linux.hpp" 44 #include "prims/jniFastGetField.hpp" 45 #include "prims/jvm_misc.hpp" 46 #include "runtime/arguments.hpp" 47 #include "runtime/atomic.hpp" 48 #include "runtime/extendedPC.hpp" 49 #include "runtime/globals.hpp" 50 #include "runtime/interfaceSupport.inline.hpp" 51 #include "runtime/init.hpp" 52 #include "runtime/java.hpp" 53 #include "runtime/javaCalls.hpp" 54 #include "runtime/mutexLocker.hpp" 55 #include "runtime/objectMonitor.hpp" 56 #include "runtime/osThread.hpp" 57 #include "runtime/perfMemory.hpp" 58 #include "runtime/sharedRuntime.hpp" 59 #include "runtime/statSampler.hpp" 60 #include "runtime/stubRoutines.hpp" 61 #include "runtime/thread.inline.hpp" 62 #include "runtime/threadCritical.hpp" 63 #include "runtime/threadSMR.hpp" 64 #include "runtime/timer.hpp" 65 #include "runtime/vm_version.hpp" 66 #include "semaphore_posix.hpp" 67 #include "services/attachListener.hpp" 68 #include "services/memTracker.hpp" 69 #include "services/runtimeService.hpp" 70 #include "utilities/align.hpp" 71 #include "utilities/decoder.hpp" 72 #include "utilities/defaultStream.hpp" 73 #include "utilities/events.hpp" 74 #include "utilities/elfFile.hpp" 75 #include "utilities/growableArray.hpp" 76 #include "utilities/macros.hpp" 77 #include "utilities/powerOfTwo.hpp" 78 #include "utilities/vmError.hpp" 79 80 // put OS-includes here 81 # include <sys/types.h> 82 # include <sys/mman.h> 83 # include <sys/stat.h> 84 # include <sys/select.h> 85 # include <pthread.h> 86 # include <signal.h> 87 # include <endian.h> 88 # include <errno.h> 89 # include <dlfcn.h> 90 # include <stdio.h> 91 # include <unistd.h> 92 # include <sys/resource.h> 93 # include <pthread.h> 94 # include <sys/stat.h> 95 # include <sys/time.h> 96 # include <sys/times.h> 97 # include <sys/utsname.h> 98 # include <sys/socket.h> 99 # include <sys/wait.h> 100 # include <pwd.h> 101 # include <poll.h> 102 # include <fcntl.h> 103 # include <string.h> 104 # include <syscall.h> 105 # include <sys/sysinfo.h> 106 # include <gnu/libc-version.h> 107 # include <sys/ipc.h> 108 # include <sys/shm.h> 109 # include <link.h> 110 # include <stdint.h> 111 # include <inttypes.h> 112 # include <sys/ioctl.h> 113 # include <linux/elf-em.h> 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 enum CoredumpFilterBit { 137 FILE_BACKED_PVT_BIT = 1 << 2, 138 FILE_BACKED_SHARED_BIT = 1 << 3, 139 LARGEPAGES_BIT = 1 << 6, 140 DAX_SHARED_BIT = 1 << 8 141 }; 142 143 //////////////////////////////////////////////////////////////////////////////// 144 // global variables 145 julong os::Linux::_physical_memory = 0; 146 147 address os::Linux::_initial_thread_stack_bottom = NULL; 148 uintptr_t os::Linux::_initial_thread_stack_size = 0; 149 150 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 151 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 152 pthread_t os::Linux::_main_thread; 153 int os::Linux::_page_size = -1; 154 bool os::Linux::_supports_fast_thread_cpu_time = false; 155 const char * os::Linux::_glibc_version = NULL; 156 const char * os::Linux::_libpthread_version = NULL; 157 size_t os::Linux::_default_large_page_size = 0; 158 159 static jlong initial_time_count=0; 160 161 static int clock_tics_per_sec = 100; 162 163 // If the VM might have been created on the primordial thread, we need to resolve the 164 // primordial thread stack bounds and check if the current thread might be the 165 // primordial thread in places. If we know that the primordial thread is never used, 166 // such as when the VM was created by one of the standard java launchers, we can 167 // avoid this 168 static bool suppress_primordial_thread_resolution = false; 169 170 // For diagnostics to print a message once. see run_periodic_checks 171 static sigset_t check_signal_done; 172 static bool check_signals = true; 173 174 // Signal number used to suspend/resume a thread 175 176 // do not use any signal number less than SIGSEGV, see 4355769 177 static int SR_signum = SIGUSR2; 178 sigset_t SR_sigset; 179 180 // utility functions 181 182 static int SR_initialize(); 183 184 julong os::available_memory() { 185 return Linux::available_memory(); 186 } 187 188 julong os::Linux::available_memory() { 189 // values in struct sysinfo are "unsigned long" 190 struct sysinfo si; 191 julong avail_mem; 192 193 if (OSContainer::is_containerized()) { 194 jlong mem_limit, mem_usage; 195 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) { 196 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 197 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 198 } 199 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) { 200 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage); 201 } 202 if (mem_limit > 0 && mem_usage > 0 ) { 203 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0; 204 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem); 205 return avail_mem; 206 } 207 } 208 209 sysinfo(&si); 210 avail_mem = (julong)si.freeram * si.mem_unit; 211 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem); 212 return avail_mem; 213 } 214 215 julong os::physical_memory() { 216 jlong phys_mem = 0; 217 if (OSContainer::is_containerized()) { 218 jlong mem_limit; 219 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) { 220 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit); 221 return mem_limit; 222 } 223 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 224 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 225 } 226 227 phys_mem = Linux::physical_memory(); 228 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem); 229 return phys_mem; 230 } 231 232 static uint64_t initial_total_ticks = 0; 233 static uint64_t initial_steal_ticks = 0; 234 static bool has_initial_tick_info = false; 235 236 static void next_line(FILE *f) { 237 int c; 238 do { 239 c = fgetc(f); 240 } while (c != '\n' && c != EOF); 241 } 242 243 bool os::Linux::get_tick_information(CPUPerfTicks* pticks, int which_logical_cpu) { 244 FILE* fh; 245 uint64_t userTicks, niceTicks, systemTicks, idleTicks; 246 // since at least kernel 2.6 : iowait: time waiting for I/O to complete 247 // irq: time servicing interrupts; softirq: time servicing softirqs 248 uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0; 249 // steal (since kernel 2.6.11): time spent in other OS when running in a virtualized environment 250 uint64_t stealTicks = 0; 251 // guest (since kernel 2.6.24): time spent running a virtual CPU for guest OS under the 252 // control of the Linux kernel 253 uint64_t guestNiceTicks = 0; 254 int logical_cpu = -1; 255 const int required_tickinfo_count = (which_logical_cpu == -1) ? 4 : 5; 256 int n; 257 258 memset(pticks, 0, sizeof(CPUPerfTicks)); 259 260 if ((fh = fopen("/proc/stat", "r")) == NULL) { 261 return false; 262 } 263 264 if (which_logical_cpu == -1) { 265 n = fscanf(fh, "cpu " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 266 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 267 UINT64_FORMAT " " UINT64_FORMAT " ", 268 &userTicks, &niceTicks, &systemTicks, &idleTicks, 269 &iowTicks, &irqTicks, &sirqTicks, 270 &stealTicks, &guestNiceTicks); 271 } else { 272 // Move to next line 273 next_line(fh); 274 275 // find the line for requested cpu faster to just iterate linefeeds? 276 for (int i = 0; i < which_logical_cpu; i++) { 277 next_line(fh); 278 } 279 280 n = fscanf(fh, "cpu%u " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 281 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 282 UINT64_FORMAT " " UINT64_FORMAT " ", 283 &logical_cpu, &userTicks, &niceTicks, 284 &systemTicks, &idleTicks, &iowTicks, &irqTicks, &sirqTicks, 285 &stealTicks, &guestNiceTicks); 286 } 287 288 fclose(fh); 289 if (n < required_tickinfo_count || logical_cpu != which_logical_cpu) { 290 return false; 291 } 292 pticks->used = userTicks + niceTicks; 293 pticks->usedKernel = systemTicks + irqTicks + sirqTicks; 294 pticks->total = userTicks + niceTicks + systemTicks + idleTicks + 295 iowTicks + irqTicks + sirqTicks + stealTicks + guestNiceTicks; 296 297 if (n > required_tickinfo_count + 3) { 298 pticks->steal = stealTicks; 299 pticks->has_steal_ticks = true; 300 } else { 301 pticks->steal = 0; 302 pticks->has_steal_ticks = false; 303 } 304 305 return true; 306 } 307 308 // Return true if user is running as root. 309 310 bool os::have_special_privileges() { 311 static bool init = false; 312 static bool privileges = false; 313 if (!init) { 314 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 315 init = true; 316 } 317 return privileges; 318 } 319 320 321 #ifndef SYS_gettid 322 // i386: 224, ia64: 1105, amd64: 186, sparc 143 323 #ifdef __ia64__ 324 #define SYS_gettid 1105 325 #else 326 #ifdef __i386__ 327 #define SYS_gettid 224 328 #else 329 #ifdef __amd64__ 330 #define SYS_gettid 186 331 #else 332 #ifdef __sparc__ 333 #define SYS_gettid 143 334 #else 335 #error define gettid for the arch 336 #endif 337 #endif 338 #endif 339 #endif 340 #endif 341 342 343 // pid_t gettid() 344 // 345 // Returns the kernel thread id of the currently running thread. Kernel 346 // thread id is used to access /proc. 347 pid_t os::Linux::gettid() { 348 int rslt = syscall(SYS_gettid); 349 assert(rslt != -1, "must be."); // old linuxthreads implementation? 350 return (pid_t)rslt; 351 } 352 353 // Most versions of linux have a bug where the number of processors are 354 // determined by looking at the /proc file system. In a chroot environment, 355 // the system call returns 1. 356 static bool unsafe_chroot_detected = false; 357 static const char *unstable_chroot_error = "/proc file system not found.\n" 358 "Java may be unstable running multithreaded in a chroot " 359 "environment on Linux when /proc filesystem is not mounted."; 360 361 void os::Linux::initialize_system_info() { 362 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 363 if (processor_count() == 1) { 364 pid_t pid = os::Linux::gettid(); 365 char fname[32]; 366 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 367 FILE *fp = fopen(fname, "r"); 368 if (fp == NULL) { 369 unsafe_chroot_detected = true; 370 } else { 371 fclose(fp); 372 } 373 } 374 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 375 assert(processor_count() > 0, "linux error"); 376 } 377 378 void os::init_system_properties_values() { 379 // The next steps are taken in the product version: 380 // 381 // Obtain the JAVA_HOME value from the location of libjvm.so. 382 // This library should be located at: 383 // <JAVA_HOME>/lib/{client|server}/libjvm.so. 384 // 385 // If "/jre/lib/" appears at the right place in the path, then we 386 // assume libjvm.so is installed in a JDK and we use this path. 387 // 388 // Otherwise exit with message: "Could not create the Java virtual machine." 389 // 390 // The following extra steps are taken in the debugging version: 391 // 392 // If "/jre/lib/" does NOT appear at the right place in the path 393 // instead of exit check for $JAVA_HOME environment variable. 394 // 395 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 396 // then we append a fake suffix "hotspot/libjvm.so" to this path so 397 // it looks like libjvm.so is installed there 398 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 399 // 400 // Otherwise exit. 401 // 402 // Important note: if the location of libjvm.so changes this 403 // code needs to be changed accordingly. 404 405 // See ld(1): 406 // The linker uses the following search paths to locate required 407 // shared libraries: 408 // 1: ... 409 // ... 410 // 7: The default directories, normally /lib and /usr/lib. 411 #ifndef OVERRIDE_LIBPATH 412 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390) 413 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 414 #else 415 #define DEFAULT_LIBPATH "/lib:/usr/lib" 416 #endif 417 #else 418 #define DEFAULT_LIBPATH OVERRIDE_LIBPATH 419 #endif 420 421 // Base path of extensions installed on the system. 422 #define SYS_EXT_DIR "/usr/java/packages" 423 #define EXTENSIONS_DIR "/lib/ext" 424 425 // Buffer that fits several sprintfs. 426 // Note that the space for the colon and the trailing null are provided 427 // by the nulls included by the sizeof operator. 428 const size_t bufsize = 429 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 430 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 431 char *buf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 432 433 // sysclasspath, java_home, dll_dir 434 { 435 char *pslash; 436 os::jvm_path(buf, bufsize); 437 438 // Found the full path to libjvm.so. 439 // Now cut the path to <java_home>/jre if we can. 440 pslash = strrchr(buf, '/'); 441 if (pslash != NULL) { 442 *pslash = '\0'; // Get rid of /libjvm.so. 443 } 444 pslash = strrchr(buf, '/'); 445 if (pslash != NULL) { 446 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 447 } 448 Arguments::set_dll_dir(buf); 449 450 if (pslash != NULL) { 451 pslash = strrchr(buf, '/'); 452 if (pslash != NULL) { 453 *pslash = '\0'; // Get rid of /lib. 454 } 455 } 456 Arguments::set_java_home(buf); 457 if (!set_boot_path('/', ':')) { 458 vm_exit_during_initialization("Failed setting boot class path.", NULL); 459 } 460 } 461 462 // Where to look for native libraries. 463 // 464 // Note: Due to a legacy implementation, most of the library path 465 // is set in the launcher. This was to accomodate linking restrictions 466 // on legacy Linux implementations (which are no longer supported). 467 // Eventually, all the library path setting will be done here. 468 // 469 // However, to prevent the proliferation of improperly built native 470 // libraries, the new path component /usr/java/packages is added here. 471 // Eventually, all the library path setting will be done here. 472 { 473 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 474 // should always exist (until the legacy problem cited above is 475 // addressed). 476 const char *v = ::getenv("LD_LIBRARY_PATH"); 477 const char *v_colon = ":"; 478 if (v == NULL) { v = ""; v_colon = ""; } 479 // That's +1 for the colon and +1 for the trailing '\0'. 480 char *ld_library_path = NEW_C_HEAP_ARRAY(char, 481 strlen(v) + 1 + 482 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1, 483 mtInternal); 484 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon); 485 Arguments::set_library_path(ld_library_path); 486 FREE_C_HEAP_ARRAY(char, ld_library_path); 487 } 488 489 // Extensions directories. 490 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 491 Arguments::set_ext_dirs(buf); 492 493 FREE_C_HEAP_ARRAY(char, buf); 494 495 #undef DEFAULT_LIBPATH 496 #undef SYS_EXT_DIR 497 #undef EXTENSIONS_DIR 498 } 499 500 //////////////////////////////////////////////////////////////////////////////// 501 // breakpoint support 502 503 void os::breakpoint() { 504 BREAKPOINT; 505 } 506 507 extern "C" void breakpoint() { 508 // use debugger to set breakpoint here 509 } 510 511 //////////////////////////////////////////////////////////////////////////////// 512 // signal support 513 514 debug_only(static bool signal_sets_initialized = false); 515 static sigset_t unblocked_sigs, vm_sigs; 516 517 void os::Linux::signal_sets_init() { 518 // Should also have an assertion stating we are still single-threaded. 519 assert(!signal_sets_initialized, "Already initialized"); 520 // Fill in signals that are necessarily unblocked for all threads in 521 // the VM. Currently, we unblock the following signals: 522 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 523 // by -Xrs (=ReduceSignalUsage)); 524 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 525 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 526 // the dispositions or masks wrt these signals. 527 // Programs embedding the VM that want to use the above signals for their 528 // own purposes must, at this time, use the "-Xrs" option to prevent 529 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 530 // (See bug 4345157, and other related bugs). 531 // In reality, though, unblocking these signals is really a nop, since 532 // these signals are not blocked by default. 533 sigemptyset(&unblocked_sigs); 534 sigaddset(&unblocked_sigs, SIGILL); 535 sigaddset(&unblocked_sigs, SIGSEGV); 536 sigaddset(&unblocked_sigs, SIGBUS); 537 sigaddset(&unblocked_sigs, SIGFPE); 538 #if defined(PPC64) 539 sigaddset(&unblocked_sigs, SIGTRAP); 540 #endif 541 sigaddset(&unblocked_sigs, SR_signum); 542 543 if (!ReduceSignalUsage) { 544 if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 545 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 546 } 547 if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 548 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 549 } 550 if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 551 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 552 } 553 } 554 // Fill in signals that are blocked by all but the VM thread. 555 sigemptyset(&vm_sigs); 556 if (!ReduceSignalUsage) { 557 sigaddset(&vm_sigs, BREAK_SIGNAL); 558 } 559 debug_only(signal_sets_initialized = true); 560 561 } 562 563 // These are signals that are unblocked while a thread is running Java. 564 // (For some reason, they get blocked by default.) 565 sigset_t* os::Linux::unblocked_signals() { 566 assert(signal_sets_initialized, "Not initialized"); 567 return &unblocked_sigs; 568 } 569 570 // These are the signals that are blocked while a (non-VM) thread is 571 // running Java. Only the VM thread handles these signals. 572 sigset_t* os::Linux::vm_signals() { 573 assert(signal_sets_initialized, "Not initialized"); 574 return &vm_sigs; 575 } 576 577 void os::Linux::hotspot_sigmask(Thread* thread) { 578 579 //Save caller's signal mask before setting VM signal mask 580 sigset_t caller_sigmask; 581 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 582 583 OSThread* osthread = thread->osthread(); 584 osthread->set_caller_sigmask(caller_sigmask); 585 586 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 587 588 if (!ReduceSignalUsage) { 589 if (thread->is_VM_thread()) { 590 // Only the VM thread handles BREAK_SIGNAL ... 591 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 592 } else { 593 // ... all other threads block BREAK_SIGNAL 594 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 595 } 596 } 597 } 598 599 ////////////////////////////////////////////////////////////////////////////// 600 // detecting pthread library 601 602 void os::Linux::libpthread_init() { 603 // Save glibc and pthread version strings. 604 #if !defined(_CS_GNU_LIBC_VERSION) || \ 605 !defined(_CS_GNU_LIBPTHREAD_VERSION) 606 #error "glibc too old (< 2.3.2)" 607 #endif 608 609 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 610 assert(n > 0, "cannot retrieve glibc version"); 611 char *str = (char *)malloc(n, mtInternal); 612 confstr(_CS_GNU_LIBC_VERSION, str, n); 613 os::Linux::set_glibc_version(str); 614 615 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 616 assert(n > 0, "cannot retrieve pthread version"); 617 str = (char *)malloc(n, mtInternal); 618 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 619 os::Linux::set_libpthread_version(str); 620 } 621 622 ///////////////////////////////////////////////////////////////////////////// 623 // thread stack expansion 624 625 // os::Linux::manually_expand_stack() takes care of expanding the thread 626 // stack. Note that this is normally not needed: pthread stacks allocate 627 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 628 // committed. Therefore it is not necessary to expand the stack manually. 629 // 630 // Manually expanding the stack was historically needed on LinuxThreads 631 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 632 // it is kept to deal with very rare corner cases: 633 // 634 // For one, user may run the VM on an own implementation of threads 635 // whose stacks are - like the old LinuxThreads - implemented using 636 // mmap(MAP_GROWSDOWN). 637 // 638 // Also, this coding may be needed if the VM is running on the primordial 639 // thread. Normally we avoid running on the primordial thread; however, 640 // user may still invoke the VM on the primordial thread. 641 // 642 // The following historical comment describes the details about running 643 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 644 645 646 // Force Linux kernel to expand current thread stack. If "bottom" is close 647 // to the stack guard, caller should block all signals. 648 // 649 // MAP_GROWSDOWN: 650 // A special mmap() flag that is used to implement thread stacks. It tells 651 // kernel that the memory region should extend downwards when needed. This 652 // allows early versions of LinuxThreads to only mmap the first few pages 653 // when creating a new thread. Linux kernel will automatically expand thread 654 // stack as needed (on page faults). 655 // 656 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 657 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 658 // region, it's hard to tell if the fault is due to a legitimate stack 659 // access or because of reading/writing non-exist memory (e.g. buffer 660 // overrun). As a rule, if the fault happens below current stack pointer, 661 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 662 // application (see Linux kernel fault.c). 663 // 664 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 665 // stack overflow detection. 666 // 667 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 668 // not use MAP_GROWSDOWN. 669 // 670 // To get around the problem and allow stack banging on Linux, we need to 671 // manually expand thread stack after receiving the SIGSEGV. 672 // 673 // There are two ways to expand thread stack to address "bottom", we used 674 // both of them in JVM before 1.5: 675 // 1. adjust stack pointer first so that it is below "bottom", and then 676 // touch "bottom" 677 // 2. mmap() the page in question 678 // 679 // Now alternate signal stack is gone, it's harder to use 2. For instance, 680 // if current sp is already near the lower end of page 101, and we need to 681 // call mmap() to map page 100, it is possible that part of the mmap() frame 682 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 683 // That will destroy the mmap() frame and cause VM to crash. 684 // 685 // The following code works by adjusting sp first, then accessing the "bottom" 686 // page to force a page fault. Linux kernel will then automatically expand the 687 // stack mapping. 688 // 689 // _expand_stack_to() assumes its frame size is less than page size, which 690 // should always be true if the function is not inlined. 691 692 static void NOINLINE _expand_stack_to(address bottom) { 693 address sp; 694 size_t size; 695 volatile char *p; 696 697 // Adjust bottom to point to the largest address within the same page, it 698 // gives us a one-page buffer if alloca() allocates slightly more memory. 699 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size()); 700 bottom += os::Linux::page_size() - 1; 701 702 // sp might be slightly above current stack pointer; if that's the case, we 703 // will alloca() a little more space than necessary, which is OK. Don't use 704 // os::current_stack_pointer(), as its result can be slightly below current 705 // stack pointer, causing us to not alloca enough to reach "bottom". 706 sp = (address)&sp; 707 708 if (sp > bottom) { 709 size = sp - bottom; 710 p = (volatile char *)alloca(size); 711 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 712 p[0] = '\0'; 713 } 714 } 715 716 void os::Linux::expand_stack_to(address bottom) { 717 _expand_stack_to(bottom); 718 } 719 720 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 721 assert(t!=NULL, "just checking"); 722 assert(t->osthread()->expanding_stack(), "expand should be set"); 723 724 if (t->is_in_usable_stack(addr)) { 725 sigset_t mask_all, old_sigset; 726 sigfillset(&mask_all); 727 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 728 _expand_stack_to(addr); 729 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 730 return true; 731 } 732 return false; 733 } 734 735 ////////////////////////////////////////////////////////////////////////////// 736 // create new thread 737 738 // Thread start routine for all newly created threads 739 static void *thread_native_entry(Thread *thread) { 740 741 thread->record_stack_base_and_size(); 742 743 // Try to randomize the cache line index of hot stack frames. 744 // This helps when threads of the same stack traces evict each other's 745 // cache lines. The threads can be either from the same JVM instance, or 746 // from different JVM instances. The benefit is especially true for 747 // processors with hyperthreading technology. 748 static int counter = 0; 749 int pid = os::current_process_id(); 750 alloca(((pid ^ counter++) & 7) * 128); 751 752 thread->initialize_thread_current(); 753 754 OSThread* osthread = thread->osthread(); 755 Monitor* sync = osthread->startThread_lock(); 756 757 osthread->set_thread_id(os::current_thread_id()); 758 759 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 760 os::current_thread_id(), (uintx) pthread_self()); 761 762 if (UseNUMA) { 763 int lgrp_id = os::numa_get_group_id(); 764 if (lgrp_id != -1) { 765 thread->set_lgrp_id(lgrp_id); 766 } 767 } 768 // initialize signal mask for this thread 769 os::Linux::hotspot_sigmask(thread); 770 771 // initialize floating point control register 772 os::Linux::init_thread_fpu_state(); 773 774 // handshaking with parent thread 775 { 776 MutexLocker ml(sync, Mutex::_no_safepoint_check_flag); 777 778 // notify parent thread 779 osthread->set_state(INITIALIZED); 780 sync->notify_all(); 781 782 // wait until os::start_thread() 783 while (osthread->get_state() == INITIALIZED) { 784 sync->wait_without_safepoint_check(); 785 } 786 } 787 788 assert(osthread->pthread_id() != 0, "pthread_id was not set as expected"); 789 790 // call one more level start routine 791 thread->call_run(); 792 793 // Note: at this point the thread object may already have deleted itself. 794 // Prevent dereferencing it from here on out. 795 thread = NULL; 796 797 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 798 os::current_thread_id(), (uintx) pthread_self()); 799 800 return 0; 801 } 802 803 // On Linux, glibc places static TLS blocks (for __thread variables) on 804 // the thread stack. This decreases the stack size actually available 805 // to threads. 806 // 807 // For large static TLS sizes, this may cause threads to malfunction due 808 // to insufficient stack space. This is a well-known issue in glibc: 809 // http://sourceware.org/bugzilla/show_bug.cgi?id=11787. 810 // 811 // As a workaround, we call a private but assumed-stable glibc function, 812 // __pthread_get_minstack() to obtain the minstack size and derive the 813 // static TLS size from it. We then increase the user requested stack 814 // size by this TLS size. 815 // 816 // Due to compatibility concerns, this size adjustment is opt-in and 817 // controlled via AdjustStackSizeForTLS. 818 typedef size_t (*GetMinStack)(const pthread_attr_t *attr); 819 820 GetMinStack _get_minstack_func = NULL; 821 822 static void get_minstack_init() { 823 _get_minstack_func = 824 (GetMinStack)dlsym(RTLD_DEFAULT, "__pthread_get_minstack"); 825 log_info(os, thread)("Lookup of __pthread_get_minstack %s", 826 _get_minstack_func == NULL ? "failed" : "succeeded"); 827 } 828 829 // Returns the size of the static TLS area glibc puts on thread stacks. 830 // The value is cached on first use, which occurs when the first thread 831 // is created during VM initialization. 832 static size_t get_static_tls_area_size(const pthread_attr_t *attr) { 833 size_t tls_size = 0; 834 if (_get_minstack_func != NULL) { 835 // Obtain the pthread minstack size by calling __pthread_get_minstack. 836 size_t minstack_size = _get_minstack_func(attr); 837 838 // Remove non-TLS area size included in minstack size returned 839 // by __pthread_get_minstack() to get the static TLS size. 840 // In glibc before 2.27, minstack size includes guard_size. 841 // In glibc 2.27 and later, guard_size is automatically added 842 // to the stack size by pthread_create and is no longer included 843 // in minstack size. In both cases, the guard_size is taken into 844 // account, so there is no need to adjust the result for that. 845 // 846 // Although __pthread_get_minstack() is a private glibc function, 847 // it is expected to have a stable behavior across future glibc 848 // versions while glibc still allocates the static TLS blocks off 849 // the stack. Following is glibc 2.28 __pthread_get_minstack(): 850 // 851 // size_t 852 // __pthread_get_minstack (const pthread_attr_t *attr) 853 // { 854 // return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN; 855 // } 856 // 857 // 858 // The following 'minstack_size > os::vm_page_size() + PTHREAD_STACK_MIN' 859 // if check is done for precaution. 860 if (minstack_size > (size_t)os::vm_page_size() + PTHREAD_STACK_MIN) { 861 tls_size = minstack_size - os::vm_page_size() - PTHREAD_STACK_MIN; 862 } 863 } 864 865 log_info(os, thread)("Stack size adjustment for TLS is " SIZE_FORMAT, 866 tls_size); 867 return tls_size; 868 } 869 870 bool os::create_thread(Thread* thread, ThreadType thr_type, 871 size_t req_stack_size) { 872 assert(thread->osthread() == NULL, "caller responsible"); 873 874 // Allocate the OSThread object 875 OSThread* osthread = new OSThread(NULL, NULL); 876 if (osthread == NULL) { 877 return false; 878 } 879 880 // set the correct thread state 881 osthread->set_thread_type(thr_type); 882 883 // Initial state is ALLOCATED but not INITIALIZED 884 osthread->set_state(ALLOCATED); 885 886 thread->set_osthread(osthread); 887 888 // init thread attributes 889 pthread_attr_t attr; 890 pthread_attr_init(&attr); 891 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 892 893 // Calculate stack size if it's not specified by caller. 894 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size); 895 // In glibc versions prior to 2.7 the guard size mechanism 896 // is not implemented properly. The posix standard requires adding 897 // the size of the guard pages to the stack size, instead Linux 898 // takes the space out of 'stacksize'. Thus we adapt the requested 899 // stack_size by the size of the guard pages to mimick proper 900 // behaviour. However, be careful not to end up with a size 901 // of zero due to overflow. Don't add the guard page in that case. 902 size_t guard_size = os::Linux::default_guard_size(thr_type); 903 // Configure glibc guard page. Must happen before calling 904 // get_static_tls_area_size(), which uses the guard_size. 905 pthread_attr_setguardsize(&attr, guard_size); 906 907 size_t stack_adjust_size = 0; 908 if (AdjustStackSizeForTLS) { 909 // Adjust the stack_size for on-stack TLS - see get_static_tls_area_size(). 910 stack_adjust_size += get_static_tls_area_size(&attr); 911 } else { 912 stack_adjust_size += guard_size; 913 } 914 915 stack_adjust_size = align_up(stack_adjust_size, os::vm_page_size()); 916 if (stack_size <= SIZE_MAX - stack_adjust_size) { 917 stack_size += stack_adjust_size; 918 } 919 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned"); 920 921 int status = pthread_attr_setstacksize(&attr, stack_size); 922 assert_status(status == 0, status, "pthread_attr_setstacksize"); 923 924 ThreadState state; 925 926 { 927 pthread_t tid; 928 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread); 929 930 char buf[64]; 931 if (ret == 0) { 932 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 933 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 934 } else { 935 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 936 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 937 // Log some OS information which might explain why creating the thread failed. 938 log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads()); 939 LogStream st(Log(os, thread)::info()); 940 os::Posix::print_rlimit_info(&st); 941 os::print_memory_info(&st); 942 os::Linux::print_proc_sys_info(&st); 943 os::Linux::print_container_info(&st); 944 } 945 946 pthread_attr_destroy(&attr); 947 948 if (ret != 0) { 949 // Need to clean up stuff we've allocated so far 950 thread->set_osthread(NULL); 951 delete osthread; 952 return false; 953 } 954 955 // Store pthread info into the OSThread 956 osthread->set_pthread_id(tid); 957 958 // Wait until child thread is either initialized or aborted 959 { 960 Monitor* sync_with_child = osthread->startThread_lock(); 961 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag); 962 while ((state = osthread->get_state()) == ALLOCATED) { 963 sync_with_child->wait_without_safepoint_check(); 964 } 965 } 966 } 967 968 // Aborted due to thread limit being reached 969 if (state == ZOMBIE) { 970 thread->set_osthread(NULL); 971 delete osthread; 972 return false; 973 } 974 975 // The thread is returned suspended (in state INITIALIZED), 976 // and is started higher up in the call chain 977 assert(state == INITIALIZED, "race condition"); 978 return true; 979 } 980 981 ///////////////////////////////////////////////////////////////////////////// 982 // attach existing thread 983 984 // bootstrap the main thread 985 bool os::create_main_thread(JavaThread* thread) { 986 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 987 return create_attached_thread(thread); 988 } 989 990 bool os::create_attached_thread(JavaThread* thread) { 991 #ifdef ASSERT 992 thread->verify_not_published(); 993 #endif 994 995 // Allocate the OSThread object 996 OSThread* osthread = new OSThread(NULL, NULL); 997 998 if (osthread == NULL) { 999 return false; 1000 } 1001 1002 // Store pthread info into the OSThread 1003 osthread->set_thread_id(os::Linux::gettid()); 1004 osthread->set_pthread_id(::pthread_self()); 1005 1006 // initialize floating point control register 1007 os::Linux::init_thread_fpu_state(); 1008 1009 // Initial thread state is RUNNABLE 1010 osthread->set_state(RUNNABLE); 1011 1012 thread->set_osthread(osthread); 1013 1014 if (UseNUMA) { 1015 int lgrp_id = os::numa_get_group_id(); 1016 if (lgrp_id != -1) { 1017 thread->set_lgrp_id(lgrp_id); 1018 } 1019 } 1020 1021 if (os::is_primordial_thread()) { 1022 // If current thread is primordial thread, its stack is mapped on demand, 1023 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 1024 // the entire stack region to avoid SEGV in stack banging. 1025 // It is also useful to get around the heap-stack-gap problem on SuSE 1026 // kernel (see 4821821 for details). We first expand stack to the top 1027 // of yellow zone, then enable stack yellow zone (order is significant, 1028 // enabling yellow zone first will crash JVM on SuSE Linux), so there 1029 // is no gap between the last two virtual memory regions. 1030 1031 JavaThread *jt = (JavaThread *)thread; 1032 address addr = jt->stack_reserved_zone_base(); 1033 assert(addr != NULL, "initialization problem?"); 1034 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 1035 1036 osthread->set_expanding_stack(); 1037 os::Linux::manually_expand_stack(jt, addr); 1038 osthread->clear_expanding_stack(); 1039 } 1040 1041 // initialize signal mask for this thread 1042 // and save the caller's signal mask 1043 os::Linux::hotspot_sigmask(thread); 1044 1045 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 1046 os::current_thread_id(), (uintx) pthread_self()); 1047 1048 return true; 1049 } 1050 1051 void os::pd_start_thread(Thread* thread) { 1052 OSThread * osthread = thread->osthread(); 1053 assert(osthread->get_state() != INITIALIZED, "just checking"); 1054 Monitor* sync_with_child = osthread->startThread_lock(); 1055 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag); 1056 sync_with_child->notify(); 1057 } 1058 1059 // Free Linux resources related to the OSThread 1060 void os::free_thread(OSThread* osthread) { 1061 assert(osthread != NULL, "osthread not set"); 1062 1063 // We are told to free resources of the argument thread, 1064 // but we can only really operate on the current thread. 1065 assert(Thread::current()->osthread() == osthread, 1066 "os::free_thread but not current thread"); 1067 1068 #ifdef ASSERT 1069 sigset_t current; 1070 sigemptyset(¤t); 1071 pthread_sigmask(SIG_SETMASK, NULL, ¤t); 1072 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!"); 1073 #endif 1074 1075 // Restore caller's signal mask 1076 sigset_t sigmask = osthread->caller_sigmask(); 1077 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1078 1079 delete osthread; 1080 } 1081 1082 ////////////////////////////////////////////////////////////////////////////// 1083 // primordial thread 1084 1085 // Check if current thread is the primordial thread, similar to Solaris thr_main. 1086 bool os::is_primordial_thread(void) { 1087 if (suppress_primordial_thread_resolution) { 1088 return false; 1089 } 1090 char dummy; 1091 // If called before init complete, thread stack bottom will be null. 1092 // Can be called if fatal error occurs before initialization. 1093 if (os::Linux::initial_thread_stack_bottom() == NULL) return false; 1094 assert(os::Linux::initial_thread_stack_bottom() != NULL && 1095 os::Linux::initial_thread_stack_size() != 0, 1096 "os::init did not locate primordial thread's stack region"); 1097 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() && 1098 (address)&dummy < os::Linux::initial_thread_stack_bottom() + 1099 os::Linux::initial_thread_stack_size()) { 1100 return true; 1101 } else { 1102 return false; 1103 } 1104 } 1105 1106 // Find the virtual memory area that contains addr 1107 static bool find_vma(address addr, address* vma_low, address* vma_high) { 1108 FILE *fp = fopen("/proc/self/maps", "r"); 1109 if (fp) { 1110 address low, high; 1111 while (!feof(fp)) { 1112 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1113 if (low <= addr && addr < high) { 1114 if (vma_low) *vma_low = low; 1115 if (vma_high) *vma_high = high; 1116 fclose(fp); 1117 return true; 1118 } 1119 } 1120 for (;;) { 1121 int ch = fgetc(fp); 1122 if (ch == EOF || ch == (int)'\n') break; 1123 } 1124 } 1125 fclose(fp); 1126 } 1127 return false; 1128 } 1129 1130 // Locate primordial thread stack. This special handling of primordial thread stack 1131 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 1132 // bogus value for the primordial process thread. While the launcher has created 1133 // the VM in a new thread since JDK 6, we still have to allow for the use of the 1134 // JNI invocation API from a primordial thread. 1135 void os::Linux::capture_initial_stack(size_t max_size) { 1136 1137 // max_size is either 0 (which means accept OS default for thread stacks) or 1138 // a user-specified value known to be at least the minimum needed. If we 1139 // are actually on the primordial thread we can make it appear that we have a 1140 // smaller max_size stack by inserting the guard pages at that location. But we 1141 // cannot do anything to emulate a larger stack than what has been provided by 1142 // the OS or threading library. In fact if we try to use a stack greater than 1143 // what is set by rlimit then we will crash the hosting process. 1144 1145 // Maximum stack size is the easy part, get it from RLIMIT_STACK. 1146 // If this is "unlimited" then it will be a huge value. 1147 struct rlimit rlim; 1148 getrlimit(RLIMIT_STACK, &rlim); 1149 size_t stack_size = rlim.rlim_cur; 1150 1151 // 6308388: a bug in ld.so will relocate its own .data section to the 1152 // lower end of primordial stack; reduce ulimit -s value a little bit 1153 // so we won't install guard page on ld.so's data section. 1154 // But ensure we don't underflow the stack size - allow 1 page spare 1155 if (stack_size >= (size_t)(3 * page_size())) { 1156 stack_size -= 2 * page_size(); 1157 } 1158 1159 // Try to figure out where the stack base (top) is. This is harder. 1160 // 1161 // When an application is started, glibc saves the initial stack pointer in 1162 // a global variable "__libc_stack_end", which is then used by system 1163 // libraries. __libc_stack_end should be pretty close to stack top. The 1164 // variable is available since the very early days. However, because it is 1165 // a private interface, it could disappear in the future. 1166 // 1167 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1168 // to __libc_stack_end, it is very close to stack top, but isn't the real 1169 // stack top. Note that /proc may not exist if VM is running as a chroot 1170 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1171 // /proc/<pid>/stat could change in the future (though unlikely). 1172 // 1173 // We try __libc_stack_end first. If that doesn't work, look for 1174 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1175 // as a hint, which should work well in most cases. 1176 1177 uintptr_t stack_start; 1178 1179 // try __libc_stack_end first 1180 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1181 if (p && *p) { 1182 stack_start = *p; 1183 } else { 1184 // see if we can get the start_stack field from /proc/self/stat 1185 FILE *fp; 1186 int pid; 1187 char state; 1188 int ppid; 1189 int pgrp; 1190 int session; 1191 int nr; 1192 int tpgrp; 1193 unsigned long flags; 1194 unsigned long minflt; 1195 unsigned long cminflt; 1196 unsigned long majflt; 1197 unsigned long cmajflt; 1198 unsigned long utime; 1199 unsigned long stime; 1200 long cutime; 1201 long cstime; 1202 long prio; 1203 long nice; 1204 long junk; 1205 long it_real; 1206 uintptr_t start; 1207 uintptr_t vsize; 1208 intptr_t rss; 1209 uintptr_t rsslim; 1210 uintptr_t scodes; 1211 uintptr_t ecode; 1212 int i; 1213 1214 // Figure what the primordial thread stack base is. Code is inspired 1215 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1216 // followed by command name surrounded by parentheses, state, etc. 1217 char stat[2048]; 1218 int statlen; 1219 1220 fp = fopen("/proc/self/stat", "r"); 1221 if (fp) { 1222 statlen = fread(stat, 1, 2047, fp); 1223 stat[statlen] = '\0'; 1224 fclose(fp); 1225 1226 // Skip pid and the command string. Note that we could be dealing with 1227 // weird command names, e.g. user could decide to rename java launcher 1228 // to "java 1.4.2 :)", then the stat file would look like 1229 // 1234 (java 1.4.2 :)) R ... ... 1230 // We don't really need to know the command string, just find the last 1231 // occurrence of ")" and then start parsing from there. See bug 4726580. 1232 char * s = strrchr(stat, ')'); 1233 1234 i = 0; 1235 if (s) { 1236 // Skip blank chars 1237 do { s++; } while (s && isspace(*s)); 1238 1239 #define _UFM UINTX_FORMAT 1240 #define _DFM INTX_FORMAT 1241 1242 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1243 // 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 1244 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, 1245 &state, // 3 %c 1246 &ppid, // 4 %d 1247 &pgrp, // 5 %d 1248 &session, // 6 %d 1249 &nr, // 7 %d 1250 &tpgrp, // 8 %d 1251 &flags, // 9 %lu 1252 &minflt, // 10 %lu 1253 &cminflt, // 11 %lu 1254 &majflt, // 12 %lu 1255 &cmajflt, // 13 %lu 1256 &utime, // 14 %lu 1257 &stime, // 15 %lu 1258 &cutime, // 16 %ld 1259 &cstime, // 17 %ld 1260 &prio, // 18 %ld 1261 &nice, // 19 %ld 1262 &junk, // 20 %ld 1263 &it_real, // 21 %ld 1264 &start, // 22 UINTX_FORMAT 1265 &vsize, // 23 UINTX_FORMAT 1266 &rss, // 24 INTX_FORMAT 1267 &rsslim, // 25 UINTX_FORMAT 1268 &scodes, // 26 UINTX_FORMAT 1269 &ecode, // 27 UINTX_FORMAT 1270 &stack_start); // 28 UINTX_FORMAT 1271 } 1272 1273 #undef _UFM 1274 #undef _DFM 1275 1276 if (i != 28 - 2) { 1277 assert(false, "Bad conversion from /proc/self/stat"); 1278 // product mode - assume we are the primordial thread, good luck in the 1279 // embedded case. 1280 warning("Can't detect primordial thread stack location - bad conversion"); 1281 stack_start = (uintptr_t) &rlim; 1282 } 1283 } else { 1284 // For some reason we can't open /proc/self/stat (for example, running on 1285 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1286 // most cases, so don't abort: 1287 warning("Can't detect primordial thread stack location - no /proc/self/stat"); 1288 stack_start = (uintptr_t) &rlim; 1289 } 1290 } 1291 1292 // Now we have a pointer (stack_start) very close to the stack top, the 1293 // next thing to do is to figure out the exact location of stack top. We 1294 // can find out the virtual memory area that contains stack_start by 1295 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1296 // and its upper limit is the real stack top. (again, this would fail if 1297 // running inside chroot, because /proc may not exist.) 1298 1299 uintptr_t stack_top; 1300 address low, high; 1301 if (find_vma((address)stack_start, &low, &high)) { 1302 // success, "high" is the true stack top. (ignore "low", because initial 1303 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1304 stack_top = (uintptr_t)high; 1305 } else { 1306 // failed, likely because /proc/self/maps does not exist 1307 warning("Can't detect primordial thread stack location - find_vma failed"); 1308 // best effort: stack_start is normally within a few pages below the real 1309 // stack top, use it as stack top, and reduce stack size so we won't put 1310 // guard page outside stack. 1311 stack_top = stack_start; 1312 stack_size -= 16 * page_size(); 1313 } 1314 1315 // stack_top could be partially down the page so align it 1316 stack_top = align_up(stack_top, page_size()); 1317 1318 // Allowed stack value is minimum of max_size and what we derived from rlimit 1319 if (max_size > 0) { 1320 _initial_thread_stack_size = MIN2(max_size, stack_size); 1321 } else { 1322 // Accept the rlimit max, but if stack is unlimited then it will be huge, so 1323 // clamp it at 8MB as we do on Solaris 1324 _initial_thread_stack_size = MIN2(stack_size, 8*M); 1325 } 1326 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size()); 1327 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1328 1329 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!"); 1330 1331 if (log_is_enabled(Info, os, thread)) { 1332 // See if we seem to be on primordial process thread 1333 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) && 1334 uintptr_t(&rlim) < stack_top; 1335 1336 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: " 1337 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT, 1338 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K, 1339 stack_top, intptr_t(_initial_thread_stack_bottom)); 1340 } 1341 } 1342 1343 //////////////////////////////////////////////////////////////////////////////// 1344 // time support 1345 1346 #ifndef SUPPORTS_CLOCK_MONOTONIC 1347 #error "Build platform doesn't support clock_gettime and related functionality" 1348 #endif 1349 1350 // Time since start-up in seconds to a fine granularity. 1351 // Used by VMSelfDestructTimer and the MemProfiler. 1352 double os::elapsedTime() { 1353 1354 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1355 } 1356 1357 jlong os::elapsed_counter() { 1358 return javaTimeNanos() - initial_time_count; 1359 } 1360 1361 jlong os::elapsed_frequency() { 1362 return NANOSECS_PER_SEC; // nanosecond resolution 1363 } 1364 1365 bool os::supports_vtime() { return true; } 1366 1367 double os::elapsedVTime() { 1368 struct rusage usage; 1369 int retval = getrusage(RUSAGE_THREAD, &usage); 1370 if (retval == 0) { 1371 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); 1372 } else { 1373 // better than nothing, but not much 1374 return elapsedTime(); 1375 } 1376 } 1377 1378 jlong os::javaTimeMillis() { 1379 if (os::Posix::supports_clock_gettime()) { 1380 struct timespec ts; 1381 int status = os::Posix::clock_gettime(CLOCK_REALTIME, &ts); 1382 assert_status(status == 0, status, "gettime error"); 1383 return jlong(ts.tv_sec) * MILLIUNITS + 1384 jlong(ts.tv_nsec) / NANOUNITS_PER_MILLIUNIT; 1385 } else { 1386 timeval time; 1387 int status = gettimeofday(&time, NULL); 1388 assert(status != -1, "linux error"); 1389 return jlong(time.tv_sec) * MILLIUNITS + 1390 jlong(time.tv_usec) / (MICROUNITS / MILLIUNITS); 1391 } 1392 } 1393 1394 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1395 if (os::Posix::supports_clock_gettime()) { 1396 struct timespec ts; 1397 int status = os::Posix::clock_gettime(CLOCK_REALTIME, &ts); 1398 assert_status(status == 0, status, "gettime error"); 1399 seconds = jlong(ts.tv_sec); 1400 nanos = jlong(ts.tv_nsec); 1401 } else { 1402 timeval time; 1403 int status = gettimeofday(&time, NULL); 1404 assert(status != -1, "linux error"); 1405 seconds = jlong(time.tv_sec); 1406 nanos = jlong(time.tv_usec) * (NANOUNITS / MICROUNITS); 1407 } 1408 } 1409 1410 void os::Linux::fast_thread_clock_init() { 1411 if (!UseLinuxPosixThreadCPUClocks) { 1412 return; 1413 } 1414 clockid_t clockid; 1415 struct timespec tp; 1416 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1417 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1418 1419 // Switch to using fast clocks for thread cpu time if 1420 // the clock_getres() returns 0 error code. 1421 // Note, that some kernels may support the current thread 1422 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1423 // returned by the pthread_getcpuclockid(). 1424 // If the fast Posix clocks are supported then the clock_getres() 1425 // must return at least tp.tv_sec == 0 which means a resolution 1426 // better than 1 sec. This is extra check for reliability. 1427 1428 if (pthread_getcpuclockid_func && 1429 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1430 os::Posix::clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1431 _supports_fast_thread_cpu_time = true; 1432 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1433 } 1434 } 1435 1436 jlong os::javaTimeNanos() { 1437 if (os::supports_monotonic_clock()) { 1438 struct timespec tp; 1439 int status = os::Posix::clock_gettime(CLOCK_MONOTONIC, &tp); 1440 assert(status == 0, "gettime error"); 1441 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1442 return result; 1443 } else { 1444 timeval time; 1445 int status = gettimeofday(&time, NULL); 1446 assert(status != -1, "linux error"); 1447 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1448 return 1000 * usecs; 1449 } 1450 } 1451 1452 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1453 if (os::supports_monotonic_clock()) { 1454 info_ptr->max_value = ALL_64_BITS; 1455 1456 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1457 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1458 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1459 } else { 1460 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1461 info_ptr->max_value = ALL_64_BITS; 1462 1463 // gettimeofday is a real time clock so it skips 1464 info_ptr->may_skip_backward = true; 1465 info_ptr->may_skip_forward = true; 1466 } 1467 1468 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1469 } 1470 1471 // Return the real, user, and system times in seconds from an 1472 // arbitrary fixed point in the past. 1473 bool os::getTimesSecs(double* process_real_time, 1474 double* process_user_time, 1475 double* process_system_time) { 1476 struct tms ticks; 1477 clock_t real_ticks = times(&ticks); 1478 1479 if (real_ticks == (clock_t) (-1)) { 1480 return false; 1481 } else { 1482 double ticks_per_second = (double) clock_tics_per_sec; 1483 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1484 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1485 *process_real_time = ((double) real_ticks) / ticks_per_second; 1486 1487 return true; 1488 } 1489 } 1490 1491 1492 char * os::local_time_string(char *buf, size_t buflen) { 1493 struct tm t; 1494 time_t long_time; 1495 time(&long_time); 1496 localtime_r(&long_time, &t); 1497 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1498 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1499 t.tm_hour, t.tm_min, t.tm_sec); 1500 return buf; 1501 } 1502 1503 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1504 return localtime_r(clock, res); 1505 } 1506 1507 //////////////////////////////////////////////////////////////////////////////// 1508 // runtime exit support 1509 1510 // Note: os::shutdown() might be called very early during initialization, or 1511 // called from signal handler. Before adding something to os::shutdown(), make 1512 // sure it is async-safe and can handle partially initialized VM. 1513 void os::shutdown() { 1514 1515 // allow PerfMemory to attempt cleanup of any persistent resources 1516 perfMemory_exit(); 1517 1518 // needs to remove object in file system 1519 AttachListener::abort(); 1520 1521 // flush buffered output, finish log files 1522 ostream_abort(); 1523 1524 // Check for abort hook 1525 abort_hook_t abort_hook = Arguments::abort_hook(); 1526 if (abort_hook != NULL) { 1527 abort_hook(); 1528 } 1529 1530 } 1531 1532 // Note: os::abort() might be called very early during initialization, or 1533 // called from signal handler. Before adding something to os::abort(), make 1534 // sure it is async-safe and can handle partially initialized VM. 1535 void os::abort(bool dump_core, void* siginfo, const void* context) { 1536 os::shutdown(); 1537 if (dump_core) { 1538 if (DumpPrivateMappingsInCore) { 1539 ClassLoader::close_jrt_image(); 1540 } 1541 ::abort(); // dump core 1542 } 1543 1544 ::exit(1); 1545 } 1546 1547 // Die immediately, no exit hook, no abort hook, no cleanup. 1548 // Dump a core file, if possible, for debugging. 1549 void os::die() { 1550 if (TestUnresponsiveErrorHandler && !CreateCoredumpOnCrash) { 1551 // For TimeoutInErrorHandlingTest.java, we just kill the VM 1552 // and don't take the time to generate a core file. 1553 os::signal_raise(SIGKILL); 1554 } else { 1555 ::abort(); 1556 } 1557 } 1558 1559 // thread_id is kernel thread id (similar to Solaris LWP id) 1560 intx os::current_thread_id() { return os::Linux::gettid(); } 1561 int os::current_process_id() { 1562 return ::getpid(); 1563 } 1564 1565 // DLL functions 1566 1567 const char* os::dll_file_extension() { return ".so"; } 1568 1569 // This must be hard coded because it's the system's temporary 1570 // directory not the java application's temp directory, ala java.io.tmpdir. 1571 const char* os::get_temp_directory() { return "/tmp"; } 1572 1573 static bool file_exists(const char* filename) { 1574 struct stat statbuf; 1575 if (filename == NULL || strlen(filename) == 0) { 1576 return false; 1577 } 1578 return os::stat(filename, &statbuf) == 0; 1579 } 1580 1581 // check if addr is inside libjvm.so 1582 bool os::address_is_in_vm(address addr) { 1583 static address libjvm_base_addr; 1584 Dl_info dlinfo; 1585 1586 if (libjvm_base_addr == NULL) { 1587 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1588 libjvm_base_addr = (address)dlinfo.dli_fbase; 1589 } 1590 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1591 } 1592 1593 if (dladdr((void *)addr, &dlinfo) != 0) { 1594 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1595 } 1596 1597 return false; 1598 } 1599 1600 bool os::dll_address_to_function_name(address addr, char *buf, 1601 int buflen, int *offset, 1602 bool demangle) { 1603 // buf is not optional, but offset is optional 1604 assert(buf != NULL, "sanity check"); 1605 1606 Dl_info dlinfo; 1607 1608 if (dladdr((void*)addr, &dlinfo) != 0) { 1609 // see if we have a matching symbol 1610 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1611 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1612 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1613 } 1614 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1615 return true; 1616 } 1617 // no matching symbol so try for just file info 1618 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1619 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1620 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1621 return true; 1622 } 1623 } 1624 } 1625 1626 buf[0] = '\0'; 1627 if (offset != NULL) *offset = -1; 1628 return false; 1629 } 1630 1631 struct _address_to_library_name { 1632 address addr; // input : memory address 1633 size_t buflen; // size of fname 1634 char* fname; // output: library name 1635 address base; // library base addr 1636 }; 1637 1638 static int address_to_library_name_callback(struct dl_phdr_info *info, 1639 size_t size, void *data) { 1640 int i; 1641 bool found = false; 1642 address libbase = NULL; 1643 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1644 1645 // iterate through all loadable segments 1646 for (i = 0; i < info->dlpi_phnum; i++) { 1647 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1648 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1649 // base address of a library is the lowest address of its loaded 1650 // segments. 1651 if (libbase == NULL || libbase > segbase) { 1652 libbase = segbase; 1653 } 1654 // see if 'addr' is within current segment 1655 if (segbase <= d->addr && 1656 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1657 found = true; 1658 } 1659 } 1660 } 1661 1662 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1663 // so dll_address_to_library_name() can fall through to use dladdr() which 1664 // can figure out executable name from argv[0]. 1665 if (found && info->dlpi_name && info->dlpi_name[0]) { 1666 d->base = libbase; 1667 if (d->fname) { 1668 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1669 } 1670 return 1; 1671 } 1672 return 0; 1673 } 1674 1675 bool os::dll_address_to_library_name(address addr, char* buf, 1676 int buflen, int* offset) { 1677 // buf is not optional, but offset is optional 1678 assert(buf != NULL, "sanity check"); 1679 1680 Dl_info dlinfo; 1681 struct _address_to_library_name data; 1682 1683 // There is a bug in old glibc dladdr() implementation that it could resolve 1684 // to wrong library name if the .so file has a base address != NULL. Here 1685 // we iterate through the program headers of all loaded libraries to find 1686 // out which library 'addr' really belongs to. This workaround can be 1687 // removed once the minimum requirement for glibc is moved to 2.3.x. 1688 data.addr = addr; 1689 data.fname = buf; 1690 data.buflen = buflen; 1691 data.base = NULL; 1692 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1693 1694 if (rslt) { 1695 // buf already contains library name 1696 if (offset) *offset = addr - data.base; 1697 return true; 1698 } 1699 if (dladdr((void*)addr, &dlinfo) != 0) { 1700 if (dlinfo.dli_fname != NULL) { 1701 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1702 } 1703 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1704 *offset = addr - (address)dlinfo.dli_fbase; 1705 } 1706 return true; 1707 } 1708 1709 buf[0] = '\0'; 1710 if (offset) *offset = -1; 1711 return false; 1712 } 1713 1714 // Loads .dll/.so and 1715 // in case of error it checks if .dll/.so was built for the 1716 // same architecture as Hotspot is running on 1717 1718 1719 // Remember the stack's state. The Linux dynamic linker will change 1720 // the stack to 'executable' at most once, so we must safepoint only once. 1721 bool os::Linux::_stack_is_executable = false; 1722 1723 // VM operation that loads a library. This is necessary if stack protection 1724 // of the Java stacks can be lost during loading the library. If we 1725 // do not stop the Java threads, they can stack overflow before the stacks 1726 // are protected again. 1727 class VM_LinuxDllLoad: public VM_Operation { 1728 private: 1729 const char *_filename; 1730 char *_ebuf; 1731 int _ebuflen; 1732 void *_lib; 1733 public: 1734 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1735 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1736 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1737 void doit() { 1738 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1739 os::Linux::_stack_is_executable = true; 1740 } 1741 void* loaded_library() { return _lib; } 1742 }; 1743 1744 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1745 void * result = NULL; 1746 bool load_attempted = false; 1747 1748 log_info(os)("attempting shared library load of %s", filename); 1749 1750 // Check whether the library to load might change execution rights 1751 // of the stack. If they are changed, the protection of the stack 1752 // guard pages will be lost. We need a safepoint to fix this. 1753 // 1754 // See Linux man page execstack(8) for more info. 1755 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1756 if (!ElfFile::specifies_noexecstack(filename)) { 1757 if (!is_init_completed()) { 1758 os::Linux::_stack_is_executable = true; 1759 // This is OK - No Java threads have been created yet, and hence no 1760 // stack guard pages to fix. 1761 // 1762 // Dynamic loader will make all stacks executable after 1763 // this function returns, and will not do that again. 1764 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet."); 1765 } else { 1766 warning("You have loaded library %s which might have disabled stack guard. " 1767 "The VM will try to fix the stack guard now.\n" 1768 "It's highly recommended that you fix the library with " 1769 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1770 filename); 1771 1772 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1773 JavaThread *jt = JavaThread::current(); 1774 if (jt->thread_state() != _thread_in_native) { 1775 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1776 // that requires ExecStack. Cannot enter safe point. Let's give up. 1777 warning("Unable to fix stack guard. Giving up."); 1778 } else { 1779 if (!LoadExecStackDllInVMThread) { 1780 // This is for the case where the DLL has an static 1781 // constructor function that executes JNI code. We cannot 1782 // load such DLLs in the VMThread. 1783 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1784 } 1785 1786 ThreadInVMfromNative tiv(jt); 1787 debug_only(VMNativeEntryWrapper vew;) 1788 1789 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1790 VMThread::execute(&op); 1791 if (LoadExecStackDllInVMThread) { 1792 result = op.loaded_library(); 1793 } 1794 load_attempted = true; 1795 } 1796 } 1797 } 1798 } 1799 1800 if (!load_attempted) { 1801 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1802 } 1803 1804 if (result != NULL) { 1805 // Successful loading 1806 return result; 1807 } 1808 1809 Elf32_Ehdr elf_head; 1810 int diag_msg_max_length=ebuflen-strlen(ebuf); 1811 char* diag_msg_buf=ebuf+strlen(ebuf); 1812 1813 if (diag_msg_max_length==0) { 1814 // No more space in ebuf for additional diagnostics message 1815 return NULL; 1816 } 1817 1818 1819 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1820 1821 if (file_descriptor < 0) { 1822 // Can't open library, report dlerror() message 1823 return NULL; 1824 } 1825 1826 bool failed_to_read_elf_head= 1827 (sizeof(elf_head)!= 1828 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1829 1830 ::close(file_descriptor); 1831 if (failed_to_read_elf_head) { 1832 // file i/o error - report dlerror() msg 1833 return NULL; 1834 } 1835 1836 if (elf_head.e_ident[EI_DATA] != LITTLE_ENDIAN_ONLY(ELFDATA2LSB) BIG_ENDIAN_ONLY(ELFDATA2MSB)) { 1837 // handle invalid/out of range endianness values 1838 if (elf_head.e_ident[EI_DATA] == 0 || elf_head.e_ident[EI_DATA] > 2) { 1839 return NULL; 1840 } 1841 1842 #if defined(VM_LITTLE_ENDIAN) 1843 // VM is LE, shared object BE 1844 elf_head.e_machine = be16toh(elf_head.e_machine); 1845 #else 1846 // VM is BE, shared object LE 1847 elf_head.e_machine = le16toh(elf_head.e_machine); 1848 #endif 1849 } 1850 1851 typedef struct { 1852 Elf32_Half code; // Actual value as defined in elf.h 1853 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1854 unsigned char elf_class; // 32 or 64 bit 1855 unsigned char endianness; // MSB or LSB 1856 char* name; // String representation 1857 } arch_t; 1858 1859 #ifndef EM_AARCH64 1860 #define EM_AARCH64 183 /* ARM AARCH64 */ 1861 #endif 1862 #ifndef EM_RISCV 1863 #define EM_RISCV 243 /* RISC-V */ 1864 #endif 1865 1866 static const arch_t arch_array[]={ 1867 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1868 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1869 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1870 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1871 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1872 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1873 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1874 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1875 #if defined(VM_LITTLE_ENDIAN) 1876 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"}, 1877 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"}, 1878 #else 1879 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1880 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"}, 1881 #endif 1882 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1883 // we only support 64 bit z architecture 1884 {EM_S390, EM_S390, ELFCLASS64, ELFDATA2MSB, (char*)"IBM System/390"}, 1885 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1886 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1887 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1888 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1889 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1890 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1891 {EM_RISCV, EM_RISCV, ELFCLASS64, ELFDATA2LSB, (char*)"RISC-V"}, 1892 }; 1893 1894 #if (defined IA32) 1895 static Elf32_Half running_arch_code=EM_386; 1896 #elif (defined AMD64) || (defined X32) 1897 static Elf32_Half running_arch_code=EM_X86_64; 1898 #elif (defined IA64) 1899 static Elf32_Half running_arch_code=EM_IA_64; 1900 #elif (defined __sparc) && (defined _LP64) 1901 static Elf32_Half running_arch_code=EM_SPARCV9; 1902 #elif (defined __sparc) && (!defined _LP64) 1903 static Elf32_Half running_arch_code=EM_SPARC; 1904 #elif (defined __powerpc64__) 1905 static Elf32_Half running_arch_code=EM_PPC64; 1906 #elif (defined __powerpc__) 1907 static Elf32_Half running_arch_code=EM_PPC; 1908 #elif (defined AARCH64) 1909 static Elf32_Half running_arch_code=EM_AARCH64; 1910 #elif (defined ARM) 1911 static Elf32_Half running_arch_code=EM_ARM; 1912 #elif (defined S390) 1913 static Elf32_Half running_arch_code=EM_S390; 1914 #elif (defined ALPHA) 1915 static Elf32_Half running_arch_code=EM_ALPHA; 1916 #elif (defined MIPSEL) 1917 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1918 #elif (defined PARISC) 1919 static Elf32_Half running_arch_code=EM_PARISC; 1920 #elif (defined MIPS) 1921 static Elf32_Half running_arch_code=EM_MIPS; 1922 #elif (defined M68K) 1923 static Elf32_Half running_arch_code=EM_68K; 1924 #elif (defined SH) 1925 static Elf32_Half running_arch_code=EM_SH; 1926 #elif (defined RISCV) 1927 static Elf32_Half running_arch_code=EM_RISCV; 1928 #else 1929 #error Method os::dll_load requires that one of following is defined:\ 1930 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, RISCV, S390, SH, __sparc 1931 #endif 1932 1933 // Identify compatibility class for VM's architecture and library's architecture 1934 // Obtain string descriptions for architectures 1935 1936 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1937 int running_arch_index=-1; 1938 1939 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1940 if (running_arch_code == arch_array[i].code) { 1941 running_arch_index = i; 1942 } 1943 if (lib_arch.code == arch_array[i].code) { 1944 lib_arch.compat_class = arch_array[i].compat_class; 1945 lib_arch.name = arch_array[i].name; 1946 } 1947 } 1948 1949 assert(running_arch_index != -1, 1950 "Didn't find running architecture code (running_arch_code) in arch_array"); 1951 if (running_arch_index == -1) { 1952 // Even though running architecture detection failed 1953 // we may still continue with reporting dlerror() message 1954 return NULL; 1955 } 1956 1957 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1958 if (lib_arch.name != NULL) { 1959 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1960 " (Possible cause: can't load %s .so on a %s platform)", 1961 lib_arch.name, arch_array[running_arch_index].name); 1962 } else { 1963 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1964 " (Possible cause: can't load this .so (machine code=0x%x) on a %s platform)", 1965 lib_arch.code, arch_array[running_arch_index].name); 1966 } 1967 return NULL; 1968 } 1969 1970 if (lib_arch.endianness != arch_array[running_arch_index].endianness) { 1971 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: endianness mismatch)"); 1972 return NULL; 1973 } 1974 1975 // ELF file class/capacity : 0 - invalid, 1 - 32bit, 2 - 64bit 1976 if (lib_arch.elf_class > 2 || lib_arch.elf_class < 1) { 1977 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: invalid ELF file class)"); 1978 return NULL; 1979 } 1980 1981 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1982 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1983 " (Possible cause: architecture word width mismatch, can't load %d-bit .so on a %d-bit platform)", 1984 (int) lib_arch.elf_class * 32, arch_array[running_arch_index].elf_class * 32); 1985 return NULL; 1986 } 1987 1988 return NULL; 1989 } 1990 1991 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1992 int ebuflen) { 1993 void * result = ::dlopen(filename, RTLD_LAZY); 1994 if (result == NULL) { 1995 const char* error_report = ::dlerror(); 1996 if (error_report == NULL) { 1997 error_report = "dlerror returned no error description"; 1998 } 1999 if (ebuf != NULL && ebuflen > 0) { 2000 ::strncpy(ebuf, error_report, ebuflen-1); 2001 ebuf[ebuflen-1]='\0'; 2002 } 2003 Events::log(NULL, "Loading shared library %s failed, %s", filename, error_report); 2004 log_info(os)("shared library load of %s failed, %s", filename, error_report); 2005 } else { 2006 Events::log(NULL, "Loaded shared library %s", filename); 2007 log_info(os)("shared library load of %s was successful", filename); 2008 } 2009 return result; 2010 } 2011 2012 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 2013 int ebuflen) { 2014 void * result = NULL; 2015 if (LoadExecStackDllInVMThread) { 2016 result = dlopen_helper(filename, ebuf, ebuflen); 2017 } 2018 2019 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 2020 // library that requires an executable stack, or which does not have this 2021 // stack attribute set, dlopen changes the stack attribute to executable. The 2022 // read protection of the guard pages gets lost. 2023 // 2024 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 2025 // may have been queued at the same time. 2026 2027 if (!_stack_is_executable) { 2028 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) { 2029 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 2030 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 2031 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 2032 warning("Attempt to reguard stack yellow zone failed."); 2033 } 2034 } 2035 } 2036 } 2037 2038 return result; 2039 } 2040 2041 void* os::dll_lookup(void* handle, const char* name) { 2042 void* res = dlsym(handle, name); 2043 return res; 2044 } 2045 2046 void* os::get_default_process_handle() { 2047 return (void*)::dlopen(NULL, RTLD_LAZY); 2048 } 2049 2050 static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) { 2051 int fd = ::open(filename, O_RDONLY); 2052 if (fd == -1) { 2053 return false; 2054 } 2055 2056 if (hdr != NULL) { 2057 st->print_cr("%s", hdr); 2058 } 2059 2060 char buf[33]; 2061 int bytes; 2062 buf[32] = '\0'; 2063 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) { 2064 st->print_raw(buf, bytes); 2065 } 2066 2067 ::close(fd); 2068 2069 return true; 2070 } 2071 2072 static void _print_ascii_file_h(const char* header, const char* filename, outputStream* st) { 2073 st->print_cr("%s:", header); 2074 if (!_print_ascii_file(filename, st)) { 2075 st->print_cr("<Not Available>"); 2076 } 2077 } 2078 2079 void os::print_dll_info(outputStream *st) { 2080 st->print_cr("Dynamic libraries:"); 2081 2082 char fname[32]; 2083 pid_t pid = os::Linux::gettid(); 2084 2085 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 2086 2087 if (!_print_ascii_file(fname, st)) { 2088 st->print("Can not get library information for pid = %d\n", pid); 2089 } 2090 } 2091 2092 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 2093 FILE *procmapsFile = NULL; 2094 2095 // Open the procfs maps file for the current process 2096 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 2097 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 2098 char line[PATH_MAX + 100]; 2099 2100 // Read line by line from 'file' 2101 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 2102 u8 base, top, inode; 2103 char name[sizeof(line)]; 2104 2105 // Parse fields from line, discard perms, offset and device 2106 int matches = sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %*s %*s %*s " INT64_FORMAT " %s", 2107 &base, &top, &inode, name); 2108 // the last entry 'name' is empty for some entries, so we might have 3 matches instead of 4 for some lines 2109 if (matches < 3) continue; 2110 if (matches == 3) name[0] = '\0'; 2111 2112 // Filter by inode 0 so that we only get file system mapped files. 2113 if (inode != 0) { 2114 2115 // Call callback with the fields of interest 2116 if(callback(name, (address)base, (address)top, param)) { 2117 // Oops abort, callback aborted 2118 fclose(procmapsFile); 2119 return 1; 2120 } 2121 } 2122 } 2123 fclose(procmapsFile); 2124 } 2125 return 0; 2126 } 2127 2128 void os::print_os_info_brief(outputStream* st) { 2129 os::Linux::print_distro_info(st); 2130 2131 os::Posix::print_uname_info(st); 2132 2133 os::Linux::print_libversion_info(st); 2134 2135 } 2136 2137 void os::print_os_info(outputStream* st) { 2138 st->print("OS:"); 2139 2140 os::Linux::print_distro_info(st); 2141 2142 os::Posix::print_uname_info(st); 2143 2144 os::Linux::print_uptime_info(st); 2145 2146 // Print warning if unsafe chroot environment detected 2147 if (unsafe_chroot_detected) { 2148 st->print("WARNING!! "); 2149 st->print_cr("%s", unstable_chroot_error); 2150 } 2151 2152 os::Linux::print_libversion_info(st); 2153 2154 os::Posix::print_rlimit_info(st); 2155 2156 os::Posix::print_load_average(st); 2157 2158 os::Linux::print_full_memory_info(st); 2159 2160 os::Linux::print_proc_sys_info(st); 2161 2162 os::Linux::print_ld_preload_file(st); 2163 2164 os::Linux::print_container_info(st); 2165 2166 VM_Version::print_platform_virtualization_info(st); 2167 2168 os::Linux::print_steal_info(st); 2169 } 2170 2171 // Try to identify popular distros. 2172 // Most Linux distributions have a /etc/XXX-release file, which contains 2173 // the OS version string. Newer Linux distributions have a /etc/lsb-release 2174 // file that also contains the OS version string. Some have more than one 2175 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2176 // /etc/redhat-release.), so the order is important. 2177 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2178 // their own specific XXX-release file as well as a redhat-release file. 2179 // Because of this the XXX-release file needs to be searched for before the 2180 // redhat-release file. 2181 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the 2182 // search for redhat-release / SuSE-release needs to be before lsb-release. 2183 // Since the lsb-release file is the new standard it needs to be searched 2184 // before the older style release files. 2185 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 2186 // next to last resort. The os-release file is a new standard that contains 2187 // distribution information and the system-release file seems to be an old 2188 // standard that has been replaced by the lsb-release and os-release files. 2189 // Searching for the debian_version file is the last resort. It contains 2190 // an informative string like "6.0.6" or "wheezy/sid". Because of this 2191 // "Debian " is printed before the contents of the debian_version file. 2192 2193 const char* distro_files[] = { 2194 "/etc/oracle-release", 2195 "/etc/mandriva-release", 2196 "/etc/mandrake-release", 2197 "/etc/sun-release", 2198 "/etc/redhat-release", 2199 "/etc/SuSE-release", 2200 "/etc/lsb-release", 2201 "/etc/turbolinux-release", 2202 "/etc/gentoo-release", 2203 "/etc/ltib-release", 2204 "/etc/angstrom-version", 2205 "/etc/system-release", 2206 "/etc/os-release", 2207 NULL }; 2208 2209 void os::Linux::print_distro_info(outputStream* st) { 2210 for (int i = 0;; i++) { 2211 const char* file = distro_files[i]; 2212 if (file == NULL) { 2213 break; // done 2214 } 2215 // If file prints, we found it. 2216 if (_print_ascii_file(file, st)) { 2217 return; 2218 } 2219 } 2220 2221 if (file_exists("/etc/debian_version")) { 2222 st->print("Debian "); 2223 _print_ascii_file("/etc/debian_version", st); 2224 } else { 2225 st->print("Linux"); 2226 } 2227 st->cr(); 2228 } 2229 2230 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) { 2231 char buf[256]; 2232 while (fgets(buf, sizeof(buf), fp)) { 2233 // Edit out extra stuff in expected format 2234 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) { 2235 char* ptr = strstr(buf, "\""); // the name is in quotes 2236 if (ptr != NULL) { 2237 ptr++; // go beyond first quote 2238 char* nl = strchr(ptr, '\"'); 2239 if (nl != NULL) *nl = '\0'; 2240 strncpy(distro, ptr, length); 2241 } else { 2242 ptr = strstr(buf, "="); 2243 ptr++; // go beyond equals then 2244 char* nl = strchr(ptr, '\n'); 2245 if (nl != NULL) *nl = '\0'; 2246 strncpy(distro, ptr, length); 2247 } 2248 return; 2249 } else if (get_first_line) { 2250 char* nl = strchr(buf, '\n'); 2251 if (nl != NULL) *nl = '\0'; 2252 strncpy(distro, buf, length); 2253 return; 2254 } 2255 } 2256 // print last line and close 2257 char* nl = strchr(buf, '\n'); 2258 if (nl != NULL) *nl = '\0'; 2259 strncpy(distro, buf, length); 2260 } 2261 2262 static void parse_os_info(char* distro, size_t length, const char* file) { 2263 FILE* fp = fopen(file, "r"); 2264 if (fp != NULL) { 2265 // if suse format, print out first line 2266 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0); 2267 parse_os_info_helper(fp, distro, length, get_first_line); 2268 fclose(fp); 2269 } 2270 } 2271 2272 void os::get_summary_os_info(char* buf, size_t buflen) { 2273 for (int i = 0;; i++) { 2274 const char* file = distro_files[i]; 2275 if (file == NULL) { 2276 break; // ran out of distro_files 2277 } 2278 if (file_exists(file)) { 2279 parse_os_info(buf, buflen, file); 2280 return; 2281 } 2282 } 2283 // special case for debian 2284 if (file_exists("/etc/debian_version")) { 2285 strncpy(buf, "Debian ", buflen); 2286 if (buflen > 7) { 2287 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2288 } 2289 } else { 2290 strncpy(buf, "Linux", buflen); 2291 } 2292 } 2293 2294 void os::Linux::print_libversion_info(outputStream* st) { 2295 // libc, pthread 2296 st->print("libc:"); 2297 st->print("%s ", os::Linux::glibc_version()); 2298 st->print("%s ", os::Linux::libpthread_version()); 2299 st->cr(); 2300 } 2301 2302 void os::Linux::print_proc_sys_info(outputStream* st) { 2303 st->cr(); 2304 _print_ascii_file_h("/proc/sys/kernel/threads-max (system-wide limit on the number of threads)", 2305 "/proc/sys/kernel/threads-max", st); 2306 _print_ascii_file_h("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have)", 2307 "/proc/sys/vm/max_map_count", st); 2308 _print_ascii_file_h("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers)", 2309 "/proc/sys/kernel/pid_max", st); 2310 } 2311 2312 void os::Linux::print_full_memory_info(outputStream* st) { 2313 _print_ascii_file_h("\n/proc/meminfo", "/proc/meminfo", st); 2314 st->cr(); 2315 2316 // some information regarding THPs; for details see 2317 // https://www.kernel.org/doc/Documentation/vm/transhuge.txt 2318 _print_ascii_file_h("/sys/kernel/mm/transparent_hugepage/enabled", 2319 "/sys/kernel/mm/transparent_hugepage/enabled", st); 2320 _print_ascii_file_h("/sys/kernel/mm/transparent_hugepage/defrag (defrag/compaction efforts parameter)", 2321 "/sys/kernel/mm/transparent_hugepage/defrag", st); 2322 } 2323 2324 void os::Linux::print_ld_preload_file(outputStream* st) { 2325 _print_ascii_file("/etc/ld.so.preload", st, "\n/etc/ld.so.preload:"); 2326 st->cr(); 2327 } 2328 2329 void os::Linux::print_uptime_info(outputStream* st) { 2330 struct sysinfo sinfo; 2331 int ret = sysinfo(&sinfo); 2332 if (ret == 0) { 2333 os::print_dhm(st, "OS uptime:", (long) sinfo.uptime); 2334 } 2335 } 2336 2337 2338 void os::Linux::print_container_info(outputStream* st) { 2339 if (!OSContainer::is_containerized()) { 2340 return; 2341 } 2342 2343 st->print("container (cgroup) information:\n"); 2344 2345 const char *p_ct = OSContainer::container_type(); 2346 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "not supported"); 2347 2348 char *p = OSContainer::cpu_cpuset_cpus(); 2349 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "not supported"); 2350 free(p); 2351 2352 p = OSContainer::cpu_cpuset_memory_nodes(); 2353 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "not supported"); 2354 free(p); 2355 2356 int i = OSContainer::active_processor_count(); 2357 st->print("active_processor_count: "); 2358 if (i > 0) { 2359 st->print("%d\n", i); 2360 } else { 2361 st->print("not supported\n"); 2362 } 2363 2364 i = OSContainer::cpu_quota(); 2365 st->print("cpu_quota: "); 2366 if (i > 0) { 2367 st->print("%d\n", i); 2368 } else { 2369 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no quota"); 2370 } 2371 2372 i = OSContainer::cpu_period(); 2373 st->print("cpu_period: "); 2374 if (i > 0) { 2375 st->print("%d\n", i); 2376 } else { 2377 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no period"); 2378 } 2379 2380 i = OSContainer::cpu_shares(); 2381 st->print("cpu_shares: "); 2382 if (i > 0) { 2383 st->print("%d\n", i); 2384 } else { 2385 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no shares"); 2386 } 2387 2388 jlong j = OSContainer::memory_limit_in_bytes(); 2389 st->print("memory_limit_in_bytes: "); 2390 if (j > 0) { 2391 st->print(JLONG_FORMAT "\n", j); 2392 } else { 2393 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2394 } 2395 2396 j = OSContainer::memory_and_swap_limit_in_bytes(); 2397 st->print("memory_and_swap_limit_in_bytes: "); 2398 if (j > 0) { 2399 st->print(JLONG_FORMAT "\n", j); 2400 } else { 2401 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2402 } 2403 2404 j = OSContainer::memory_soft_limit_in_bytes(); 2405 st->print("memory_soft_limit_in_bytes: "); 2406 if (j > 0) { 2407 st->print(JLONG_FORMAT "\n", j); 2408 } else { 2409 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2410 } 2411 2412 j = OSContainer::OSContainer::memory_usage_in_bytes(); 2413 st->print("memory_usage_in_bytes: "); 2414 if (j > 0) { 2415 st->print(JLONG_FORMAT "\n", j); 2416 } else { 2417 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2418 } 2419 2420 j = OSContainer::OSContainer::memory_max_usage_in_bytes(); 2421 st->print("memory_max_usage_in_bytes: "); 2422 if (j > 0) { 2423 st->print(JLONG_FORMAT "\n", j); 2424 } else { 2425 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2426 } 2427 st->cr(); 2428 } 2429 2430 void os::Linux::print_steal_info(outputStream* st) { 2431 if (has_initial_tick_info) { 2432 CPUPerfTicks pticks; 2433 bool res = os::Linux::get_tick_information(&pticks, -1); 2434 2435 if (res && pticks.has_steal_ticks) { 2436 uint64_t steal_ticks_difference = pticks.steal - initial_steal_ticks; 2437 uint64_t total_ticks_difference = pticks.total - initial_total_ticks; 2438 double steal_ticks_perc = 0.0; 2439 if (total_ticks_difference != 0) { 2440 steal_ticks_perc = (double) steal_ticks_difference / total_ticks_difference; 2441 } 2442 st->print_cr("Steal ticks since vm start: " UINT64_FORMAT, steal_ticks_difference); 2443 st->print_cr("Steal ticks percentage since vm start:%7.3f", steal_ticks_perc); 2444 } 2445 } 2446 } 2447 2448 void os::print_memory_info(outputStream* st) { 2449 2450 st->print("Memory:"); 2451 st->print(" %dk page", os::vm_page_size()>>10); 2452 2453 // values in struct sysinfo are "unsigned long" 2454 struct sysinfo si; 2455 sysinfo(&si); 2456 2457 st->print(", physical " UINT64_FORMAT "k", 2458 os::physical_memory() >> 10); 2459 st->print("(" UINT64_FORMAT "k free)", 2460 os::available_memory() >> 10); 2461 st->print(", swap " UINT64_FORMAT "k", 2462 ((jlong)si.totalswap * si.mem_unit) >> 10); 2463 st->print("(" UINT64_FORMAT "k free)", 2464 ((jlong)si.freeswap * si.mem_unit) >> 10); 2465 st->cr(); 2466 } 2467 2468 // Print the first "model name" line and the first "flags" line 2469 // that we find and nothing more. We assume "model name" comes 2470 // before "flags" so if we find a second "model name", then the 2471 // "flags" field is considered missing. 2472 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2473 #if defined(IA32) || defined(AMD64) 2474 // Other platforms have less repetitive cpuinfo files 2475 FILE *fp = fopen("/proc/cpuinfo", "r"); 2476 if (fp) { 2477 while (!feof(fp)) { 2478 if (fgets(buf, buflen, fp)) { 2479 // Assume model name comes before flags 2480 bool model_name_printed = false; 2481 if (strstr(buf, "model name") != NULL) { 2482 if (!model_name_printed) { 2483 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n"); 2484 st->print_raw(buf); 2485 model_name_printed = true; 2486 } else { 2487 // model name printed but not flags? Odd, just return 2488 fclose(fp); 2489 return true; 2490 } 2491 } 2492 // print the flags line too 2493 if (strstr(buf, "flags") != NULL) { 2494 st->print_raw(buf); 2495 fclose(fp); 2496 return true; 2497 } 2498 } 2499 } 2500 fclose(fp); 2501 } 2502 #endif // x86 platforms 2503 return false; 2504 } 2505 2506 // additional information about CPU e.g. available frequency ranges 2507 static void print_sys_devices_cpu_info(outputStream* st, char* buf, size_t buflen) { 2508 _print_ascii_file_h("Online cpus", "/sys/devices/system/cpu/online", st); 2509 _print_ascii_file_h("Offline cpus", "/sys/devices/system/cpu/offline", st); 2510 2511 if (ExtensiveErrorReports) { 2512 // cache related info (cpu 0, should be similar for other CPUs) 2513 for (unsigned int i=0; i < 10; i++) { // handle max. 10 cache entries 2514 char hbuf_level[60]; 2515 char hbuf_type[60]; 2516 char hbuf_size[60]; 2517 char hbuf_coherency_line_size[80]; 2518 snprintf(hbuf_level, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/level", i); 2519 snprintf(hbuf_type, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/type", i); 2520 snprintf(hbuf_size, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/size", i); 2521 snprintf(hbuf_coherency_line_size, 80, "/sys/devices/system/cpu/cpu0/cache/index%u/coherency_line_size", i); 2522 if (file_exists(hbuf_level)) { 2523 _print_ascii_file_h("cache level", hbuf_level, st); 2524 _print_ascii_file_h("cache type", hbuf_type, st); 2525 _print_ascii_file_h("cache size", hbuf_size, st); 2526 _print_ascii_file_h("cache coherency line size", hbuf_coherency_line_size, st); 2527 } 2528 } 2529 } 2530 2531 // we miss the cpufreq entries on Power and s390x 2532 #if defined(IA32) || defined(AMD64) 2533 _print_ascii_file_h("BIOS frequency limitation", "/sys/devices/system/cpu/cpu0/cpufreq/bios_limit", st); 2534 _print_ascii_file_h("Frequency switch latency (ns)", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_transition_latency", st); 2535 _print_ascii_file_h("Available cpu frequencies", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies", st); 2536 // min and max should be in the Available range but still print them (not all info might be available for all kernels) 2537 if (ExtensiveErrorReports) { 2538 _print_ascii_file_h("Maximum cpu frequency", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq", st); 2539 _print_ascii_file_h("Minimum cpu frequency", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq", st); 2540 _print_ascii_file_h("Current cpu frequency", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq", st); 2541 } 2542 // governors are power schemes, see https://wiki.archlinux.org/index.php/CPU_frequency_scaling 2543 if (ExtensiveErrorReports) { 2544 _print_ascii_file_h("Available governors", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors", st); 2545 } 2546 _print_ascii_file_h("Current governor", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor", st); 2547 // Core performance boost, see https://www.kernel.org/doc/Documentation/cpu-freq/boost.txt 2548 // Raise operating frequency of some cores in a multi-core package if certain conditions apply, e.g. 2549 // whole chip is not fully utilized 2550 _print_ascii_file_h("Core performance/turbo boost", "/sys/devices/system/cpu/cpufreq/boost", st); 2551 #endif 2552 } 2553 2554 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2555 // Only print the model name if the platform provides this as a summary 2556 if (!print_model_name_and_flags(st, buf, buflen)) { 2557 _print_ascii_file_h("\n/proc/cpuinfo", "/proc/cpuinfo", st); 2558 } 2559 print_sys_devices_cpu_info(st, buf, buflen); 2560 } 2561 2562 #if defined(AMD64) || defined(IA32) || defined(X32) 2563 const char* search_string = "model name"; 2564 #elif defined(M68K) 2565 const char* search_string = "CPU"; 2566 #elif defined(PPC64) 2567 const char* search_string = "cpu"; 2568 #elif defined(S390) 2569 const char* search_string = "machine ="; 2570 #elif defined(SPARC) 2571 const char* search_string = "cpu"; 2572 #else 2573 const char* search_string = "Processor"; 2574 #endif 2575 2576 // Parses the cpuinfo file for string representing the model name. 2577 void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2578 FILE* fp = fopen("/proc/cpuinfo", "r"); 2579 if (fp != NULL) { 2580 while (!feof(fp)) { 2581 char buf[256]; 2582 if (fgets(buf, sizeof(buf), fp)) { 2583 char* start = strstr(buf, search_string); 2584 if (start != NULL) { 2585 char *ptr = start + strlen(search_string); 2586 char *end = buf + strlen(buf); 2587 while (ptr != end) { 2588 // skip whitespace and colon for the rest of the name. 2589 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2590 break; 2591 } 2592 ptr++; 2593 } 2594 if (ptr != end) { 2595 // reasonable string, get rid of newline and keep the rest 2596 char* nl = strchr(buf, '\n'); 2597 if (nl != NULL) *nl = '\0'; 2598 strncpy(cpuinfo, ptr, length); 2599 fclose(fp); 2600 return; 2601 } 2602 } 2603 } 2604 } 2605 fclose(fp); 2606 } 2607 // cpuinfo not found or parsing failed, just print generic string. The entire 2608 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2609 #if defined(AARCH64) 2610 strncpy(cpuinfo, "AArch64", length); 2611 #elif defined(AMD64) 2612 strncpy(cpuinfo, "x86_64", length); 2613 #elif defined(ARM) // Order wrt. AARCH64 is relevant! 2614 strncpy(cpuinfo, "ARM", length); 2615 #elif defined(IA32) 2616 strncpy(cpuinfo, "x86_32", length); 2617 #elif defined(IA64) 2618 strncpy(cpuinfo, "IA64", length); 2619 #elif defined(PPC) 2620 strncpy(cpuinfo, "PPC64", length); 2621 #elif defined(S390) 2622 strncpy(cpuinfo, "S390", length); 2623 #elif defined(SPARC) 2624 strncpy(cpuinfo, "sparcv9", length); 2625 #elif defined(ZERO_LIBARCH) 2626 strncpy(cpuinfo, ZERO_LIBARCH, length); 2627 #else 2628 strncpy(cpuinfo, "unknown", length); 2629 #endif 2630 } 2631 2632 static void print_signal_handler(outputStream* st, int sig, 2633 char* buf, size_t buflen); 2634 2635 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2636 st->print_cr("Signal Handlers:"); 2637 print_signal_handler(st, SIGSEGV, buf, buflen); 2638 print_signal_handler(st, SIGBUS , buf, buflen); 2639 print_signal_handler(st, SIGFPE , buf, buflen); 2640 print_signal_handler(st, SIGPIPE, buf, buflen); 2641 print_signal_handler(st, SIGXFSZ, buf, buflen); 2642 print_signal_handler(st, SIGILL , buf, buflen); 2643 print_signal_handler(st, SR_signum, buf, buflen); 2644 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2645 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2646 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2647 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2648 #if defined(PPC64) 2649 print_signal_handler(st, SIGTRAP, buf, buflen); 2650 #endif 2651 } 2652 2653 static char saved_jvm_path[MAXPATHLEN] = {0}; 2654 2655 // Find the full path to the current module, libjvm.so 2656 void os::jvm_path(char *buf, jint buflen) { 2657 // Error checking. 2658 if (buflen < MAXPATHLEN) { 2659 assert(false, "must use a large-enough buffer"); 2660 buf[0] = '\0'; 2661 return; 2662 } 2663 // Lazy resolve the path to current module. 2664 if (saved_jvm_path[0] != 0) { 2665 strcpy(buf, saved_jvm_path); 2666 return; 2667 } 2668 2669 char dli_fname[MAXPATHLEN]; 2670 bool ret = dll_address_to_library_name( 2671 CAST_FROM_FN_PTR(address, os::jvm_path), 2672 dli_fname, sizeof(dli_fname), NULL); 2673 assert(ret, "cannot locate libjvm"); 2674 char *rp = NULL; 2675 if (ret && dli_fname[0] != '\0') { 2676 rp = os::Posix::realpath(dli_fname, buf, buflen); 2677 } 2678 if (rp == NULL) { 2679 return; 2680 } 2681 2682 if (Arguments::sun_java_launcher_is_altjvm()) { 2683 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2684 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so". 2685 // If "/jre/lib/" appears at the right place in the string, then 2686 // assume we are installed in a JDK and we're done. Otherwise, check 2687 // for a JAVA_HOME environment variable and fix up the path so it 2688 // looks like libjvm.so is installed there (append a fake suffix 2689 // hotspot/libjvm.so). 2690 const char *p = buf + strlen(buf) - 1; 2691 for (int count = 0; p > buf && count < 5; ++count) { 2692 for (--p; p > buf && *p != '/'; --p) 2693 /* empty */ ; 2694 } 2695 2696 if (strncmp(p, "/jre/lib/", 9) != 0) { 2697 // Look for JAVA_HOME in the environment. 2698 char* java_home_var = ::getenv("JAVA_HOME"); 2699 if (java_home_var != NULL && java_home_var[0] != 0) { 2700 char* jrelib_p; 2701 int len; 2702 2703 // Check the current module name "libjvm.so". 2704 p = strrchr(buf, '/'); 2705 if (p == NULL) { 2706 return; 2707 } 2708 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2709 2710 rp = os::Posix::realpath(java_home_var, buf, buflen); 2711 if (rp == NULL) { 2712 return; 2713 } 2714 2715 // determine if this is a legacy image or modules image 2716 // modules image doesn't have "jre" subdirectory 2717 len = strlen(buf); 2718 assert(len < buflen, "Ran out of buffer room"); 2719 jrelib_p = buf + len; 2720 snprintf(jrelib_p, buflen-len, "/jre/lib"); 2721 if (0 != access(buf, F_OK)) { 2722 snprintf(jrelib_p, buflen-len, "/lib"); 2723 } 2724 2725 if (0 == access(buf, F_OK)) { 2726 // Use current module name "libjvm.so" 2727 len = strlen(buf); 2728 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2729 } else { 2730 // Go back to path of .so 2731 rp = os::Posix::realpath(dli_fname, buf, buflen); 2732 if (rp == NULL) { 2733 return; 2734 } 2735 } 2736 } 2737 } 2738 } 2739 2740 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2741 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2742 } 2743 2744 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2745 // no prefix required, not even "_" 2746 } 2747 2748 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2749 // no suffix required 2750 } 2751 2752 //////////////////////////////////////////////////////////////////////////////// 2753 // sun.misc.Signal support 2754 2755 static void UserHandler(int sig, void *siginfo, void *context) { 2756 // Ctrl-C is pressed during error reporting, likely because the error 2757 // handler fails to abort. Let VM die immediately. 2758 if (sig == SIGINT && VMError::is_error_reported()) { 2759 os::die(); 2760 } 2761 2762 os::signal_notify(sig); 2763 } 2764 2765 void* os::user_handler() { 2766 return CAST_FROM_FN_PTR(void*, UserHandler); 2767 } 2768 2769 extern "C" { 2770 typedef void (*sa_handler_t)(int); 2771 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2772 } 2773 2774 void* os::signal(int signal_number, void* handler) { 2775 struct sigaction sigAct, oldSigAct; 2776 2777 sigfillset(&(sigAct.sa_mask)); 2778 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2779 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2780 2781 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2782 // -1 means registration failed 2783 return (void *)-1; 2784 } 2785 2786 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2787 } 2788 2789 void os::signal_raise(int signal_number) { 2790 ::raise(signal_number); 2791 } 2792 2793 // The following code is moved from os.cpp for making this 2794 // code platform specific, which it is by its very nature. 2795 2796 // Will be modified when max signal is changed to be dynamic 2797 int os::sigexitnum_pd() { 2798 return NSIG; 2799 } 2800 2801 // a counter for each possible signal value 2802 static volatile jint pending_signals[NSIG+1] = { 0 }; 2803 2804 // Linux(POSIX) specific hand shaking semaphore. 2805 static Semaphore* sig_sem = NULL; 2806 static PosixSemaphore sr_semaphore; 2807 2808 static void jdk_misc_signal_init() { 2809 // Initialize signal structures 2810 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2811 2812 // Initialize signal semaphore 2813 sig_sem = new Semaphore(); 2814 } 2815 2816 void os::signal_notify(int sig) { 2817 if (sig_sem != NULL) { 2818 Atomic::inc(&pending_signals[sig]); 2819 sig_sem->signal(); 2820 } else { 2821 // Signal thread is not created with ReduceSignalUsage and jdk_misc_signal_init 2822 // initialization isn't called. 2823 assert(ReduceSignalUsage, "signal semaphore should be created"); 2824 } 2825 } 2826 2827 static int check_pending_signals() { 2828 for (;;) { 2829 for (int i = 0; i < NSIG + 1; i++) { 2830 jint n = pending_signals[i]; 2831 if (n > 0 && n == Atomic::cmpxchg(&pending_signals[i], n, n - 1)) { 2832 return i; 2833 } 2834 } 2835 JavaThread *thread = JavaThread::current(); 2836 ThreadBlockInVM tbivm(thread); 2837 2838 bool threadIsSuspended; 2839 do { 2840 thread->set_suspend_equivalent(); 2841 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2842 sig_sem->wait(); 2843 2844 // were we externally suspended while we were waiting? 2845 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2846 if (threadIsSuspended) { 2847 // The semaphore has been incremented, but while we were waiting 2848 // another thread suspended us. We don't want to continue running 2849 // while suspended because that would surprise the thread that 2850 // suspended us. 2851 sig_sem->signal(); 2852 2853 thread->java_suspend_self(); 2854 } 2855 } while (threadIsSuspended); 2856 } 2857 } 2858 2859 int os::signal_wait() { 2860 return check_pending_signals(); 2861 } 2862 2863 //////////////////////////////////////////////////////////////////////////////// 2864 // Virtual Memory 2865 2866 int os::vm_page_size() { 2867 // Seems redundant as all get out 2868 assert(os::Linux::page_size() != -1, "must call os::init"); 2869 return os::Linux::page_size(); 2870 } 2871 2872 // Solaris allocates memory by pages. 2873 int os::vm_allocation_granularity() { 2874 assert(os::Linux::page_size() != -1, "must call os::init"); 2875 return os::Linux::page_size(); 2876 } 2877 2878 // Rationale behind this function: 2879 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2880 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2881 // samples for JITted code. Here we create private executable mapping over the code cache 2882 // and then we can use standard (well, almost, as mapping can change) way to provide 2883 // info for the reporting script by storing timestamp and location of symbol 2884 void linux_wrap_code(char* base, size_t size) { 2885 static volatile jint cnt = 0; 2886 2887 if (!UseOprofile) { 2888 return; 2889 } 2890 2891 char buf[PATH_MAX+1]; 2892 int num = Atomic::add(&cnt, 1); 2893 2894 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2895 os::get_temp_directory(), os::current_process_id(), num); 2896 unlink(buf); 2897 2898 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2899 2900 if (fd != -1) { 2901 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2902 if (rv != (off_t)-1) { 2903 if (::write(fd, "", 1) == 1) { 2904 mmap(base, size, 2905 PROT_READ|PROT_WRITE|PROT_EXEC, 2906 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2907 } 2908 } 2909 ::close(fd); 2910 unlink(buf); 2911 } 2912 } 2913 2914 static bool recoverable_mmap_error(int err) { 2915 // See if the error is one we can let the caller handle. This 2916 // list of errno values comes from JBS-6843484. I can't find a 2917 // Linux man page that documents this specific set of errno 2918 // values so while this list currently matches Solaris, it may 2919 // change as we gain experience with this failure mode. 2920 switch (err) { 2921 case EBADF: 2922 case EINVAL: 2923 case ENOTSUP: 2924 // let the caller deal with these errors 2925 return true; 2926 2927 default: 2928 // Any remaining errors on this OS can cause our reserved mapping 2929 // to be lost. That can cause confusion where different data 2930 // structures think they have the same memory mapped. The worst 2931 // scenario is if both the VM and a library think they have the 2932 // same memory mapped. 2933 return false; 2934 } 2935 } 2936 2937 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2938 int err) { 2939 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2940 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2941 os::strerror(err), err); 2942 } 2943 2944 static void warn_fail_commit_memory(char* addr, size_t size, 2945 size_t alignment_hint, bool exec, 2946 int err) { 2947 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2948 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2949 alignment_hint, exec, os::strerror(err), err); 2950 } 2951 2952 // NOTE: Linux kernel does not really reserve the pages for us. 2953 // All it does is to check if there are enough free pages 2954 // left at the time of mmap(). This could be a potential 2955 // problem. 2956 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2957 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2958 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2959 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2960 if (res != (uintptr_t) MAP_FAILED) { 2961 if (UseNUMAInterleaving) { 2962 numa_make_global(addr, size); 2963 } 2964 return 0; 2965 } 2966 2967 int err = errno; // save errno from mmap() call above 2968 2969 if (!recoverable_mmap_error(err)) { 2970 warn_fail_commit_memory(addr, size, exec, err); 2971 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2972 } 2973 2974 return err; 2975 } 2976 2977 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2978 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2979 } 2980 2981 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2982 const char* mesg) { 2983 assert(mesg != NULL, "mesg must be specified"); 2984 int err = os::Linux::commit_memory_impl(addr, size, exec); 2985 if (err != 0) { 2986 // the caller wants all commit errors to exit with the specified mesg: 2987 warn_fail_commit_memory(addr, size, exec, err); 2988 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2989 } 2990 } 2991 2992 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2993 #ifndef MAP_HUGETLB 2994 #define MAP_HUGETLB 0x40000 2995 #endif 2996 2997 // If mmap flags are set with MAP_HUGETLB and the system supports multiple 2998 // huge page sizes, flag bits [26:31] can be used to encode the log2 of the 2999 // desired huge page size. Otherwise, the system's default huge page size will be used. 3000 // See mmap(2) man page for more info (since Linux 3.8). 3001 // https://lwn.net/Articles/533499/ 3002 #ifndef MAP_HUGE_SHIFT 3003 #define MAP_HUGE_SHIFT 26 3004 #endif 3005 3006 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 3007 #ifndef MADV_HUGEPAGE 3008 #define MADV_HUGEPAGE 14 3009 #endif 3010 3011 int os::Linux::commit_memory_impl(char* addr, size_t size, 3012 size_t alignment_hint, bool exec) { 3013 int err = os::Linux::commit_memory_impl(addr, size, exec); 3014 if (err == 0) { 3015 realign_memory(addr, size, alignment_hint); 3016 } 3017 return err; 3018 } 3019 3020 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 3021 bool exec) { 3022 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 3023 } 3024 3025 void os::pd_commit_memory_or_exit(char* addr, size_t size, 3026 size_t alignment_hint, bool exec, 3027 const char* mesg) { 3028 assert(mesg != NULL, "mesg must be specified"); 3029 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 3030 if (err != 0) { 3031 // the caller wants all commit errors to exit with the specified mesg: 3032 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 3033 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 3034 } 3035 } 3036 3037 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 3038 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 3039 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 3040 // be supported or the memory may already be backed by huge pages. 3041 ::madvise(addr, bytes, MADV_HUGEPAGE); 3042 } 3043 } 3044 3045 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 3046 // This method works by doing an mmap over an existing mmaping and effectively discarding 3047 // the existing pages. However it won't work for SHM-based large pages that cannot be 3048 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 3049 // small pages on top of the SHM segment. This method always works for small pages, so we 3050 // allow that in any case. 3051 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 3052 commit_memory(addr, bytes, alignment_hint, !ExecMem); 3053 } 3054 } 3055 3056 void os::numa_make_global(char *addr, size_t bytes) { 3057 Linux::numa_interleave_memory(addr, bytes); 3058 } 3059 3060 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 3061 // bind policy to MPOL_PREFERRED for the current thread. 3062 #define USE_MPOL_PREFERRED 0 3063 3064 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 3065 // To make NUMA and large pages more robust when both enabled, we need to ease 3066 // the requirements on where the memory should be allocated. MPOL_BIND is the 3067 // default policy and it will force memory to be allocated on the specified 3068 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 3069 // the specified node, but will not force it. Using this policy will prevent 3070 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 3071 // free large pages. 3072 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 3073 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 3074 } 3075 3076 bool os::numa_topology_changed() { return false; } 3077 3078 size_t os::numa_get_groups_num() { 3079 // Return just the number of nodes in which it's possible to allocate memory 3080 // (in numa terminology, configured nodes). 3081 return Linux::numa_num_configured_nodes(); 3082 } 3083 3084 int os::numa_get_group_id() { 3085 int cpu_id = Linux::sched_getcpu(); 3086 if (cpu_id != -1) { 3087 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 3088 if (lgrp_id != -1) { 3089 return lgrp_id; 3090 } 3091 } 3092 return 0; 3093 } 3094 3095 int os::numa_get_group_id_for_address(const void* address) { 3096 void** pages = const_cast<void**>(&address); 3097 int id = -1; 3098 3099 if (os::Linux::numa_move_pages(0, 1, pages, NULL, &id, 0) == -1) { 3100 return -1; 3101 } 3102 if (id < 0) { 3103 return -1; 3104 } 3105 return id; 3106 } 3107 3108 int os::Linux::get_existing_num_nodes() { 3109 int node; 3110 int highest_node_number = Linux::numa_max_node(); 3111 int num_nodes = 0; 3112 3113 // Get the total number of nodes in the system including nodes without memory. 3114 for (node = 0; node <= highest_node_number; node++) { 3115 if (is_node_in_existing_nodes(node)) { 3116 num_nodes++; 3117 } 3118 } 3119 return num_nodes; 3120 } 3121 3122 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 3123 int highest_node_number = Linux::numa_max_node(); 3124 size_t i = 0; 3125 3126 // Map all node ids in which it is possible to allocate memory. Also nodes are 3127 // not always consecutively available, i.e. available from 0 to the highest 3128 // node number. If the nodes have been bound explicitly using numactl membind, 3129 // then allocate memory from those nodes only. 3130 for (int node = 0; node <= highest_node_number; node++) { 3131 if (Linux::is_node_in_bound_nodes((unsigned int)node)) { 3132 ids[i++] = node; 3133 } 3134 } 3135 return i; 3136 } 3137 3138 bool os::get_page_info(char *start, page_info* info) { 3139 return false; 3140 } 3141 3142 char *os::scan_pages(char *start, char* end, page_info* page_expected, 3143 page_info* page_found) { 3144 return end; 3145 } 3146 3147 3148 int os::Linux::sched_getcpu_syscall(void) { 3149 unsigned int cpu = 0; 3150 int retval = -1; 3151 3152 #if defined(IA32) 3153 #ifndef SYS_getcpu 3154 #define SYS_getcpu 318 3155 #endif 3156 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 3157 #elif defined(AMD64) 3158 // Unfortunately we have to bring all these macros here from vsyscall.h 3159 // to be able to compile on old linuxes. 3160 #define __NR_vgetcpu 2 3161 #define VSYSCALL_START (-10UL << 20) 3162 #define VSYSCALL_SIZE 1024 3163 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 3164 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 3165 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 3166 retval = vgetcpu(&cpu, NULL, NULL); 3167 #endif 3168 3169 return (retval == -1) ? retval : cpu; 3170 } 3171 3172 void os::Linux::sched_getcpu_init() { 3173 // sched_getcpu() should be in libc. 3174 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 3175 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 3176 3177 // If it's not, try a direct syscall. 3178 if (sched_getcpu() == -1) { 3179 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 3180 (void*)&sched_getcpu_syscall)); 3181 } 3182 3183 if (sched_getcpu() == -1) { 3184 vm_exit_during_initialization("getcpu(2) system call not supported by kernel"); 3185 } 3186 } 3187 3188 // Something to do with the numa-aware allocator needs these symbols 3189 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 3190 extern "C" JNIEXPORT void numa_error(char *where) { } 3191 3192 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails 3193 // load symbol from base version instead. 3194 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 3195 void *f = dlvsym(handle, name, "libnuma_1.1"); 3196 if (f == NULL) { 3197 f = dlsym(handle, name); 3198 } 3199 return f; 3200 } 3201 3202 // Handle request to load libnuma symbol version 1.2 (API v2) only. 3203 // Return NULL if the symbol is not defined in this particular version. 3204 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) { 3205 return dlvsym(handle, name, "libnuma_1.2"); 3206 } 3207 3208 bool os::Linux::libnuma_init() { 3209 if (sched_getcpu() != -1) { // Requires sched_getcpu() support 3210 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 3211 if (handle != NULL) { 3212 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 3213 libnuma_dlsym(handle, "numa_node_to_cpus"))); 3214 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 3215 libnuma_dlsym(handle, "numa_max_node"))); 3216 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t, 3217 libnuma_dlsym(handle, "numa_num_configured_nodes"))); 3218 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 3219 libnuma_dlsym(handle, "numa_available"))); 3220 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 3221 libnuma_dlsym(handle, "numa_tonode_memory"))); 3222 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 3223 libnuma_dlsym(handle, "numa_interleave_memory"))); 3224 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t, 3225 libnuma_v2_dlsym(handle, "numa_interleave_memory"))); 3226 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 3227 libnuma_dlsym(handle, "numa_set_bind_policy"))); 3228 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t, 3229 libnuma_dlsym(handle, "numa_bitmask_isbitset"))); 3230 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t, 3231 libnuma_dlsym(handle, "numa_distance"))); 3232 set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t, 3233 libnuma_v2_dlsym(handle, "numa_get_membind"))); 3234 set_numa_get_interleave_mask(CAST_TO_FN_PTR(numa_get_interleave_mask_func_t, 3235 libnuma_v2_dlsym(handle, "numa_get_interleave_mask"))); 3236 set_numa_move_pages(CAST_TO_FN_PTR(numa_move_pages_func_t, 3237 libnuma_dlsym(handle, "numa_move_pages"))); 3238 set_numa_set_preferred(CAST_TO_FN_PTR(numa_set_preferred_func_t, 3239 libnuma_dlsym(handle, "numa_set_preferred"))); 3240 3241 if (numa_available() != -1) { 3242 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 3243 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr")); 3244 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr")); 3245 set_numa_interleave_bitmask(_numa_get_interleave_mask()); 3246 set_numa_membind_bitmask(_numa_get_membind()); 3247 // Create an index -> node mapping, since nodes are not always consecutive 3248 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 3249 rebuild_nindex_to_node_map(); 3250 // Create a cpu -> node mapping 3251 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 3252 rebuild_cpu_to_node_map(); 3253 return true; 3254 } 3255 } 3256 } 3257 return false; 3258 } 3259 3260 size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 3261 // Creating guard page is very expensive. Java thread has HotSpot 3262 // guard pages, only enable glibc guard page for non-Java threads. 3263 // (Remember: compiler thread is a Java thread, too!) 3264 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size()); 3265 } 3266 3267 void os::Linux::rebuild_nindex_to_node_map() { 3268 int highest_node_number = Linux::numa_max_node(); 3269 3270 nindex_to_node()->clear(); 3271 for (int node = 0; node <= highest_node_number; node++) { 3272 if (Linux::is_node_in_existing_nodes(node)) { 3273 nindex_to_node()->append(node); 3274 } 3275 } 3276 } 3277 3278 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 3279 // The table is later used in get_node_by_cpu(). 3280 void os::Linux::rebuild_cpu_to_node_map() { 3281 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 3282 // in libnuma (possible values are starting from 16, 3283 // and continuing up with every other power of 2, but less 3284 // than the maximum number of CPUs supported by kernel), and 3285 // is a subject to change (in libnuma version 2 the requirements 3286 // are more reasonable) we'll just hardcode the number they use 3287 // in the library. 3288 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 3289 3290 size_t cpu_num = processor_count(); 3291 size_t cpu_map_size = NCPUS / BitsPerCLong; 3292 size_t cpu_map_valid_size = 3293 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 3294 3295 cpu_to_node()->clear(); 3296 cpu_to_node()->at_grow(cpu_num - 1); 3297 3298 size_t node_num = get_existing_num_nodes(); 3299 3300 int distance = 0; 3301 int closest_distance = INT_MAX; 3302 int closest_node = 0; 3303 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 3304 for (size_t i = 0; i < node_num; i++) { 3305 // Check if node is configured (not a memory-less node). If it is not, find 3306 // the closest configured node. Check also if node is bound, i.e. it's allowed 3307 // to allocate memory from the node. If it's not allowed, map cpus in that node 3308 // to the closest node from which memory allocation is allowed. 3309 if (!is_node_in_configured_nodes(nindex_to_node()->at(i)) || 3310 !is_node_in_bound_nodes(nindex_to_node()->at(i))) { 3311 closest_distance = INT_MAX; 3312 // Check distance from all remaining nodes in the system. Ignore distance 3313 // from itself, from another non-configured node, and from another non-bound 3314 // node. 3315 for (size_t m = 0; m < node_num; m++) { 3316 if (m != i && 3317 is_node_in_configured_nodes(nindex_to_node()->at(m)) && 3318 is_node_in_bound_nodes(nindex_to_node()->at(m))) { 3319 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m)); 3320 // If a closest node is found, update. There is always at least one 3321 // configured and bound node in the system so there is always at least 3322 // one node close. 3323 if (distance != 0 && distance < closest_distance) { 3324 closest_distance = distance; 3325 closest_node = nindex_to_node()->at(m); 3326 } 3327 } 3328 } 3329 } else { 3330 // Current node is already a configured node. 3331 closest_node = nindex_to_node()->at(i); 3332 } 3333 3334 // Get cpus from the original node and map them to the closest node. If node 3335 // is a configured node (not a memory-less node), then original node and 3336 // closest node are the same. 3337 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 3338 for (size_t j = 0; j < cpu_map_valid_size; j++) { 3339 if (cpu_map[j] != 0) { 3340 for (size_t k = 0; k < BitsPerCLong; k++) { 3341 if (cpu_map[j] & (1UL << k)) { 3342 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node); 3343 } 3344 } 3345 } 3346 } 3347 } 3348 } 3349 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 3350 } 3351 3352 int os::Linux::get_node_by_cpu(int cpu_id) { 3353 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 3354 return cpu_to_node()->at(cpu_id); 3355 } 3356 return -1; 3357 } 3358 3359 GrowableArray<int>* os::Linux::_cpu_to_node; 3360 GrowableArray<int>* os::Linux::_nindex_to_node; 3361 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 3362 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 3363 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 3364 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes; 3365 os::Linux::numa_available_func_t os::Linux::_numa_available; 3366 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 3367 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 3368 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2; 3369 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 3370 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset; 3371 os::Linux::numa_distance_func_t os::Linux::_numa_distance; 3372 os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind; 3373 os::Linux::numa_get_interleave_mask_func_t os::Linux::_numa_get_interleave_mask; 3374 os::Linux::numa_move_pages_func_t os::Linux::_numa_move_pages; 3375 os::Linux::numa_set_preferred_func_t os::Linux::_numa_set_preferred; 3376 os::Linux::NumaAllocationPolicy os::Linux::_current_numa_policy; 3377 unsigned long* os::Linux::_numa_all_nodes; 3378 struct bitmask* os::Linux::_numa_all_nodes_ptr; 3379 struct bitmask* os::Linux::_numa_nodes_ptr; 3380 struct bitmask* os::Linux::_numa_interleave_bitmask; 3381 struct bitmask* os::Linux::_numa_membind_bitmask; 3382 3383 bool os::pd_uncommit_memory(char* addr, size_t size) { 3384 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 3385 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 3386 return res != (uintptr_t) MAP_FAILED; 3387 } 3388 3389 static address get_stack_commited_bottom(address bottom, size_t size) { 3390 address nbot = bottom; 3391 address ntop = bottom + size; 3392 3393 size_t page_sz = os::vm_page_size(); 3394 unsigned pages = size / page_sz; 3395 3396 unsigned char vec[1]; 3397 unsigned imin = 1, imax = pages + 1, imid; 3398 int mincore_return_value = 0; 3399 3400 assert(imin <= imax, "Unexpected page size"); 3401 3402 while (imin < imax) { 3403 imid = (imax + imin) / 2; 3404 nbot = ntop - (imid * page_sz); 3405 3406 // Use a trick with mincore to check whether the page is mapped or not. 3407 // mincore sets vec to 1 if page resides in memory and to 0 if page 3408 // is swapped output but if page we are asking for is unmapped 3409 // it returns -1,ENOMEM 3410 mincore_return_value = mincore(nbot, page_sz, vec); 3411 3412 if (mincore_return_value == -1) { 3413 // Page is not mapped go up 3414 // to find first mapped page 3415 if (errno != EAGAIN) { 3416 assert(errno == ENOMEM, "Unexpected mincore errno"); 3417 imax = imid; 3418 } 3419 } else { 3420 // Page is mapped go down 3421 // to find first not mapped page 3422 imin = imid + 1; 3423 } 3424 } 3425 3426 nbot = nbot + page_sz; 3427 3428 // Adjust stack bottom one page up if last checked page is not mapped 3429 if (mincore_return_value == -1) { 3430 nbot = nbot + page_sz; 3431 } 3432 3433 return nbot; 3434 } 3435 3436 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) { 3437 int mincore_return_value; 3438 const size_t stripe = 1024; // query this many pages each time 3439 unsigned char vec[stripe + 1]; 3440 // set a guard 3441 vec[stripe] = 'X'; 3442 3443 const size_t page_sz = os::vm_page_size(); 3444 size_t pages = size / page_sz; 3445 3446 assert(is_aligned(start, page_sz), "Start address must be page aligned"); 3447 assert(is_aligned(size, page_sz), "Size must be page aligned"); 3448 3449 committed_start = NULL; 3450 3451 int loops = (pages + stripe - 1) / stripe; 3452 int committed_pages = 0; 3453 address loop_base = start; 3454 bool found_range = false; 3455 3456 for (int index = 0; index < loops && !found_range; index ++) { 3457 assert(pages > 0, "Nothing to do"); 3458 int pages_to_query = (pages >= stripe) ? stripe : pages; 3459 pages -= pages_to_query; 3460 3461 // Get stable read 3462 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN); 3463 3464 // During shutdown, some memory goes away without properly notifying NMT, 3465 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object. 3466 // Bailout and return as not committed for now. 3467 if (mincore_return_value == -1 && errno == ENOMEM) { 3468 return false; 3469 } 3470 3471 assert(vec[stripe] == 'X', "overflow guard"); 3472 assert(mincore_return_value == 0, "Range must be valid"); 3473 // Process this stripe 3474 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) { 3475 if ((vec[vecIdx] & 0x01) == 0) { // not committed 3476 // End of current contiguous region 3477 if (committed_start != NULL) { 3478 found_range = true; 3479 break; 3480 } 3481 } else { // committed 3482 // Start of region 3483 if (committed_start == NULL) { 3484 committed_start = loop_base + page_sz * vecIdx; 3485 } 3486 committed_pages ++; 3487 } 3488 } 3489 3490 loop_base += pages_to_query * page_sz; 3491 } 3492 3493 if (committed_start != NULL) { 3494 assert(committed_pages > 0, "Must have committed region"); 3495 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has"); 3496 assert(committed_start >= start && committed_start < start + size, "Out of range"); 3497 committed_size = page_sz * committed_pages; 3498 return true; 3499 } else { 3500 assert(committed_pages == 0, "Should not have committed region"); 3501 return false; 3502 } 3503 } 3504 3505 3506 // Linux uses a growable mapping for the stack, and if the mapping for 3507 // the stack guard pages is not removed when we detach a thread the 3508 // stack cannot grow beyond the pages where the stack guard was 3509 // mapped. If at some point later in the process the stack expands to 3510 // that point, the Linux kernel cannot expand the stack any further 3511 // because the guard pages are in the way, and a segfault occurs. 3512 // 3513 // However, it's essential not to split the stack region by unmapping 3514 // a region (leaving a hole) that's already part of the stack mapping, 3515 // so if the stack mapping has already grown beyond the guard pages at 3516 // the time we create them, we have to truncate the stack mapping. 3517 // So, we need to know the extent of the stack mapping when 3518 // create_stack_guard_pages() is called. 3519 3520 // We only need this for stacks that are growable: at the time of 3521 // writing thread stacks don't use growable mappings (i.e. those 3522 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 3523 // only applies to the main thread. 3524 3525 // If the (growable) stack mapping already extends beyond the point 3526 // where we're going to put our guard pages, truncate the mapping at 3527 // that point by munmap()ping it. This ensures that when we later 3528 // munmap() the guard pages we don't leave a hole in the stack 3529 // mapping. This only affects the main/primordial thread 3530 3531 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3532 if (os::is_primordial_thread()) { 3533 // As we manually grow stack up to bottom inside create_attached_thread(), 3534 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3535 // we don't need to do anything special. 3536 // Check it first, before calling heavy function. 3537 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3538 unsigned char vec[1]; 3539 3540 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3541 // Fallback to slow path on all errors, including EAGAIN 3542 stack_extent = (uintptr_t) get_stack_commited_bottom( 3543 os::Linux::initial_thread_stack_bottom(), 3544 (size_t)addr - stack_extent); 3545 } 3546 3547 if (stack_extent < (uintptr_t)addr) { 3548 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3549 } 3550 } 3551 3552 return os::commit_memory(addr, size, !ExecMem); 3553 } 3554 3555 // If this is a growable mapping, remove the guard pages entirely by 3556 // munmap()ping them. If not, just call uncommit_memory(). This only 3557 // affects the main/primordial thread, but guard against future OS changes. 3558 // It's safe to always unmap guard pages for primordial thread because we 3559 // always place it right after end of the mapped region. 3560 3561 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3562 uintptr_t stack_extent, stack_base; 3563 3564 if (os::is_primordial_thread()) { 3565 return ::munmap(addr, size) == 0; 3566 } 3567 3568 return os::uncommit_memory(addr, size); 3569 } 3570 3571 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3572 // at 'requested_addr'. If there are existing memory mappings at the same 3573 // location, however, they will be overwritten. If 'fixed' is false, 3574 // 'requested_addr' is only treated as a hint, the return value may or 3575 // may not start from the requested address. Unlike Linux mmap(), this 3576 // function returns NULL to indicate failure. 3577 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3578 char * addr; 3579 int flags; 3580 3581 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3582 if (fixed) { 3583 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3584 flags |= MAP_FIXED; 3585 } 3586 3587 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3588 // touch an uncommitted page. Otherwise, the read/write might 3589 // succeed if we have enough swap space to back the physical page. 3590 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3591 flags, -1, 0); 3592 3593 return addr == MAP_FAILED ? NULL : addr; 3594 } 3595 3596 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3597 // (req_addr != NULL) or with a given alignment. 3598 // - bytes shall be a multiple of alignment. 3599 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3600 // - alignment sets the alignment at which memory shall be allocated. 3601 // It must be a multiple of allocation granularity. 3602 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3603 // req_addr or NULL. 3604 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3605 3606 size_t extra_size = bytes; 3607 if (req_addr == NULL && alignment > 0) { 3608 extra_size += alignment; 3609 } 3610 3611 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3612 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3613 -1, 0); 3614 if (start == MAP_FAILED) { 3615 start = NULL; 3616 } else { 3617 if (req_addr != NULL) { 3618 if (start != req_addr) { 3619 ::munmap(start, extra_size); 3620 start = NULL; 3621 } 3622 } else { 3623 char* const start_aligned = align_up(start, alignment); 3624 char* const end_aligned = start_aligned + bytes; 3625 char* const end = start + extra_size; 3626 if (start_aligned > start) { 3627 ::munmap(start, start_aligned - start); 3628 } 3629 if (end_aligned < end) { 3630 ::munmap(end_aligned, end - end_aligned); 3631 } 3632 start = start_aligned; 3633 } 3634 } 3635 return start; 3636 } 3637 3638 static int anon_munmap(char * addr, size_t size) { 3639 return ::munmap(addr, size) == 0; 3640 } 3641 3642 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3643 size_t alignment_hint) { 3644 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3645 } 3646 3647 bool os::pd_release_memory(char* addr, size_t size) { 3648 return anon_munmap(addr, size); 3649 } 3650 3651 static bool linux_mprotect(char* addr, size_t size, int prot) { 3652 // Linux wants the mprotect address argument to be page aligned. 3653 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size()); 3654 3655 // According to SUSv3, mprotect() should only be used with mappings 3656 // established by mmap(), and mmap() always maps whole pages. Unaligned 3657 // 'addr' likely indicates problem in the VM (e.g. trying to change 3658 // protection of malloc'ed or statically allocated memory). Check the 3659 // caller if you hit this assert. 3660 assert(addr == bottom, "sanity check"); 3661 3662 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3663 Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with protection modes %x", p2i(bottom), p2i(bottom+size), prot); 3664 return ::mprotect(bottom, size, prot) == 0; 3665 } 3666 3667 // Set protections specified 3668 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3669 bool is_committed) { 3670 unsigned int p = 0; 3671 switch (prot) { 3672 case MEM_PROT_NONE: p = PROT_NONE; break; 3673 case MEM_PROT_READ: p = PROT_READ; break; 3674 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3675 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3676 default: 3677 ShouldNotReachHere(); 3678 } 3679 // is_committed is unused. 3680 return linux_mprotect(addr, bytes, p); 3681 } 3682 3683 bool os::guard_memory(char* addr, size_t size) { 3684 return linux_mprotect(addr, size, PROT_NONE); 3685 } 3686 3687 bool os::unguard_memory(char* addr, size_t size) { 3688 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3689 } 3690 3691 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3692 size_t page_size) { 3693 bool result = false; 3694 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3695 MAP_ANONYMOUS|MAP_PRIVATE, 3696 -1, 0); 3697 if (p != MAP_FAILED) { 3698 void *aligned_p = align_up(p, page_size); 3699 3700 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3701 3702 munmap(p, page_size * 2); 3703 } 3704 3705 if (warn && !result) { 3706 warning("TransparentHugePages is not supported by the operating system."); 3707 } 3708 3709 return result; 3710 } 3711 3712 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3713 bool result = false; 3714 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3715 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3716 -1, 0); 3717 3718 if (p != MAP_FAILED) { 3719 // We don't know if this really is a huge page or not. 3720 FILE *fp = fopen("/proc/self/maps", "r"); 3721 if (fp) { 3722 while (!feof(fp)) { 3723 char chars[257]; 3724 long x = 0; 3725 if (fgets(chars, sizeof(chars), fp)) { 3726 if (sscanf(chars, "%lx-%*x", &x) == 1 3727 && x == (long)p) { 3728 if (strstr (chars, "hugepage")) { 3729 result = true; 3730 break; 3731 } 3732 } 3733 } 3734 } 3735 fclose(fp); 3736 } 3737 munmap(p, page_size); 3738 } 3739 3740 if (warn && !result) { 3741 warning("HugeTLBFS is not supported by the operating system."); 3742 } 3743 3744 return result; 3745 } 3746 3747 // From the coredump_filter documentation: 3748 // 3749 // - (bit 0) anonymous private memory 3750 // - (bit 1) anonymous shared memory 3751 // - (bit 2) file-backed private memory 3752 // - (bit 3) file-backed shared memory 3753 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3754 // effective only if the bit 2 is cleared) 3755 // - (bit 5) hugetlb private memory 3756 // - (bit 6) hugetlb shared memory 3757 // - (bit 7) dax private memory 3758 // - (bit 8) dax shared memory 3759 // 3760 static void set_coredump_filter(CoredumpFilterBit bit) { 3761 FILE *f; 3762 long cdm; 3763 3764 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3765 return; 3766 } 3767 3768 if (fscanf(f, "%lx", &cdm) != 1) { 3769 fclose(f); 3770 return; 3771 } 3772 3773 long saved_cdm = cdm; 3774 rewind(f); 3775 cdm |= bit; 3776 3777 if (cdm != saved_cdm) { 3778 fprintf(f, "%#lx", cdm); 3779 } 3780 3781 fclose(f); 3782 } 3783 3784 // Large page support 3785 3786 static size_t _large_page_size = 0; 3787 3788 size_t os::Linux::find_default_large_page_size() { 3789 if (_default_large_page_size != 0) { 3790 return _default_large_page_size; 3791 } 3792 size_t large_page_size = 0; 3793 3794 // large_page_size on Linux is used to round up heap size. x86 uses either 3795 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3796 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3797 // page as large as 256M. 3798 // 3799 // Here we try to figure out page size by parsing /proc/meminfo and looking 3800 // for a line with the following format: 3801 // Hugepagesize: 2048 kB 3802 // 3803 // If we can't determine the value (e.g. /proc is not mounted, or the text 3804 // format has been changed), we'll use the largest page size supported by 3805 // the processor. 3806 3807 #ifndef ZERO 3808 large_page_size = 3809 AARCH64_ONLY(2 * M) 3810 AMD64_ONLY(2 * M) 3811 ARM32_ONLY(2 * M) 3812 IA32_ONLY(4 * M) 3813 IA64_ONLY(256 * M) 3814 PPC_ONLY(4 * M) 3815 S390_ONLY(1 * M); 3816 #endif // ZERO 3817 3818 FILE *fp = fopen("/proc/meminfo", "r"); 3819 if (fp) { 3820 while (!feof(fp)) { 3821 int x = 0; 3822 char buf[16]; 3823 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3824 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3825 large_page_size = x * K; 3826 break; 3827 } 3828 } else { 3829 // skip to next line 3830 for (;;) { 3831 int ch = fgetc(fp); 3832 if (ch == EOF || ch == (int)'\n') break; 3833 } 3834 } 3835 } 3836 fclose(fp); 3837 } 3838 return large_page_size; 3839 } 3840 3841 size_t os::Linux::find_large_page_size(size_t large_page_size) { 3842 if (_default_large_page_size == 0) { 3843 _default_large_page_size = Linux::find_default_large_page_size(); 3844 } 3845 // We need to scan /sys/kernel/mm/hugepages 3846 // to discover the available page sizes 3847 const char* sys_hugepages = "/sys/kernel/mm/hugepages"; 3848 3849 DIR *dir = opendir(sys_hugepages); 3850 if (dir == NULL) { 3851 return _default_large_page_size; 3852 } 3853 3854 struct dirent *entry; 3855 size_t page_size; 3856 while ((entry = readdir(dir)) != NULL) { 3857 if (entry->d_type == DT_DIR && 3858 sscanf(entry->d_name, "hugepages-%zukB", &page_size) == 1) { 3859 // The kernel is using kB, hotspot uses bytes 3860 if (large_page_size == page_size * K) { 3861 closedir(dir); 3862 return large_page_size; 3863 } 3864 } 3865 } 3866 closedir(dir); 3867 return _default_large_page_size; 3868 } 3869 3870 size_t os::Linux::setup_large_page_size() { 3871 _default_large_page_size = Linux::find_default_large_page_size(); 3872 3873 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != _default_large_page_size ) { 3874 _large_page_size = find_large_page_size(LargePageSizeInBytes); 3875 if (_large_page_size == _default_large_page_size) { 3876 warning("Setting LargePageSizeInBytes=" SIZE_FORMAT " has no effect on this OS. Using the default large page size " 3877 SIZE_FORMAT "%s.", 3878 LargePageSizeInBytes, 3879 byte_size_in_proper_unit(_large_page_size), proper_unit_for_byte_size(_large_page_size)); 3880 } 3881 } else { 3882 _large_page_size = _default_large_page_size; 3883 } 3884 3885 const size_t default_page_size = (size_t)Linux::page_size(); 3886 if (_large_page_size > default_page_size) { 3887 _page_sizes[0] = _large_page_size; 3888 _page_sizes[1] = default_page_size; 3889 _page_sizes[2] = 0; 3890 } 3891 3892 return _large_page_size; 3893 } 3894 3895 size_t os::Linux::default_large_page_size() { 3896 return _default_large_page_size; 3897 } 3898 3899 bool os::Linux::setup_large_page_type(size_t page_size) { 3900 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3901 FLAG_IS_DEFAULT(UseSHM) && 3902 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3903 3904 // The type of large pages has not been specified by the user. 3905 3906 // Try UseHugeTLBFS and then UseSHM. 3907 UseHugeTLBFS = UseSHM = true; 3908 3909 // Don't try UseTransparentHugePages since there are known 3910 // performance issues with it turned on. This might change in the future. 3911 UseTransparentHugePages = false; 3912 } 3913 3914 if (UseTransparentHugePages) { 3915 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3916 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3917 UseHugeTLBFS = false; 3918 UseSHM = false; 3919 return true; 3920 } 3921 UseTransparentHugePages = false; 3922 } 3923 3924 if (UseHugeTLBFS) { 3925 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3926 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3927 UseSHM = false; 3928 return true; 3929 } 3930 UseHugeTLBFS = false; 3931 } 3932 3933 return UseSHM; 3934 } 3935 3936 void os::large_page_init() { 3937 if (!UseLargePages && 3938 !UseTransparentHugePages && 3939 !UseHugeTLBFS && 3940 !UseSHM) { 3941 // Not using large pages. 3942 return; 3943 } 3944 3945 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3946 // The user explicitly turned off large pages. 3947 // Ignore the rest of the large pages flags. 3948 UseTransparentHugePages = false; 3949 UseHugeTLBFS = false; 3950 UseSHM = false; 3951 return; 3952 } 3953 3954 size_t large_page_size = Linux::setup_large_page_size(); 3955 UseLargePages = Linux::setup_large_page_type(large_page_size); 3956 3957 set_coredump_filter(LARGEPAGES_BIT); 3958 } 3959 3960 #ifndef SHM_HUGETLB 3961 #define SHM_HUGETLB 04000 3962 #endif 3963 3964 #define shm_warning_format(format, ...) \ 3965 do { \ 3966 if (UseLargePages && \ 3967 (!FLAG_IS_DEFAULT(UseLargePages) || \ 3968 !FLAG_IS_DEFAULT(UseSHM) || \ 3969 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \ 3970 warning(format, __VA_ARGS__); \ 3971 } \ 3972 } while (0) 3973 3974 #define shm_warning(str) shm_warning_format("%s", str) 3975 3976 #define shm_warning_with_errno(str) \ 3977 do { \ 3978 int err = errno; \ 3979 shm_warning_format(str " (error = %d)", err); \ 3980 } while (0) 3981 3982 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) { 3983 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment"); 3984 3985 if (!is_aligned(alignment, SHMLBA)) { 3986 assert(false, "Code below assumes that alignment is at least SHMLBA aligned"); 3987 return NULL; 3988 } 3989 3990 // To ensure that we get 'alignment' aligned memory from shmat, 3991 // we pre-reserve aligned virtual memory and then attach to that. 3992 3993 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL); 3994 if (pre_reserved_addr == NULL) { 3995 // Couldn't pre-reserve aligned memory. 3996 shm_warning("Failed to pre-reserve aligned memory for shmat."); 3997 return NULL; 3998 } 3999 4000 // SHM_REMAP is needed to allow shmat to map over an existing mapping. 4001 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP); 4002 4003 if ((intptr_t)addr == -1) { 4004 int err = errno; 4005 shm_warning_with_errno("Failed to attach shared memory."); 4006 4007 assert(err != EACCES, "Unexpected error"); 4008 assert(err != EIDRM, "Unexpected error"); 4009 assert(err != EINVAL, "Unexpected error"); 4010 4011 // Since we don't know if the kernel unmapped the pre-reserved memory area 4012 // we can't unmap it, since that would potentially unmap memory that was 4013 // mapped from other threads. 4014 return NULL; 4015 } 4016 4017 return addr; 4018 } 4019 4020 static char* shmat_at_address(int shmid, char* req_addr) { 4021 if (!is_aligned(req_addr, SHMLBA)) { 4022 assert(false, "Requested address needs to be SHMLBA aligned"); 4023 return NULL; 4024 } 4025 4026 char* addr = (char*)shmat(shmid, req_addr, 0); 4027 4028 if ((intptr_t)addr == -1) { 4029 shm_warning_with_errno("Failed to attach shared memory."); 4030 return NULL; 4031 } 4032 4033 return addr; 4034 } 4035 4036 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) { 4037 // If a req_addr has been provided, we assume that the caller has already aligned the address. 4038 if (req_addr != NULL) { 4039 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size"); 4040 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment"); 4041 return shmat_at_address(shmid, req_addr); 4042 } 4043 4044 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically 4045 // return large page size aligned memory addresses when req_addr == NULL. 4046 // However, if the alignment is larger than the large page size, we have 4047 // to manually ensure that the memory returned is 'alignment' aligned. 4048 if (alignment > os::large_page_size()) { 4049 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size"); 4050 return shmat_with_alignment(shmid, bytes, alignment); 4051 } else { 4052 return shmat_at_address(shmid, NULL); 4053 } 4054 } 4055 4056 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 4057 char* req_addr, bool exec) { 4058 // "exec" is passed in but not used. Creating the shared image for 4059 // the code cache doesn't have an SHM_X executable permission to check. 4060 assert(UseLargePages && UseSHM, "only for SHM large pages"); 4061 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 4062 assert(is_aligned(req_addr, alignment), "Unaligned address"); 4063 4064 if (!is_aligned(bytes, os::large_page_size())) { 4065 return NULL; // Fallback to small pages. 4066 } 4067 4068 // Create a large shared memory region to attach to based on size. 4069 // Currently, size is the total size of the heap. 4070 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 4071 if (shmid == -1) { 4072 // Possible reasons for shmget failure: 4073 // 1. shmmax is too small for Java heap. 4074 // > check shmmax value: cat /proc/sys/kernel/shmmax 4075 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 4076 // 2. not enough large page memory. 4077 // > check available large pages: cat /proc/meminfo 4078 // > increase amount of large pages: 4079 // echo new_value > /proc/sys/vm/nr_hugepages 4080 // Note 1: different Linux may use different name for this property, 4081 // e.g. on Redhat AS-3 it is "hugetlb_pool". 4082 // Note 2: it's possible there's enough physical memory available but 4083 // they are so fragmented after a long run that they can't 4084 // coalesce into large pages. Try to reserve large pages when 4085 // the system is still "fresh". 4086 shm_warning_with_errno("Failed to reserve shared memory."); 4087 return NULL; 4088 } 4089 4090 // Attach to the region. 4091 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr); 4092 4093 // Remove shmid. If shmat() is successful, the actual shared memory segment 4094 // will be deleted when it's detached by shmdt() or when the process 4095 // terminates. If shmat() is not successful this will remove the shared 4096 // segment immediately. 4097 shmctl(shmid, IPC_RMID, NULL); 4098 4099 return addr; 4100 } 4101 4102 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 4103 int error) { 4104 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 4105 4106 bool warn_on_failure = UseLargePages && 4107 (!FLAG_IS_DEFAULT(UseLargePages) || 4108 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 4109 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 4110 4111 if (warn_on_failure) { 4112 char msg[128]; 4113 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 4114 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 4115 warning("%s", msg); 4116 } 4117 } 4118 4119 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 4120 char* req_addr, 4121 bool exec) { 4122 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 4123 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size"); 4124 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 4125 4126 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 4127 int flags = MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB; 4128 4129 if (os::large_page_size() != default_large_page_size()) { 4130 flags |= (exact_log2(os::large_page_size()) << MAP_HUGE_SHIFT); 4131 } 4132 char* addr = (char*)::mmap(req_addr, bytes, prot, flags, -1, 0); 4133 4134 if (addr == MAP_FAILED) { 4135 warn_on_large_pages_failure(req_addr, bytes, errno); 4136 return NULL; 4137 } 4138 4139 assert(is_aligned(addr, os::large_page_size()), "Must be"); 4140 4141 return addr; 4142 } 4143 4144 // Reserve memory using mmap(MAP_HUGETLB). 4145 // - bytes shall be a multiple of alignment. 4146 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 4147 // - alignment sets the alignment at which memory shall be allocated. 4148 // It must be a multiple of allocation granularity. 4149 // Returns address of memory or NULL. If req_addr was not NULL, will only return 4150 // req_addr or NULL. 4151 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 4152 size_t alignment, 4153 char* req_addr, 4154 bool exec) { 4155 size_t large_page_size = os::large_page_size(); 4156 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 4157 4158 assert(is_aligned(req_addr, alignment), "Must be"); 4159 assert(is_aligned(bytes, alignment), "Must be"); 4160 4161 // First reserve - but not commit - the address range in small pages. 4162 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 4163 4164 if (start == NULL) { 4165 return NULL; 4166 } 4167 4168 assert(is_aligned(start, alignment), "Must be"); 4169 4170 char* end = start + bytes; 4171 4172 // Find the regions of the allocated chunk that can be promoted to large pages. 4173 char* lp_start = align_up(start, large_page_size); 4174 char* lp_end = align_down(end, large_page_size); 4175 4176 size_t lp_bytes = lp_end - lp_start; 4177 4178 assert(is_aligned(lp_bytes, large_page_size), "Must be"); 4179 4180 if (lp_bytes == 0) { 4181 // The mapped region doesn't even span the start and the end of a large page. 4182 // Fall back to allocate a non-special area. 4183 ::munmap(start, end - start); 4184 return NULL; 4185 } 4186 4187 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 4188 int flags = MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED; 4189 void* result; 4190 4191 // Commit small-paged leading area. 4192 if (start != lp_start) { 4193 result = ::mmap(start, lp_start - start, prot, flags, -1, 0); 4194 if (result == MAP_FAILED) { 4195 ::munmap(lp_start, end - lp_start); 4196 return NULL; 4197 } 4198 } 4199 4200 // Commit large-paged area. 4201 flags |= MAP_HUGETLB; 4202 4203 if (os::large_page_size() != default_large_page_size()) { 4204 flags |= (exact_log2(os::large_page_size()) << MAP_HUGE_SHIFT); 4205 } 4206 4207 result = ::mmap(lp_start, lp_bytes, prot, flags, -1, 0); 4208 if (result == MAP_FAILED) { 4209 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 4210 // If the mmap above fails, the large pages region will be unmapped and we 4211 // have regions before and after with small pages. Release these regions. 4212 // 4213 // | mapped | unmapped | mapped | 4214 // ^ ^ ^ ^ 4215 // start lp_start lp_end end 4216 // 4217 ::munmap(start, lp_start - start); 4218 ::munmap(lp_end, end - lp_end); 4219 return NULL; 4220 } 4221 4222 // Commit small-paged trailing area. 4223 if (lp_end != end) { 4224 result = ::mmap(lp_end, end - lp_end, prot, 4225 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 4226 -1, 0); 4227 if (result == MAP_FAILED) { 4228 ::munmap(start, lp_end - start); 4229 return NULL; 4230 } 4231 } 4232 4233 return start; 4234 } 4235 4236 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 4237 size_t alignment, 4238 char* req_addr, 4239 bool exec) { 4240 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 4241 assert(is_aligned(req_addr, alignment), "Must be"); 4242 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 4243 assert(is_power_of_2(os::large_page_size()), "Must be"); 4244 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 4245 4246 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 4247 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 4248 } else { 4249 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 4250 } 4251 } 4252 4253 char* os::pd_reserve_memory_special(size_t bytes, size_t alignment, 4254 char* req_addr, bool exec) { 4255 assert(UseLargePages, "only for large pages"); 4256 4257 char* addr; 4258 if (UseSHM) { 4259 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 4260 } else { 4261 assert(UseHugeTLBFS, "must be"); 4262 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 4263 } 4264 4265 if (addr != NULL) { 4266 if (UseNUMAInterleaving) { 4267 numa_make_global(addr, bytes); 4268 } 4269 } 4270 4271 return addr; 4272 } 4273 4274 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 4275 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 4276 return shmdt(base) == 0; 4277 } 4278 4279 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 4280 return pd_release_memory(base, bytes); 4281 } 4282 4283 bool os::pd_release_memory_special(char* base, size_t bytes) { 4284 assert(UseLargePages, "only for large pages"); 4285 bool res; 4286 4287 if (UseSHM) { 4288 res = os::Linux::release_memory_special_shm(base, bytes); 4289 } else { 4290 assert(UseHugeTLBFS, "must be"); 4291 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 4292 } 4293 return res; 4294 } 4295 4296 size_t os::large_page_size() { 4297 return _large_page_size; 4298 } 4299 4300 // With SysV SHM the entire memory region must be allocated as shared 4301 // memory. 4302 // HugeTLBFS allows application to commit large page memory on demand. 4303 // However, when committing memory with HugeTLBFS fails, the region 4304 // that was supposed to be committed will lose the old reservation 4305 // and allow other threads to steal that memory region. Because of this 4306 // behavior we can't commit HugeTLBFS memory. 4307 bool os::can_commit_large_page_memory() { 4308 return UseTransparentHugePages; 4309 } 4310 4311 bool os::can_execute_large_page_memory() { 4312 return UseTransparentHugePages || UseHugeTLBFS; 4313 } 4314 4315 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) { 4316 assert(file_desc >= 0, "file_desc is not valid"); 4317 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr); 4318 if (result != NULL) { 4319 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) { 4320 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory")); 4321 } 4322 } 4323 return result; 4324 } 4325 4326 // Reserve memory at an arbitrary address, only if that area is 4327 // available (and not reserved for something else). 4328 4329 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 4330 // Assert only that the size is a multiple of the page size, since 4331 // that's all that mmap requires, and since that's all we really know 4332 // about at this low abstraction level. If we need higher alignment, 4333 // we can either pass an alignment to this method or verify alignment 4334 // in one of the methods further up the call chain. See bug 5044738. 4335 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 4336 4337 // Repeatedly allocate blocks until the block is allocated at the 4338 // right spot. 4339 4340 // Linux mmap allows caller to pass an address as hint; give it a try first, 4341 // if kernel honors the hint then we can return immediately. 4342 char * addr = anon_mmap(requested_addr, bytes, false); 4343 if (addr == requested_addr) { 4344 return requested_addr; 4345 } 4346 4347 if (addr != NULL) { 4348 // mmap() is successful but it fails to reserve at the requested address 4349 anon_munmap(addr, bytes); 4350 } 4351 4352 return NULL; 4353 } 4354 4355 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 4356 void os::infinite_sleep() { 4357 while (true) { // sleep forever ... 4358 ::sleep(100); // ... 100 seconds at a time 4359 } 4360 } 4361 4362 // Used to convert frequent JVM_Yield() to nops 4363 bool os::dont_yield() { 4364 return DontYieldALot; 4365 } 4366 4367 // Linux CFS scheduler (since 2.6.23) does not guarantee sched_yield(2) will 4368 // actually give up the CPU. Since skip buddy (v2.6.28): 4369 // 4370 // * Sets the yielding task as skip buddy for current CPU's run queue. 4371 // * Picks next from run queue, if empty, picks a skip buddy (can be the yielding task). 4372 // * Clears skip buddies for this run queue (yielding task no longer a skip buddy). 4373 // 4374 // An alternative is calling os::naked_short_nanosleep with a small number to avoid 4375 // getting re-scheduled immediately. 4376 // 4377 void os::naked_yield() { 4378 sched_yield(); 4379 } 4380 4381 //////////////////////////////////////////////////////////////////////////////// 4382 // thread priority support 4383 4384 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 4385 // only supports dynamic priority, static priority must be zero. For real-time 4386 // applications, Linux supports SCHED_RR which allows static priority (1-99). 4387 // However, for large multi-threaded applications, SCHED_RR is not only slower 4388 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 4389 // of 5 runs - Sep 2005). 4390 // 4391 // The following code actually changes the niceness of kernel-thread/LWP. It 4392 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 4393 // not the entire user process, and user level threads are 1:1 mapped to kernel 4394 // threads. It has always been the case, but could change in the future. For 4395 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 4396 // It is only used when ThreadPriorityPolicy=1 and may require system level permission 4397 // (e.g., root privilege or CAP_SYS_NICE capability). 4398 4399 int os::java_to_os_priority[CriticalPriority + 1] = { 4400 19, // 0 Entry should never be used 4401 4402 4, // 1 MinPriority 4403 3, // 2 4404 2, // 3 4405 4406 1, // 4 4407 0, // 5 NormPriority 4408 -1, // 6 4409 4410 -2, // 7 4411 -3, // 8 4412 -4, // 9 NearMaxPriority 4413 4414 -5, // 10 MaxPriority 4415 4416 -5 // 11 CriticalPriority 4417 }; 4418 4419 static int prio_init() { 4420 if (ThreadPriorityPolicy == 1) { 4421 if (geteuid() != 0) { 4422 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy) && !FLAG_IS_JIMAGE_RESOURCE(ThreadPriorityPolicy)) { 4423 warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \ 4424 "e.g., being the root user. If the necessary permission is not " \ 4425 "possessed, changes to priority will be silently ignored."); 4426 } 4427 } 4428 } 4429 if (UseCriticalJavaThreadPriority) { 4430 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 4431 } 4432 return 0; 4433 } 4434 4435 OSReturn os::set_native_priority(Thread* thread, int newpri) { 4436 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 4437 4438 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 4439 return (ret == 0) ? OS_OK : OS_ERR; 4440 } 4441 4442 OSReturn os::get_native_priority(const Thread* const thread, 4443 int *priority_ptr) { 4444 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 4445 *priority_ptr = java_to_os_priority[NormPriority]; 4446 return OS_OK; 4447 } 4448 4449 errno = 0; 4450 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 4451 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 4452 } 4453 4454 //////////////////////////////////////////////////////////////////////////////// 4455 // suspend/resume support 4456 4457 // The low-level signal-based suspend/resume support is a remnant from the 4458 // old VM-suspension that used to be for java-suspension, safepoints etc, 4459 // within hotspot. Currently used by JFR's OSThreadSampler 4460 // 4461 // The remaining code is greatly simplified from the more general suspension 4462 // code that used to be used. 4463 // 4464 // The protocol is quite simple: 4465 // - suspend: 4466 // - sends a signal to the target thread 4467 // - polls the suspend state of the osthread using a yield loop 4468 // - target thread signal handler (SR_handler) sets suspend state 4469 // and blocks in sigsuspend until continued 4470 // - resume: 4471 // - sets target osthread state to continue 4472 // - sends signal to end the sigsuspend loop in the SR_handler 4473 // 4474 // Note that the SR_lock plays no role in this suspend/resume protocol, 4475 // but is checked for NULL in SR_handler as a thread termination indicator. 4476 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs. 4477 // 4478 // Note that resume_clear_context() and suspend_save_context() are needed 4479 // by SR_handler(), so that fetch_frame_from_ucontext() works, 4480 // which in part is used by: 4481 // - Forte Analyzer: AsyncGetCallTrace() 4482 // - StackBanging: get_frame_at_stack_banging_point() 4483 4484 static void resume_clear_context(OSThread *osthread) { 4485 osthread->set_ucontext(NULL); 4486 osthread->set_siginfo(NULL); 4487 } 4488 4489 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 4490 ucontext_t* context) { 4491 osthread->set_ucontext(context); 4492 osthread->set_siginfo(siginfo); 4493 } 4494 4495 // Handler function invoked when a thread's execution is suspended or 4496 // resumed. We have to be careful that only async-safe functions are 4497 // called here (Note: most pthread functions are not async safe and 4498 // should be avoided.) 4499 // 4500 // Note: sigwait() is a more natural fit than sigsuspend() from an 4501 // interface point of view, but sigwait() prevents the signal hander 4502 // from being run. libpthread would get very confused by not having 4503 // its signal handlers run and prevents sigwait()'s use with the 4504 // mutex granting granting signal. 4505 // 4506 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 4507 // 4508 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 4509 // Save and restore errno to avoid confusing native code with EINTR 4510 // after sigsuspend. 4511 int old_errno = errno; 4512 4513 Thread* thread = Thread::current_or_null_safe(); 4514 assert(thread != NULL, "Missing current thread in SR_handler"); 4515 4516 // On some systems we have seen signal delivery get "stuck" until the signal 4517 // mask is changed as part of thread termination. Check that the current thread 4518 // has not already terminated (via SR_lock()) - else the following assertion 4519 // will fail because the thread is no longer a JavaThread as the ~JavaThread 4520 // destructor has completed. 4521 4522 if (thread->SR_lock() == NULL) { 4523 return; 4524 } 4525 4526 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 4527 4528 OSThread* osthread = thread->osthread(); 4529 4530 os::SuspendResume::State current = osthread->sr.state(); 4531 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 4532 suspend_save_context(osthread, siginfo, context); 4533 4534 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 4535 os::SuspendResume::State state = osthread->sr.suspended(); 4536 if (state == os::SuspendResume::SR_SUSPENDED) { 4537 sigset_t suspend_set; // signals for sigsuspend() 4538 sigemptyset(&suspend_set); 4539 // get current set of blocked signals and unblock resume signal 4540 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 4541 sigdelset(&suspend_set, SR_signum); 4542 4543 sr_semaphore.signal(); 4544 // wait here until we are resumed 4545 while (1) { 4546 sigsuspend(&suspend_set); 4547 4548 os::SuspendResume::State result = osthread->sr.running(); 4549 if (result == os::SuspendResume::SR_RUNNING) { 4550 sr_semaphore.signal(); 4551 break; 4552 } 4553 } 4554 4555 } else if (state == os::SuspendResume::SR_RUNNING) { 4556 // request was cancelled, continue 4557 } else { 4558 ShouldNotReachHere(); 4559 } 4560 4561 resume_clear_context(osthread); 4562 } else if (current == os::SuspendResume::SR_RUNNING) { 4563 // request was cancelled, continue 4564 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 4565 // ignore 4566 } else { 4567 // ignore 4568 } 4569 4570 errno = old_errno; 4571 } 4572 4573 static int SR_initialize() { 4574 struct sigaction act; 4575 char *s; 4576 4577 // Get signal number to use for suspend/resume 4578 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4579 int sig = ::strtol(s, 0, 10); 4580 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 4581 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 4582 SR_signum = sig; 4583 } else { 4584 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 4585 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 4586 } 4587 } 4588 4589 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4590 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4591 4592 sigemptyset(&SR_sigset); 4593 sigaddset(&SR_sigset, SR_signum); 4594 4595 // Set up signal handler for suspend/resume 4596 act.sa_flags = SA_RESTART|SA_SIGINFO; 4597 act.sa_handler = (void (*)(int)) SR_handler; 4598 4599 // SR_signum is blocked by default. 4600 // 4528190 - We also need to block pthread restart signal (32 on all 4601 // supported Linux platforms). Note that LinuxThreads need to block 4602 // this signal for all threads to work properly. So we don't have 4603 // to use hard-coded signal number when setting up the mask. 4604 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4605 4606 if (sigaction(SR_signum, &act, 0) == -1) { 4607 return -1; 4608 } 4609 4610 // Save signal flag 4611 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4612 return 0; 4613 } 4614 4615 static int sr_notify(OSThread* osthread) { 4616 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4617 assert_status(status == 0, status, "pthread_kill"); 4618 return status; 4619 } 4620 4621 // "Randomly" selected value for how long we want to spin 4622 // before bailing out on suspending a thread, also how often 4623 // we send a signal to a thread we want to resume 4624 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4625 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4626 4627 // returns true on success and false on error - really an error is fatal 4628 // but this seems the normal response to library errors 4629 static bool do_suspend(OSThread* osthread) { 4630 assert(osthread->sr.is_running(), "thread should be running"); 4631 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4632 4633 // mark as suspended and send signal 4634 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4635 // failed to switch, state wasn't running? 4636 ShouldNotReachHere(); 4637 return false; 4638 } 4639 4640 if (sr_notify(osthread) != 0) { 4641 ShouldNotReachHere(); 4642 } 4643 4644 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4645 while (true) { 4646 if (sr_semaphore.timedwait(2)) { 4647 break; 4648 } else { 4649 // timeout 4650 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4651 if (cancelled == os::SuspendResume::SR_RUNNING) { 4652 return false; 4653 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4654 // make sure that we consume the signal on the semaphore as well 4655 sr_semaphore.wait(); 4656 break; 4657 } else { 4658 ShouldNotReachHere(); 4659 return false; 4660 } 4661 } 4662 } 4663 4664 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4665 return true; 4666 } 4667 4668 static void do_resume(OSThread* osthread) { 4669 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4670 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4671 4672 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4673 // failed to switch to WAKEUP_REQUEST 4674 ShouldNotReachHere(); 4675 return; 4676 } 4677 4678 while (true) { 4679 if (sr_notify(osthread) == 0) { 4680 if (sr_semaphore.timedwait(2)) { 4681 if (osthread->sr.is_running()) { 4682 return; 4683 } 4684 } 4685 } else { 4686 ShouldNotReachHere(); 4687 } 4688 } 4689 4690 guarantee(osthread->sr.is_running(), "Must be running!"); 4691 } 4692 4693 /////////////////////////////////////////////////////////////////////////////////// 4694 // signal handling (except suspend/resume) 4695 4696 // This routine may be used by user applications as a "hook" to catch signals. 4697 // The user-defined signal handler must pass unrecognized signals to this 4698 // routine, and if it returns true (non-zero), then the signal handler must 4699 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4700 // routine will never retun false (zero), but instead will execute a VM panic 4701 // routine kill the process. 4702 // 4703 // If this routine returns false, it is OK to call it again. This allows 4704 // the user-defined signal handler to perform checks either before or after 4705 // the VM performs its own checks. Naturally, the user code would be making 4706 // a serious error if it tried to handle an exception (such as a null check 4707 // or breakpoint) that the VM was generating for its own correct operation. 4708 // 4709 // This routine may recognize any of the following kinds of signals: 4710 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4711 // It should be consulted by handlers for any of those signals. 4712 // 4713 // The caller of this routine must pass in the three arguments supplied 4714 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4715 // field of the structure passed to sigaction(). This routine assumes that 4716 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4717 // 4718 // Note that the VM will print warnings if it detects conflicting signal 4719 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4720 // 4721 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4722 siginfo_t* siginfo, 4723 void* ucontext, 4724 int abort_if_unrecognized); 4725 4726 static void signalHandler(int sig, siginfo_t* info, void* uc) { 4727 assert(info != NULL && uc != NULL, "it must be old kernel"); 4728 int orig_errno = errno; // Preserve errno value over signal handler. 4729 JVM_handle_linux_signal(sig, info, uc, true); 4730 errno = orig_errno; 4731 } 4732 4733 4734 // This boolean allows users to forward their own non-matching signals 4735 // to JVM_handle_linux_signal, harmlessly. 4736 bool os::Linux::signal_handlers_are_installed = false; 4737 4738 // For signal-chaining 4739 bool os::Linux::libjsig_is_loaded = false; 4740 typedef struct sigaction *(*get_signal_t)(int); 4741 get_signal_t os::Linux::get_signal_action = NULL; 4742 4743 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4744 struct sigaction *actp = NULL; 4745 4746 if (libjsig_is_loaded) { 4747 // Retrieve the old signal handler from libjsig 4748 actp = (*get_signal_action)(sig); 4749 } 4750 if (actp == NULL) { 4751 // Retrieve the preinstalled signal handler from jvm 4752 actp = os::Posix::get_preinstalled_handler(sig); 4753 } 4754 4755 return actp; 4756 } 4757 4758 static bool call_chained_handler(struct sigaction *actp, int sig, 4759 siginfo_t *siginfo, void *context) { 4760 // Call the old signal handler 4761 if (actp->sa_handler == SIG_DFL) { 4762 // It's more reasonable to let jvm treat it as an unexpected exception 4763 // instead of taking the default action. 4764 return false; 4765 } else if (actp->sa_handler != SIG_IGN) { 4766 if ((actp->sa_flags & SA_NODEFER) == 0) { 4767 // automaticlly block the signal 4768 sigaddset(&(actp->sa_mask), sig); 4769 } 4770 4771 sa_handler_t hand = NULL; 4772 sa_sigaction_t sa = NULL; 4773 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4774 // retrieve the chained handler 4775 if (siginfo_flag_set) { 4776 sa = actp->sa_sigaction; 4777 } else { 4778 hand = actp->sa_handler; 4779 } 4780 4781 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4782 actp->sa_handler = SIG_DFL; 4783 } 4784 4785 // try to honor the signal mask 4786 sigset_t oset; 4787 sigemptyset(&oset); 4788 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4789 4790 // call into the chained handler 4791 if (siginfo_flag_set) { 4792 (*sa)(sig, siginfo, context); 4793 } else { 4794 (*hand)(sig); 4795 } 4796 4797 // restore the signal mask 4798 pthread_sigmask(SIG_SETMASK, &oset, NULL); 4799 } 4800 // Tell jvm's signal handler the signal is taken care of. 4801 return true; 4802 } 4803 4804 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4805 bool chained = false; 4806 // signal-chaining 4807 if (UseSignalChaining) { 4808 struct sigaction *actp = get_chained_signal_action(sig); 4809 if (actp != NULL) { 4810 chained = call_chained_handler(actp, sig, siginfo, context); 4811 } 4812 } 4813 return chained; 4814 } 4815 4816 // for diagnostic 4817 int sigflags[NSIG]; 4818 4819 int os::Linux::get_our_sigflags(int sig) { 4820 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4821 return sigflags[sig]; 4822 } 4823 4824 void os::Linux::set_our_sigflags(int sig, int flags) { 4825 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4826 if (sig > 0 && sig < NSIG) { 4827 sigflags[sig] = flags; 4828 } 4829 } 4830 4831 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4832 // Check for overwrite. 4833 struct sigaction oldAct; 4834 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4835 4836 void* oldhand = oldAct.sa_sigaction 4837 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4838 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4839 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4840 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4841 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4842 if (AllowUserSignalHandlers || !set_installed) { 4843 // Do not overwrite; user takes responsibility to forward to us. 4844 return; 4845 } else if (UseSignalChaining) { 4846 // save the old handler in jvm 4847 os::Posix::save_preinstalled_handler(sig, oldAct); 4848 // libjsig also interposes the sigaction() call below and saves the 4849 // old sigaction on it own. 4850 } else { 4851 fatal("Encountered unexpected pre-existing sigaction handler " 4852 "%#lx for signal %d.", (long)oldhand, sig); 4853 } 4854 } 4855 4856 struct sigaction sigAct; 4857 sigfillset(&(sigAct.sa_mask)); 4858 sigAct.sa_handler = SIG_DFL; 4859 if (!set_installed) { 4860 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4861 } else { 4862 sigAct.sa_sigaction = signalHandler; 4863 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4864 } 4865 // Save flags, which are set by ours 4866 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4867 sigflags[sig] = sigAct.sa_flags; 4868 4869 int ret = sigaction(sig, &sigAct, &oldAct); 4870 assert(ret == 0, "check"); 4871 4872 void* oldhand2 = oldAct.sa_sigaction 4873 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4874 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4875 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4876 } 4877 4878 // install signal handlers for signals that HotSpot needs to 4879 // handle in order to support Java-level exception handling. 4880 4881 void os::Linux::install_signal_handlers() { 4882 if (!signal_handlers_are_installed) { 4883 signal_handlers_are_installed = true; 4884 4885 // signal-chaining 4886 typedef void (*signal_setting_t)(); 4887 signal_setting_t begin_signal_setting = NULL; 4888 signal_setting_t end_signal_setting = NULL; 4889 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4890 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4891 if (begin_signal_setting != NULL) { 4892 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4893 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4894 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4895 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4896 libjsig_is_loaded = true; 4897 assert(UseSignalChaining, "should enable signal-chaining"); 4898 } 4899 if (libjsig_is_loaded) { 4900 // Tell libjsig jvm is setting signal handlers 4901 (*begin_signal_setting)(); 4902 } 4903 4904 set_signal_handler(SIGSEGV, true); 4905 set_signal_handler(SIGPIPE, true); 4906 set_signal_handler(SIGBUS, true); 4907 set_signal_handler(SIGILL, true); 4908 set_signal_handler(SIGFPE, true); 4909 #if defined(PPC64) 4910 set_signal_handler(SIGTRAP, true); 4911 #endif 4912 set_signal_handler(SIGXFSZ, true); 4913 4914 if (libjsig_is_loaded) { 4915 // Tell libjsig jvm finishes setting signal handlers 4916 (*end_signal_setting)(); 4917 } 4918 4919 // We don't activate signal checker if libjsig is in place, we trust ourselves 4920 // and if UserSignalHandler is installed all bets are off. 4921 // Log that signal checking is off only if -verbose:jni is specified. 4922 if (CheckJNICalls) { 4923 if (libjsig_is_loaded) { 4924 log_debug(jni, resolve)("Info: libjsig is activated, all active signal checking is disabled"); 4925 check_signals = false; 4926 } 4927 if (AllowUserSignalHandlers) { 4928 log_debug(jni, resolve)("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4929 check_signals = false; 4930 } 4931 } 4932 } 4933 } 4934 4935 // This is the fastest way to get thread cpu time on Linux. 4936 // Returns cpu time (user+sys) for any thread, not only for current. 4937 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4938 // It might work on 2.6.10+ with a special kernel/glibc patch. 4939 // For reference, please, see IEEE Std 1003.1-2004: 4940 // http://www.unix.org/single_unix_specification 4941 4942 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4943 struct timespec tp; 4944 int rc = os::Posix::clock_gettime(clockid, &tp); 4945 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4946 4947 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4948 } 4949 4950 ///// 4951 // glibc on Linux platform uses non-documented flag 4952 // to indicate, that some special sort of signal 4953 // trampoline is used. 4954 // We will never set this flag, and we should 4955 // ignore this flag in our diagnostic 4956 #ifdef SIGNIFICANT_SIGNAL_MASK 4957 #undef SIGNIFICANT_SIGNAL_MASK 4958 #endif 4959 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4960 4961 static const char* get_signal_handler_name(address handler, 4962 char* buf, int buflen) { 4963 int offset = 0; 4964 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4965 if (found) { 4966 // skip directory names 4967 const char *p1, *p2; 4968 p1 = buf; 4969 size_t len = strlen(os::file_separator()); 4970 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4971 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4972 } else { 4973 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4974 } 4975 return buf; 4976 } 4977 4978 static void print_signal_handler(outputStream* st, int sig, 4979 char* buf, size_t buflen) { 4980 struct sigaction sa; 4981 4982 sigaction(sig, NULL, &sa); 4983 4984 // See comment for SIGNIFICANT_SIGNAL_MASK define 4985 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4986 4987 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4988 4989 address handler = (sa.sa_flags & SA_SIGINFO) 4990 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4991 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4992 4993 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4994 st->print("SIG_DFL"); 4995 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4996 st->print("SIG_IGN"); 4997 } else { 4998 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4999 } 5000 5001 st->print(", sa_mask[0]="); 5002 os::Posix::print_signal_set_short(st, &sa.sa_mask); 5003 5004 address rh = VMError::get_resetted_sighandler(sig); 5005 // May be, handler was resetted by VMError? 5006 if (rh != NULL) { 5007 handler = rh; 5008 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 5009 } 5010 5011 st->print(", sa_flags="); 5012 os::Posix::print_sa_flags(st, sa.sa_flags); 5013 5014 // Check: is it our handler? 5015 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 5016 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 5017 // It is our signal handler 5018 // check for flags, reset system-used one! 5019 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 5020 st->print( 5021 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 5022 os::Linux::get_our_sigflags(sig)); 5023 } 5024 } 5025 st->cr(); 5026 } 5027 5028 5029 #define DO_SIGNAL_CHECK(sig) \ 5030 do { \ 5031 if (!sigismember(&check_signal_done, sig)) { \ 5032 os::Linux::check_signal_handler(sig); \ 5033 } \ 5034 } while (0) 5035 5036 // This method is a periodic task to check for misbehaving JNI applications 5037 // under CheckJNI, we can add any periodic checks here 5038 5039 void os::run_periodic_checks() { 5040 if (check_signals == false) return; 5041 5042 // SEGV and BUS if overridden could potentially prevent 5043 // generation of hs*.log in the event of a crash, debugging 5044 // such a case can be very challenging, so we absolutely 5045 // check the following for a good measure: 5046 DO_SIGNAL_CHECK(SIGSEGV); 5047 DO_SIGNAL_CHECK(SIGILL); 5048 DO_SIGNAL_CHECK(SIGFPE); 5049 DO_SIGNAL_CHECK(SIGBUS); 5050 DO_SIGNAL_CHECK(SIGPIPE); 5051 DO_SIGNAL_CHECK(SIGXFSZ); 5052 #if defined(PPC64) 5053 DO_SIGNAL_CHECK(SIGTRAP); 5054 #endif 5055 5056 // ReduceSignalUsage allows the user to override these handlers 5057 // see comments at the very top and jvm_md.h 5058 if (!ReduceSignalUsage) { 5059 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 5060 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 5061 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 5062 DO_SIGNAL_CHECK(BREAK_SIGNAL); 5063 } 5064 5065 DO_SIGNAL_CHECK(SR_signum); 5066 } 5067 5068 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 5069 5070 static os_sigaction_t os_sigaction = NULL; 5071 5072 void os::Linux::check_signal_handler(int sig) { 5073 char buf[O_BUFLEN]; 5074 address jvmHandler = NULL; 5075 5076 5077 struct sigaction act; 5078 if (os_sigaction == NULL) { 5079 // only trust the default sigaction, in case it has been interposed 5080 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 5081 if (os_sigaction == NULL) return; 5082 } 5083 5084 os_sigaction(sig, (struct sigaction*)NULL, &act); 5085 5086 5087 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 5088 5089 address thisHandler = (act.sa_flags & SA_SIGINFO) 5090 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 5091 : CAST_FROM_FN_PTR(address, act.sa_handler); 5092 5093 5094 switch (sig) { 5095 case SIGSEGV: 5096 case SIGBUS: 5097 case SIGFPE: 5098 case SIGPIPE: 5099 case SIGILL: 5100 case SIGXFSZ: 5101 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 5102 break; 5103 5104 case SHUTDOWN1_SIGNAL: 5105 case SHUTDOWN2_SIGNAL: 5106 case SHUTDOWN3_SIGNAL: 5107 case BREAK_SIGNAL: 5108 jvmHandler = (address)user_handler(); 5109 break; 5110 5111 default: 5112 if (sig == SR_signum) { 5113 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 5114 } else { 5115 return; 5116 } 5117 break; 5118 } 5119 5120 if (thisHandler != jvmHandler) { 5121 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 5122 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 5123 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 5124 // No need to check this sig any longer 5125 sigaddset(&check_signal_done, sig); 5126 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 5127 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 5128 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 5129 exception_name(sig, buf, O_BUFLEN)); 5130 } 5131 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 5132 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 5133 tty->print("expected:"); 5134 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 5135 tty->cr(); 5136 tty->print(" found:"); 5137 os::Posix::print_sa_flags(tty, act.sa_flags); 5138 tty->cr(); 5139 // No need to check this sig any longer 5140 sigaddset(&check_signal_done, sig); 5141 } 5142 5143 // Dump all the signal 5144 if (sigismember(&check_signal_done, sig)) { 5145 print_signal_handlers(tty, buf, O_BUFLEN); 5146 } 5147 } 5148 5149 extern void report_error(char* file_name, int line_no, char* title, 5150 char* format, ...); 5151 5152 // this is called _before_ most of the global arguments have been parsed 5153 void os::init(void) { 5154 char dummy; // used to get a guess on initial stack address 5155 5156 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 5157 5158 init_random(1234567); 5159 5160 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 5161 if (Linux::page_size() == -1) { 5162 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 5163 os::strerror(errno)); 5164 } 5165 init_page_sizes((size_t) Linux::page_size()); 5166 5167 Linux::initialize_system_info(); 5168 5169 os::Linux::CPUPerfTicks pticks; 5170 bool res = os::Linux::get_tick_information(&pticks, -1); 5171 5172 if (res && pticks.has_steal_ticks) { 5173 has_initial_tick_info = true; 5174 initial_total_ticks = pticks.total; 5175 initial_steal_ticks = pticks.steal; 5176 } 5177 5178 // _main_thread points to the thread that created/loaded the JVM. 5179 Linux::_main_thread = pthread_self(); 5180 5181 // retrieve entry point for pthread_setname_np 5182 Linux::_pthread_setname_np = 5183 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 5184 5185 os::Posix::init(); 5186 5187 initial_time_count = javaTimeNanos(); 5188 5189 // Always warn if no monotonic clock available 5190 if (!os::Posix::supports_monotonic_clock()) { 5191 warning("No monotonic clock was available - timed services may " \ 5192 "be adversely affected if the time-of-day clock changes"); 5193 } 5194 } 5195 5196 // To install functions for atexit system call 5197 extern "C" { 5198 static void perfMemory_exit_helper() { 5199 perfMemory_exit(); 5200 } 5201 } 5202 5203 void os::pd_init_container_support() { 5204 OSContainer::init(); 5205 } 5206 5207 void os::Linux::numa_init() { 5208 5209 // Java can be invoked as 5210 // 1. Without numactl and heap will be allocated/configured on all nodes as 5211 // per the system policy. 5212 // 2. With numactl --interleave: 5213 // Use numa_get_interleave_mask(v2) API to get nodes bitmask. The same 5214 // API for membind case bitmask is reset. 5215 // Interleave is only hint and Kernel can fallback to other nodes if 5216 // no memory is available on the target nodes. 5217 // 3. With numactl --membind: 5218 // Use numa_get_membind(v2) API to get nodes bitmask. The same API for 5219 // interleave case returns bitmask of all nodes. 5220 // numa_all_nodes_ptr holds bitmask of all nodes. 5221 // numa_get_interleave_mask(v2) and numa_get_membind(v2) APIs returns correct 5222 // bitmask when externally configured to run on all or fewer nodes. 5223 5224 if (!Linux::libnuma_init()) { 5225 FLAG_SET_ERGO(UseNUMA, false); 5226 FLAG_SET_ERGO(UseNUMAInterleaving, false); // Also depends on libnuma. 5227 } else { 5228 if ((Linux::numa_max_node() < 1) || Linux::is_bound_to_single_node()) { 5229 // If there's only one node (they start from 0) or if the process 5230 // is bound explicitly to a single node using membind, disable NUMA unless 5231 // user explicilty forces NUMA optimizations on single-node/UMA systems 5232 UseNUMA = ForceNUMA; 5233 } else { 5234 5235 LogTarget(Info,os) log; 5236 LogStream ls(log); 5237 5238 Linux::set_configured_numa_policy(Linux::identify_numa_policy()); 5239 5240 struct bitmask* bmp = Linux::_numa_membind_bitmask; 5241 const char* numa_mode = "membind"; 5242 5243 if (Linux::is_running_in_interleave_mode()) { 5244 bmp = Linux::_numa_interleave_bitmask; 5245 numa_mode = "interleave"; 5246 } 5247 5248 ls.print("UseNUMA is enabled and invoked in '%s' mode." 5249 " Heap will be configured using NUMA memory nodes:", numa_mode); 5250 5251 for (int node = 0; node <= Linux::numa_max_node(); node++) { 5252 if (Linux::_numa_bitmask_isbitset(bmp, node)) { 5253 ls.print(" %d", node); 5254 } 5255 } 5256 } 5257 } 5258 5259 // When NUMA requested, not-NUMA-aware allocations default to interleaving. 5260 if (UseNUMA && !UseNUMAInterleaving) { 5261 FLAG_SET_ERGO_IF_DEFAULT(UseNUMAInterleaving, true); 5262 } 5263 5264 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 5265 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 5266 // we can make the adaptive lgrp chunk resizing work. If the user specified both 5267 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn 5268 // and disable adaptive resizing. 5269 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 5270 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, " 5271 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 5272 UseAdaptiveSizePolicy = false; 5273 UseAdaptiveNUMAChunkSizing = false; 5274 } 5275 } 5276 } 5277 5278 // this is called _after_ the global arguments have been parsed 5279 jint os::init_2(void) { 5280 5281 // This could be set after os::Posix::init() but all platforms 5282 // have to set it the same so we have to mirror Solaris. 5283 DEBUG_ONLY(os::set_mutex_init_done();) 5284 5285 os::Posix::init_2(); 5286 5287 Linux::fast_thread_clock_init(); 5288 5289 // initialize suspend/resume support - must do this before signal_sets_init() 5290 if (SR_initialize() != 0) { 5291 perror("SR_initialize failed"); 5292 return JNI_ERR; 5293 } 5294 5295 Linux::signal_sets_init(); 5296 Linux::install_signal_handlers(); 5297 // Initialize data for jdk.internal.misc.Signal 5298 if (!ReduceSignalUsage) { 5299 jdk_misc_signal_init(); 5300 } 5301 5302 if (AdjustStackSizeForTLS) { 5303 get_minstack_init(); 5304 } 5305 5306 // Check and sets minimum stack sizes against command line options 5307 if (Posix::set_minimum_stack_sizes() == JNI_ERR) { 5308 return JNI_ERR; 5309 } 5310 5311 #if defined(IA32) 5312 // Need to ensure we've determined the process's initial stack to 5313 // perform the workaround 5314 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 5315 workaround_expand_exec_shield_cs_limit(); 5316 #else 5317 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher(); 5318 if (!suppress_primordial_thread_resolution) { 5319 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 5320 } 5321 #endif 5322 5323 Linux::libpthread_init(); 5324 Linux::sched_getcpu_init(); 5325 log_info(os)("HotSpot is running with %s, %s", 5326 Linux::glibc_version(), Linux::libpthread_version()); 5327 5328 if (UseNUMA || UseNUMAInterleaving) { 5329 Linux::numa_init(); 5330 } 5331 5332 if (MaxFDLimit) { 5333 // set the number of file descriptors to max. print out error 5334 // if getrlimit/setrlimit fails but continue regardless. 5335 struct rlimit nbr_files; 5336 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 5337 if (status != 0) { 5338 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno)); 5339 } else { 5340 nbr_files.rlim_cur = nbr_files.rlim_max; 5341 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 5342 if (status != 0) { 5343 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno)); 5344 } 5345 } 5346 } 5347 5348 // at-exit methods are called in the reverse order of their registration. 5349 // atexit functions are called on return from main or as a result of a 5350 // call to exit(3C). There can be only 32 of these functions registered 5351 // and atexit() does not set errno. 5352 5353 if (PerfAllowAtExitRegistration) { 5354 // only register atexit functions if PerfAllowAtExitRegistration is set. 5355 // atexit functions can be delayed until process exit time, which 5356 // can be problematic for embedded VM situations. Embedded VMs should 5357 // call DestroyJavaVM() to assure that VM resources are released. 5358 5359 // note: perfMemory_exit_helper atexit function may be removed in 5360 // the future if the appropriate cleanup code can be added to the 5361 // VM_Exit VMOperation's doit method. 5362 if (atexit(perfMemory_exit_helper) != 0) { 5363 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 5364 } 5365 } 5366 5367 // initialize thread priority policy 5368 prio_init(); 5369 5370 if (!FLAG_IS_DEFAULT(AllocateHeapAt) || !FLAG_IS_DEFAULT(AllocateOldGenAt)) { 5371 set_coredump_filter(DAX_SHARED_BIT); 5372 } 5373 5374 if (DumpPrivateMappingsInCore) { 5375 set_coredump_filter(FILE_BACKED_PVT_BIT); 5376 } 5377 5378 if (DumpSharedMappingsInCore) { 5379 set_coredump_filter(FILE_BACKED_SHARED_BIT); 5380 } 5381 5382 return JNI_OK; 5383 } 5384 5385 // older glibc versions don't have this macro (which expands to 5386 // an optimized bit-counting function) so we have to roll our own 5387 #ifndef CPU_COUNT 5388 5389 static int _cpu_count(const cpu_set_t* cpus) { 5390 int count = 0; 5391 // only look up to the number of configured processors 5392 for (int i = 0; i < os::processor_count(); i++) { 5393 if (CPU_ISSET(i, cpus)) { 5394 count++; 5395 } 5396 } 5397 return count; 5398 } 5399 5400 #define CPU_COUNT(cpus) _cpu_count(cpus) 5401 5402 #endif // CPU_COUNT 5403 5404 // Get the current number of available processors for this process. 5405 // This value can change at any time during a process's lifetime. 5406 // sched_getaffinity gives an accurate answer as it accounts for cpusets. 5407 // If it appears there may be more than 1024 processors then we do a 5408 // dynamic check - see 6515172 for details. 5409 // If anything goes wrong we fallback to returning the number of online 5410 // processors - which can be greater than the number available to the process. 5411 int os::Linux::active_processor_count() { 5412 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 5413 cpu_set_t* cpus_p = &cpus; 5414 int cpus_size = sizeof(cpu_set_t); 5415 5416 int configured_cpus = os::processor_count(); // upper bound on available cpus 5417 int cpu_count = 0; 5418 5419 // old build platforms may not support dynamic cpu sets 5420 #ifdef CPU_ALLOC 5421 5422 // To enable easy testing of the dynamic path on different platforms we 5423 // introduce a diagnostic flag: UseCpuAllocPath 5424 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 5425 // kernel may use a mask bigger than cpu_set_t 5426 log_trace(os)("active_processor_count: using dynamic path %s" 5427 "- configured processors: %d", 5428 UseCpuAllocPath ? "(forced) " : "", 5429 configured_cpus); 5430 cpus_p = CPU_ALLOC(configured_cpus); 5431 if (cpus_p != NULL) { 5432 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 5433 // zero it just to be safe 5434 CPU_ZERO_S(cpus_size, cpus_p); 5435 } 5436 else { 5437 // failed to allocate so fallback to online cpus 5438 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 5439 log_trace(os)("active_processor_count: " 5440 "CPU_ALLOC failed (%s) - using " 5441 "online processor count: %d", 5442 os::strerror(errno), online_cpus); 5443 return online_cpus; 5444 } 5445 } 5446 else { 5447 log_trace(os)("active_processor_count: using static path - configured processors: %d", 5448 configured_cpus); 5449 } 5450 #else // CPU_ALLOC 5451 // these stubs won't be executed 5452 #define CPU_COUNT_S(size, cpus) -1 5453 #define CPU_FREE(cpus) 5454 5455 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 5456 configured_cpus); 5457 #endif // CPU_ALLOC 5458 5459 // pid 0 means the current thread - which we have to assume represents the process 5460 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 5461 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5462 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 5463 } 5464 else { 5465 cpu_count = CPU_COUNT(cpus_p); 5466 } 5467 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 5468 } 5469 else { 5470 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 5471 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 5472 "which may exceed available processors", os::strerror(errno), cpu_count); 5473 } 5474 5475 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5476 CPU_FREE(cpus_p); 5477 } 5478 5479 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check"); 5480 return cpu_count; 5481 } 5482 5483 // Determine the active processor count from one of 5484 // three different sources: 5485 // 5486 // 1. User option -XX:ActiveProcessorCount 5487 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN) 5488 // 3. extracted from cgroup cpu subsystem (shares and quotas) 5489 // 5490 // Option 1, if specified, will always override. 5491 // If the cgroup subsystem is active and configured, we 5492 // will return the min of the cgroup and option 2 results. 5493 // This is required since tools, such as numactl, that 5494 // alter cpu affinity do not update cgroup subsystem 5495 // cpuset configuration files. 5496 int os::active_processor_count() { 5497 // User has overridden the number of active processors 5498 if (ActiveProcessorCount > 0) { 5499 log_trace(os)("active_processor_count: " 5500 "active processor count set by user : %d", 5501 ActiveProcessorCount); 5502 return ActiveProcessorCount; 5503 } 5504 5505 int active_cpus; 5506 if (OSContainer::is_containerized()) { 5507 active_cpus = OSContainer::active_processor_count(); 5508 log_trace(os)("active_processor_count: determined by OSContainer: %d", 5509 active_cpus); 5510 } else { 5511 active_cpus = os::Linux::active_processor_count(); 5512 } 5513 5514 return active_cpus; 5515 } 5516 5517 uint os::processor_id() { 5518 const int id = Linux::sched_getcpu(); 5519 assert(id >= 0 && id < _processor_count, "Invalid processor id"); 5520 return (uint)id; 5521 } 5522 5523 void os::set_native_thread_name(const char *name) { 5524 if (Linux::_pthread_setname_np) { 5525 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 5526 snprintf(buf, sizeof(buf), "%s", name); 5527 buf[sizeof(buf) - 1] = '\0'; 5528 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 5529 // ERANGE should not happen; all other errors should just be ignored. 5530 assert(rc != ERANGE, "pthread_setname_np failed"); 5531 } 5532 } 5533 5534 bool os::bind_to_processor(uint processor_id) { 5535 // Not yet implemented. 5536 return false; 5537 } 5538 5539 /// 5540 5541 void os::SuspendedThreadTask::internal_do_task() { 5542 if (do_suspend(_thread->osthread())) { 5543 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 5544 do_task(context); 5545 do_resume(_thread->osthread()); 5546 } 5547 } 5548 5549 //////////////////////////////////////////////////////////////////////////////// 5550 // debug support 5551 5552 bool os::find(address addr, outputStream* st) { 5553 Dl_info dlinfo; 5554 memset(&dlinfo, 0, sizeof(dlinfo)); 5555 if (dladdr(addr, &dlinfo) != 0) { 5556 st->print(PTR_FORMAT ": ", p2i(addr)); 5557 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5558 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 5559 p2i(addr) - p2i(dlinfo.dli_saddr)); 5560 } else if (dlinfo.dli_fbase != NULL) { 5561 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 5562 } else { 5563 st->print("<absolute address>"); 5564 } 5565 if (dlinfo.dli_fname != NULL) { 5566 st->print(" in %s", dlinfo.dli_fname); 5567 } 5568 if (dlinfo.dli_fbase != NULL) { 5569 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 5570 } 5571 st->cr(); 5572 5573 if (Verbose) { 5574 // decode some bytes around the PC 5575 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5576 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5577 address lowest = (address) dlinfo.dli_sname; 5578 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5579 if (begin < lowest) begin = lowest; 5580 Dl_info dlinfo2; 5581 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5582 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 5583 end = (address) dlinfo2.dli_saddr; 5584 } 5585 Disassembler::decode(begin, end, st); 5586 } 5587 return true; 5588 } 5589 return false; 5590 } 5591 5592 //////////////////////////////////////////////////////////////////////////////// 5593 // misc 5594 5595 // This does not do anything on Linux. This is basically a hook for being 5596 // able to use structured exception handling (thread-local exception filters) 5597 // on, e.g., Win32. 5598 void 5599 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5600 JavaCallArguments* args, Thread* thread) { 5601 f(value, method, args, thread); 5602 } 5603 5604 void os::print_statistics() { 5605 } 5606 5607 bool os::message_box(const char* title, const char* message) { 5608 int i; 5609 fdStream err(defaultStream::error_fd()); 5610 for (i = 0; i < 78; i++) err.print_raw("="); 5611 err.cr(); 5612 err.print_raw_cr(title); 5613 for (i = 0; i < 78; i++) err.print_raw("-"); 5614 err.cr(); 5615 err.print_raw_cr(message); 5616 for (i = 0; i < 78; i++) err.print_raw("="); 5617 err.cr(); 5618 5619 char buf[16]; 5620 // Prevent process from exiting upon "read error" without consuming all CPU 5621 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5622 5623 return buf[0] == 'y' || buf[0] == 'Y'; 5624 } 5625 5626 // Is a (classpath) directory empty? 5627 bool os::dir_is_empty(const char* path) { 5628 DIR *dir = NULL; 5629 struct dirent *ptr; 5630 5631 dir = opendir(path); 5632 if (dir == NULL) return true; 5633 5634 // Scan the directory 5635 bool result = true; 5636 while (result && (ptr = readdir(dir)) != NULL) { 5637 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5638 result = false; 5639 } 5640 } 5641 closedir(dir); 5642 return result; 5643 } 5644 5645 // This code originates from JDK's sysOpen and open64_w 5646 // from src/solaris/hpi/src/system_md.c 5647 5648 int os::open(const char *path, int oflag, int mode) { 5649 if (strlen(path) > MAX_PATH - 1) { 5650 errno = ENAMETOOLONG; 5651 return -1; 5652 } 5653 5654 // All file descriptors that are opened in the Java process and not 5655 // specifically destined for a subprocess should have the close-on-exec 5656 // flag set. If we don't set it, then careless 3rd party native code 5657 // might fork and exec without closing all appropriate file descriptors 5658 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5659 // turn might: 5660 // 5661 // - cause end-of-file to fail to be detected on some file 5662 // descriptors, resulting in mysterious hangs, or 5663 // 5664 // - might cause an fopen in the subprocess to fail on a system 5665 // suffering from bug 1085341. 5666 // 5667 // (Yes, the default setting of the close-on-exec flag is a Unix 5668 // design flaw) 5669 // 5670 // See: 5671 // 1085341: 32-bit stdio routines should support file descriptors >255 5672 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5673 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5674 // 5675 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5676 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5677 // because it saves a system call and removes a small window where the flag 5678 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5679 // and we fall back to using FD_CLOEXEC (see below). 5680 #ifdef O_CLOEXEC 5681 oflag |= O_CLOEXEC; 5682 #endif 5683 5684 int fd = ::open64(path, oflag, mode); 5685 if (fd == -1) return -1; 5686 5687 //If the open succeeded, the file might still be a directory 5688 { 5689 struct stat64 buf64; 5690 int ret = ::fstat64(fd, &buf64); 5691 int st_mode = buf64.st_mode; 5692 5693 if (ret != -1) { 5694 if ((st_mode & S_IFMT) == S_IFDIR) { 5695 errno = EISDIR; 5696 ::close(fd); 5697 return -1; 5698 } 5699 } else { 5700 ::close(fd); 5701 return -1; 5702 } 5703 } 5704 5705 #ifdef FD_CLOEXEC 5706 // Validate that the use of the O_CLOEXEC flag on open above worked. 5707 // With recent kernels, we will perform this check exactly once. 5708 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5709 if (!O_CLOEXEC_is_known_to_work) { 5710 int flags = ::fcntl(fd, F_GETFD); 5711 if (flags != -1) { 5712 if ((flags & FD_CLOEXEC) != 0) 5713 O_CLOEXEC_is_known_to_work = 1; 5714 else 5715 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5716 } 5717 } 5718 #endif 5719 5720 return fd; 5721 } 5722 5723 5724 // create binary file, rewriting existing file if required 5725 int os::create_binary_file(const char* path, bool rewrite_existing) { 5726 int oflags = O_WRONLY | O_CREAT; 5727 if (!rewrite_existing) { 5728 oflags |= O_EXCL; 5729 } 5730 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5731 } 5732 5733 // return current position of file pointer 5734 jlong os::current_file_offset(int fd) { 5735 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5736 } 5737 5738 // move file pointer to the specified offset 5739 jlong os::seek_to_file_offset(int fd, jlong offset) { 5740 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5741 } 5742 5743 // This code originates from JDK's sysAvailable 5744 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5745 5746 int os::available(int fd, jlong *bytes) { 5747 jlong cur, end; 5748 int mode; 5749 struct stat64 buf64; 5750 5751 if (::fstat64(fd, &buf64) >= 0) { 5752 mode = buf64.st_mode; 5753 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5754 int n; 5755 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5756 *bytes = n; 5757 return 1; 5758 } 5759 } 5760 } 5761 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5762 return 0; 5763 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5764 return 0; 5765 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5766 return 0; 5767 } 5768 *bytes = end - cur; 5769 return 1; 5770 } 5771 5772 // Map a block of memory. 5773 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5774 char *addr, size_t bytes, bool read_only, 5775 bool allow_exec) { 5776 int prot; 5777 int flags = MAP_PRIVATE; 5778 5779 if (read_only) { 5780 prot = PROT_READ; 5781 } else { 5782 prot = PROT_READ | PROT_WRITE; 5783 } 5784 5785 if (allow_exec) { 5786 prot |= PROT_EXEC; 5787 } 5788 5789 if (addr != NULL) { 5790 flags |= MAP_FIXED; 5791 } 5792 5793 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5794 fd, file_offset); 5795 if (mapped_address == MAP_FAILED) { 5796 return NULL; 5797 } 5798 return mapped_address; 5799 } 5800 5801 5802 // Remap a block of memory. 5803 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5804 char *addr, size_t bytes, bool read_only, 5805 bool allow_exec) { 5806 // same as map_memory() on this OS 5807 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5808 allow_exec); 5809 } 5810 5811 5812 // Unmap a block of memory. 5813 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5814 return munmap(addr, bytes) == 0; 5815 } 5816 5817 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5818 5819 static jlong fast_cpu_time(Thread *thread) { 5820 clockid_t clockid; 5821 int rc = os::Linux::pthread_getcpuclockid(thread->osthread()->pthread_id(), 5822 &clockid); 5823 if (rc == 0) { 5824 return os::Linux::fast_thread_cpu_time(clockid); 5825 } else { 5826 // It's possible to encounter a terminated native thread that failed 5827 // to detach itself from the VM - which should result in ESRCH. 5828 assert_status(rc == ESRCH, rc, "pthread_getcpuclockid failed"); 5829 return -1; 5830 } 5831 } 5832 5833 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5834 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5835 // of a thread. 5836 // 5837 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5838 // the fast estimate available on the platform. 5839 5840 jlong os::current_thread_cpu_time() { 5841 if (os::Linux::supports_fast_thread_cpu_time()) { 5842 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5843 } else { 5844 // return user + sys since the cost is the same 5845 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5846 } 5847 } 5848 5849 jlong os::thread_cpu_time(Thread* thread) { 5850 // consistent with what current_thread_cpu_time() returns 5851 if (os::Linux::supports_fast_thread_cpu_time()) { 5852 return fast_cpu_time(thread); 5853 } else { 5854 return slow_thread_cpu_time(thread, true /* user + sys */); 5855 } 5856 } 5857 5858 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5859 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5860 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5861 } else { 5862 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5863 } 5864 } 5865 5866 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5867 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5868 return fast_cpu_time(thread); 5869 } else { 5870 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5871 } 5872 } 5873 5874 // -1 on error. 5875 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5876 pid_t tid = thread->osthread()->thread_id(); 5877 char *s; 5878 char stat[2048]; 5879 int statlen; 5880 char proc_name[64]; 5881 int count; 5882 long sys_time, user_time; 5883 char cdummy; 5884 int idummy; 5885 long ldummy; 5886 FILE *fp; 5887 5888 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5889 fp = fopen(proc_name, "r"); 5890 if (fp == NULL) return -1; 5891 statlen = fread(stat, 1, 2047, fp); 5892 stat[statlen] = '\0'; 5893 fclose(fp); 5894 5895 // Skip pid and the command string. Note that we could be dealing with 5896 // weird command names, e.g. user could decide to rename java launcher 5897 // to "java 1.4.2 :)", then the stat file would look like 5898 // 1234 (java 1.4.2 :)) R ... ... 5899 // We don't really need to know the command string, just find the last 5900 // occurrence of ")" and then start parsing from there. See bug 4726580. 5901 s = strrchr(stat, ')'); 5902 if (s == NULL) return -1; 5903 5904 // Skip blank chars 5905 do { s++; } while (s && isspace(*s)); 5906 5907 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5908 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5909 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5910 &user_time, &sys_time); 5911 if (count != 13) return -1; 5912 if (user_sys_cpu_time) { 5913 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5914 } else { 5915 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5916 } 5917 } 5918 5919 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5920 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5921 info_ptr->may_skip_backward = false; // elapsed time not wall time 5922 info_ptr->may_skip_forward = false; // elapsed time not wall time 5923 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5924 } 5925 5926 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5927 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5928 info_ptr->may_skip_backward = false; // elapsed time not wall time 5929 info_ptr->may_skip_forward = false; // elapsed time not wall time 5930 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5931 } 5932 5933 bool os::is_thread_cpu_time_supported() { 5934 return true; 5935 } 5936 5937 // System loadavg support. Returns -1 if load average cannot be obtained. 5938 // Linux doesn't yet have a (official) notion of processor sets, 5939 // so just return the system wide load average. 5940 int os::loadavg(double loadavg[], int nelem) { 5941 return ::getloadavg(loadavg, nelem); 5942 } 5943 5944 void os::pause() { 5945 char filename[MAX_PATH]; 5946 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5947 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5948 } else { 5949 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5950 } 5951 5952 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5953 if (fd != -1) { 5954 struct stat buf; 5955 ::close(fd); 5956 while (::stat(filename, &buf) == 0) { 5957 (void)::poll(NULL, 0, 100); 5958 } 5959 } else { 5960 jio_fprintf(stderr, 5961 "Could not open pause file '%s', continuing immediately.\n", filename); 5962 } 5963 } 5964 5965 extern char** environ; 5966 5967 // Run the specified command in a separate process. Return its exit value, 5968 // or -1 on failure (e.g. can't fork a new process). 5969 // Unlike system(), this function can be called from signal handler. It 5970 // doesn't block SIGINT et al. 5971 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) { 5972 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5973 5974 pid_t pid ; 5975 5976 if (use_vfork_if_available) { 5977 pid = vfork(); 5978 } else { 5979 pid = fork(); 5980 } 5981 5982 if (pid < 0) { 5983 // fork failed 5984 return -1; 5985 5986 } else if (pid == 0) { 5987 // child process 5988 5989 execve("/bin/sh", (char* const*)argv, environ); 5990 5991 // execve failed 5992 _exit(-1); 5993 5994 } else { 5995 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5996 // care about the actual exit code, for now. 5997 5998 int status; 5999 6000 // Wait for the child process to exit. This returns immediately if 6001 // the child has already exited. */ 6002 while (waitpid(pid, &status, 0) < 0) { 6003 switch (errno) { 6004 case ECHILD: return 0; 6005 case EINTR: break; 6006 default: return -1; 6007 } 6008 } 6009 6010 if (WIFEXITED(status)) { 6011 // The child exited normally; get its exit code. 6012 return WEXITSTATUS(status); 6013 } else if (WIFSIGNALED(status)) { 6014 // The child exited because of a signal 6015 // The best value to return is 0x80 + signal number, 6016 // because that is what all Unix shells do, and because 6017 // it allows callers to distinguish between process exit and 6018 // process death by signal. 6019 return 0x80 + WTERMSIG(status); 6020 } else { 6021 // Unknown exit code; pass it through 6022 return status; 6023 } 6024 } 6025 } 6026 6027 // Get the default path to the core file 6028 // Returns the length of the string 6029 int os::get_core_path(char* buffer, size_t bufferSize) { 6030 /* 6031 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 6032 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 6033 */ 6034 const int core_pattern_len = 129; 6035 char core_pattern[core_pattern_len] = {0}; 6036 6037 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 6038 if (core_pattern_file == -1) { 6039 return -1; 6040 } 6041 6042 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 6043 ::close(core_pattern_file); 6044 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 6045 return -1; 6046 } 6047 if (core_pattern[ret-1] == '\n') { 6048 core_pattern[ret-1] = '\0'; 6049 } else { 6050 core_pattern[ret] = '\0'; 6051 } 6052 6053 // Replace the %p in the core pattern with the process id. NOTE: we do this 6054 // only if the pattern doesn't start with "|", and we support only one %p in 6055 // the pattern. 6056 char *pid_pos = strstr(core_pattern, "%p"); 6057 const char* tail = (pid_pos != NULL) ? (pid_pos + 2) : ""; // skip over the "%p" 6058 int written; 6059 6060 if (core_pattern[0] == '/') { 6061 if (pid_pos != NULL) { 6062 *pid_pos = '\0'; 6063 written = jio_snprintf(buffer, bufferSize, "%s%d%s", core_pattern, 6064 current_process_id(), tail); 6065 } else { 6066 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 6067 } 6068 } else { 6069 char cwd[PATH_MAX]; 6070 6071 const char* p = get_current_directory(cwd, PATH_MAX); 6072 if (p == NULL) { 6073 return -1; 6074 } 6075 6076 if (core_pattern[0] == '|') { 6077 written = jio_snprintf(buffer, bufferSize, 6078 "\"%s\" (or dumping to %s/core.%d)", 6079 &core_pattern[1], p, current_process_id()); 6080 } else if (pid_pos != NULL) { 6081 *pid_pos = '\0'; 6082 written = jio_snprintf(buffer, bufferSize, "%s/%s%d%s", p, core_pattern, 6083 current_process_id(), tail); 6084 } else { 6085 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 6086 } 6087 } 6088 6089 if (written < 0) { 6090 return -1; 6091 } 6092 6093 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 6094 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 6095 6096 if (core_uses_pid_file != -1) { 6097 char core_uses_pid = 0; 6098 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 6099 ::close(core_uses_pid_file); 6100 6101 if (core_uses_pid == '1') { 6102 jio_snprintf(buffer + written, bufferSize - written, 6103 ".%d", current_process_id()); 6104 } 6105 } 6106 } 6107 6108 return strlen(buffer); 6109 } 6110 6111 bool os::start_debugging(char *buf, int buflen) { 6112 int len = (int)strlen(buf); 6113 char *p = &buf[len]; 6114 6115 jio_snprintf(p, buflen-len, 6116 "\n\n" 6117 "Do you want to debug the problem?\n\n" 6118 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 6119 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 6120 "Otherwise, press RETURN to abort...", 6121 os::current_process_id(), os::current_process_id(), 6122 os::current_thread_id(), os::current_thread_id()); 6123 6124 bool yes = os::message_box("Unexpected Error", buf); 6125 6126 if (yes) { 6127 // yes, user asked VM to launch debugger 6128 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d", 6129 os::current_process_id(), os::current_process_id()); 6130 6131 os::fork_and_exec(buf); 6132 yes = false; 6133 } 6134 return yes; 6135 } 6136 6137 6138 // Java/Compiler thread: 6139 // 6140 // Low memory addresses 6141 // P0 +------------------------+ 6142 // | |\ Java thread created by VM does not have glibc 6143 // | glibc guard page | - guard page, attached Java thread usually has 6144 // | |/ 1 glibc guard page. 6145 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 6146 // | |\ 6147 // | HotSpot Guard Pages | - red, yellow and reserved pages 6148 // | |/ 6149 // +------------------------+ JavaThread::stack_reserved_zone_base() 6150 // | |\ 6151 // | Normal Stack | - 6152 // | |/ 6153 // P2 +------------------------+ Thread::stack_base() 6154 // 6155 // Non-Java thread: 6156 // 6157 // Low memory addresses 6158 // P0 +------------------------+ 6159 // | |\ 6160 // | glibc guard page | - usually 1 page 6161 // | |/ 6162 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 6163 // | |\ 6164 // | Normal Stack | - 6165 // | |/ 6166 // P2 +------------------------+ Thread::stack_base() 6167 // 6168 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size 6169 // returned from pthread_attr_getstack(). 6170 // ** Due to NPTL implementation error, linux takes the glibc guard page out 6171 // of the stack size given in pthread_attr. We work around this for 6172 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.) 6173 // 6174 #ifndef ZERO 6175 static void current_stack_region(address * bottom, size_t * size) { 6176 if (os::is_primordial_thread()) { 6177 // primordial thread needs special handling because pthread_getattr_np() 6178 // may return bogus value. 6179 *bottom = os::Linux::initial_thread_stack_bottom(); 6180 *size = os::Linux::initial_thread_stack_size(); 6181 } else { 6182 pthread_attr_t attr; 6183 6184 int rslt = pthread_getattr_np(pthread_self(), &attr); 6185 6186 // JVM needs to know exact stack location, abort if it fails 6187 if (rslt != 0) { 6188 if (rslt == ENOMEM) { 6189 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 6190 } else { 6191 fatal("pthread_getattr_np failed with error = %d", rslt); 6192 } 6193 } 6194 6195 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 6196 fatal("Cannot locate current stack attributes!"); 6197 } 6198 6199 // Work around NPTL stack guard error. 6200 size_t guard_size = 0; 6201 rslt = pthread_attr_getguardsize(&attr, &guard_size); 6202 if (rslt != 0) { 6203 fatal("pthread_attr_getguardsize failed with error = %d", rslt); 6204 } 6205 *bottom += guard_size; 6206 *size -= guard_size; 6207 6208 pthread_attr_destroy(&attr); 6209 6210 } 6211 assert(os::current_stack_pointer() >= *bottom && 6212 os::current_stack_pointer() < *bottom + *size, "just checking"); 6213 } 6214 6215 address os::current_stack_base() { 6216 address bottom; 6217 size_t size; 6218 current_stack_region(&bottom, &size); 6219 return (bottom + size); 6220 } 6221 6222 size_t os::current_stack_size() { 6223 // This stack size includes the usable stack and HotSpot guard pages 6224 // (for the threads that have Hotspot guard pages). 6225 address bottom; 6226 size_t size; 6227 current_stack_region(&bottom, &size); 6228 return size; 6229 } 6230 #endif 6231 6232 static inline struct timespec get_mtime(const char* filename) { 6233 struct stat st; 6234 int ret = os::stat(filename, &st); 6235 assert(ret == 0, "failed to stat() file '%s': %s", filename, os::strerror(errno)); 6236 return st.st_mtim; 6237 } 6238 6239 int os::compare_file_modified_times(const char* file1, const char* file2) { 6240 struct timespec filetime1 = get_mtime(file1); 6241 struct timespec filetime2 = get_mtime(file2); 6242 int diff = filetime1.tv_sec - filetime2.tv_sec; 6243 if (diff == 0) { 6244 return filetime1.tv_nsec - filetime2.tv_nsec; 6245 } 6246 return diff; 6247 } 6248 6249 bool os::supports_map_sync() { 6250 return true; 6251 } 6252 6253 /////////////// Unit tests /////////////// 6254 6255 #ifndef PRODUCT 6256 6257 class TestReserveMemorySpecial : AllStatic { 6258 public: 6259 static void small_page_write(void* addr, size_t size) { 6260 size_t page_size = os::vm_page_size(); 6261 6262 char* end = (char*)addr + size; 6263 for (char* p = (char*)addr; p < end; p += page_size) { 6264 *p = 1; 6265 } 6266 } 6267 6268 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6269 if (!UseHugeTLBFS) { 6270 return; 6271 } 6272 6273 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6274 6275 if (addr != NULL) { 6276 small_page_write(addr, size); 6277 6278 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6279 } 6280 } 6281 6282 static void test_reserve_memory_special_huge_tlbfs_only() { 6283 if (!UseHugeTLBFS) { 6284 return; 6285 } 6286 6287 size_t lp = os::large_page_size(); 6288 6289 for (size_t size = lp; size <= lp * 10; size += lp) { 6290 test_reserve_memory_special_huge_tlbfs_only(size); 6291 } 6292 } 6293 6294 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6295 size_t lp = os::large_page_size(); 6296 size_t ag = os::vm_allocation_granularity(); 6297 6298 // sizes to test 6299 const size_t sizes[] = { 6300 lp, lp + ag, lp + lp / 2, lp * 2, 6301 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6302 lp * 10, lp * 10 + lp / 2 6303 }; 6304 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6305 6306 // For each size/alignment combination, we test three scenarios: 6307 // 1) with req_addr == NULL 6308 // 2) with a non-null req_addr at which we expect to successfully allocate 6309 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6310 // expect the allocation to either fail or to ignore req_addr 6311 6312 // Pre-allocate two areas; they shall be as large as the largest allocation 6313 // and aligned to the largest alignment we will be testing. 6314 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6315 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6316 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6317 -1, 0); 6318 assert(mapping1 != MAP_FAILED, "should work"); 6319 6320 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6321 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6322 -1, 0); 6323 assert(mapping2 != MAP_FAILED, "should work"); 6324 6325 // Unmap the first mapping, but leave the second mapping intact: the first 6326 // mapping will serve as a value for a "good" req_addr (case 2). The second 6327 // mapping, still intact, as "bad" req_addr (case 3). 6328 ::munmap(mapping1, mapping_size); 6329 6330 // Case 1 6331 for (int i = 0; i < num_sizes; i++) { 6332 const size_t size = sizes[i]; 6333 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6334 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6335 if (p != NULL) { 6336 assert(is_aligned(p, alignment), "must be"); 6337 small_page_write(p, size); 6338 os::Linux::release_memory_special_huge_tlbfs(p, size); 6339 } 6340 } 6341 } 6342 6343 // Case 2 6344 for (int i = 0; i < num_sizes; i++) { 6345 const size_t size = sizes[i]; 6346 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6347 char* const req_addr = align_up(mapping1, alignment); 6348 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6349 if (p != NULL) { 6350 assert(p == req_addr, "must be"); 6351 small_page_write(p, size); 6352 os::Linux::release_memory_special_huge_tlbfs(p, size); 6353 } 6354 } 6355 } 6356 6357 // Case 3 6358 for (int i = 0; i < num_sizes; i++) { 6359 const size_t size = sizes[i]; 6360 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6361 char* const req_addr = align_up(mapping2, alignment); 6362 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6363 // as the area around req_addr contains already existing mappings, the API should always 6364 // return NULL (as per contract, it cannot return another address) 6365 assert(p == NULL, "must be"); 6366 } 6367 } 6368 6369 ::munmap(mapping2, mapping_size); 6370 6371 } 6372 6373 static void test_reserve_memory_special_huge_tlbfs() { 6374 if (!UseHugeTLBFS) { 6375 return; 6376 } 6377 6378 test_reserve_memory_special_huge_tlbfs_only(); 6379 test_reserve_memory_special_huge_tlbfs_mixed(); 6380 } 6381 6382 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6383 if (!UseSHM) { 6384 return; 6385 } 6386 6387 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6388 6389 if (addr != NULL) { 6390 assert(is_aligned(addr, alignment), "Check"); 6391 assert(is_aligned(addr, os::large_page_size()), "Check"); 6392 6393 small_page_write(addr, size); 6394 6395 os::Linux::release_memory_special_shm(addr, size); 6396 } 6397 } 6398 6399 static void test_reserve_memory_special_shm() { 6400 size_t lp = os::large_page_size(); 6401 size_t ag = os::vm_allocation_granularity(); 6402 6403 for (size_t size = ag; size < lp * 3; size += ag) { 6404 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6405 test_reserve_memory_special_shm(size, alignment); 6406 } 6407 } 6408 } 6409 6410 static void test() { 6411 test_reserve_memory_special_huge_tlbfs(); 6412 test_reserve_memory_special_shm(); 6413 } 6414 }; 6415 6416 void TestReserveMemorySpecial_test() { 6417 TestReserveMemorySpecial::test(); 6418 } 6419 6420 #endif