1 /* 2 * Copyright (c) 1999, 2019, 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/orderAccess.hpp" 57 #include "runtime/osThread.hpp" 58 #include "runtime/perfMemory.hpp" 59 #include "runtime/sharedRuntime.hpp" 60 #include "runtime/statSampler.hpp" 61 #include "runtime/stubRoutines.hpp" 62 #include "runtime/thread.inline.hpp" 63 #include "runtime/threadCritical.hpp" 64 #include "runtime/threadSMR.hpp" 65 #include "runtime/timer.hpp" 66 #include "runtime/vm_version.hpp" 67 #include "semaphore_posix.hpp" 68 #include "services/attachListener.hpp" 69 #include "services/memTracker.hpp" 70 #include "services/runtimeService.hpp" 71 #include "utilities/align.hpp" 72 #include "utilities/decoder.hpp" 73 #include "utilities/defaultStream.hpp" 74 #include "utilities/events.hpp" 75 #include "utilities/elfFile.hpp" 76 #include "utilities/growableArray.hpp" 77 #include "utilities/macros.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 <errno.h> 88 # include <dlfcn.h> 89 # include <stdio.h> 90 # include <unistd.h> 91 # include <sys/resource.h> 92 # include <pthread.h> 93 # include <sys/stat.h> 94 # include <sys/time.h> 95 # include <sys/times.h> 96 # include <sys/utsname.h> 97 # include <sys/socket.h> 98 # include <sys/wait.h> 99 # include <pwd.h> 100 # include <poll.h> 101 # include <fcntl.h> 102 # include <string.h> 103 # include <syscall.h> 104 # include <sys/sysinfo.h> 105 # include <gnu/libc-version.h> 106 # include <sys/ipc.h> 107 # include <sys/shm.h> 108 # include <link.h> 109 # include <stdint.h> 110 # include <inttypes.h> 111 # include <sys/ioctl.h> 112 113 #ifndef _GNU_SOURCE 114 #define _GNU_SOURCE 115 #include <sched.h> 116 #undef _GNU_SOURCE 117 #else 118 #include <sched.h> 119 #endif 120 121 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 122 // getrusage() is prepared to handle the associated failure. 123 #ifndef RUSAGE_THREAD 124 #define RUSAGE_THREAD (1) /* only the calling thread */ 125 #endif 126 127 #define MAX_PATH (2 * K) 128 129 #define MAX_SECS 100000000 130 131 // for timer info max values which include all bits 132 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 133 134 enum CoredumpFilterBit { 135 FILE_BACKED_PVT_BIT = 1 << 2, 136 FILE_BACKED_SHARED_BIT = 1 << 3, 137 LARGEPAGES_BIT = 1 << 6, 138 DAX_SHARED_BIT = 1 << 8 139 }; 140 141 //////////////////////////////////////////////////////////////////////////////// 142 // global variables 143 julong os::Linux::_physical_memory = 0; 144 145 address os::Linux::_initial_thread_stack_bottom = NULL; 146 uintptr_t os::Linux::_initial_thread_stack_size = 0; 147 148 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 149 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 150 Mutex* os::Linux::_createThread_lock = NULL; 151 pthread_t os::Linux::_main_thread; 152 int os::Linux::_page_size = -1; 153 bool os::Linux::_supports_fast_thread_cpu_time = false; 154 uint32_t os::Linux::_os_version = 0; 155 const char * os::Linux::_glibc_version = NULL; 156 const char * os::Linux::_libpthread_version = NULL; 157 158 static jlong initial_time_count=0; 159 160 static int clock_tics_per_sec = 100; 161 162 // If the VM might have been created on the primordial thread, we need to resolve the 163 // primordial thread stack bounds and check if the current thread might be the 164 // primordial thread in places. If we know that the primordial thread is never used, 165 // such as when the VM was created by one of the standard java launchers, we can 166 // avoid this 167 static bool suppress_primordial_thread_resolution = false; 168 169 // For diagnostics to print a message once. see run_periodic_checks 170 static sigset_t check_signal_done; 171 static bool check_signals = true; 172 173 // Signal number used to suspend/resume a thread 174 175 // do not use any signal number less than SIGSEGV, see 4355769 176 static int SR_signum = SIGUSR2; 177 sigset_t SR_sigset; 178 179 // utility functions 180 181 static int SR_initialize(); 182 183 julong os::available_memory() { 184 return Linux::available_memory(); 185 } 186 187 julong os::Linux::available_memory() { 188 // values in struct sysinfo are "unsigned long" 189 struct sysinfo si; 190 julong avail_mem; 191 192 if (OSContainer::is_containerized()) { 193 jlong mem_limit, mem_usage; 194 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) { 195 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 196 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 197 } 198 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) { 199 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage); 200 } 201 if (mem_limit > 0 && mem_usage > 0 ) { 202 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0; 203 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem); 204 return avail_mem; 205 } 206 } 207 208 sysinfo(&si); 209 avail_mem = (julong)si.freeram * si.mem_unit; 210 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem); 211 return avail_mem; 212 } 213 214 julong os::physical_memory() { 215 jlong phys_mem = 0; 216 if (OSContainer::is_containerized()) { 217 jlong mem_limit; 218 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) { 219 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit); 220 return mem_limit; 221 } 222 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 223 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 224 } 225 226 phys_mem = Linux::physical_memory(); 227 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem); 228 return phys_mem; 229 } 230 231 static uint64_t initial_total_ticks = 0; 232 static uint64_t initial_steal_ticks = 0; 233 static bool has_initial_tick_info = false; 234 235 static void next_line(FILE *f) { 236 int c; 237 do { 238 c = fgetc(f); 239 } while (c != '\n' && c != EOF); 240 } 241 242 bool os::Linux::get_tick_information(CPUPerfTicks* pticks, int which_logical_cpu) { 243 FILE* fh; 244 uint64_t userTicks, niceTicks, systemTicks, idleTicks; 245 // since at least kernel 2.6 : iowait: time waiting for I/O to complete 246 // irq: time servicing interrupts; softirq: time servicing softirqs 247 uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0; 248 // steal (since kernel 2.6.11): time spent in other OS when running in a virtualized environment 249 uint64_t stealTicks = 0; 250 // guest (since kernel 2.6.24): time spent running a virtual CPU for guest OS under the 251 // control of the Linux kernel 252 uint64_t guestNiceTicks = 0; 253 int logical_cpu = -1; 254 const int required_tickinfo_count = (which_logical_cpu == -1) ? 4 : 5; 255 int n; 256 257 memset(pticks, 0, sizeof(CPUPerfTicks)); 258 259 if ((fh = fopen("/proc/stat", "r")) == NULL) { 260 return false; 261 } 262 263 if (which_logical_cpu == -1) { 264 n = fscanf(fh, "cpu " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 265 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 266 UINT64_FORMAT " " UINT64_FORMAT " ", 267 &userTicks, &niceTicks, &systemTicks, &idleTicks, 268 &iowTicks, &irqTicks, &sirqTicks, 269 &stealTicks, &guestNiceTicks); 270 } else { 271 // Move to next line 272 next_line(fh); 273 274 // find the line for requested cpu faster to just iterate linefeeds? 275 for (int i = 0; i < which_logical_cpu; i++) { 276 next_line(fh); 277 } 278 279 n = fscanf(fh, "cpu%u " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 280 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 281 UINT64_FORMAT " " UINT64_FORMAT " ", 282 &logical_cpu, &userTicks, &niceTicks, 283 &systemTicks, &idleTicks, &iowTicks, &irqTicks, &sirqTicks, 284 &stealTicks, &guestNiceTicks); 285 } 286 287 fclose(fh); 288 if (n < required_tickinfo_count || logical_cpu != which_logical_cpu) { 289 return false; 290 } 291 pticks->used = userTicks + niceTicks; 292 pticks->usedKernel = systemTicks + irqTicks + sirqTicks; 293 pticks->total = userTicks + niceTicks + systemTicks + idleTicks + 294 iowTicks + irqTicks + sirqTicks + stealTicks + guestNiceTicks; 295 296 if (n > required_tickinfo_count + 3) { 297 pticks->steal = stealTicks; 298 pticks->has_steal_ticks = true; 299 } else { 300 pticks->steal = 0; 301 pticks->has_steal_ticks = false; 302 } 303 304 return true; 305 } 306 307 // Return true if user is running as root. 308 309 bool os::have_special_privileges() { 310 static bool init = false; 311 static bool privileges = false; 312 if (!init) { 313 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 314 init = true; 315 } 316 return privileges; 317 } 318 319 320 #ifndef SYS_gettid 321 // i386: 224, ia64: 1105, amd64: 186, sparc 143 322 #ifdef __ia64__ 323 #define SYS_gettid 1105 324 #else 325 #ifdef __i386__ 326 #define SYS_gettid 224 327 #else 328 #ifdef __amd64__ 329 #define SYS_gettid 186 330 #else 331 #ifdef __sparc__ 332 #define SYS_gettid 143 333 #else 334 #error define gettid for the arch 335 #endif 336 #endif 337 #endif 338 #endif 339 #endif 340 341 342 // pid_t gettid() 343 // 344 // Returns the kernel thread id of the currently running thread. Kernel 345 // thread id is used to access /proc. 346 pid_t os::Linux::gettid() { 347 int rslt = syscall(SYS_gettid); 348 assert(rslt != -1, "must be."); // old linuxthreads implementation? 349 return (pid_t)rslt; 350 } 351 352 // Most versions of linux have a bug where the number of processors are 353 // determined by looking at the /proc file system. In a chroot environment, 354 // the system call returns 1. 355 static bool unsafe_chroot_detected = false; 356 static const char *unstable_chroot_error = "/proc file system not found.\n" 357 "Java may be unstable running multithreaded in a chroot " 358 "environment on Linux when /proc filesystem is not mounted."; 359 360 void os::Linux::initialize_system_info() { 361 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 362 if (processor_count() == 1) { 363 pid_t pid = os::Linux::gettid(); 364 char fname[32]; 365 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 366 FILE *fp = fopen(fname, "r"); 367 if (fp == NULL) { 368 unsafe_chroot_detected = true; 369 } else { 370 fclose(fp); 371 } 372 } 373 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 374 assert(processor_count() > 0, "linux error"); 375 } 376 377 void os::init_system_properties_values() { 378 // The next steps are taken in the product version: 379 // 380 // Obtain the JAVA_HOME value from the location of libjvm.so. 381 // This library should be located at: 382 // <JAVA_HOME>/lib/{client|server}/libjvm.so. 383 // 384 // If "/jre/lib/" appears at the right place in the path, then we 385 // assume libjvm.so is installed in a JDK and we use this path. 386 // 387 // Otherwise exit with message: "Could not create the Java virtual machine." 388 // 389 // The following extra steps are taken in the debugging version: 390 // 391 // If "/jre/lib/" does NOT appear at the right place in the path 392 // instead of exit check for $JAVA_HOME environment variable. 393 // 394 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 395 // then we append a fake suffix "hotspot/libjvm.so" to this path so 396 // it looks like libjvm.so is installed there 397 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 398 // 399 // Otherwise exit. 400 // 401 // Important note: if the location of libjvm.so changes this 402 // code needs to be changed accordingly. 403 404 // See ld(1): 405 // The linker uses the following search paths to locate required 406 // shared libraries: 407 // 1: ... 408 // ... 409 // 7: The default directories, normally /lib and /usr/lib. 410 #ifndef OVERRIDE_LIBPATH 411 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390) 412 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 413 #else 414 #define DEFAULT_LIBPATH "/lib:/usr/lib" 415 #endif 416 #else 417 #define DEFAULT_LIBPATH OVERRIDE_LIBPATH 418 #endif 419 420 // Base path of extensions installed on the system. 421 #define SYS_EXT_DIR "/usr/java/packages" 422 #define EXTENSIONS_DIR "/lib/ext" 423 424 // Buffer that fits several sprintfs. 425 // Note that the space for the colon and the trailing null are provided 426 // by the nulls included by the sizeof operator. 427 const size_t bufsize = 428 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 429 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 430 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 431 432 // sysclasspath, java_home, dll_dir 433 { 434 char *pslash; 435 os::jvm_path(buf, bufsize); 436 437 // Found the full path to libjvm.so. 438 // Now cut the path to <java_home>/jre if we can. 439 pslash = strrchr(buf, '/'); 440 if (pslash != NULL) { 441 *pslash = '\0'; // Get rid of /libjvm.so. 442 } 443 pslash = strrchr(buf, '/'); 444 if (pslash != NULL) { 445 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 446 } 447 Arguments::set_dll_dir(buf); 448 449 if (pslash != NULL) { 450 pslash = strrchr(buf, '/'); 451 if (pslash != NULL) { 452 *pslash = '\0'; // Get rid of /lib. 453 } 454 } 455 Arguments::set_java_home(buf); 456 if (!set_boot_path('/', ':')) { 457 vm_exit_during_initialization("Failed setting boot class path.", NULL); 458 } 459 } 460 461 // Where to look for native libraries. 462 // 463 // Note: Due to a legacy implementation, most of the library path 464 // is set in the launcher. This was to accomodate linking restrictions 465 // on legacy Linux implementations (which are no longer supported). 466 // Eventually, all the library path setting will be done here. 467 // 468 // However, to prevent the proliferation of improperly built native 469 // libraries, the new path component /usr/java/packages is added here. 470 // Eventually, all the library path setting will be done here. 471 { 472 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 473 // should always exist (until the legacy problem cited above is 474 // addressed). 475 const char *v = ::getenv("LD_LIBRARY_PATH"); 476 const char *v_colon = ":"; 477 if (v == NULL) { v = ""; v_colon = ""; } 478 // That's +1 for the colon and +1 for the trailing '\0'. 479 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 480 strlen(v) + 1 + 481 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1, 482 mtInternal); 483 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon); 484 Arguments::set_library_path(ld_library_path); 485 FREE_C_HEAP_ARRAY(char, ld_library_path); 486 } 487 488 // Extensions directories. 489 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 490 Arguments::set_ext_dirs(buf); 491 492 FREE_C_HEAP_ARRAY(char, buf); 493 494 #undef DEFAULT_LIBPATH 495 #undef SYS_EXT_DIR 496 #undef EXTENSIONS_DIR 497 } 498 499 //////////////////////////////////////////////////////////////////////////////// 500 // breakpoint support 501 502 void os::breakpoint() { 503 BREAKPOINT; 504 } 505 506 extern "C" void breakpoint() { 507 // use debugger to set breakpoint here 508 } 509 510 //////////////////////////////////////////////////////////////////////////////// 511 // signal support 512 513 debug_only(static bool signal_sets_initialized = false); 514 static sigset_t unblocked_sigs, vm_sigs; 515 516 void os::Linux::signal_sets_init() { 517 // Should also have an assertion stating we are still single-threaded. 518 assert(!signal_sets_initialized, "Already initialized"); 519 // Fill in signals that are necessarily unblocked for all threads in 520 // the VM. Currently, we unblock the following signals: 521 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 522 // by -Xrs (=ReduceSignalUsage)); 523 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 524 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 525 // the dispositions or masks wrt these signals. 526 // Programs embedding the VM that want to use the above signals for their 527 // own purposes must, at this time, use the "-Xrs" option to prevent 528 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 529 // (See bug 4345157, and other related bugs). 530 // In reality, though, unblocking these signals is really a nop, since 531 // these signals are not blocked by default. 532 sigemptyset(&unblocked_sigs); 533 sigaddset(&unblocked_sigs, SIGILL); 534 sigaddset(&unblocked_sigs, SIGSEGV); 535 sigaddset(&unblocked_sigs, SIGBUS); 536 sigaddset(&unblocked_sigs, SIGFPE); 537 #if defined(PPC64) 538 sigaddset(&unblocked_sigs, SIGTRAP); 539 #endif 540 sigaddset(&unblocked_sigs, SR_signum); 541 542 if (!ReduceSignalUsage) { 543 if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 544 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 545 } 546 if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 547 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 548 } 549 if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 550 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 551 } 552 } 553 // Fill in signals that are blocked by all but the VM thread. 554 sigemptyset(&vm_sigs); 555 if (!ReduceSignalUsage) { 556 sigaddset(&vm_sigs, BREAK_SIGNAL); 557 } 558 debug_only(signal_sets_initialized = true); 559 560 } 561 562 // These are signals that are unblocked while a thread is running Java. 563 // (For some reason, they get blocked by default.) 564 sigset_t* os::Linux::unblocked_signals() { 565 assert(signal_sets_initialized, "Not initialized"); 566 return &unblocked_sigs; 567 } 568 569 // These are the signals that are blocked while a (non-VM) thread is 570 // running Java. Only the VM thread handles these signals. 571 sigset_t* os::Linux::vm_signals() { 572 assert(signal_sets_initialized, "Not initialized"); 573 return &vm_sigs; 574 } 575 576 void os::Linux::hotspot_sigmask(Thread* thread) { 577 578 //Save caller's signal mask before setting VM signal mask 579 sigset_t caller_sigmask; 580 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 581 582 OSThread* osthread = thread->osthread(); 583 osthread->set_caller_sigmask(caller_sigmask); 584 585 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 586 587 if (!ReduceSignalUsage) { 588 if (thread->is_VM_thread()) { 589 // Only the VM thread handles BREAK_SIGNAL ... 590 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 591 } else { 592 // ... all other threads block BREAK_SIGNAL 593 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 594 } 595 } 596 } 597 598 ////////////////////////////////////////////////////////////////////////////// 599 // detecting pthread library 600 601 void os::Linux::libpthread_init() { 602 // Save glibc and pthread version strings. 603 #if !defined(_CS_GNU_LIBC_VERSION) || \ 604 !defined(_CS_GNU_LIBPTHREAD_VERSION) 605 #error "glibc too old (< 2.3.2)" 606 #endif 607 608 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 609 assert(n > 0, "cannot retrieve glibc version"); 610 char *str = (char *)malloc(n, mtInternal); 611 confstr(_CS_GNU_LIBC_VERSION, str, n); 612 os::Linux::set_glibc_version(str); 613 614 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 615 assert(n > 0, "cannot retrieve pthread version"); 616 str = (char *)malloc(n, mtInternal); 617 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 618 os::Linux::set_libpthread_version(str); 619 } 620 621 ///////////////////////////////////////////////////////////////////////////// 622 // thread stack expansion 623 624 // os::Linux::manually_expand_stack() takes care of expanding the thread 625 // stack. Note that this is normally not needed: pthread stacks allocate 626 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 627 // committed. Therefore it is not necessary to expand the stack manually. 628 // 629 // Manually expanding the stack was historically needed on LinuxThreads 630 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 631 // it is kept to deal with very rare corner cases: 632 // 633 // For one, user may run the VM on an own implementation of threads 634 // whose stacks are - like the old LinuxThreads - implemented using 635 // mmap(MAP_GROWSDOWN). 636 // 637 // Also, this coding may be needed if the VM is running on the primordial 638 // thread. Normally we avoid running on the primordial thread; however, 639 // user may still invoke the VM on the primordial thread. 640 // 641 // The following historical comment describes the details about running 642 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 643 644 645 // Force Linux kernel to expand current thread stack. If "bottom" is close 646 // to the stack guard, caller should block all signals. 647 // 648 // MAP_GROWSDOWN: 649 // A special mmap() flag that is used to implement thread stacks. It tells 650 // kernel that the memory region should extend downwards when needed. This 651 // allows early versions of LinuxThreads to only mmap the first few pages 652 // when creating a new thread. Linux kernel will automatically expand thread 653 // stack as needed (on page faults). 654 // 655 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 656 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 657 // region, it's hard to tell if the fault is due to a legitimate stack 658 // access or because of reading/writing non-exist memory (e.g. buffer 659 // overrun). As a rule, if the fault happens below current stack pointer, 660 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 661 // application (see Linux kernel fault.c). 662 // 663 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 664 // stack overflow detection. 665 // 666 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 667 // not use MAP_GROWSDOWN. 668 // 669 // To get around the problem and allow stack banging on Linux, we need to 670 // manually expand thread stack after receiving the SIGSEGV. 671 // 672 // There are two ways to expand thread stack to address "bottom", we used 673 // both of them in JVM before 1.5: 674 // 1. adjust stack pointer first so that it is below "bottom", and then 675 // touch "bottom" 676 // 2. mmap() the page in question 677 // 678 // Now alternate signal stack is gone, it's harder to use 2. For instance, 679 // if current sp is already near the lower end of page 101, and we need to 680 // call mmap() to map page 100, it is possible that part of the mmap() frame 681 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 682 // That will destroy the mmap() frame and cause VM to crash. 683 // 684 // The following code works by adjusting sp first, then accessing the "bottom" 685 // page to force a page fault. Linux kernel will then automatically expand the 686 // stack mapping. 687 // 688 // _expand_stack_to() assumes its frame size is less than page size, which 689 // should always be true if the function is not inlined. 690 691 static void NOINLINE _expand_stack_to(address bottom) { 692 address sp; 693 size_t size; 694 volatile char *p; 695 696 // Adjust bottom to point to the largest address within the same page, it 697 // gives us a one-page buffer if alloca() allocates slightly more memory. 698 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size()); 699 bottom += os::Linux::page_size() - 1; 700 701 // sp might be slightly above current stack pointer; if that's the case, we 702 // will alloca() a little more space than necessary, which is OK. Don't use 703 // os::current_stack_pointer(), as its result can be slightly below current 704 // stack pointer, causing us to not alloca enough to reach "bottom". 705 sp = (address)&sp; 706 707 if (sp > bottom) { 708 size = sp - bottom; 709 p = (volatile char *)alloca(size); 710 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 711 p[0] = '\0'; 712 } 713 } 714 715 void os::Linux::expand_stack_to(address bottom) { 716 _expand_stack_to(bottom); 717 } 718 719 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 720 assert(t!=NULL, "just checking"); 721 assert(t->osthread()->expanding_stack(), "expand should be set"); 722 assert(t->stack_base() != NULL, "stack_base was not initialized"); 723 724 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) { 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 bool os::create_thread(Thread* thread, ThreadType thr_type, 804 size_t req_stack_size) { 805 assert(thread->osthread() == NULL, "caller responsible"); 806 807 // Allocate the OSThread object 808 OSThread* osthread = new OSThread(NULL, NULL); 809 if (osthread == NULL) { 810 return false; 811 } 812 813 // set the correct thread state 814 osthread->set_thread_type(thr_type); 815 816 // Initial state is ALLOCATED but not INITIALIZED 817 osthread->set_state(ALLOCATED); 818 819 thread->set_osthread(osthread); 820 821 // init thread attributes 822 pthread_attr_t attr; 823 pthread_attr_init(&attr); 824 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 825 826 // Calculate stack size if it's not specified by caller. 827 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size); 828 // In the Linux NPTL pthread implementation the guard size mechanism 829 // is not implemented properly. The posix standard requires adding 830 // the size of the guard pages to the stack size, instead Linux 831 // takes the space out of 'stacksize'. Thus we adapt the requested 832 // stack_size by the size of the guard pages to mimick proper 833 // behaviour. However, be careful not to end up with a size 834 // of zero due to overflow. Don't add the guard page in that case. 835 size_t guard_size = os::Linux::default_guard_size(thr_type); 836 if (stack_size <= SIZE_MAX - guard_size) { 837 stack_size += guard_size; 838 } 839 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned"); 840 841 int status = pthread_attr_setstacksize(&attr, stack_size); 842 assert_status(status == 0, status, "pthread_attr_setstacksize"); 843 844 // Configure glibc guard page. 845 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 846 847 ThreadState state; 848 849 { 850 pthread_t tid; 851 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread); 852 853 char buf[64]; 854 if (ret == 0) { 855 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 856 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 857 } else { 858 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 859 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 860 // Log some OS information which might explain why creating the thread failed. 861 log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads()); 862 LogStream st(Log(os, thread)::info()); 863 os::Posix::print_rlimit_info(&st); 864 os::print_memory_info(&st); 865 os::Linux::print_proc_sys_info(&st); 866 os::Linux::print_container_info(&st); 867 } 868 869 pthread_attr_destroy(&attr); 870 871 if (ret != 0) { 872 // Need to clean up stuff we've allocated so far 873 thread->set_osthread(NULL); 874 delete osthread; 875 return false; 876 } 877 878 // Store pthread info into the OSThread 879 osthread->set_pthread_id(tid); 880 881 // Wait until child thread is either initialized or aborted 882 { 883 Monitor* sync_with_child = osthread->startThread_lock(); 884 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag); 885 while ((state = osthread->get_state()) == ALLOCATED) { 886 sync_with_child->wait_without_safepoint_check(); 887 } 888 } 889 } 890 891 // Aborted due to thread limit being reached 892 if (state == ZOMBIE) { 893 thread->set_osthread(NULL); 894 delete osthread; 895 return false; 896 } 897 898 // The thread is returned suspended (in state INITIALIZED), 899 // and is started higher up in the call chain 900 assert(state == INITIALIZED, "race condition"); 901 return true; 902 } 903 904 ///////////////////////////////////////////////////////////////////////////// 905 // attach existing thread 906 907 // bootstrap the main thread 908 bool os::create_main_thread(JavaThread* thread) { 909 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 910 return create_attached_thread(thread); 911 } 912 913 bool os::create_attached_thread(JavaThread* thread) { 914 #ifdef ASSERT 915 thread->verify_not_published(); 916 #endif 917 918 // Allocate the OSThread object 919 OSThread* osthread = new OSThread(NULL, NULL); 920 921 if (osthread == NULL) { 922 return false; 923 } 924 925 // Store pthread info into the OSThread 926 osthread->set_thread_id(os::Linux::gettid()); 927 osthread->set_pthread_id(::pthread_self()); 928 929 // initialize floating point control register 930 os::Linux::init_thread_fpu_state(); 931 932 // Initial thread state is RUNNABLE 933 osthread->set_state(RUNNABLE); 934 935 thread->set_osthread(osthread); 936 937 if (UseNUMA) { 938 int lgrp_id = os::numa_get_group_id(); 939 if (lgrp_id != -1) { 940 thread->set_lgrp_id(lgrp_id); 941 } 942 } 943 944 if (os::is_primordial_thread()) { 945 // If current thread is primordial thread, its stack is mapped on demand, 946 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 947 // the entire stack region to avoid SEGV in stack banging. 948 // It is also useful to get around the heap-stack-gap problem on SuSE 949 // kernel (see 4821821 for details). We first expand stack to the top 950 // of yellow zone, then enable stack yellow zone (order is significant, 951 // enabling yellow zone first will crash JVM on SuSE Linux), so there 952 // is no gap between the last two virtual memory regions. 953 954 JavaThread *jt = (JavaThread *)thread; 955 address addr = jt->stack_reserved_zone_base(); 956 assert(addr != NULL, "initialization problem?"); 957 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 958 959 osthread->set_expanding_stack(); 960 os::Linux::manually_expand_stack(jt, addr); 961 osthread->clear_expanding_stack(); 962 } 963 964 // initialize signal mask for this thread 965 // and save the caller's signal mask 966 os::Linux::hotspot_sigmask(thread); 967 968 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 969 os::current_thread_id(), (uintx) pthread_self()); 970 971 return true; 972 } 973 974 void os::pd_start_thread(Thread* thread) { 975 OSThread * osthread = thread->osthread(); 976 assert(osthread->get_state() != INITIALIZED, "just checking"); 977 Monitor* sync_with_child = osthread->startThread_lock(); 978 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag); 979 sync_with_child->notify(); 980 } 981 982 // Free Linux resources related to the OSThread 983 void os::free_thread(OSThread* osthread) { 984 assert(osthread != NULL, "osthread not set"); 985 986 // We are told to free resources of the argument thread, 987 // but we can only really operate on the current thread. 988 assert(Thread::current()->osthread() == osthread, 989 "os::free_thread but not current thread"); 990 991 #ifdef ASSERT 992 sigset_t current; 993 sigemptyset(¤t); 994 pthread_sigmask(SIG_SETMASK, NULL, ¤t); 995 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!"); 996 #endif 997 998 // Restore caller's signal mask 999 sigset_t sigmask = osthread->caller_sigmask(); 1000 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1001 1002 delete osthread; 1003 } 1004 1005 ////////////////////////////////////////////////////////////////////////////// 1006 // primordial thread 1007 1008 // Check if current thread is the primordial thread, similar to Solaris thr_main. 1009 bool os::is_primordial_thread(void) { 1010 if (suppress_primordial_thread_resolution) { 1011 return false; 1012 } 1013 char dummy; 1014 // If called before init complete, thread stack bottom will be null. 1015 // Can be called if fatal error occurs before initialization. 1016 if (os::Linux::initial_thread_stack_bottom() == NULL) return false; 1017 assert(os::Linux::initial_thread_stack_bottom() != NULL && 1018 os::Linux::initial_thread_stack_size() != 0, 1019 "os::init did not locate primordial thread's stack region"); 1020 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() && 1021 (address)&dummy < os::Linux::initial_thread_stack_bottom() + 1022 os::Linux::initial_thread_stack_size()) { 1023 return true; 1024 } else { 1025 return false; 1026 } 1027 } 1028 1029 // Find the virtual memory area that contains addr 1030 static bool find_vma(address addr, address* vma_low, address* vma_high) { 1031 FILE *fp = fopen("/proc/self/maps", "r"); 1032 if (fp) { 1033 address low, high; 1034 while (!feof(fp)) { 1035 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1036 if (low <= addr && addr < high) { 1037 if (vma_low) *vma_low = low; 1038 if (vma_high) *vma_high = high; 1039 fclose(fp); 1040 return true; 1041 } 1042 } 1043 for (;;) { 1044 int ch = fgetc(fp); 1045 if (ch == EOF || ch == (int)'\n') break; 1046 } 1047 } 1048 fclose(fp); 1049 } 1050 return false; 1051 } 1052 1053 // Locate primordial thread stack. This special handling of primordial thread stack 1054 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 1055 // bogus value for the primordial process thread. While the launcher has created 1056 // the VM in a new thread since JDK 6, we still have to allow for the use of the 1057 // JNI invocation API from a primordial thread. 1058 void os::Linux::capture_initial_stack(size_t max_size) { 1059 1060 // max_size is either 0 (which means accept OS default for thread stacks) or 1061 // a user-specified value known to be at least the minimum needed. If we 1062 // are actually on the primordial thread we can make it appear that we have a 1063 // smaller max_size stack by inserting the guard pages at that location. But we 1064 // cannot do anything to emulate a larger stack than what has been provided by 1065 // the OS or threading library. In fact if we try to use a stack greater than 1066 // what is set by rlimit then we will crash the hosting process. 1067 1068 // Maximum stack size is the easy part, get it from RLIMIT_STACK. 1069 // If this is "unlimited" then it will be a huge value. 1070 struct rlimit rlim; 1071 getrlimit(RLIMIT_STACK, &rlim); 1072 size_t stack_size = rlim.rlim_cur; 1073 1074 // 6308388: a bug in ld.so will relocate its own .data section to the 1075 // lower end of primordial stack; reduce ulimit -s value a little bit 1076 // so we won't install guard page on ld.so's data section. 1077 // But ensure we don't underflow the stack size - allow 1 page spare 1078 if (stack_size >= (size_t)(3 * page_size())) { 1079 stack_size -= 2 * page_size(); 1080 } 1081 1082 // Try to figure out where the stack base (top) is. This is harder. 1083 // 1084 // When an application is started, glibc saves the initial stack pointer in 1085 // a global variable "__libc_stack_end", which is then used by system 1086 // libraries. __libc_stack_end should be pretty close to stack top. The 1087 // variable is available since the very early days. However, because it is 1088 // a private interface, it could disappear in the future. 1089 // 1090 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1091 // to __libc_stack_end, it is very close to stack top, but isn't the real 1092 // stack top. Note that /proc may not exist if VM is running as a chroot 1093 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1094 // /proc/<pid>/stat could change in the future (though unlikely). 1095 // 1096 // We try __libc_stack_end first. If that doesn't work, look for 1097 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1098 // as a hint, which should work well in most cases. 1099 1100 uintptr_t stack_start; 1101 1102 // try __libc_stack_end first 1103 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1104 if (p && *p) { 1105 stack_start = *p; 1106 } else { 1107 // see if we can get the start_stack field from /proc/self/stat 1108 FILE *fp; 1109 int pid; 1110 char state; 1111 int ppid; 1112 int pgrp; 1113 int session; 1114 int nr; 1115 int tpgrp; 1116 unsigned long flags; 1117 unsigned long minflt; 1118 unsigned long cminflt; 1119 unsigned long majflt; 1120 unsigned long cmajflt; 1121 unsigned long utime; 1122 unsigned long stime; 1123 long cutime; 1124 long cstime; 1125 long prio; 1126 long nice; 1127 long junk; 1128 long it_real; 1129 uintptr_t start; 1130 uintptr_t vsize; 1131 intptr_t rss; 1132 uintptr_t rsslim; 1133 uintptr_t scodes; 1134 uintptr_t ecode; 1135 int i; 1136 1137 // Figure what the primordial thread stack base is. Code is inspired 1138 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1139 // followed by command name surrounded by parentheses, state, etc. 1140 char stat[2048]; 1141 int statlen; 1142 1143 fp = fopen("/proc/self/stat", "r"); 1144 if (fp) { 1145 statlen = fread(stat, 1, 2047, fp); 1146 stat[statlen] = '\0'; 1147 fclose(fp); 1148 1149 // Skip pid and the command string. Note that we could be dealing with 1150 // weird command names, e.g. user could decide to rename java launcher 1151 // to "java 1.4.2 :)", then the stat file would look like 1152 // 1234 (java 1.4.2 :)) R ... ... 1153 // We don't really need to know the command string, just find the last 1154 // occurrence of ")" and then start parsing from there. See bug 4726580. 1155 char * s = strrchr(stat, ')'); 1156 1157 i = 0; 1158 if (s) { 1159 // Skip blank chars 1160 do { s++; } while (s && isspace(*s)); 1161 1162 #define _UFM UINTX_FORMAT 1163 #define _DFM INTX_FORMAT 1164 1165 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1166 // 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 1167 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM, 1168 &state, // 3 %c 1169 &ppid, // 4 %d 1170 &pgrp, // 5 %d 1171 &session, // 6 %d 1172 &nr, // 7 %d 1173 &tpgrp, // 8 %d 1174 &flags, // 9 %lu 1175 &minflt, // 10 %lu 1176 &cminflt, // 11 %lu 1177 &majflt, // 12 %lu 1178 &cmajflt, // 13 %lu 1179 &utime, // 14 %lu 1180 &stime, // 15 %lu 1181 &cutime, // 16 %ld 1182 &cstime, // 17 %ld 1183 &prio, // 18 %ld 1184 &nice, // 19 %ld 1185 &junk, // 20 %ld 1186 &it_real, // 21 %ld 1187 &start, // 22 UINTX_FORMAT 1188 &vsize, // 23 UINTX_FORMAT 1189 &rss, // 24 INTX_FORMAT 1190 &rsslim, // 25 UINTX_FORMAT 1191 &scodes, // 26 UINTX_FORMAT 1192 &ecode, // 27 UINTX_FORMAT 1193 &stack_start); // 28 UINTX_FORMAT 1194 } 1195 1196 #undef _UFM 1197 #undef _DFM 1198 1199 if (i != 28 - 2) { 1200 assert(false, "Bad conversion from /proc/self/stat"); 1201 // product mode - assume we are the primordial thread, good luck in the 1202 // embedded case. 1203 warning("Can't detect primordial thread stack location - bad conversion"); 1204 stack_start = (uintptr_t) &rlim; 1205 } 1206 } else { 1207 // For some reason we can't open /proc/self/stat (for example, running on 1208 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1209 // most cases, so don't abort: 1210 warning("Can't detect primordial thread stack location - no /proc/self/stat"); 1211 stack_start = (uintptr_t) &rlim; 1212 } 1213 } 1214 1215 // Now we have a pointer (stack_start) very close to the stack top, the 1216 // next thing to do is to figure out the exact location of stack top. We 1217 // can find out the virtual memory area that contains stack_start by 1218 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1219 // and its upper limit is the real stack top. (again, this would fail if 1220 // running inside chroot, because /proc may not exist.) 1221 1222 uintptr_t stack_top; 1223 address low, high; 1224 if (find_vma((address)stack_start, &low, &high)) { 1225 // success, "high" is the true stack top. (ignore "low", because initial 1226 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1227 stack_top = (uintptr_t)high; 1228 } else { 1229 // failed, likely because /proc/self/maps does not exist 1230 warning("Can't detect primordial thread stack location - find_vma failed"); 1231 // best effort: stack_start is normally within a few pages below the real 1232 // stack top, use it as stack top, and reduce stack size so we won't put 1233 // guard page outside stack. 1234 stack_top = stack_start; 1235 stack_size -= 16 * page_size(); 1236 } 1237 1238 // stack_top could be partially down the page so align it 1239 stack_top = align_up(stack_top, page_size()); 1240 1241 // Allowed stack value is minimum of max_size and what we derived from rlimit 1242 if (max_size > 0) { 1243 _initial_thread_stack_size = MIN2(max_size, stack_size); 1244 } else { 1245 // Accept the rlimit max, but if stack is unlimited then it will be huge, so 1246 // clamp it at 8MB as we do on Solaris 1247 _initial_thread_stack_size = MIN2(stack_size, 8*M); 1248 } 1249 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size()); 1250 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1251 1252 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!"); 1253 1254 if (log_is_enabled(Info, os, thread)) { 1255 // See if we seem to be on primordial process thread 1256 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) && 1257 uintptr_t(&rlim) < stack_top; 1258 1259 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: " 1260 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT, 1261 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K, 1262 stack_top, intptr_t(_initial_thread_stack_bottom)); 1263 } 1264 } 1265 1266 //////////////////////////////////////////////////////////////////////////////// 1267 // time support 1268 1269 #ifndef SUPPORTS_CLOCK_MONOTONIC 1270 #error "Build platform doesn't support clock_gettime and related functionality" 1271 #endif 1272 1273 // Time since start-up in seconds to a fine granularity. 1274 // Used by VMSelfDestructTimer and the MemProfiler. 1275 double os::elapsedTime() { 1276 1277 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1278 } 1279 1280 jlong os::elapsed_counter() { 1281 return javaTimeNanos() - initial_time_count; 1282 } 1283 1284 jlong os::elapsed_frequency() { 1285 return NANOSECS_PER_SEC; // nanosecond resolution 1286 } 1287 1288 bool os::supports_vtime() { return true; } 1289 bool os::enable_vtime() { return false; } 1290 bool os::vtime_enabled() { return false; } 1291 1292 double os::elapsedVTime() { 1293 struct rusage usage; 1294 int retval = getrusage(RUSAGE_THREAD, &usage); 1295 if (retval == 0) { 1296 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); 1297 } else { 1298 // better than nothing, but not much 1299 return elapsedTime(); 1300 } 1301 } 1302 1303 jlong os::javaTimeMillis() { 1304 timeval time; 1305 int status = gettimeofday(&time, NULL); 1306 assert(status != -1, "linux error"); 1307 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1308 } 1309 1310 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1311 timeval time; 1312 int status = gettimeofday(&time, NULL); 1313 assert(status != -1, "linux error"); 1314 seconds = jlong(time.tv_sec); 1315 nanos = jlong(time.tv_usec) * 1000; 1316 } 1317 1318 void os::Linux::fast_thread_clock_init() { 1319 if (!UseLinuxPosixThreadCPUClocks) { 1320 return; 1321 } 1322 clockid_t clockid; 1323 struct timespec tp; 1324 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1325 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1326 1327 // Switch to using fast clocks for thread cpu time if 1328 // the clock_getres() returns 0 error code. 1329 // Note, that some kernels may support the current thread 1330 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1331 // returned by the pthread_getcpuclockid(). 1332 // If the fast Posix clocks are supported then the clock_getres() 1333 // must return at least tp.tv_sec == 0 which means a resolution 1334 // better than 1 sec. This is extra check for reliability. 1335 1336 if (pthread_getcpuclockid_func && 1337 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1338 os::Posix::clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1339 _supports_fast_thread_cpu_time = true; 1340 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1341 } 1342 } 1343 1344 jlong os::javaTimeNanos() { 1345 if (os::supports_monotonic_clock()) { 1346 struct timespec tp; 1347 int status = os::Posix::clock_gettime(CLOCK_MONOTONIC, &tp); 1348 assert(status == 0, "gettime error"); 1349 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1350 return result; 1351 } else { 1352 timeval time; 1353 int status = gettimeofday(&time, NULL); 1354 assert(status != -1, "linux error"); 1355 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1356 return 1000 * usecs; 1357 } 1358 } 1359 1360 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1361 if (os::supports_monotonic_clock()) { 1362 info_ptr->max_value = ALL_64_BITS; 1363 1364 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1365 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1366 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1367 } else { 1368 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1369 info_ptr->max_value = ALL_64_BITS; 1370 1371 // gettimeofday is a real time clock so it skips 1372 info_ptr->may_skip_backward = true; 1373 info_ptr->may_skip_forward = true; 1374 } 1375 1376 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1377 } 1378 1379 // Return the real, user, and system times in seconds from an 1380 // arbitrary fixed point in the past. 1381 bool os::getTimesSecs(double* process_real_time, 1382 double* process_user_time, 1383 double* process_system_time) { 1384 struct tms ticks; 1385 clock_t real_ticks = times(&ticks); 1386 1387 if (real_ticks == (clock_t) (-1)) { 1388 return false; 1389 } else { 1390 double ticks_per_second = (double) clock_tics_per_sec; 1391 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1392 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1393 *process_real_time = ((double) real_ticks) / ticks_per_second; 1394 1395 return true; 1396 } 1397 } 1398 1399 1400 char * os::local_time_string(char *buf, size_t buflen) { 1401 struct tm t; 1402 time_t long_time; 1403 time(&long_time); 1404 localtime_r(&long_time, &t); 1405 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1406 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1407 t.tm_hour, t.tm_min, t.tm_sec); 1408 return buf; 1409 } 1410 1411 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1412 return localtime_r(clock, res); 1413 } 1414 1415 //////////////////////////////////////////////////////////////////////////////// 1416 // runtime exit support 1417 1418 // Note: os::shutdown() might be called very early during initialization, or 1419 // called from signal handler. Before adding something to os::shutdown(), make 1420 // sure it is async-safe and can handle partially initialized VM. 1421 void os::shutdown() { 1422 1423 // allow PerfMemory to attempt cleanup of any persistent resources 1424 perfMemory_exit(); 1425 1426 // needs to remove object in file system 1427 AttachListener::abort(); 1428 1429 // flush buffered output, finish log files 1430 ostream_abort(); 1431 1432 // Check for abort hook 1433 abort_hook_t abort_hook = Arguments::abort_hook(); 1434 if (abort_hook != NULL) { 1435 abort_hook(); 1436 } 1437 1438 } 1439 1440 // Note: os::abort() might be called very early during initialization, or 1441 // called from signal handler. Before adding something to os::abort(), make 1442 // sure it is async-safe and can handle partially initialized VM. 1443 void os::abort(bool dump_core, void* siginfo, const void* context) { 1444 os::shutdown(); 1445 if (dump_core) { 1446 if (DumpPrivateMappingsInCore) { 1447 ClassLoader::close_jrt_image(); 1448 } 1449 #ifndef PRODUCT 1450 fdStream out(defaultStream::output_fd()); 1451 out.print_raw("Current thread is "); 1452 char buf[16]; 1453 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1454 out.print_raw_cr(buf); 1455 out.print_raw_cr("Dumping core ..."); 1456 #endif 1457 ::abort(); // dump core 1458 } 1459 1460 ::exit(1); 1461 } 1462 1463 // Die immediately, no exit hook, no abort hook, no cleanup. 1464 // Dump a core file, if possible, for debugging. 1465 void os::die() { 1466 if (TestUnresponsiveErrorHandler && !CreateCoredumpOnCrash) { 1467 // For TimeoutInErrorHandlingTest.java, we just kill the VM 1468 // and don't take the time to generate a core file. 1469 os::signal_raise(SIGKILL); 1470 } else { 1471 ::abort(); 1472 } 1473 } 1474 1475 // thread_id is kernel thread id (similar to Solaris LWP id) 1476 intx os::current_thread_id() { return os::Linux::gettid(); } 1477 int os::current_process_id() { 1478 return ::getpid(); 1479 } 1480 1481 // DLL functions 1482 1483 const char* os::dll_file_extension() { return ".so"; } 1484 1485 // This must be hard coded because it's the system's temporary 1486 // directory not the java application's temp directory, ala java.io.tmpdir. 1487 const char* os::get_temp_directory() { return "/tmp"; } 1488 1489 static bool file_exists(const char* filename) { 1490 struct stat statbuf; 1491 if (filename == NULL || strlen(filename) == 0) { 1492 return false; 1493 } 1494 return os::stat(filename, &statbuf) == 0; 1495 } 1496 1497 // check if addr is inside libjvm.so 1498 bool os::address_is_in_vm(address addr) { 1499 static address libjvm_base_addr; 1500 Dl_info dlinfo; 1501 1502 if (libjvm_base_addr == NULL) { 1503 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1504 libjvm_base_addr = (address)dlinfo.dli_fbase; 1505 } 1506 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1507 } 1508 1509 if (dladdr((void *)addr, &dlinfo) != 0) { 1510 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1511 } 1512 1513 return false; 1514 } 1515 1516 bool os::dll_address_to_function_name(address addr, char *buf, 1517 int buflen, int *offset, 1518 bool demangle) { 1519 // buf is not optional, but offset is optional 1520 assert(buf != NULL, "sanity check"); 1521 1522 Dl_info dlinfo; 1523 1524 if (dladdr((void*)addr, &dlinfo) != 0) { 1525 // see if we have a matching symbol 1526 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1527 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1528 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1529 } 1530 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1531 return true; 1532 } 1533 // no matching symbol so try for just file info 1534 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1535 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1536 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1537 return true; 1538 } 1539 } 1540 } 1541 1542 buf[0] = '\0'; 1543 if (offset != NULL) *offset = -1; 1544 return false; 1545 } 1546 1547 struct _address_to_library_name { 1548 address addr; // input : memory address 1549 size_t buflen; // size of fname 1550 char* fname; // output: library name 1551 address base; // library base addr 1552 }; 1553 1554 static int address_to_library_name_callback(struct dl_phdr_info *info, 1555 size_t size, void *data) { 1556 int i; 1557 bool found = false; 1558 address libbase = NULL; 1559 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1560 1561 // iterate through all loadable segments 1562 for (i = 0; i < info->dlpi_phnum; i++) { 1563 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1564 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1565 // base address of a library is the lowest address of its loaded 1566 // segments. 1567 if (libbase == NULL || libbase > segbase) { 1568 libbase = segbase; 1569 } 1570 // see if 'addr' is within current segment 1571 if (segbase <= d->addr && 1572 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1573 found = true; 1574 } 1575 } 1576 } 1577 1578 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1579 // so dll_address_to_library_name() can fall through to use dladdr() which 1580 // can figure out executable name from argv[0]. 1581 if (found && info->dlpi_name && info->dlpi_name[0]) { 1582 d->base = libbase; 1583 if (d->fname) { 1584 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1585 } 1586 return 1; 1587 } 1588 return 0; 1589 } 1590 1591 bool os::dll_address_to_library_name(address addr, char* buf, 1592 int buflen, int* offset) { 1593 // buf is not optional, but offset is optional 1594 assert(buf != NULL, "sanity check"); 1595 1596 Dl_info dlinfo; 1597 struct _address_to_library_name data; 1598 1599 // There is a bug in old glibc dladdr() implementation that it could resolve 1600 // to wrong library name if the .so file has a base address != NULL. Here 1601 // we iterate through the program headers of all loaded libraries to find 1602 // out which library 'addr' really belongs to. This workaround can be 1603 // removed once the minimum requirement for glibc is moved to 2.3.x. 1604 data.addr = addr; 1605 data.fname = buf; 1606 data.buflen = buflen; 1607 data.base = NULL; 1608 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1609 1610 if (rslt) { 1611 // buf already contains library name 1612 if (offset) *offset = addr - data.base; 1613 return true; 1614 } 1615 if (dladdr((void*)addr, &dlinfo) != 0) { 1616 if (dlinfo.dli_fname != NULL) { 1617 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1618 } 1619 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1620 *offset = addr - (address)dlinfo.dli_fbase; 1621 } 1622 return true; 1623 } 1624 1625 buf[0] = '\0'; 1626 if (offset) *offset = -1; 1627 return false; 1628 } 1629 1630 // Loads .dll/.so and 1631 // in case of error it checks if .dll/.so was built for the 1632 // same architecture as Hotspot is running on 1633 1634 1635 // Remember the stack's state. The Linux dynamic linker will change 1636 // the stack to 'executable' at most once, so we must safepoint only once. 1637 bool os::Linux::_stack_is_executable = false; 1638 1639 // VM operation that loads a library. This is necessary if stack protection 1640 // of the Java stacks can be lost during loading the library. If we 1641 // do not stop the Java threads, they can stack overflow before the stacks 1642 // are protected again. 1643 class VM_LinuxDllLoad: public VM_Operation { 1644 private: 1645 const char *_filename; 1646 char *_ebuf; 1647 int _ebuflen; 1648 void *_lib; 1649 public: 1650 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1651 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1652 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1653 void doit() { 1654 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1655 os::Linux::_stack_is_executable = true; 1656 } 1657 void* loaded_library() { return _lib; } 1658 }; 1659 1660 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1661 void * result = NULL; 1662 bool load_attempted = false; 1663 1664 // Check whether the library to load might change execution rights 1665 // of the stack. If they are changed, the protection of the stack 1666 // guard pages will be lost. We need a safepoint to fix this. 1667 // 1668 // See Linux man page execstack(8) for more info. 1669 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1670 if (!ElfFile::specifies_noexecstack(filename)) { 1671 if (!is_init_completed()) { 1672 os::Linux::_stack_is_executable = true; 1673 // This is OK - No Java threads have been created yet, and hence no 1674 // stack guard pages to fix. 1675 // 1676 // Dynamic loader will make all stacks executable after 1677 // this function returns, and will not do that again. 1678 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet."); 1679 } else { 1680 warning("You have loaded library %s which might have disabled stack guard. " 1681 "The VM will try to fix the stack guard now.\n" 1682 "It's highly recommended that you fix the library with " 1683 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1684 filename); 1685 1686 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1687 JavaThread *jt = JavaThread::current(); 1688 if (jt->thread_state() != _thread_in_native) { 1689 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1690 // that requires ExecStack. Cannot enter safe point. Let's give up. 1691 warning("Unable to fix stack guard. Giving up."); 1692 } else { 1693 if (!LoadExecStackDllInVMThread) { 1694 // This is for the case where the DLL has an static 1695 // constructor function that executes JNI code. We cannot 1696 // load such DLLs in the VMThread. 1697 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1698 } 1699 1700 ThreadInVMfromNative tiv(jt); 1701 debug_only(VMNativeEntryWrapper vew;) 1702 1703 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1704 VMThread::execute(&op); 1705 if (LoadExecStackDllInVMThread) { 1706 result = op.loaded_library(); 1707 } 1708 load_attempted = true; 1709 } 1710 } 1711 } 1712 } 1713 1714 if (!load_attempted) { 1715 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1716 } 1717 1718 if (result != NULL) { 1719 // Successful loading 1720 return result; 1721 } 1722 1723 Elf32_Ehdr elf_head; 1724 int diag_msg_max_length=ebuflen-strlen(ebuf); 1725 char* diag_msg_buf=ebuf+strlen(ebuf); 1726 1727 if (diag_msg_max_length==0) { 1728 // No more space in ebuf for additional diagnostics message 1729 return NULL; 1730 } 1731 1732 1733 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1734 1735 if (file_descriptor < 0) { 1736 // Can't open library, report dlerror() message 1737 return NULL; 1738 } 1739 1740 bool failed_to_read_elf_head= 1741 (sizeof(elf_head)!= 1742 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1743 1744 ::close(file_descriptor); 1745 if (failed_to_read_elf_head) { 1746 // file i/o error - report dlerror() msg 1747 return NULL; 1748 } 1749 1750 typedef struct { 1751 Elf32_Half code; // Actual value as defined in elf.h 1752 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1753 unsigned char elf_class; // 32 or 64 bit 1754 unsigned char endianess; // MSB or LSB 1755 char* name; // String representation 1756 } arch_t; 1757 1758 #ifndef EM_486 1759 #define EM_486 6 /* Intel 80486 */ 1760 #endif 1761 #ifndef EM_AARCH64 1762 #define EM_AARCH64 183 /* ARM AARCH64 */ 1763 #endif 1764 1765 static const arch_t arch_array[]={ 1766 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1767 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1768 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1769 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1770 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1771 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1772 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1773 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1774 #if defined(VM_LITTLE_ENDIAN) 1775 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"}, 1776 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"}, 1777 #else 1778 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1779 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"}, 1780 #endif 1781 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1782 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1783 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1784 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1785 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1786 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1787 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1788 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1789 }; 1790 1791 #if (defined IA32) 1792 static Elf32_Half running_arch_code=EM_386; 1793 #elif (defined AMD64) || (defined X32) 1794 static Elf32_Half running_arch_code=EM_X86_64; 1795 #elif (defined IA64) 1796 static Elf32_Half running_arch_code=EM_IA_64; 1797 #elif (defined __sparc) && (defined _LP64) 1798 static Elf32_Half running_arch_code=EM_SPARCV9; 1799 #elif (defined __sparc) && (!defined _LP64) 1800 static Elf32_Half running_arch_code=EM_SPARC; 1801 #elif (defined __powerpc64__) 1802 static Elf32_Half running_arch_code=EM_PPC64; 1803 #elif (defined __powerpc__) 1804 static Elf32_Half running_arch_code=EM_PPC; 1805 #elif (defined AARCH64) 1806 static Elf32_Half running_arch_code=EM_AARCH64; 1807 #elif (defined ARM) 1808 static Elf32_Half running_arch_code=EM_ARM; 1809 #elif (defined S390) 1810 static Elf32_Half running_arch_code=EM_S390; 1811 #elif (defined ALPHA) 1812 static Elf32_Half running_arch_code=EM_ALPHA; 1813 #elif (defined MIPSEL) 1814 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1815 #elif (defined PARISC) 1816 static Elf32_Half running_arch_code=EM_PARISC; 1817 #elif (defined MIPS) 1818 static Elf32_Half running_arch_code=EM_MIPS; 1819 #elif (defined M68K) 1820 static Elf32_Half running_arch_code=EM_68K; 1821 #elif (defined SH) 1822 static Elf32_Half running_arch_code=EM_SH; 1823 #else 1824 #error Method os::dll_load requires that one of following is defined:\ 1825 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, SH, __sparc 1826 #endif 1827 1828 // Identify compatability class for VM's architecture and library's architecture 1829 // Obtain string descriptions for architectures 1830 1831 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1832 int running_arch_index=-1; 1833 1834 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1835 if (running_arch_code == arch_array[i].code) { 1836 running_arch_index = i; 1837 } 1838 if (lib_arch.code == arch_array[i].code) { 1839 lib_arch.compat_class = arch_array[i].compat_class; 1840 lib_arch.name = arch_array[i].name; 1841 } 1842 } 1843 1844 assert(running_arch_index != -1, 1845 "Didn't find running architecture code (running_arch_code) in arch_array"); 1846 if (running_arch_index == -1) { 1847 // Even though running architecture detection failed 1848 // we may still continue with reporting dlerror() message 1849 return NULL; 1850 } 1851 1852 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1853 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1854 return NULL; 1855 } 1856 1857 #ifndef S390 1858 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1859 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1860 return NULL; 1861 } 1862 #endif // !S390 1863 1864 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1865 if (lib_arch.name!=NULL) { 1866 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1867 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1868 lib_arch.name, arch_array[running_arch_index].name); 1869 } else { 1870 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1871 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1872 lib_arch.code, 1873 arch_array[running_arch_index].name); 1874 } 1875 } 1876 1877 return NULL; 1878 } 1879 1880 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1881 int ebuflen) { 1882 void * result = ::dlopen(filename, RTLD_LAZY); 1883 if (result == NULL) { 1884 const char* error_report = ::dlerror(); 1885 if (error_report == NULL) { 1886 error_report = "dlerror returned no error description"; 1887 } 1888 if (ebuf != NULL && ebuflen > 0) { 1889 ::strncpy(ebuf, error_report, ebuflen-1); 1890 ebuf[ebuflen-1]='\0'; 1891 } 1892 Events::log(NULL, "Loading shared library %s failed, %s", filename, error_report); 1893 } else { 1894 Events::log(NULL, "Loaded shared library %s", filename); 1895 } 1896 return result; 1897 } 1898 1899 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1900 int ebuflen) { 1901 void * result = NULL; 1902 if (LoadExecStackDllInVMThread) { 1903 result = dlopen_helper(filename, ebuf, ebuflen); 1904 } 1905 1906 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1907 // library that requires an executable stack, or which does not have this 1908 // stack attribute set, dlopen changes the stack attribute to executable. The 1909 // read protection of the guard pages gets lost. 1910 // 1911 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1912 // may have been queued at the same time. 1913 1914 if (!_stack_is_executable) { 1915 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) { 1916 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1917 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 1918 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 1919 warning("Attempt to reguard stack yellow zone failed."); 1920 } 1921 } 1922 } 1923 } 1924 1925 return result; 1926 } 1927 1928 void* os::dll_lookup(void* handle, const char* name) { 1929 void* res = dlsym(handle, name); 1930 return res; 1931 } 1932 1933 void* os::get_default_process_handle() { 1934 return (void*)::dlopen(NULL, RTLD_LAZY); 1935 } 1936 1937 static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) { 1938 int fd = ::open(filename, O_RDONLY); 1939 if (fd == -1) { 1940 return false; 1941 } 1942 1943 if (hdr != NULL) { 1944 st->print_cr("%s", hdr); 1945 } 1946 1947 char buf[33]; 1948 int bytes; 1949 buf[32] = '\0'; 1950 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) { 1951 st->print_raw(buf, bytes); 1952 } 1953 1954 ::close(fd); 1955 1956 return true; 1957 } 1958 1959 void os::print_dll_info(outputStream *st) { 1960 st->print_cr("Dynamic libraries:"); 1961 1962 char fname[32]; 1963 pid_t pid = os::Linux::gettid(); 1964 1965 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1966 1967 if (!_print_ascii_file(fname, st)) { 1968 st->print("Can not get library information for pid = %d\n", pid); 1969 } 1970 } 1971 1972 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1973 FILE *procmapsFile = NULL; 1974 1975 // Open the procfs maps file for the current process 1976 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1977 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1978 char line[PATH_MAX + 100]; 1979 1980 // Read line by line from 'file' 1981 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1982 u8 base, top, offset, inode; 1983 char permissions[5]; 1984 char device[6]; 1985 char name[PATH_MAX + 1]; 1986 1987 // Parse fields from line 1988 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %7s " INT64_FORMAT " %s", 1989 &base, &top, permissions, &offset, device, &inode, name); 1990 1991 // Filter by device id '00:00' so that we only get file system mapped files. 1992 if (strcmp(device, "00:00") != 0) { 1993 1994 // Call callback with the fields of interest 1995 if(callback(name, (address)base, (address)top, param)) { 1996 // Oops abort, callback aborted 1997 fclose(procmapsFile); 1998 return 1; 1999 } 2000 } 2001 } 2002 fclose(procmapsFile); 2003 } 2004 return 0; 2005 } 2006 2007 void os::print_os_info_brief(outputStream* st) { 2008 os::Linux::print_distro_info(st); 2009 2010 os::Posix::print_uname_info(st); 2011 2012 os::Linux::print_libversion_info(st); 2013 2014 } 2015 2016 void os::print_os_info(outputStream* st) { 2017 st->print("OS:"); 2018 2019 os::Linux::print_distro_info(st); 2020 2021 os::Posix::print_uname_info(st); 2022 2023 // Print warning if unsafe chroot environment detected 2024 if (unsafe_chroot_detected) { 2025 st->print("WARNING!! "); 2026 st->print_cr("%s", unstable_chroot_error); 2027 } 2028 2029 os::Linux::print_libversion_info(st); 2030 2031 os::Posix::print_rlimit_info(st); 2032 2033 os::Posix::print_load_average(st); 2034 2035 os::Linux::print_full_memory_info(st); 2036 2037 os::Linux::print_proc_sys_info(st); 2038 2039 os::Linux::print_ld_preload_file(st); 2040 2041 os::Linux::print_container_info(st); 2042 2043 VM_Version::print_platform_virtualization_info(st); 2044 2045 os::Linux::print_steal_info(st); 2046 } 2047 2048 // Try to identify popular distros. 2049 // Most Linux distributions have a /etc/XXX-release file, which contains 2050 // the OS version string. Newer Linux distributions have a /etc/lsb-release 2051 // file that also contains the OS version string. Some have more than one 2052 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2053 // /etc/redhat-release.), so the order is important. 2054 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2055 // their own specific XXX-release file as well as a redhat-release file. 2056 // Because of this the XXX-release file needs to be searched for before the 2057 // redhat-release file. 2058 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the 2059 // search for redhat-release / SuSE-release needs to be before lsb-release. 2060 // Since the lsb-release file is the new standard it needs to be searched 2061 // before the older style release files. 2062 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 2063 // next to last resort. The os-release file is a new standard that contains 2064 // distribution information and the system-release file seems to be an old 2065 // standard that has been replaced by the lsb-release and os-release files. 2066 // Searching for the debian_version file is the last resort. It contains 2067 // an informative string like "6.0.6" or "wheezy/sid". Because of this 2068 // "Debian " is printed before the contents of the debian_version file. 2069 2070 const char* distro_files[] = { 2071 "/etc/oracle-release", 2072 "/etc/mandriva-release", 2073 "/etc/mandrake-release", 2074 "/etc/sun-release", 2075 "/etc/redhat-release", 2076 "/etc/SuSE-release", 2077 "/etc/lsb-release", 2078 "/etc/turbolinux-release", 2079 "/etc/gentoo-release", 2080 "/etc/ltib-release", 2081 "/etc/angstrom-version", 2082 "/etc/system-release", 2083 "/etc/os-release", 2084 NULL }; 2085 2086 void os::Linux::print_distro_info(outputStream* st) { 2087 for (int i = 0;; i++) { 2088 const char* file = distro_files[i]; 2089 if (file == NULL) { 2090 break; // done 2091 } 2092 // If file prints, we found it. 2093 if (_print_ascii_file(file, st)) { 2094 return; 2095 } 2096 } 2097 2098 if (file_exists("/etc/debian_version")) { 2099 st->print("Debian "); 2100 _print_ascii_file("/etc/debian_version", st); 2101 } else { 2102 st->print("Linux"); 2103 } 2104 st->cr(); 2105 } 2106 2107 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) { 2108 char buf[256]; 2109 while (fgets(buf, sizeof(buf), fp)) { 2110 // Edit out extra stuff in expected format 2111 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) { 2112 char* ptr = strstr(buf, "\""); // the name is in quotes 2113 if (ptr != NULL) { 2114 ptr++; // go beyond first quote 2115 char* nl = strchr(ptr, '\"'); 2116 if (nl != NULL) *nl = '\0'; 2117 strncpy(distro, ptr, length); 2118 } else { 2119 ptr = strstr(buf, "="); 2120 ptr++; // go beyond equals then 2121 char* nl = strchr(ptr, '\n'); 2122 if (nl != NULL) *nl = '\0'; 2123 strncpy(distro, ptr, length); 2124 } 2125 return; 2126 } else if (get_first_line) { 2127 char* nl = strchr(buf, '\n'); 2128 if (nl != NULL) *nl = '\0'; 2129 strncpy(distro, buf, length); 2130 return; 2131 } 2132 } 2133 // print last line and close 2134 char* nl = strchr(buf, '\n'); 2135 if (nl != NULL) *nl = '\0'; 2136 strncpy(distro, buf, length); 2137 } 2138 2139 static void parse_os_info(char* distro, size_t length, const char* file) { 2140 FILE* fp = fopen(file, "r"); 2141 if (fp != NULL) { 2142 // if suse format, print out first line 2143 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0); 2144 parse_os_info_helper(fp, distro, length, get_first_line); 2145 fclose(fp); 2146 } 2147 } 2148 2149 void os::get_summary_os_info(char* buf, size_t buflen) { 2150 for (int i = 0;; i++) { 2151 const char* file = distro_files[i]; 2152 if (file == NULL) { 2153 break; // ran out of distro_files 2154 } 2155 if (file_exists(file)) { 2156 parse_os_info(buf, buflen, file); 2157 return; 2158 } 2159 } 2160 // special case for debian 2161 if (file_exists("/etc/debian_version")) { 2162 strncpy(buf, "Debian ", buflen); 2163 if (buflen > 7) { 2164 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2165 } 2166 } else { 2167 strncpy(buf, "Linux", buflen); 2168 } 2169 } 2170 2171 void os::Linux::print_libversion_info(outputStream* st) { 2172 // libc, pthread 2173 st->print("libc:"); 2174 st->print("%s ", os::Linux::glibc_version()); 2175 st->print("%s ", os::Linux::libpthread_version()); 2176 st->cr(); 2177 } 2178 2179 void os::Linux::print_proc_sys_info(outputStream* st) { 2180 st->cr(); 2181 st->print_cr("/proc/sys/kernel/threads-max (system-wide limit on the number of threads):"); 2182 _print_ascii_file("/proc/sys/kernel/threads-max", st); 2183 st->cr(); 2184 st->cr(); 2185 2186 st->print_cr("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have):"); 2187 _print_ascii_file("/proc/sys/vm/max_map_count", st); 2188 st->cr(); 2189 st->cr(); 2190 2191 st->print_cr("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers):"); 2192 _print_ascii_file("/proc/sys/kernel/pid_max", st); 2193 st->cr(); 2194 st->cr(); 2195 } 2196 2197 void os::Linux::print_full_memory_info(outputStream* st) { 2198 st->print("\n/proc/meminfo:\n"); 2199 _print_ascii_file("/proc/meminfo", st); 2200 st->cr(); 2201 } 2202 2203 void os::Linux::print_ld_preload_file(outputStream* st) { 2204 _print_ascii_file("/etc/ld.so.preload", st, "\n/etc/ld.so.preload:"); 2205 st->cr(); 2206 } 2207 2208 void os::Linux::print_container_info(outputStream* st) { 2209 if (!OSContainer::is_containerized()) { 2210 return; 2211 } 2212 2213 st->print("container (cgroup) information:\n"); 2214 2215 const char *p_ct = OSContainer::container_type(); 2216 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "not supported"); 2217 2218 char *p = OSContainer::cpu_cpuset_cpus(); 2219 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "not supported"); 2220 free(p); 2221 2222 p = OSContainer::cpu_cpuset_memory_nodes(); 2223 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "not supported"); 2224 free(p); 2225 2226 int i = OSContainer::active_processor_count(); 2227 st->print("active_processor_count: "); 2228 if (i > 0) { 2229 st->print("%d\n", i); 2230 } else { 2231 st->print("not supported\n"); 2232 } 2233 2234 i = OSContainer::cpu_quota(); 2235 st->print("cpu_quota: "); 2236 if (i > 0) { 2237 st->print("%d\n", i); 2238 } else { 2239 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no quota"); 2240 } 2241 2242 i = OSContainer::cpu_period(); 2243 st->print("cpu_period: "); 2244 if (i > 0) { 2245 st->print("%d\n", i); 2246 } else { 2247 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no period"); 2248 } 2249 2250 i = OSContainer::cpu_shares(); 2251 st->print("cpu_shares: "); 2252 if (i > 0) { 2253 st->print("%d\n", i); 2254 } else { 2255 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no shares"); 2256 } 2257 2258 jlong j = OSContainer::memory_limit_in_bytes(); 2259 st->print("memory_limit_in_bytes: "); 2260 if (j > 0) { 2261 st->print(JLONG_FORMAT "\n", j); 2262 } else { 2263 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2264 } 2265 2266 j = OSContainer::memory_and_swap_limit_in_bytes(); 2267 st->print("memory_and_swap_limit_in_bytes: "); 2268 if (j > 0) { 2269 st->print(JLONG_FORMAT "\n", j); 2270 } else { 2271 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2272 } 2273 2274 j = OSContainer::memory_soft_limit_in_bytes(); 2275 st->print("memory_soft_limit_in_bytes: "); 2276 if (j > 0) { 2277 st->print(JLONG_FORMAT "\n", j); 2278 } else { 2279 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2280 } 2281 2282 j = OSContainer::OSContainer::memory_usage_in_bytes(); 2283 st->print("memory_usage_in_bytes: "); 2284 if (j > 0) { 2285 st->print(JLONG_FORMAT "\n", j); 2286 } else { 2287 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2288 } 2289 2290 j = OSContainer::OSContainer::memory_max_usage_in_bytes(); 2291 st->print("memory_max_usage_in_bytes: "); 2292 if (j > 0) { 2293 st->print(JLONG_FORMAT "\n", j); 2294 } else { 2295 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2296 } 2297 st->cr(); 2298 } 2299 2300 void os::Linux::print_steal_info(outputStream* st) { 2301 if (has_initial_tick_info) { 2302 CPUPerfTicks pticks; 2303 bool res = os::Linux::get_tick_information(&pticks, -1); 2304 2305 if (res && pticks.has_steal_ticks) { 2306 uint64_t steal_ticks_difference = pticks.steal - initial_steal_ticks; 2307 uint64_t total_ticks_difference = pticks.total - initial_total_ticks; 2308 double steal_ticks_perc = 0.0; 2309 if (total_ticks_difference != 0) { 2310 steal_ticks_perc = (double) steal_ticks_difference / total_ticks_difference; 2311 } 2312 st->print_cr("Steal ticks since vm start: " UINT64_FORMAT, steal_ticks_difference); 2313 st->print_cr("Steal ticks percentage since vm start:%7.3f", steal_ticks_perc); 2314 } 2315 } 2316 } 2317 2318 void os::print_memory_info(outputStream* st) { 2319 2320 st->print("Memory:"); 2321 st->print(" %dk page", os::vm_page_size()>>10); 2322 2323 // values in struct sysinfo are "unsigned long" 2324 struct sysinfo si; 2325 sysinfo(&si); 2326 2327 st->print(", physical " UINT64_FORMAT "k", 2328 os::physical_memory() >> 10); 2329 st->print("(" UINT64_FORMAT "k free)", 2330 os::available_memory() >> 10); 2331 st->print(", swap " UINT64_FORMAT "k", 2332 ((jlong)si.totalswap * si.mem_unit) >> 10); 2333 st->print("(" UINT64_FORMAT "k free)", 2334 ((jlong)si.freeswap * si.mem_unit) >> 10); 2335 st->cr(); 2336 } 2337 2338 // Print the first "model name" line and the first "flags" line 2339 // that we find and nothing more. We assume "model name" comes 2340 // before "flags" so if we find a second "model name", then the 2341 // "flags" field is considered missing. 2342 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2343 #if defined(IA32) || defined(AMD64) 2344 // Other platforms have less repetitive cpuinfo files 2345 FILE *fp = fopen("/proc/cpuinfo", "r"); 2346 if (fp) { 2347 while (!feof(fp)) { 2348 if (fgets(buf, buflen, fp)) { 2349 // Assume model name comes before flags 2350 bool model_name_printed = false; 2351 if (strstr(buf, "model name") != NULL) { 2352 if (!model_name_printed) { 2353 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n"); 2354 st->print_raw(buf); 2355 model_name_printed = true; 2356 } else { 2357 // model name printed but not flags? Odd, just return 2358 fclose(fp); 2359 return true; 2360 } 2361 } 2362 // print the flags line too 2363 if (strstr(buf, "flags") != NULL) { 2364 st->print_raw(buf); 2365 fclose(fp); 2366 return true; 2367 } 2368 } 2369 } 2370 fclose(fp); 2371 } 2372 #endif // x86 platforms 2373 return false; 2374 } 2375 2376 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2377 // Only print the model name if the platform provides this as a summary 2378 if (!print_model_name_and_flags(st, buf, buflen)) { 2379 st->print("\n/proc/cpuinfo:\n"); 2380 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2381 st->print_cr(" <Not Available>"); 2382 } 2383 } 2384 } 2385 2386 #if defined(AMD64) || defined(IA32) || defined(X32) 2387 const char* search_string = "model name"; 2388 #elif defined(M68K) 2389 const char* search_string = "CPU"; 2390 #elif defined(PPC64) 2391 const char* search_string = "cpu"; 2392 #elif defined(S390) 2393 const char* search_string = "machine ="; 2394 #elif defined(SPARC) 2395 const char* search_string = "cpu"; 2396 #else 2397 const char* search_string = "Processor"; 2398 #endif 2399 2400 // Parses the cpuinfo file for string representing the model name. 2401 void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2402 FILE* fp = fopen("/proc/cpuinfo", "r"); 2403 if (fp != NULL) { 2404 while (!feof(fp)) { 2405 char buf[256]; 2406 if (fgets(buf, sizeof(buf), fp)) { 2407 char* start = strstr(buf, search_string); 2408 if (start != NULL) { 2409 char *ptr = start + strlen(search_string); 2410 char *end = buf + strlen(buf); 2411 while (ptr != end) { 2412 // skip whitespace and colon for the rest of the name. 2413 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2414 break; 2415 } 2416 ptr++; 2417 } 2418 if (ptr != end) { 2419 // reasonable string, get rid of newline and keep the rest 2420 char* nl = strchr(buf, '\n'); 2421 if (nl != NULL) *nl = '\0'; 2422 strncpy(cpuinfo, ptr, length); 2423 fclose(fp); 2424 return; 2425 } 2426 } 2427 } 2428 } 2429 fclose(fp); 2430 } 2431 // cpuinfo not found or parsing failed, just print generic string. The entire 2432 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2433 #if defined(AARCH64) 2434 strncpy(cpuinfo, "AArch64", length); 2435 #elif defined(AMD64) 2436 strncpy(cpuinfo, "x86_64", length); 2437 #elif defined(ARM) // Order wrt. AARCH64 is relevant! 2438 strncpy(cpuinfo, "ARM", length); 2439 #elif defined(IA32) 2440 strncpy(cpuinfo, "x86_32", length); 2441 #elif defined(IA64) 2442 strncpy(cpuinfo, "IA64", length); 2443 #elif defined(PPC) 2444 strncpy(cpuinfo, "PPC64", length); 2445 #elif defined(S390) 2446 strncpy(cpuinfo, "S390", length); 2447 #elif defined(SPARC) 2448 strncpy(cpuinfo, "sparcv9", length); 2449 #elif defined(ZERO_LIBARCH) 2450 strncpy(cpuinfo, ZERO_LIBARCH, length); 2451 #else 2452 strncpy(cpuinfo, "unknown", length); 2453 #endif 2454 } 2455 2456 static void print_signal_handler(outputStream* st, int sig, 2457 char* buf, size_t buflen); 2458 2459 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2460 st->print_cr("Signal Handlers:"); 2461 print_signal_handler(st, SIGSEGV, buf, buflen); 2462 print_signal_handler(st, SIGBUS , buf, buflen); 2463 print_signal_handler(st, SIGFPE , buf, buflen); 2464 print_signal_handler(st, SIGPIPE, buf, buflen); 2465 print_signal_handler(st, SIGXFSZ, buf, buflen); 2466 print_signal_handler(st, SIGILL , buf, buflen); 2467 print_signal_handler(st, SR_signum, buf, buflen); 2468 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2469 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2470 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2471 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2472 #if defined(PPC64) 2473 print_signal_handler(st, SIGTRAP, buf, buflen); 2474 #endif 2475 } 2476 2477 static char saved_jvm_path[MAXPATHLEN] = {0}; 2478 2479 // Find the full path to the current module, libjvm.so 2480 void os::jvm_path(char *buf, jint buflen) { 2481 // Error checking. 2482 if (buflen < MAXPATHLEN) { 2483 assert(false, "must use a large-enough buffer"); 2484 buf[0] = '\0'; 2485 return; 2486 } 2487 // Lazy resolve the path to current module. 2488 if (saved_jvm_path[0] != 0) { 2489 strcpy(buf, saved_jvm_path); 2490 return; 2491 } 2492 2493 char dli_fname[MAXPATHLEN]; 2494 bool ret = dll_address_to_library_name( 2495 CAST_FROM_FN_PTR(address, os::jvm_path), 2496 dli_fname, sizeof(dli_fname), NULL); 2497 assert(ret, "cannot locate libjvm"); 2498 char *rp = NULL; 2499 if (ret && dli_fname[0] != '\0') { 2500 rp = os::Posix::realpath(dli_fname, buf, buflen); 2501 } 2502 if (rp == NULL) { 2503 return; 2504 } 2505 2506 if (Arguments::sun_java_launcher_is_altjvm()) { 2507 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2508 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so". 2509 // If "/jre/lib/" appears at the right place in the string, then 2510 // assume we are installed in a JDK and we're done. Otherwise, check 2511 // for a JAVA_HOME environment variable and fix up the path so it 2512 // looks like libjvm.so is installed there (append a fake suffix 2513 // hotspot/libjvm.so). 2514 const char *p = buf + strlen(buf) - 1; 2515 for (int count = 0; p > buf && count < 5; ++count) { 2516 for (--p; p > buf && *p != '/'; --p) 2517 /* empty */ ; 2518 } 2519 2520 if (strncmp(p, "/jre/lib/", 9) != 0) { 2521 // Look for JAVA_HOME in the environment. 2522 char* java_home_var = ::getenv("JAVA_HOME"); 2523 if (java_home_var != NULL && java_home_var[0] != 0) { 2524 char* jrelib_p; 2525 int len; 2526 2527 // Check the current module name "libjvm.so". 2528 p = strrchr(buf, '/'); 2529 if (p == NULL) { 2530 return; 2531 } 2532 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2533 2534 rp = os::Posix::realpath(java_home_var, buf, buflen); 2535 if (rp == NULL) { 2536 return; 2537 } 2538 2539 // determine if this is a legacy image or modules image 2540 // modules image doesn't have "jre" subdirectory 2541 len = strlen(buf); 2542 assert(len < buflen, "Ran out of buffer room"); 2543 jrelib_p = buf + len; 2544 snprintf(jrelib_p, buflen-len, "/jre/lib"); 2545 if (0 != access(buf, F_OK)) { 2546 snprintf(jrelib_p, buflen-len, "/lib"); 2547 } 2548 2549 if (0 == access(buf, F_OK)) { 2550 // Use current module name "libjvm.so" 2551 len = strlen(buf); 2552 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2553 } else { 2554 // Go back to path of .so 2555 rp = os::Posix::realpath(dli_fname, buf, buflen); 2556 if (rp == NULL) { 2557 return; 2558 } 2559 } 2560 } 2561 } 2562 } 2563 2564 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2565 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2566 } 2567 2568 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2569 // no prefix required, not even "_" 2570 } 2571 2572 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2573 // no suffix required 2574 } 2575 2576 //////////////////////////////////////////////////////////////////////////////// 2577 // sun.misc.Signal support 2578 2579 static volatile jint sigint_count = 0; 2580 2581 static void UserHandler(int sig, void *siginfo, void *context) { 2582 // 4511530 - sem_post is serialized and handled by the manager thread. When 2583 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2584 // don't want to flood the manager thread with sem_post requests. 2585 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2586 return; 2587 } 2588 2589 // Ctrl-C is pressed during error reporting, likely because the error 2590 // handler fails to abort. Let VM die immediately. 2591 if (sig == SIGINT && VMError::is_error_reported()) { 2592 os::die(); 2593 } 2594 2595 os::signal_notify(sig); 2596 } 2597 2598 void* os::user_handler() { 2599 return CAST_FROM_FN_PTR(void*, UserHandler); 2600 } 2601 2602 extern "C" { 2603 typedef void (*sa_handler_t)(int); 2604 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2605 } 2606 2607 void* os::signal(int signal_number, void* handler) { 2608 struct sigaction sigAct, oldSigAct; 2609 2610 sigfillset(&(sigAct.sa_mask)); 2611 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2612 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2613 2614 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2615 // -1 means registration failed 2616 return (void *)-1; 2617 } 2618 2619 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2620 } 2621 2622 void os::signal_raise(int signal_number) { 2623 ::raise(signal_number); 2624 } 2625 2626 // The following code is moved from os.cpp for making this 2627 // code platform specific, which it is by its very nature. 2628 2629 // Will be modified when max signal is changed to be dynamic 2630 int os::sigexitnum_pd() { 2631 return NSIG; 2632 } 2633 2634 // a counter for each possible signal value 2635 static volatile jint pending_signals[NSIG+1] = { 0 }; 2636 2637 // Linux(POSIX) specific hand shaking semaphore. 2638 static Semaphore* sig_sem = NULL; 2639 static PosixSemaphore sr_semaphore; 2640 2641 static void jdk_misc_signal_init() { 2642 // Initialize signal structures 2643 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2644 2645 // Initialize signal semaphore 2646 sig_sem = new Semaphore(); 2647 } 2648 2649 void os::signal_notify(int sig) { 2650 if (sig_sem != NULL) { 2651 Atomic::inc(&pending_signals[sig]); 2652 sig_sem->signal(); 2653 } else { 2654 // Signal thread is not created with ReduceSignalUsage and jdk_misc_signal_init 2655 // initialization isn't called. 2656 assert(ReduceSignalUsage, "signal semaphore should be created"); 2657 } 2658 } 2659 2660 static int check_pending_signals() { 2661 Atomic::store(0, &sigint_count); 2662 for (;;) { 2663 for (int i = 0; i < NSIG + 1; i++) { 2664 jint n = pending_signals[i]; 2665 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2666 return i; 2667 } 2668 } 2669 JavaThread *thread = JavaThread::current(); 2670 ThreadBlockInVM tbivm(thread); 2671 2672 bool threadIsSuspended; 2673 do { 2674 thread->set_suspend_equivalent(); 2675 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2676 sig_sem->wait(); 2677 2678 // were we externally suspended while we were waiting? 2679 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2680 if (threadIsSuspended) { 2681 // The semaphore has been incremented, but while we were waiting 2682 // another thread suspended us. We don't want to continue running 2683 // while suspended because that would surprise the thread that 2684 // suspended us. 2685 sig_sem->signal(); 2686 2687 thread->java_suspend_self(); 2688 } 2689 } while (threadIsSuspended); 2690 } 2691 } 2692 2693 int os::signal_wait() { 2694 return check_pending_signals(); 2695 } 2696 2697 //////////////////////////////////////////////////////////////////////////////// 2698 // Virtual Memory 2699 2700 int os::vm_page_size() { 2701 // Seems redundant as all get out 2702 assert(os::Linux::page_size() != -1, "must call os::init"); 2703 return os::Linux::page_size(); 2704 } 2705 2706 // Solaris allocates memory by pages. 2707 int os::vm_allocation_granularity() { 2708 assert(os::Linux::page_size() != -1, "must call os::init"); 2709 return os::Linux::page_size(); 2710 } 2711 2712 // Rationale behind this function: 2713 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2714 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2715 // samples for JITted code. Here we create private executable mapping over the code cache 2716 // and then we can use standard (well, almost, as mapping can change) way to provide 2717 // info for the reporting script by storing timestamp and location of symbol 2718 void linux_wrap_code(char* base, size_t size) { 2719 static volatile jint cnt = 0; 2720 2721 if (!UseOprofile) { 2722 return; 2723 } 2724 2725 char buf[PATH_MAX+1]; 2726 int num = Atomic::add(1, &cnt); 2727 2728 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2729 os::get_temp_directory(), os::current_process_id(), num); 2730 unlink(buf); 2731 2732 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2733 2734 if (fd != -1) { 2735 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2736 if (rv != (off_t)-1) { 2737 if (::write(fd, "", 1) == 1) { 2738 mmap(base, size, 2739 PROT_READ|PROT_WRITE|PROT_EXEC, 2740 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2741 } 2742 } 2743 ::close(fd); 2744 unlink(buf); 2745 } 2746 } 2747 2748 static bool recoverable_mmap_error(int err) { 2749 // See if the error is one we can let the caller handle. This 2750 // list of errno values comes from JBS-6843484. I can't find a 2751 // Linux man page that documents this specific set of errno 2752 // values so while this list currently matches Solaris, it may 2753 // change as we gain experience with this failure mode. 2754 switch (err) { 2755 case EBADF: 2756 case EINVAL: 2757 case ENOTSUP: 2758 // let the caller deal with these errors 2759 return true; 2760 2761 default: 2762 // Any remaining errors on this OS can cause our reserved mapping 2763 // to be lost. That can cause confusion where different data 2764 // structures think they have the same memory mapped. The worst 2765 // scenario is if both the VM and a library think they have the 2766 // same memory mapped. 2767 return false; 2768 } 2769 } 2770 2771 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2772 int err) { 2773 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2774 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2775 os::strerror(err), err); 2776 } 2777 2778 static void warn_fail_commit_memory(char* addr, size_t size, 2779 size_t alignment_hint, bool exec, 2780 int err) { 2781 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2782 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2783 alignment_hint, exec, os::strerror(err), err); 2784 } 2785 2786 // NOTE: Linux kernel does not really reserve the pages for us. 2787 // All it does is to check if there are enough free pages 2788 // left at the time of mmap(). This could be a potential 2789 // problem. 2790 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2791 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2792 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2793 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2794 if (res != (uintptr_t) MAP_FAILED) { 2795 if (UseNUMAInterleaving) { 2796 numa_make_global(addr, size); 2797 } 2798 return 0; 2799 } 2800 2801 int err = errno; // save errno from mmap() call above 2802 2803 if (!recoverable_mmap_error(err)) { 2804 warn_fail_commit_memory(addr, size, exec, err); 2805 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2806 } 2807 2808 return err; 2809 } 2810 2811 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2812 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2813 } 2814 2815 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2816 const char* mesg) { 2817 assert(mesg != NULL, "mesg must be specified"); 2818 int err = os::Linux::commit_memory_impl(addr, size, exec); 2819 if (err != 0) { 2820 // the caller wants all commit errors to exit with the specified mesg: 2821 warn_fail_commit_memory(addr, size, exec, err); 2822 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2823 } 2824 } 2825 2826 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2827 #ifndef MAP_HUGETLB 2828 #define MAP_HUGETLB 0x40000 2829 #endif 2830 2831 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2832 #ifndef MADV_HUGEPAGE 2833 #define MADV_HUGEPAGE 14 2834 #endif 2835 2836 int os::Linux::commit_memory_impl(char* addr, size_t size, 2837 size_t alignment_hint, bool exec) { 2838 int err = os::Linux::commit_memory_impl(addr, size, exec); 2839 if (err == 0) { 2840 realign_memory(addr, size, alignment_hint); 2841 } 2842 return err; 2843 } 2844 2845 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2846 bool exec) { 2847 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2848 } 2849 2850 void os::pd_commit_memory_or_exit(char* addr, size_t size, 2851 size_t alignment_hint, bool exec, 2852 const char* mesg) { 2853 assert(mesg != NULL, "mesg must be specified"); 2854 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2855 if (err != 0) { 2856 // the caller wants all commit errors to exit with the specified mesg: 2857 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2858 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2859 } 2860 } 2861 2862 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2863 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2864 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2865 // be supported or the memory may already be backed by huge pages. 2866 ::madvise(addr, bytes, MADV_HUGEPAGE); 2867 } 2868 } 2869 2870 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2871 // This method works by doing an mmap over an existing mmaping and effectively discarding 2872 // the existing pages. However it won't work for SHM-based large pages that cannot be 2873 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2874 // small pages on top of the SHM segment. This method always works for small pages, so we 2875 // allow that in any case. 2876 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2877 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2878 } 2879 } 2880 2881 void os::numa_make_global(char *addr, size_t bytes) { 2882 Linux::numa_interleave_memory(addr, bytes); 2883 } 2884 2885 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2886 // bind policy to MPOL_PREFERRED for the current thread. 2887 #define USE_MPOL_PREFERRED 0 2888 2889 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2890 // To make NUMA and large pages more robust when both enabled, we need to ease 2891 // the requirements on where the memory should be allocated. MPOL_BIND is the 2892 // default policy and it will force memory to be allocated on the specified 2893 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2894 // the specified node, but will not force it. Using this policy will prevent 2895 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2896 // free large pages. 2897 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2898 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2899 } 2900 2901 bool os::numa_topology_changed() { return false; } 2902 2903 size_t os::numa_get_groups_num() { 2904 // Return just the number of nodes in which it's possible to allocate memory 2905 // (in numa terminology, configured nodes). 2906 return Linux::numa_num_configured_nodes(); 2907 } 2908 2909 int os::numa_get_group_id() { 2910 int cpu_id = Linux::sched_getcpu(); 2911 if (cpu_id != -1) { 2912 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2913 if (lgrp_id != -1) { 2914 return lgrp_id; 2915 } 2916 } 2917 return 0; 2918 } 2919 2920 int os::Linux::get_existing_num_nodes() { 2921 int node; 2922 int highest_node_number = Linux::numa_max_node(); 2923 int num_nodes = 0; 2924 2925 // Get the total number of nodes in the system including nodes without memory. 2926 for (node = 0; node <= highest_node_number; node++) { 2927 if (is_node_in_existing_nodes(node)) { 2928 num_nodes++; 2929 } 2930 } 2931 return num_nodes; 2932 } 2933 2934 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2935 int highest_node_number = Linux::numa_max_node(); 2936 size_t i = 0; 2937 2938 // Map all node ids in which it is possible to allocate memory. Also nodes are 2939 // not always consecutively available, i.e. available from 0 to the highest 2940 // node number. If the nodes have been bound explicitly using numactl membind, 2941 // then allocate memory from those nodes only. 2942 for (int node = 0; node <= highest_node_number; node++) { 2943 if (Linux::is_node_in_bound_nodes((unsigned int)node)) { 2944 ids[i++] = node; 2945 } 2946 } 2947 return i; 2948 } 2949 2950 bool os::get_page_info(char *start, page_info* info) { 2951 return false; 2952 } 2953 2954 char *os::scan_pages(char *start, char* end, page_info* page_expected, 2955 page_info* page_found) { 2956 return end; 2957 } 2958 2959 2960 int os::Linux::sched_getcpu_syscall(void) { 2961 unsigned int cpu = 0; 2962 int retval = -1; 2963 2964 #if defined(IA32) 2965 #ifndef SYS_getcpu 2966 #define SYS_getcpu 318 2967 #endif 2968 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2969 #elif defined(AMD64) 2970 // Unfortunately we have to bring all these macros here from vsyscall.h 2971 // to be able to compile on old linuxes. 2972 #define __NR_vgetcpu 2 2973 #define VSYSCALL_START (-10UL << 20) 2974 #define VSYSCALL_SIZE 1024 2975 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2976 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2977 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2978 retval = vgetcpu(&cpu, NULL, NULL); 2979 #endif 2980 2981 return (retval == -1) ? retval : cpu; 2982 } 2983 2984 void os::Linux::sched_getcpu_init() { 2985 // sched_getcpu() should be in libc. 2986 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2987 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2988 2989 // If it's not, try a direct syscall. 2990 if (sched_getcpu() == -1) { 2991 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2992 (void*)&sched_getcpu_syscall)); 2993 } 2994 2995 if (sched_getcpu() == -1) { 2996 vm_exit_during_initialization("getcpu(2) system call not supported by kernel"); 2997 } 2998 } 2999 3000 // Something to do with the numa-aware allocator needs these symbols 3001 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 3002 extern "C" JNIEXPORT void numa_error(char *where) { } 3003 3004 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails 3005 // load symbol from base version instead. 3006 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 3007 void *f = dlvsym(handle, name, "libnuma_1.1"); 3008 if (f == NULL) { 3009 f = dlsym(handle, name); 3010 } 3011 return f; 3012 } 3013 3014 // Handle request to load libnuma symbol version 1.2 (API v2) only. 3015 // Return NULL if the symbol is not defined in this particular version. 3016 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) { 3017 return dlvsym(handle, name, "libnuma_1.2"); 3018 } 3019 3020 bool os::Linux::libnuma_init() { 3021 if (sched_getcpu() != -1) { // Requires sched_getcpu() support 3022 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 3023 if (handle != NULL) { 3024 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 3025 libnuma_dlsym(handle, "numa_node_to_cpus"))); 3026 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 3027 libnuma_dlsym(handle, "numa_max_node"))); 3028 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t, 3029 libnuma_dlsym(handle, "numa_num_configured_nodes"))); 3030 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 3031 libnuma_dlsym(handle, "numa_available"))); 3032 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 3033 libnuma_dlsym(handle, "numa_tonode_memory"))); 3034 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 3035 libnuma_dlsym(handle, "numa_interleave_memory"))); 3036 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t, 3037 libnuma_v2_dlsym(handle, "numa_interleave_memory"))); 3038 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 3039 libnuma_dlsym(handle, "numa_set_bind_policy"))); 3040 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t, 3041 libnuma_dlsym(handle, "numa_bitmask_isbitset"))); 3042 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t, 3043 libnuma_dlsym(handle, "numa_distance"))); 3044 set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t, 3045 libnuma_v2_dlsym(handle, "numa_get_membind"))); 3046 set_numa_get_interleave_mask(CAST_TO_FN_PTR(numa_get_interleave_mask_func_t, 3047 libnuma_v2_dlsym(handle, "numa_get_interleave_mask"))); 3048 3049 if (numa_available() != -1) { 3050 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 3051 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr")); 3052 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr")); 3053 set_numa_interleave_bitmask(_numa_get_interleave_mask()); 3054 set_numa_membind_bitmask(_numa_get_membind()); 3055 // Create an index -> node mapping, since nodes are not always consecutive 3056 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 3057 rebuild_nindex_to_node_map(); 3058 // Create a cpu -> node mapping 3059 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 3060 rebuild_cpu_to_node_map(); 3061 return true; 3062 } 3063 } 3064 } 3065 return false; 3066 } 3067 3068 size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 3069 // Creating guard page is very expensive. Java thread has HotSpot 3070 // guard pages, only enable glibc guard page for non-Java threads. 3071 // (Remember: compiler thread is a Java thread, too!) 3072 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size()); 3073 } 3074 3075 void os::Linux::rebuild_nindex_to_node_map() { 3076 int highest_node_number = Linux::numa_max_node(); 3077 3078 nindex_to_node()->clear(); 3079 for (int node = 0; node <= highest_node_number; node++) { 3080 if (Linux::is_node_in_existing_nodes(node)) { 3081 nindex_to_node()->append(node); 3082 } 3083 } 3084 } 3085 3086 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 3087 // The table is later used in get_node_by_cpu(). 3088 void os::Linux::rebuild_cpu_to_node_map() { 3089 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 3090 // in libnuma (possible values are starting from 16, 3091 // and continuing up with every other power of 2, but less 3092 // than the maximum number of CPUs supported by kernel), and 3093 // is a subject to change (in libnuma version 2 the requirements 3094 // are more reasonable) we'll just hardcode the number they use 3095 // in the library. 3096 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 3097 3098 size_t cpu_num = processor_count(); 3099 size_t cpu_map_size = NCPUS / BitsPerCLong; 3100 size_t cpu_map_valid_size = 3101 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 3102 3103 cpu_to_node()->clear(); 3104 cpu_to_node()->at_grow(cpu_num - 1); 3105 3106 size_t node_num = get_existing_num_nodes(); 3107 3108 int distance = 0; 3109 int closest_distance = INT_MAX; 3110 int closest_node = 0; 3111 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 3112 for (size_t i = 0; i < node_num; i++) { 3113 // Check if node is configured (not a memory-less node). If it is not, find 3114 // the closest configured node. Check also if node is bound, i.e. it's allowed 3115 // to allocate memory from the node. If it's not allowed, map cpus in that node 3116 // to the closest node from which memory allocation is allowed. 3117 if (!is_node_in_configured_nodes(nindex_to_node()->at(i)) || 3118 !is_node_in_bound_nodes(nindex_to_node()->at(i))) { 3119 closest_distance = INT_MAX; 3120 // Check distance from all remaining nodes in the system. Ignore distance 3121 // from itself, from another non-configured node, and from another non-bound 3122 // node. 3123 for (size_t m = 0; m < node_num; m++) { 3124 if (m != i && 3125 is_node_in_configured_nodes(nindex_to_node()->at(m)) && 3126 is_node_in_bound_nodes(nindex_to_node()->at(m))) { 3127 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m)); 3128 // If a closest node is found, update. There is always at least one 3129 // configured and bound node in the system so there is always at least 3130 // one node close. 3131 if (distance != 0 && distance < closest_distance) { 3132 closest_distance = distance; 3133 closest_node = nindex_to_node()->at(m); 3134 } 3135 } 3136 } 3137 } else { 3138 // Current node is already a configured node. 3139 closest_node = nindex_to_node()->at(i); 3140 } 3141 3142 // Get cpus from the original node and map them to the closest node. If node 3143 // is a configured node (not a memory-less node), then original node and 3144 // closest node are the same. 3145 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 3146 for (size_t j = 0; j < cpu_map_valid_size; j++) { 3147 if (cpu_map[j] != 0) { 3148 for (size_t k = 0; k < BitsPerCLong; k++) { 3149 if (cpu_map[j] & (1UL << k)) { 3150 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node); 3151 } 3152 } 3153 } 3154 } 3155 } 3156 } 3157 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 3158 } 3159 3160 int os::Linux::get_node_by_cpu(int cpu_id) { 3161 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 3162 return cpu_to_node()->at(cpu_id); 3163 } 3164 return -1; 3165 } 3166 3167 GrowableArray<int>* os::Linux::_cpu_to_node; 3168 GrowableArray<int>* os::Linux::_nindex_to_node; 3169 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 3170 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 3171 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 3172 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes; 3173 os::Linux::numa_available_func_t os::Linux::_numa_available; 3174 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 3175 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 3176 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2; 3177 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 3178 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset; 3179 os::Linux::numa_distance_func_t os::Linux::_numa_distance; 3180 os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind; 3181 os::Linux::numa_get_interleave_mask_func_t os::Linux::_numa_get_interleave_mask; 3182 os::Linux::NumaAllocationPolicy os::Linux::_current_numa_policy; 3183 unsigned long* os::Linux::_numa_all_nodes; 3184 struct bitmask* os::Linux::_numa_all_nodes_ptr; 3185 struct bitmask* os::Linux::_numa_nodes_ptr; 3186 struct bitmask* os::Linux::_numa_interleave_bitmask; 3187 struct bitmask* os::Linux::_numa_membind_bitmask; 3188 3189 bool os::pd_uncommit_memory(char* addr, size_t size) { 3190 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 3191 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 3192 return res != (uintptr_t) MAP_FAILED; 3193 } 3194 3195 static address get_stack_commited_bottom(address bottom, size_t size) { 3196 address nbot = bottom; 3197 address ntop = bottom + size; 3198 3199 size_t page_sz = os::vm_page_size(); 3200 unsigned pages = size / page_sz; 3201 3202 unsigned char vec[1]; 3203 unsigned imin = 1, imax = pages + 1, imid; 3204 int mincore_return_value = 0; 3205 3206 assert(imin <= imax, "Unexpected page size"); 3207 3208 while (imin < imax) { 3209 imid = (imax + imin) / 2; 3210 nbot = ntop - (imid * page_sz); 3211 3212 // Use a trick with mincore to check whether the page is mapped or not. 3213 // mincore sets vec to 1 if page resides in memory and to 0 if page 3214 // is swapped output but if page we are asking for is unmapped 3215 // it returns -1,ENOMEM 3216 mincore_return_value = mincore(nbot, page_sz, vec); 3217 3218 if (mincore_return_value == -1) { 3219 // Page is not mapped go up 3220 // to find first mapped page 3221 if (errno != EAGAIN) { 3222 assert(errno == ENOMEM, "Unexpected mincore errno"); 3223 imax = imid; 3224 } 3225 } else { 3226 // Page is mapped go down 3227 // to find first not mapped page 3228 imin = imid + 1; 3229 } 3230 } 3231 3232 nbot = nbot + page_sz; 3233 3234 // Adjust stack bottom one page up if last checked page is not mapped 3235 if (mincore_return_value == -1) { 3236 nbot = nbot + page_sz; 3237 } 3238 3239 return nbot; 3240 } 3241 3242 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) { 3243 int mincore_return_value; 3244 const size_t stripe = 1024; // query this many pages each time 3245 unsigned char vec[stripe + 1]; 3246 // set a guard 3247 vec[stripe] = 'X'; 3248 3249 const size_t page_sz = os::vm_page_size(); 3250 size_t pages = size / page_sz; 3251 3252 assert(is_aligned(start, page_sz), "Start address must be page aligned"); 3253 assert(is_aligned(size, page_sz), "Size must be page aligned"); 3254 3255 committed_start = NULL; 3256 3257 int loops = (pages + stripe - 1) / stripe; 3258 int committed_pages = 0; 3259 address loop_base = start; 3260 bool found_range = false; 3261 3262 for (int index = 0; index < loops && !found_range; index ++) { 3263 assert(pages > 0, "Nothing to do"); 3264 int pages_to_query = (pages >= stripe) ? stripe : pages; 3265 pages -= pages_to_query; 3266 3267 // Get stable read 3268 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN); 3269 3270 // During shutdown, some memory goes away without properly notifying NMT, 3271 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object. 3272 // Bailout and return as not committed for now. 3273 if (mincore_return_value == -1 && errno == ENOMEM) { 3274 return false; 3275 } 3276 3277 assert(vec[stripe] == 'X', "overflow guard"); 3278 assert(mincore_return_value == 0, "Range must be valid"); 3279 // Process this stripe 3280 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) { 3281 if ((vec[vecIdx] & 0x01) == 0) { // not committed 3282 // End of current contiguous region 3283 if (committed_start != NULL) { 3284 found_range = true; 3285 break; 3286 } 3287 } else { // committed 3288 // Start of region 3289 if (committed_start == NULL) { 3290 committed_start = loop_base + page_sz * vecIdx; 3291 } 3292 committed_pages ++; 3293 } 3294 } 3295 3296 loop_base += pages_to_query * page_sz; 3297 } 3298 3299 if (committed_start != NULL) { 3300 assert(committed_pages > 0, "Must have committed region"); 3301 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has"); 3302 assert(committed_start >= start && committed_start < start + size, "Out of range"); 3303 committed_size = page_sz * committed_pages; 3304 return true; 3305 } else { 3306 assert(committed_pages == 0, "Should not have committed region"); 3307 return false; 3308 } 3309 } 3310 3311 3312 // Linux uses a growable mapping for the stack, and if the mapping for 3313 // the stack guard pages is not removed when we detach a thread the 3314 // stack cannot grow beyond the pages where the stack guard was 3315 // mapped. If at some point later in the process the stack expands to 3316 // that point, the Linux kernel cannot expand the stack any further 3317 // because the guard pages are in the way, and a segfault occurs. 3318 // 3319 // However, it's essential not to split the stack region by unmapping 3320 // a region (leaving a hole) that's already part of the stack mapping, 3321 // so if the stack mapping has already grown beyond the guard pages at 3322 // the time we create them, we have to truncate the stack mapping. 3323 // So, we need to know the extent of the stack mapping when 3324 // create_stack_guard_pages() is called. 3325 3326 // We only need this for stacks that are growable: at the time of 3327 // writing thread stacks don't use growable mappings (i.e. those 3328 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 3329 // only applies to the main thread. 3330 3331 // If the (growable) stack mapping already extends beyond the point 3332 // where we're going to put our guard pages, truncate the mapping at 3333 // that point by munmap()ping it. This ensures that when we later 3334 // munmap() the guard pages we don't leave a hole in the stack 3335 // mapping. This only affects the main/primordial thread 3336 3337 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3338 if (os::is_primordial_thread()) { 3339 // As we manually grow stack up to bottom inside create_attached_thread(), 3340 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3341 // we don't need to do anything special. 3342 // Check it first, before calling heavy function. 3343 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3344 unsigned char vec[1]; 3345 3346 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3347 // Fallback to slow path on all errors, including EAGAIN 3348 stack_extent = (uintptr_t) get_stack_commited_bottom( 3349 os::Linux::initial_thread_stack_bottom(), 3350 (size_t)addr - stack_extent); 3351 } 3352 3353 if (stack_extent < (uintptr_t)addr) { 3354 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3355 } 3356 } 3357 3358 return os::commit_memory(addr, size, !ExecMem); 3359 } 3360 3361 // If this is a growable mapping, remove the guard pages entirely by 3362 // munmap()ping them. If not, just call uncommit_memory(). This only 3363 // affects the main/primordial thread, but guard against future OS changes. 3364 // It's safe to always unmap guard pages for primordial thread because we 3365 // always place it right after end of the mapped region. 3366 3367 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3368 uintptr_t stack_extent, stack_base; 3369 3370 if (os::is_primordial_thread()) { 3371 return ::munmap(addr, size) == 0; 3372 } 3373 3374 return os::uncommit_memory(addr, size); 3375 } 3376 3377 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3378 // at 'requested_addr'. If there are existing memory mappings at the same 3379 // location, however, they will be overwritten. If 'fixed' is false, 3380 // 'requested_addr' is only treated as a hint, the return value may or 3381 // may not start from the requested address. Unlike Linux mmap(), this 3382 // function returns NULL to indicate failure. 3383 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3384 char * addr; 3385 int flags; 3386 3387 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3388 if (fixed) { 3389 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3390 flags |= MAP_FIXED; 3391 } 3392 3393 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3394 // touch an uncommitted page. Otherwise, the read/write might 3395 // succeed if we have enough swap space to back the physical page. 3396 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3397 flags, -1, 0); 3398 3399 return addr == MAP_FAILED ? NULL : addr; 3400 } 3401 3402 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3403 // (req_addr != NULL) or with a given alignment. 3404 // - bytes shall be a multiple of alignment. 3405 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3406 // - alignment sets the alignment at which memory shall be allocated. 3407 // It must be a multiple of allocation granularity. 3408 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3409 // req_addr or NULL. 3410 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3411 3412 size_t extra_size = bytes; 3413 if (req_addr == NULL && alignment > 0) { 3414 extra_size += alignment; 3415 } 3416 3417 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3418 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3419 -1, 0); 3420 if (start == MAP_FAILED) { 3421 start = NULL; 3422 } else { 3423 if (req_addr != NULL) { 3424 if (start != req_addr) { 3425 ::munmap(start, extra_size); 3426 start = NULL; 3427 } 3428 } else { 3429 char* const start_aligned = align_up(start, alignment); 3430 char* const end_aligned = start_aligned + bytes; 3431 char* const end = start + extra_size; 3432 if (start_aligned > start) { 3433 ::munmap(start, start_aligned - start); 3434 } 3435 if (end_aligned < end) { 3436 ::munmap(end_aligned, end - end_aligned); 3437 } 3438 start = start_aligned; 3439 } 3440 } 3441 return start; 3442 } 3443 3444 static int anon_munmap(char * addr, size_t size) { 3445 return ::munmap(addr, size) == 0; 3446 } 3447 3448 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3449 size_t alignment_hint) { 3450 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3451 } 3452 3453 bool os::pd_release_memory(char* addr, size_t size) { 3454 return anon_munmap(addr, size); 3455 } 3456 3457 static bool linux_mprotect(char* addr, size_t size, int prot) { 3458 // Linux wants the mprotect address argument to be page aligned. 3459 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size()); 3460 3461 // According to SUSv3, mprotect() should only be used with mappings 3462 // established by mmap(), and mmap() always maps whole pages. Unaligned 3463 // 'addr' likely indicates problem in the VM (e.g. trying to change 3464 // protection of malloc'ed or statically allocated memory). Check the 3465 // caller if you hit this assert. 3466 assert(addr == bottom, "sanity check"); 3467 3468 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3469 Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with protection modes %x", p2i(bottom), p2i(bottom+size), prot); 3470 return ::mprotect(bottom, size, prot) == 0; 3471 } 3472 3473 // Set protections specified 3474 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3475 bool is_committed) { 3476 unsigned int p = 0; 3477 switch (prot) { 3478 case MEM_PROT_NONE: p = PROT_NONE; break; 3479 case MEM_PROT_READ: p = PROT_READ; break; 3480 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3481 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3482 default: 3483 ShouldNotReachHere(); 3484 } 3485 // is_committed is unused. 3486 return linux_mprotect(addr, bytes, p); 3487 } 3488 3489 bool os::guard_memory(char* addr, size_t size) { 3490 return linux_mprotect(addr, size, PROT_NONE); 3491 } 3492 3493 bool os::unguard_memory(char* addr, size_t size) { 3494 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3495 } 3496 3497 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3498 size_t page_size) { 3499 bool result = false; 3500 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3501 MAP_ANONYMOUS|MAP_PRIVATE, 3502 -1, 0); 3503 if (p != MAP_FAILED) { 3504 void *aligned_p = align_up(p, page_size); 3505 3506 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3507 3508 munmap(p, page_size * 2); 3509 } 3510 3511 if (warn && !result) { 3512 warning("TransparentHugePages is not supported by the operating system."); 3513 } 3514 3515 return result; 3516 } 3517 3518 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3519 bool result = false; 3520 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3521 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3522 -1, 0); 3523 3524 if (p != MAP_FAILED) { 3525 // We don't know if this really is a huge page or not. 3526 FILE *fp = fopen("/proc/self/maps", "r"); 3527 if (fp) { 3528 while (!feof(fp)) { 3529 char chars[257]; 3530 long x = 0; 3531 if (fgets(chars, sizeof(chars), fp)) { 3532 if (sscanf(chars, "%lx-%*x", &x) == 1 3533 && x == (long)p) { 3534 if (strstr (chars, "hugepage")) { 3535 result = true; 3536 break; 3537 } 3538 } 3539 } 3540 } 3541 fclose(fp); 3542 } 3543 munmap(p, page_size); 3544 } 3545 3546 if (warn && !result) { 3547 warning("HugeTLBFS is not supported by the operating system."); 3548 } 3549 3550 return result; 3551 } 3552 3553 // From the coredump_filter documentation: 3554 // 3555 // - (bit 0) anonymous private memory 3556 // - (bit 1) anonymous shared memory 3557 // - (bit 2) file-backed private memory 3558 // - (bit 3) file-backed shared memory 3559 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3560 // effective only if the bit 2 is cleared) 3561 // - (bit 5) hugetlb private memory 3562 // - (bit 6) hugetlb shared memory 3563 // - (bit 7) dax private memory 3564 // - (bit 8) dax shared memory 3565 // 3566 static void set_coredump_filter(CoredumpFilterBit bit) { 3567 FILE *f; 3568 long cdm; 3569 3570 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3571 return; 3572 } 3573 3574 if (fscanf(f, "%lx", &cdm) != 1) { 3575 fclose(f); 3576 return; 3577 } 3578 3579 long saved_cdm = cdm; 3580 rewind(f); 3581 cdm |= bit; 3582 3583 if (cdm != saved_cdm) { 3584 fprintf(f, "%#lx", cdm); 3585 } 3586 3587 fclose(f); 3588 } 3589 3590 // Large page support 3591 3592 static size_t _large_page_size = 0; 3593 3594 size_t os::Linux::find_large_page_size() { 3595 size_t large_page_size = 0; 3596 3597 // large_page_size on Linux is used to round up heap size. x86 uses either 3598 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3599 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3600 // page as large as 256M. 3601 // 3602 // Here we try to figure out page size by parsing /proc/meminfo and looking 3603 // for a line with the following format: 3604 // Hugepagesize: 2048 kB 3605 // 3606 // If we can't determine the value (e.g. /proc is not mounted, or the text 3607 // format has been changed), we'll use the largest page size supported by 3608 // the processor. 3609 3610 #ifndef ZERO 3611 large_page_size = 3612 AARCH64_ONLY(2 * M) 3613 AMD64_ONLY(2 * M) 3614 ARM32_ONLY(2 * M) 3615 IA32_ONLY(4 * M) 3616 IA64_ONLY(256 * M) 3617 PPC_ONLY(4 * M) 3618 S390_ONLY(1 * M) 3619 SPARC_ONLY(4 * M); 3620 #endif // ZERO 3621 3622 FILE *fp = fopen("/proc/meminfo", "r"); 3623 if (fp) { 3624 while (!feof(fp)) { 3625 int x = 0; 3626 char buf[16]; 3627 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3628 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3629 large_page_size = x * K; 3630 break; 3631 } 3632 } else { 3633 // skip to next line 3634 for (;;) { 3635 int ch = fgetc(fp); 3636 if (ch == EOF || ch == (int)'\n') break; 3637 } 3638 } 3639 } 3640 fclose(fp); 3641 } 3642 3643 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3644 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3645 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3646 proper_unit_for_byte_size(large_page_size)); 3647 } 3648 3649 return large_page_size; 3650 } 3651 3652 size_t os::Linux::setup_large_page_size() { 3653 _large_page_size = Linux::find_large_page_size(); 3654 const size_t default_page_size = (size_t)Linux::page_size(); 3655 if (_large_page_size > default_page_size) { 3656 _page_sizes[0] = _large_page_size; 3657 _page_sizes[1] = default_page_size; 3658 _page_sizes[2] = 0; 3659 } 3660 3661 return _large_page_size; 3662 } 3663 3664 bool os::Linux::setup_large_page_type(size_t page_size) { 3665 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3666 FLAG_IS_DEFAULT(UseSHM) && 3667 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3668 3669 // The type of large pages has not been specified by the user. 3670 3671 // Try UseHugeTLBFS and then UseSHM. 3672 UseHugeTLBFS = UseSHM = true; 3673 3674 // Don't try UseTransparentHugePages since there are known 3675 // performance issues with it turned on. This might change in the future. 3676 UseTransparentHugePages = false; 3677 } 3678 3679 if (UseTransparentHugePages) { 3680 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3681 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3682 UseHugeTLBFS = false; 3683 UseSHM = false; 3684 return true; 3685 } 3686 UseTransparentHugePages = false; 3687 } 3688 3689 if (UseHugeTLBFS) { 3690 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3691 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3692 UseSHM = false; 3693 return true; 3694 } 3695 UseHugeTLBFS = false; 3696 } 3697 3698 return UseSHM; 3699 } 3700 3701 void os::large_page_init() { 3702 if (!UseLargePages && 3703 !UseTransparentHugePages && 3704 !UseHugeTLBFS && 3705 !UseSHM) { 3706 // Not using large pages. 3707 return; 3708 } 3709 3710 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3711 // The user explicitly turned off large pages. 3712 // Ignore the rest of the large pages flags. 3713 UseTransparentHugePages = false; 3714 UseHugeTLBFS = false; 3715 UseSHM = false; 3716 return; 3717 } 3718 3719 size_t large_page_size = Linux::setup_large_page_size(); 3720 UseLargePages = Linux::setup_large_page_type(large_page_size); 3721 3722 set_coredump_filter(LARGEPAGES_BIT); 3723 } 3724 3725 #ifndef SHM_HUGETLB 3726 #define SHM_HUGETLB 04000 3727 #endif 3728 3729 #define shm_warning_format(format, ...) \ 3730 do { \ 3731 if (UseLargePages && \ 3732 (!FLAG_IS_DEFAULT(UseLargePages) || \ 3733 !FLAG_IS_DEFAULT(UseSHM) || \ 3734 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \ 3735 warning(format, __VA_ARGS__); \ 3736 } \ 3737 } while (0) 3738 3739 #define shm_warning(str) shm_warning_format("%s", str) 3740 3741 #define shm_warning_with_errno(str) \ 3742 do { \ 3743 int err = errno; \ 3744 shm_warning_format(str " (error = %d)", err); \ 3745 } while (0) 3746 3747 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) { 3748 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment"); 3749 3750 if (!is_aligned(alignment, SHMLBA)) { 3751 assert(false, "Code below assumes that alignment is at least SHMLBA aligned"); 3752 return NULL; 3753 } 3754 3755 // To ensure that we get 'alignment' aligned memory from shmat, 3756 // we pre-reserve aligned virtual memory and then attach to that. 3757 3758 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL); 3759 if (pre_reserved_addr == NULL) { 3760 // Couldn't pre-reserve aligned memory. 3761 shm_warning("Failed to pre-reserve aligned memory for shmat."); 3762 return NULL; 3763 } 3764 3765 // SHM_REMAP is needed to allow shmat to map over an existing mapping. 3766 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP); 3767 3768 if ((intptr_t)addr == -1) { 3769 int err = errno; 3770 shm_warning_with_errno("Failed to attach shared memory."); 3771 3772 assert(err != EACCES, "Unexpected error"); 3773 assert(err != EIDRM, "Unexpected error"); 3774 assert(err != EINVAL, "Unexpected error"); 3775 3776 // Since we don't know if the kernel unmapped the pre-reserved memory area 3777 // we can't unmap it, since that would potentially unmap memory that was 3778 // mapped from other threads. 3779 return NULL; 3780 } 3781 3782 return addr; 3783 } 3784 3785 static char* shmat_at_address(int shmid, char* req_addr) { 3786 if (!is_aligned(req_addr, SHMLBA)) { 3787 assert(false, "Requested address needs to be SHMLBA aligned"); 3788 return NULL; 3789 } 3790 3791 char* addr = (char*)shmat(shmid, req_addr, 0); 3792 3793 if ((intptr_t)addr == -1) { 3794 shm_warning_with_errno("Failed to attach shared memory."); 3795 return NULL; 3796 } 3797 3798 return addr; 3799 } 3800 3801 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) { 3802 // If a req_addr has been provided, we assume that the caller has already aligned the address. 3803 if (req_addr != NULL) { 3804 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size"); 3805 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment"); 3806 return shmat_at_address(shmid, req_addr); 3807 } 3808 3809 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically 3810 // return large page size aligned memory addresses when req_addr == NULL. 3811 // However, if the alignment is larger than the large page size, we have 3812 // to manually ensure that the memory returned is 'alignment' aligned. 3813 if (alignment > os::large_page_size()) { 3814 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size"); 3815 return shmat_with_alignment(shmid, bytes, alignment); 3816 } else { 3817 return shmat_at_address(shmid, NULL); 3818 } 3819 } 3820 3821 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3822 char* req_addr, bool exec) { 3823 // "exec" is passed in but not used. Creating the shared image for 3824 // the code cache doesn't have an SHM_X executable permission to check. 3825 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3826 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3827 assert(is_aligned(req_addr, alignment), "Unaligned address"); 3828 3829 if (!is_aligned(bytes, os::large_page_size())) { 3830 return NULL; // Fallback to small pages. 3831 } 3832 3833 // Create a large shared memory region to attach to based on size. 3834 // Currently, size is the total size of the heap. 3835 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3836 if (shmid == -1) { 3837 // Possible reasons for shmget failure: 3838 // 1. shmmax is too small for Java heap. 3839 // > check shmmax value: cat /proc/sys/kernel/shmmax 3840 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3841 // 2. not enough large page memory. 3842 // > check available large pages: cat /proc/meminfo 3843 // > increase amount of large pages: 3844 // echo new_value > /proc/sys/vm/nr_hugepages 3845 // Note 1: different Linux may use different name for this property, 3846 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3847 // Note 2: it's possible there's enough physical memory available but 3848 // they are so fragmented after a long run that they can't 3849 // coalesce into large pages. Try to reserve large pages when 3850 // the system is still "fresh". 3851 shm_warning_with_errno("Failed to reserve shared memory."); 3852 return NULL; 3853 } 3854 3855 // Attach to the region. 3856 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr); 3857 3858 // Remove shmid. If shmat() is successful, the actual shared memory segment 3859 // will be deleted when it's detached by shmdt() or when the process 3860 // terminates. If shmat() is not successful this will remove the shared 3861 // segment immediately. 3862 shmctl(shmid, IPC_RMID, NULL); 3863 3864 return addr; 3865 } 3866 3867 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3868 int error) { 3869 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3870 3871 bool warn_on_failure = UseLargePages && 3872 (!FLAG_IS_DEFAULT(UseLargePages) || 3873 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3874 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3875 3876 if (warn_on_failure) { 3877 char msg[128]; 3878 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3879 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3880 warning("%s", msg); 3881 } 3882 } 3883 3884 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3885 char* req_addr, 3886 bool exec) { 3887 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3888 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size"); 3889 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3890 3891 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3892 char* addr = (char*)::mmap(req_addr, bytes, prot, 3893 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3894 -1, 0); 3895 3896 if (addr == MAP_FAILED) { 3897 warn_on_large_pages_failure(req_addr, bytes, errno); 3898 return NULL; 3899 } 3900 3901 assert(is_aligned(addr, os::large_page_size()), "Must be"); 3902 3903 return addr; 3904 } 3905 3906 // Reserve memory using mmap(MAP_HUGETLB). 3907 // - bytes shall be a multiple of alignment. 3908 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3909 // - alignment sets the alignment at which memory shall be allocated. 3910 // It must be a multiple of allocation granularity. 3911 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3912 // req_addr or NULL. 3913 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3914 size_t alignment, 3915 char* req_addr, 3916 bool exec) { 3917 size_t large_page_size = os::large_page_size(); 3918 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3919 3920 assert(is_aligned(req_addr, alignment), "Must be"); 3921 assert(is_aligned(bytes, alignment), "Must be"); 3922 3923 // First reserve - but not commit - the address range in small pages. 3924 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3925 3926 if (start == NULL) { 3927 return NULL; 3928 } 3929 3930 assert(is_aligned(start, alignment), "Must be"); 3931 3932 char* end = start + bytes; 3933 3934 // Find the regions of the allocated chunk that can be promoted to large pages. 3935 char* lp_start = align_up(start, large_page_size); 3936 char* lp_end = align_down(end, large_page_size); 3937 3938 size_t lp_bytes = lp_end - lp_start; 3939 3940 assert(is_aligned(lp_bytes, large_page_size), "Must be"); 3941 3942 if (lp_bytes == 0) { 3943 // The mapped region doesn't even span the start and the end of a large page. 3944 // Fall back to allocate a non-special area. 3945 ::munmap(start, end - start); 3946 return NULL; 3947 } 3948 3949 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3950 3951 void* result; 3952 3953 // Commit small-paged leading area. 3954 if (start != lp_start) { 3955 result = ::mmap(start, lp_start - start, prot, 3956 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3957 -1, 0); 3958 if (result == MAP_FAILED) { 3959 ::munmap(lp_start, end - lp_start); 3960 return NULL; 3961 } 3962 } 3963 3964 // Commit large-paged area. 3965 result = ::mmap(lp_start, lp_bytes, prot, 3966 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3967 -1, 0); 3968 if (result == MAP_FAILED) { 3969 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3970 // If the mmap above fails, the large pages region will be unmapped and we 3971 // have regions before and after with small pages. Release these regions. 3972 // 3973 // | mapped | unmapped | mapped | 3974 // ^ ^ ^ ^ 3975 // start lp_start lp_end end 3976 // 3977 ::munmap(start, lp_start - start); 3978 ::munmap(lp_end, end - lp_end); 3979 return NULL; 3980 } 3981 3982 // Commit small-paged trailing area. 3983 if (lp_end != end) { 3984 result = ::mmap(lp_end, end - lp_end, prot, 3985 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3986 -1, 0); 3987 if (result == MAP_FAILED) { 3988 ::munmap(start, lp_end - start); 3989 return NULL; 3990 } 3991 } 3992 3993 return start; 3994 } 3995 3996 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3997 size_t alignment, 3998 char* req_addr, 3999 bool exec) { 4000 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 4001 assert(is_aligned(req_addr, alignment), "Must be"); 4002 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 4003 assert(is_power_of_2(os::large_page_size()), "Must be"); 4004 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 4005 4006 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 4007 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 4008 } else { 4009 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 4010 } 4011 } 4012 4013 char* os::reserve_memory_special(size_t bytes, size_t alignment, 4014 char* req_addr, bool exec) { 4015 assert(UseLargePages, "only for large pages"); 4016 4017 char* addr; 4018 if (UseSHM) { 4019 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 4020 } else { 4021 assert(UseHugeTLBFS, "must be"); 4022 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 4023 } 4024 4025 if (addr != NULL) { 4026 if (UseNUMAInterleaving) { 4027 numa_make_global(addr, bytes); 4028 } 4029 4030 // The memory is committed 4031 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 4032 } 4033 4034 return addr; 4035 } 4036 4037 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 4038 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 4039 return shmdt(base) == 0; 4040 } 4041 4042 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 4043 return pd_release_memory(base, bytes); 4044 } 4045 4046 bool os::release_memory_special(char* base, size_t bytes) { 4047 bool res; 4048 if (MemTracker::tracking_level() > NMT_minimal) { 4049 Tracker tkr(Tracker::release); 4050 res = os::Linux::release_memory_special_impl(base, bytes); 4051 if (res) { 4052 tkr.record((address)base, bytes); 4053 } 4054 4055 } else { 4056 res = os::Linux::release_memory_special_impl(base, bytes); 4057 } 4058 return res; 4059 } 4060 4061 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 4062 assert(UseLargePages, "only for large pages"); 4063 bool res; 4064 4065 if (UseSHM) { 4066 res = os::Linux::release_memory_special_shm(base, bytes); 4067 } else { 4068 assert(UseHugeTLBFS, "must be"); 4069 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 4070 } 4071 return res; 4072 } 4073 4074 size_t os::large_page_size() { 4075 return _large_page_size; 4076 } 4077 4078 // With SysV SHM the entire memory region must be allocated as shared 4079 // memory. 4080 // HugeTLBFS allows application to commit large page memory on demand. 4081 // However, when committing memory with HugeTLBFS fails, the region 4082 // that was supposed to be committed will lose the old reservation 4083 // and allow other threads to steal that memory region. Because of this 4084 // behavior we can't commit HugeTLBFS memory. 4085 bool os::can_commit_large_page_memory() { 4086 return UseTransparentHugePages; 4087 } 4088 4089 bool os::can_execute_large_page_memory() { 4090 return UseTransparentHugePages || UseHugeTLBFS; 4091 } 4092 4093 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) { 4094 assert(file_desc >= 0, "file_desc is not valid"); 4095 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr); 4096 if (result != NULL) { 4097 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) { 4098 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory")); 4099 } 4100 } 4101 return result; 4102 } 4103 4104 // Reserve memory at an arbitrary address, only if that area is 4105 // available (and not reserved for something else). 4106 4107 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 4108 // Assert only that the size is a multiple of the page size, since 4109 // that's all that mmap requires, and since that's all we really know 4110 // about at this low abstraction level. If we need higher alignment, 4111 // we can either pass an alignment to this method or verify alignment 4112 // in one of the methods further up the call chain. See bug 5044738. 4113 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 4114 4115 // Repeatedly allocate blocks until the block is allocated at the 4116 // right spot. 4117 4118 // Linux mmap allows caller to pass an address as hint; give it a try first, 4119 // if kernel honors the hint then we can return immediately. 4120 char * addr = anon_mmap(requested_addr, bytes, false); 4121 if (addr == requested_addr) { 4122 return requested_addr; 4123 } 4124 4125 if (addr != NULL) { 4126 // mmap() is successful but it fails to reserve at the requested address 4127 anon_munmap(addr, bytes); 4128 } 4129 4130 return NULL; 4131 } 4132 4133 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 4134 void os::infinite_sleep() { 4135 while (true) { // sleep forever ... 4136 ::sleep(100); // ... 100 seconds at a time 4137 } 4138 } 4139 4140 // Used to convert frequent JVM_Yield() to nops 4141 bool os::dont_yield() { 4142 return DontYieldALot; 4143 } 4144 4145 // Linux CFS scheduler (since 2.6.23) does not guarantee sched_yield(2) will 4146 // actually give up the CPU. Since skip buddy (v2.6.28): 4147 // 4148 // * Sets the yielding task as skip buddy for current CPU's run queue. 4149 // * Picks next from run queue, if empty, picks a skip buddy (can be the yielding task). 4150 // * Clears skip buddies for this run queue (yielding task no longer a skip buddy). 4151 // 4152 // An alternative is calling os::naked_short_nanosleep with a small number to avoid 4153 // getting re-scheduled immediately. 4154 // 4155 void os::naked_yield() { 4156 sched_yield(); 4157 } 4158 4159 //////////////////////////////////////////////////////////////////////////////// 4160 // thread priority support 4161 4162 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 4163 // only supports dynamic priority, static priority must be zero. For real-time 4164 // applications, Linux supports SCHED_RR which allows static priority (1-99). 4165 // However, for large multi-threaded applications, SCHED_RR is not only slower 4166 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 4167 // of 5 runs - Sep 2005). 4168 // 4169 // The following code actually changes the niceness of kernel-thread/LWP. It 4170 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 4171 // not the entire user process, and user level threads are 1:1 mapped to kernel 4172 // threads. It has always been the case, but could change in the future. For 4173 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 4174 // It is only used when ThreadPriorityPolicy=1 and may require system level permission 4175 // (e.g., root privilege or CAP_SYS_NICE capability). 4176 4177 int os::java_to_os_priority[CriticalPriority + 1] = { 4178 19, // 0 Entry should never be used 4179 4180 4, // 1 MinPriority 4181 3, // 2 4182 2, // 3 4183 4184 1, // 4 4185 0, // 5 NormPriority 4186 -1, // 6 4187 4188 -2, // 7 4189 -3, // 8 4190 -4, // 9 NearMaxPriority 4191 4192 -5, // 10 MaxPriority 4193 4194 -5 // 11 CriticalPriority 4195 }; 4196 4197 static int prio_init() { 4198 if (ThreadPriorityPolicy == 1) { 4199 if (geteuid() != 0) { 4200 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 4201 warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \ 4202 "e.g., being the root user. If the necessary permission is not " \ 4203 "possessed, changes to priority will be silently ignored."); 4204 } 4205 } 4206 } 4207 if (UseCriticalJavaThreadPriority) { 4208 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 4209 } 4210 return 0; 4211 } 4212 4213 OSReturn os::set_native_priority(Thread* thread, int newpri) { 4214 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 4215 4216 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 4217 return (ret == 0) ? OS_OK : OS_ERR; 4218 } 4219 4220 OSReturn os::get_native_priority(const Thread* const thread, 4221 int *priority_ptr) { 4222 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 4223 *priority_ptr = java_to_os_priority[NormPriority]; 4224 return OS_OK; 4225 } 4226 4227 errno = 0; 4228 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 4229 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 4230 } 4231 4232 //////////////////////////////////////////////////////////////////////////////// 4233 // suspend/resume support 4234 4235 // The low-level signal-based suspend/resume support is a remnant from the 4236 // old VM-suspension that used to be for java-suspension, safepoints etc, 4237 // within hotspot. Currently used by JFR's OSThreadSampler 4238 // 4239 // The remaining code is greatly simplified from the more general suspension 4240 // code that used to be used. 4241 // 4242 // The protocol is quite simple: 4243 // - suspend: 4244 // - sends a signal to the target thread 4245 // - polls the suspend state of the osthread using a yield loop 4246 // - target thread signal handler (SR_handler) sets suspend state 4247 // and blocks in sigsuspend until continued 4248 // - resume: 4249 // - sets target osthread state to continue 4250 // - sends signal to end the sigsuspend loop in the SR_handler 4251 // 4252 // Note that the SR_lock plays no role in this suspend/resume protocol, 4253 // but is checked for NULL in SR_handler as a thread termination indicator. 4254 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs. 4255 // 4256 // Note that resume_clear_context() and suspend_save_context() are needed 4257 // by SR_handler(), so that fetch_frame_from_ucontext() works, 4258 // which in part is used by: 4259 // - Forte Analyzer: AsyncGetCallTrace() 4260 // - StackBanging: get_frame_at_stack_banging_point() 4261 4262 static void resume_clear_context(OSThread *osthread) { 4263 osthread->set_ucontext(NULL); 4264 osthread->set_siginfo(NULL); 4265 } 4266 4267 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 4268 ucontext_t* context) { 4269 osthread->set_ucontext(context); 4270 osthread->set_siginfo(siginfo); 4271 } 4272 4273 // Handler function invoked when a thread's execution is suspended or 4274 // resumed. We have to be careful that only async-safe functions are 4275 // called here (Note: most pthread functions are not async safe and 4276 // should be avoided.) 4277 // 4278 // Note: sigwait() is a more natural fit than sigsuspend() from an 4279 // interface point of view, but sigwait() prevents the signal hander 4280 // from being run. libpthread would get very confused by not having 4281 // its signal handlers run and prevents sigwait()'s use with the 4282 // mutex granting granting signal. 4283 // 4284 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 4285 // 4286 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 4287 // Save and restore errno to avoid confusing native code with EINTR 4288 // after sigsuspend. 4289 int old_errno = errno; 4290 4291 Thread* thread = Thread::current_or_null_safe(); 4292 assert(thread != NULL, "Missing current thread in SR_handler"); 4293 4294 // On some systems we have seen signal delivery get "stuck" until the signal 4295 // mask is changed as part of thread termination. Check that the current thread 4296 // has not already terminated (via SR_lock()) - else the following assertion 4297 // will fail because the thread is no longer a JavaThread as the ~JavaThread 4298 // destructor has completed. 4299 4300 if (thread->SR_lock() == NULL) { 4301 return; 4302 } 4303 4304 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 4305 4306 OSThread* osthread = thread->osthread(); 4307 4308 os::SuspendResume::State current = osthread->sr.state(); 4309 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 4310 suspend_save_context(osthread, siginfo, context); 4311 4312 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 4313 os::SuspendResume::State state = osthread->sr.suspended(); 4314 if (state == os::SuspendResume::SR_SUSPENDED) { 4315 sigset_t suspend_set; // signals for sigsuspend() 4316 sigemptyset(&suspend_set); 4317 // get current set of blocked signals and unblock resume signal 4318 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 4319 sigdelset(&suspend_set, SR_signum); 4320 4321 sr_semaphore.signal(); 4322 // wait here until we are resumed 4323 while (1) { 4324 sigsuspend(&suspend_set); 4325 4326 os::SuspendResume::State result = osthread->sr.running(); 4327 if (result == os::SuspendResume::SR_RUNNING) { 4328 sr_semaphore.signal(); 4329 break; 4330 } 4331 } 4332 4333 } else if (state == os::SuspendResume::SR_RUNNING) { 4334 // request was cancelled, continue 4335 } else { 4336 ShouldNotReachHere(); 4337 } 4338 4339 resume_clear_context(osthread); 4340 } else if (current == os::SuspendResume::SR_RUNNING) { 4341 // request was cancelled, continue 4342 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 4343 // ignore 4344 } else { 4345 // ignore 4346 } 4347 4348 errno = old_errno; 4349 } 4350 4351 static int SR_initialize() { 4352 struct sigaction act; 4353 char *s; 4354 4355 // Get signal number to use for suspend/resume 4356 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4357 int sig = ::strtol(s, 0, 10); 4358 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 4359 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 4360 SR_signum = sig; 4361 } else { 4362 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 4363 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 4364 } 4365 } 4366 4367 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4368 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4369 4370 sigemptyset(&SR_sigset); 4371 sigaddset(&SR_sigset, SR_signum); 4372 4373 // Set up signal handler for suspend/resume 4374 act.sa_flags = SA_RESTART|SA_SIGINFO; 4375 act.sa_handler = (void (*)(int)) SR_handler; 4376 4377 // SR_signum is blocked by default. 4378 // 4528190 - We also need to block pthread restart signal (32 on all 4379 // supported Linux platforms). Note that LinuxThreads need to block 4380 // this signal for all threads to work properly. So we don't have 4381 // to use hard-coded signal number when setting up the mask. 4382 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4383 4384 if (sigaction(SR_signum, &act, 0) == -1) { 4385 return -1; 4386 } 4387 4388 // Save signal flag 4389 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4390 return 0; 4391 } 4392 4393 static int sr_notify(OSThread* osthread) { 4394 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4395 assert_status(status == 0, status, "pthread_kill"); 4396 return status; 4397 } 4398 4399 // "Randomly" selected value for how long we want to spin 4400 // before bailing out on suspending a thread, also how often 4401 // we send a signal to a thread we want to resume 4402 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4403 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4404 4405 // returns true on success and false on error - really an error is fatal 4406 // but this seems the normal response to library errors 4407 static bool do_suspend(OSThread* osthread) { 4408 assert(osthread->sr.is_running(), "thread should be running"); 4409 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4410 4411 // mark as suspended and send signal 4412 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4413 // failed to switch, state wasn't running? 4414 ShouldNotReachHere(); 4415 return false; 4416 } 4417 4418 if (sr_notify(osthread) != 0) { 4419 ShouldNotReachHere(); 4420 } 4421 4422 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4423 while (true) { 4424 if (sr_semaphore.timedwait(2)) { 4425 break; 4426 } else { 4427 // timeout 4428 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4429 if (cancelled == os::SuspendResume::SR_RUNNING) { 4430 return false; 4431 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4432 // make sure that we consume the signal on the semaphore as well 4433 sr_semaphore.wait(); 4434 break; 4435 } else { 4436 ShouldNotReachHere(); 4437 return false; 4438 } 4439 } 4440 } 4441 4442 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4443 return true; 4444 } 4445 4446 static void do_resume(OSThread* osthread) { 4447 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4448 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4449 4450 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4451 // failed to switch to WAKEUP_REQUEST 4452 ShouldNotReachHere(); 4453 return; 4454 } 4455 4456 while (true) { 4457 if (sr_notify(osthread) == 0) { 4458 if (sr_semaphore.timedwait(2)) { 4459 if (osthread->sr.is_running()) { 4460 return; 4461 } 4462 } 4463 } else { 4464 ShouldNotReachHere(); 4465 } 4466 } 4467 4468 guarantee(osthread->sr.is_running(), "Must be running!"); 4469 } 4470 4471 /////////////////////////////////////////////////////////////////////////////////// 4472 // signal handling (except suspend/resume) 4473 4474 // This routine may be used by user applications as a "hook" to catch signals. 4475 // The user-defined signal handler must pass unrecognized signals to this 4476 // routine, and if it returns true (non-zero), then the signal handler must 4477 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4478 // routine will never retun false (zero), but instead will execute a VM panic 4479 // routine kill the process. 4480 // 4481 // If this routine returns false, it is OK to call it again. This allows 4482 // the user-defined signal handler to perform checks either before or after 4483 // the VM performs its own checks. Naturally, the user code would be making 4484 // a serious error if it tried to handle an exception (such as a null check 4485 // or breakpoint) that the VM was generating for its own correct operation. 4486 // 4487 // This routine may recognize any of the following kinds of signals: 4488 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4489 // It should be consulted by handlers for any of those signals. 4490 // 4491 // The caller of this routine must pass in the three arguments supplied 4492 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4493 // field of the structure passed to sigaction(). This routine assumes that 4494 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4495 // 4496 // Note that the VM will print warnings if it detects conflicting signal 4497 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4498 // 4499 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4500 siginfo_t* siginfo, 4501 void* ucontext, 4502 int abort_if_unrecognized); 4503 4504 static void signalHandler(int sig, siginfo_t* info, void* uc) { 4505 assert(info != NULL && uc != NULL, "it must be old kernel"); 4506 int orig_errno = errno; // Preserve errno value over signal handler. 4507 JVM_handle_linux_signal(sig, info, uc, true); 4508 errno = orig_errno; 4509 } 4510 4511 4512 // This boolean allows users to forward their own non-matching signals 4513 // to JVM_handle_linux_signal, harmlessly. 4514 bool os::Linux::signal_handlers_are_installed = false; 4515 4516 // For signal-chaining 4517 bool os::Linux::libjsig_is_loaded = false; 4518 typedef struct sigaction *(*get_signal_t)(int); 4519 get_signal_t os::Linux::get_signal_action = NULL; 4520 4521 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4522 struct sigaction *actp = NULL; 4523 4524 if (libjsig_is_loaded) { 4525 // Retrieve the old signal handler from libjsig 4526 actp = (*get_signal_action)(sig); 4527 } 4528 if (actp == NULL) { 4529 // Retrieve the preinstalled signal handler from jvm 4530 actp = os::Posix::get_preinstalled_handler(sig); 4531 } 4532 4533 return actp; 4534 } 4535 4536 static bool call_chained_handler(struct sigaction *actp, int sig, 4537 siginfo_t *siginfo, void *context) { 4538 // Call the old signal handler 4539 if (actp->sa_handler == SIG_DFL) { 4540 // It's more reasonable to let jvm treat it as an unexpected exception 4541 // instead of taking the default action. 4542 return false; 4543 } else if (actp->sa_handler != SIG_IGN) { 4544 if ((actp->sa_flags & SA_NODEFER) == 0) { 4545 // automaticlly block the signal 4546 sigaddset(&(actp->sa_mask), sig); 4547 } 4548 4549 sa_handler_t hand = NULL; 4550 sa_sigaction_t sa = NULL; 4551 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4552 // retrieve the chained handler 4553 if (siginfo_flag_set) { 4554 sa = actp->sa_sigaction; 4555 } else { 4556 hand = actp->sa_handler; 4557 } 4558 4559 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4560 actp->sa_handler = SIG_DFL; 4561 } 4562 4563 // try to honor the signal mask 4564 sigset_t oset; 4565 sigemptyset(&oset); 4566 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4567 4568 // call into the chained handler 4569 if (siginfo_flag_set) { 4570 (*sa)(sig, siginfo, context); 4571 } else { 4572 (*hand)(sig); 4573 } 4574 4575 // restore the signal mask 4576 pthread_sigmask(SIG_SETMASK, &oset, NULL); 4577 } 4578 // Tell jvm's signal handler the signal is taken care of. 4579 return true; 4580 } 4581 4582 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4583 bool chained = false; 4584 // signal-chaining 4585 if (UseSignalChaining) { 4586 struct sigaction *actp = get_chained_signal_action(sig); 4587 if (actp != NULL) { 4588 chained = call_chained_handler(actp, sig, siginfo, context); 4589 } 4590 } 4591 return chained; 4592 } 4593 4594 // for diagnostic 4595 int sigflags[NSIG]; 4596 4597 int os::Linux::get_our_sigflags(int sig) { 4598 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4599 return sigflags[sig]; 4600 } 4601 4602 void os::Linux::set_our_sigflags(int sig, int flags) { 4603 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4604 if (sig > 0 && sig < NSIG) { 4605 sigflags[sig] = flags; 4606 } 4607 } 4608 4609 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4610 // Check for overwrite. 4611 struct sigaction oldAct; 4612 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4613 4614 void* oldhand = oldAct.sa_sigaction 4615 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4616 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4617 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4618 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4619 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4620 if (AllowUserSignalHandlers || !set_installed) { 4621 // Do not overwrite; user takes responsibility to forward to us. 4622 return; 4623 } else if (UseSignalChaining) { 4624 // save the old handler in jvm 4625 os::Posix::save_preinstalled_handler(sig, oldAct); 4626 // libjsig also interposes the sigaction() call below and saves the 4627 // old sigaction on it own. 4628 } else { 4629 fatal("Encountered unexpected pre-existing sigaction handler " 4630 "%#lx for signal %d.", (long)oldhand, sig); 4631 } 4632 } 4633 4634 struct sigaction sigAct; 4635 sigfillset(&(sigAct.sa_mask)); 4636 sigAct.sa_handler = SIG_DFL; 4637 if (!set_installed) { 4638 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4639 } else { 4640 sigAct.sa_sigaction = signalHandler; 4641 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4642 } 4643 // Save flags, which are set by ours 4644 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4645 sigflags[sig] = sigAct.sa_flags; 4646 4647 int ret = sigaction(sig, &sigAct, &oldAct); 4648 assert(ret == 0, "check"); 4649 4650 void* oldhand2 = oldAct.sa_sigaction 4651 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4652 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4653 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4654 } 4655 4656 // install signal handlers for signals that HotSpot needs to 4657 // handle in order to support Java-level exception handling. 4658 4659 void os::Linux::install_signal_handlers() { 4660 if (!signal_handlers_are_installed) { 4661 signal_handlers_are_installed = true; 4662 4663 // signal-chaining 4664 typedef void (*signal_setting_t)(); 4665 signal_setting_t begin_signal_setting = NULL; 4666 signal_setting_t end_signal_setting = NULL; 4667 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4668 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4669 if (begin_signal_setting != NULL) { 4670 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4671 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4672 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4673 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4674 libjsig_is_loaded = true; 4675 assert(UseSignalChaining, "should enable signal-chaining"); 4676 } 4677 if (libjsig_is_loaded) { 4678 // Tell libjsig jvm is setting signal handlers 4679 (*begin_signal_setting)(); 4680 } 4681 4682 set_signal_handler(SIGSEGV, true); 4683 set_signal_handler(SIGPIPE, true); 4684 set_signal_handler(SIGBUS, true); 4685 set_signal_handler(SIGILL, true); 4686 set_signal_handler(SIGFPE, true); 4687 #if defined(PPC64) 4688 set_signal_handler(SIGTRAP, true); 4689 #endif 4690 set_signal_handler(SIGXFSZ, true); 4691 4692 if (libjsig_is_loaded) { 4693 // Tell libjsig jvm finishes setting signal handlers 4694 (*end_signal_setting)(); 4695 } 4696 4697 // We don't activate signal checker if libjsig is in place, we trust ourselves 4698 // and if UserSignalHandler is installed all bets are off. 4699 // Log that signal checking is off only if -verbose:jni is specified. 4700 if (CheckJNICalls) { 4701 if (libjsig_is_loaded) { 4702 if (PrintJNIResolving) { 4703 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4704 } 4705 check_signals = false; 4706 } 4707 if (AllowUserSignalHandlers) { 4708 if (PrintJNIResolving) { 4709 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4710 } 4711 check_signals = false; 4712 } 4713 } 4714 } 4715 } 4716 4717 // This is the fastest way to get thread cpu time on Linux. 4718 // Returns cpu time (user+sys) for any thread, not only for current. 4719 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4720 // It might work on 2.6.10+ with a special kernel/glibc patch. 4721 // For reference, please, see IEEE Std 1003.1-2004: 4722 // http://www.unix.org/single_unix_specification 4723 4724 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4725 struct timespec tp; 4726 int rc = os::Posix::clock_gettime(clockid, &tp); 4727 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4728 4729 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4730 } 4731 4732 void os::Linux::initialize_os_info() { 4733 assert(_os_version == 0, "OS info already initialized"); 4734 4735 struct utsname _uname; 4736 4737 uint32_t major; 4738 uint32_t minor; 4739 uint32_t fix; 4740 4741 int rc; 4742 4743 // Kernel version is unknown if 4744 // verification below fails. 4745 _os_version = 0x01000000; 4746 4747 rc = uname(&_uname); 4748 if (rc != -1) { 4749 4750 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix); 4751 if (rc == 3) { 4752 4753 if (major < 256 && minor < 256 && fix < 256) { 4754 // Kernel version format is as expected, 4755 // set it overriding unknown state. 4756 _os_version = (major << 16) | 4757 (minor << 8 ) | 4758 (fix << 0 ) ; 4759 } 4760 } 4761 } 4762 } 4763 4764 uint32_t os::Linux::os_version() { 4765 assert(_os_version != 0, "not initialized"); 4766 return _os_version & 0x00FFFFFF; 4767 } 4768 4769 bool os::Linux::os_version_is_known() { 4770 assert(_os_version != 0, "not initialized"); 4771 return _os_version & 0x01000000 ? false : true; 4772 } 4773 4774 ///// 4775 // glibc on Linux platform uses non-documented flag 4776 // to indicate, that some special sort of signal 4777 // trampoline is used. 4778 // We will never set this flag, and we should 4779 // ignore this flag in our diagnostic 4780 #ifdef SIGNIFICANT_SIGNAL_MASK 4781 #undef SIGNIFICANT_SIGNAL_MASK 4782 #endif 4783 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4784 4785 static const char* get_signal_handler_name(address handler, 4786 char* buf, int buflen) { 4787 int offset = 0; 4788 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4789 if (found) { 4790 // skip directory names 4791 const char *p1, *p2; 4792 p1 = buf; 4793 size_t len = strlen(os::file_separator()); 4794 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4795 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4796 } else { 4797 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4798 } 4799 return buf; 4800 } 4801 4802 static void print_signal_handler(outputStream* st, int sig, 4803 char* buf, size_t buflen) { 4804 struct sigaction sa; 4805 4806 sigaction(sig, NULL, &sa); 4807 4808 // See comment for SIGNIFICANT_SIGNAL_MASK define 4809 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4810 4811 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4812 4813 address handler = (sa.sa_flags & SA_SIGINFO) 4814 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4815 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4816 4817 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4818 st->print("SIG_DFL"); 4819 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4820 st->print("SIG_IGN"); 4821 } else { 4822 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4823 } 4824 4825 st->print(", sa_mask[0]="); 4826 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4827 4828 address rh = VMError::get_resetted_sighandler(sig); 4829 // May be, handler was resetted by VMError? 4830 if (rh != NULL) { 4831 handler = rh; 4832 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4833 } 4834 4835 st->print(", sa_flags="); 4836 os::Posix::print_sa_flags(st, sa.sa_flags); 4837 4838 // Check: is it our handler? 4839 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4840 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4841 // It is our signal handler 4842 // check for flags, reset system-used one! 4843 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4844 st->print( 4845 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4846 os::Linux::get_our_sigflags(sig)); 4847 } 4848 } 4849 st->cr(); 4850 } 4851 4852 4853 #define DO_SIGNAL_CHECK(sig) \ 4854 do { \ 4855 if (!sigismember(&check_signal_done, sig)) { \ 4856 os::Linux::check_signal_handler(sig); \ 4857 } \ 4858 } while (0) 4859 4860 // This method is a periodic task to check for misbehaving JNI applications 4861 // under CheckJNI, we can add any periodic checks here 4862 4863 void os::run_periodic_checks() { 4864 if (check_signals == false) return; 4865 4866 // SEGV and BUS if overridden could potentially prevent 4867 // generation of hs*.log in the event of a crash, debugging 4868 // such a case can be very challenging, so we absolutely 4869 // check the following for a good measure: 4870 DO_SIGNAL_CHECK(SIGSEGV); 4871 DO_SIGNAL_CHECK(SIGILL); 4872 DO_SIGNAL_CHECK(SIGFPE); 4873 DO_SIGNAL_CHECK(SIGBUS); 4874 DO_SIGNAL_CHECK(SIGPIPE); 4875 DO_SIGNAL_CHECK(SIGXFSZ); 4876 #if defined(PPC64) 4877 DO_SIGNAL_CHECK(SIGTRAP); 4878 #endif 4879 4880 // ReduceSignalUsage allows the user to override these handlers 4881 // see comments at the very top and jvm_md.h 4882 if (!ReduceSignalUsage) { 4883 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4884 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4885 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4886 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4887 } 4888 4889 DO_SIGNAL_CHECK(SR_signum); 4890 } 4891 4892 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4893 4894 static os_sigaction_t os_sigaction = NULL; 4895 4896 void os::Linux::check_signal_handler(int sig) { 4897 char buf[O_BUFLEN]; 4898 address jvmHandler = NULL; 4899 4900 4901 struct sigaction act; 4902 if (os_sigaction == NULL) { 4903 // only trust the default sigaction, in case it has been interposed 4904 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4905 if (os_sigaction == NULL) return; 4906 } 4907 4908 os_sigaction(sig, (struct sigaction*)NULL, &act); 4909 4910 4911 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4912 4913 address thisHandler = (act.sa_flags & SA_SIGINFO) 4914 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4915 : CAST_FROM_FN_PTR(address, act.sa_handler); 4916 4917 4918 switch (sig) { 4919 case SIGSEGV: 4920 case SIGBUS: 4921 case SIGFPE: 4922 case SIGPIPE: 4923 case SIGILL: 4924 case SIGXFSZ: 4925 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4926 break; 4927 4928 case SHUTDOWN1_SIGNAL: 4929 case SHUTDOWN2_SIGNAL: 4930 case SHUTDOWN3_SIGNAL: 4931 case BREAK_SIGNAL: 4932 jvmHandler = (address)user_handler(); 4933 break; 4934 4935 default: 4936 if (sig == SR_signum) { 4937 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4938 } else { 4939 return; 4940 } 4941 break; 4942 } 4943 4944 if (thisHandler != jvmHandler) { 4945 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4946 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4947 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4948 // No need to check this sig any longer 4949 sigaddset(&check_signal_done, sig); 4950 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4951 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4952 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4953 exception_name(sig, buf, O_BUFLEN)); 4954 } 4955 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4956 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4957 tty->print("expected:"); 4958 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 4959 tty->cr(); 4960 tty->print(" found:"); 4961 os::Posix::print_sa_flags(tty, act.sa_flags); 4962 tty->cr(); 4963 // No need to check this sig any longer 4964 sigaddset(&check_signal_done, sig); 4965 } 4966 4967 // Dump all the signal 4968 if (sigismember(&check_signal_done, sig)) { 4969 print_signal_handlers(tty, buf, O_BUFLEN); 4970 } 4971 } 4972 4973 extern void report_error(char* file_name, int line_no, char* title, 4974 char* format, ...); 4975 4976 // this is called _before_ most of the global arguments have been parsed 4977 void os::init(void) { 4978 char dummy; // used to get a guess on initial stack address 4979 4980 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4981 4982 init_random(1234567); 4983 4984 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4985 if (Linux::page_size() == -1) { 4986 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 4987 os::strerror(errno)); 4988 } 4989 init_page_sizes((size_t) Linux::page_size()); 4990 4991 Linux::initialize_system_info(); 4992 4993 Linux::initialize_os_info(); 4994 4995 os::Linux::CPUPerfTicks pticks; 4996 bool res = os::Linux::get_tick_information(&pticks, -1); 4997 4998 if (res && pticks.has_steal_ticks) { 4999 has_initial_tick_info = true; 5000 initial_total_ticks = pticks.total; 5001 initial_steal_ticks = pticks.steal; 5002 } 5003 5004 // _main_thread points to the thread that created/loaded the JVM. 5005 Linux::_main_thread = pthread_self(); 5006 5007 // retrieve entry point for pthread_setname_np 5008 Linux::_pthread_setname_np = 5009 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 5010 5011 os::Posix::init(); 5012 5013 initial_time_count = javaTimeNanos(); 5014 5015 // Always warn if no monotonic clock available 5016 if (!os::Posix::supports_monotonic_clock()) { 5017 warning("No monotonic clock was available - timed services may " \ 5018 "be adversely affected if the time-of-day clock changes"); 5019 } 5020 } 5021 5022 // To install functions for atexit system call 5023 extern "C" { 5024 static void perfMemory_exit_helper() { 5025 perfMemory_exit(); 5026 } 5027 } 5028 5029 void os::pd_init_container_support() { 5030 OSContainer::init(); 5031 } 5032 5033 void os::Linux::numa_init() { 5034 5035 // Java can be invoked as 5036 // 1. Without numactl and heap will be allocated/configured on all nodes as 5037 // per the system policy. 5038 // 2. With numactl --interleave: 5039 // Use numa_get_interleave_mask(v2) API to get nodes bitmask. The same 5040 // API for membind case bitmask is reset. 5041 // Interleave is only hint and Kernel can fallback to other nodes if 5042 // no memory is available on the target nodes. 5043 // 3. With numactl --membind: 5044 // Use numa_get_membind(v2) API to get nodes bitmask. The same API for 5045 // interleave case returns bitmask of all nodes. 5046 // numa_all_nodes_ptr holds bitmask of all nodes. 5047 // numa_get_interleave_mask(v2) and numa_get_membind(v2) APIs returns correct 5048 // bitmask when externally configured to run on all or fewer nodes. 5049 5050 if (!Linux::libnuma_init()) { 5051 UseNUMA = false; 5052 } else { 5053 if ((Linux::numa_max_node() < 1) || Linux::is_bound_to_single_node()) { 5054 // If there's only one node (they start from 0) or if the process 5055 // is bound explicitly to a single node using membind, disable NUMA. 5056 UseNUMA = false; 5057 } else { 5058 5059 LogTarget(Info,os) log; 5060 LogStream ls(log); 5061 5062 Linux::set_configured_numa_policy(Linux::identify_numa_policy()); 5063 5064 struct bitmask* bmp = Linux::_numa_membind_bitmask; 5065 const char* numa_mode = "membind"; 5066 5067 if (Linux::is_running_in_interleave_mode()) { 5068 bmp = Linux::_numa_interleave_bitmask; 5069 numa_mode = "interleave"; 5070 } 5071 5072 ls.print("UseNUMA is enabled and invoked in '%s' mode." 5073 " Heap will be configured using NUMA memory nodes:", numa_mode); 5074 5075 for (int node = 0; node <= Linux::numa_max_node(); node++) { 5076 if (Linux::_numa_bitmask_isbitset(bmp, node)) { 5077 ls.print(" %d", node); 5078 } 5079 } 5080 } 5081 } 5082 5083 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 5084 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 5085 // we can make the adaptive lgrp chunk resizing work. If the user specified both 5086 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn 5087 // and disable adaptive resizing. 5088 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 5089 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, " 5090 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 5091 UseAdaptiveSizePolicy = false; 5092 UseAdaptiveNUMAChunkSizing = false; 5093 } 5094 } 5095 5096 if (!UseNUMA && ForceNUMA) { 5097 UseNUMA = true; 5098 } 5099 } 5100 5101 // this is called _after_ the global arguments have been parsed 5102 jint os::init_2(void) { 5103 5104 // This could be set after os::Posix::init() but all platforms 5105 // have to set it the same so we have to mirror Solaris. 5106 DEBUG_ONLY(os::set_mutex_init_done();) 5107 5108 os::Posix::init_2(); 5109 5110 Linux::fast_thread_clock_init(); 5111 5112 // initialize suspend/resume support - must do this before signal_sets_init() 5113 if (SR_initialize() != 0) { 5114 perror("SR_initialize failed"); 5115 return JNI_ERR; 5116 } 5117 5118 Linux::signal_sets_init(); 5119 Linux::install_signal_handlers(); 5120 // Initialize data for jdk.internal.misc.Signal 5121 if (!ReduceSignalUsage) { 5122 jdk_misc_signal_init(); 5123 } 5124 5125 // Check and sets minimum stack sizes against command line options 5126 if (Posix::set_minimum_stack_sizes() == JNI_ERR) { 5127 return JNI_ERR; 5128 } 5129 5130 #if defined(IA32) 5131 // Need to ensure we've determined the process's initial stack to 5132 // perform the workaround 5133 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 5134 workaround_expand_exec_shield_cs_limit(); 5135 #else 5136 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher(); 5137 if (!suppress_primordial_thread_resolution) { 5138 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 5139 } 5140 #endif 5141 5142 Linux::libpthread_init(); 5143 Linux::sched_getcpu_init(); 5144 log_info(os)("HotSpot is running with %s, %s", 5145 Linux::glibc_version(), Linux::libpthread_version()); 5146 5147 if (UseNUMA) { 5148 Linux::numa_init(); 5149 } 5150 5151 if (MaxFDLimit) { 5152 // set the number of file descriptors to max. print out error 5153 // if getrlimit/setrlimit fails but continue regardless. 5154 struct rlimit nbr_files; 5155 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 5156 if (status != 0) { 5157 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno)); 5158 } else { 5159 nbr_files.rlim_cur = nbr_files.rlim_max; 5160 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 5161 if (status != 0) { 5162 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno)); 5163 } 5164 } 5165 } 5166 5167 // Initialize lock used to serialize thread creation (see os::create_thread) 5168 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 5169 5170 // at-exit methods are called in the reverse order of their registration. 5171 // atexit functions are called on return from main or as a result of a 5172 // call to exit(3C). There can be only 32 of these functions registered 5173 // and atexit() does not set errno. 5174 5175 if (PerfAllowAtExitRegistration) { 5176 // only register atexit functions if PerfAllowAtExitRegistration is set. 5177 // atexit functions can be delayed until process exit time, which 5178 // can be problematic for embedded VM situations. Embedded VMs should 5179 // call DestroyJavaVM() to assure that VM resources are released. 5180 5181 // note: perfMemory_exit_helper atexit function may be removed in 5182 // the future if the appropriate cleanup code can be added to the 5183 // VM_Exit VMOperation's doit method. 5184 if (atexit(perfMemory_exit_helper) != 0) { 5185 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 5186 } 5187 } 5188 5189 // initialize thread priority policy 5190 prio_init(); 5191 5192 if (!FLAG_IS_DEFAULT(AllocateHeapAt) || !FLAG_IS_DEFAULT(AllocateOldGenAt)) { 5193 set_coredump_filter(DAX_SHARED_BIT); 5194 } 5195 5196 if (DumpPrivateMappingsInCore) { 5197 set_coredump_filter(FILE_BACKED_PVT_BIT); 5198 } 5199 5200 if (DumpSharedMappingsInCore) { 5201 set_coredump_filter(FILE_BACKED_SHARED_BIT); 5202 } 5203 5204 return JNI_OK; 5205 } 5206 5207 // Mark the polling page as unreadable 5208 void os::make_polling_page_unreadable(void) { 5209 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 5210 fatal("Could not disable polling page"); 5211 } 5212 } 5213 5214 // Mark the polling page as readable 5215 void os::make_polling_page_readable(void) { 5216 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 5217 fatal("Could not enable polling page"); 5218 } 5219 } 5220 5221 // older glibc versions don't have this macro (which expands to 5222 // an optimized bit-counting function) so we have to roll our own 5223 #ifndef CPU_COUNT 5224 5225 static int _cpu_count(const cpu_set_t* cpus) { 5226 int count = 0; 5227 // only look up to the number of configured processors 5228 for (int i = 0; i < os::processor_count(); i++) { 5229 if (CPU_ISSET(i, cpus)) { 5230 count++; 5231 } 5232 } 5233 return count; 5234 } 5235 5236 #define CPU_COUNT(cpus) _cpu_count(cpus) 5237 5238 #endif // CPU_COUNT 5239 5240 // Get the current number of available processors for this process. 5241 // This value can change at any time during a process's lifetime. 5242 // sched_getaffinity gives an accurate answer as it accounts for cpusets. 5243 // If it appears there may be more than 1024 processors then we do a 5244 // dynamic check - see 6515172 for details. 5245 // If anything goes wrong we fallback to returning the number of online 5246 // processors - which can be greater than the number available to the process. 5247 int os::Linux::active_processor_count() { 5248 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 5249 cpu_set_t* cpus_p = &cpus; 5250 int cpus_size = sizeof(cpu_set_t); 5251 5252 int configured_cpus = os::processor_count(); // upper bound on available cpus 5253 int cpu_count = 0; 5254 5255 // old build platforms may not support dynamic cpu sets 5256 #ifdef CPU_ALLOC 5257 5258 // To enable easy testing of the dynamic path on different platforms we 5259 // introduce a diagnostic flag: UseCpuAllocPath 5260 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 5261 // kernel may use a mask bigger than cpu_set_t 5262 log_trace(os)("active_processor_count: using dynamic path %s" 5263 "- configured processors: %d", 5264 UseCpuAllocPath ? "(forced) " : "", 5265 configured_cpus); 5266 cpus_p = CPU_ALLOC(configured_cpus); 5267 if (cpus_p != NULL) { 5268 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 5269 // zero it just to be safe 5270 CPU_ZERO_S(cpus_size, cpus_p); 5271 } 5272 else { 5273 // failed to allocate so fallback to online cpus 5274 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 5275 log_trace(os)("active_processor_count: " 5276 "CPU_ALLOC failed (%s) - using " 5277 "online processor count: %d", 5278 os::strerror(errno), online_cpus); 5279 return online_cpus; 5280 } 5281 } 5282 else { 5283 log_trace(os)("active_processor_count: using static path - configured processors: %d", 5284 configured_cpus); 5285 } 5286 #else // CPU_ALLOC 5287 // these stubs won't be executed 5288 #define CPU_COUNT_S(size, cpus) -1 5289 #define CPU_FREE(cpus) 5290 5291 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 5292 configured_cpus); 5293 #endif // CPU_ALLOC 5294 5295 // pid 0 means the current thread - which we have to assume represents the process 5296 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 5297 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5298 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 5299 } 5300 else { 5301 cpu_count = CPU_COUNT(cpus_p); 5302 } 5303 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 5304 } 5305 else { 5306 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 5307 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 5308 "which may exceed available processors", os::strerror(errno), cpu_count); 5309 } 5310 5311 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5312 CPU_FREE(cpus_p); 5313 } 5314 5315 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check"); 5316 return cpu_count; 5317 } 5318 5319 // Determine the active processor count from one of 5320 // three different sources: 5321 // 5322 // 1. User option -XX:ActiveProcessorCount 5323 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN) 5324 // 3. extracted from cgroup cpu subsystem (shares and quotas) 5325 // 5326 // Option 1, if specified, will always override. 5327 // If the cgroup subsystem is active and configured, we 5328 // will return the min of the cgroup and option 2 results. 5329 // This is required since tools, such as numactl, that 5330 // alter cpu affinity do not update cgroup subsystem 5331 // cpuset configuration files. 5332 int os::active_processor_count() { 5333 // User has overridden the number of active processors 5334 if (ActiveProcessorCount > 0) { 5335 log_trace(os)("active_processor_count: " 5336 "active processor count set by user : %d", 5337 ActiveProcessorCount); 5338 return ActiveProcessorCount; 5339 } 5340 5341 int active_cpus; 5342 if (OSContainer::is_containerized()) { 5343 active_cpus = OSContainer::active_processor_count(); 5344 log_trace(os)("active_processor_count: determined by OSContainer: %d", 5345 active_cpus); 5346 } else { 5347 active_cpus = os::Linux::active_processor_count(); 5348 } 5349 5350 return active_cpus; 5351 } 5352 5353 uint os::processor_id() { 5354 const int id = Linux::sched_getcpu(); 5355 assert(id >= 0 && id < _processor_count, "Invalid processor id"); 5356 return (uint)id; 5357 } 5358 5359 void os::set_native_thread_name(const char *name) { 5360 if (Linux::_pthread_setname_np) { 5361 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 5362 snprintf(buf, sizeof(buf), "%s", name); 5363 buf[sizeof(buf) - 1] = '\0'; 5364 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 5365 // ERANGE should not happen; all other errors should just be ignored. 5366 assert(rc != ERANGE, "pthread_setname_np failed"); 5367 } 5368 } 5369 5370 bool os::distribute_processes(uint length, uint* distribution) { 5371 // Not yet implemented. 5372 return false; 5373 } 5374 5375 bool os::bind_to_processor(uint processor_id) { 5376 // Not yet implemented. 5377 return false; 5378 } 5379 5380 /// 5381 5382 void os::SuspendedThreadTask::internal_do_task() { 5383 if (do_suspend(_thread->osthread())) { 5384 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 5385 do_task(context); 5386 do_resume(_thread->osthread()); 5387 } 5388 } 5389 5390 //////////////////////////////////////////////////////////////////////////////// 5391 // debug support 5392 5393 bool os::find(address addr, outputStream* st) { 5394 Dl_info dlinfo; 5395 memset(&dlinfo, 0, sizeof(dlinfo)); 5396 if (dladdr(addr, &dlinfo) != 0) { 5397 st->print(PTR_FORMAT ": ", p2i(addr)); 5398 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5399 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 5400 p2i(addr) - p2i(dlinfo.dli_saddr)); 5401 } else if (dlinfo.dli_fbase != NULL) { 5402 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 5403 } else { 5404 st->print("<absolute address>"); 5405 } 5406 if (dlinfo.dli_fname != NULL) { 5407 st->print(" in %s", dlinfo.dli_fname); 5408 } 5409 if (dlinfo.dli_fbase != NULL) { 5410 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 5411 } 5412 st->cr(); 5413 5414 if (Verbose) { 5415 // decode some bytes around the PC 5416 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5417 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5418 address lowest = (address) dlinfo.dli_sname; 5419 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5420 if (begin < lowest) begin = lowest; 5421 Dl_info dlinfo2; 5422 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5423 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 5424 end = (address) dlinfo2.dli_saddr; 5425 } 5426 Disassembler::decode(begin, end, st); 5427 } 5428 return true; 5429 } 5430 return false; 5431 } 5432 5433 //////////////////////////////////////////////////////////////////////////////// 5434 // misc 5435 5436 // This does not do anything on Linux. This is basically a hook for being 5437 // able to use structured exception handling (thread-local exception filters) 5438 // on, e.g., Win32. 5439 void 5440 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5441 JavaCallArguments* args, Thread* thread) { 5442 f(value, method, args, thread); 5443 } 5444 5445 void os::print_statistics() { 5446 } 5447 5448 bool os::message_box(const char* title, const char* message) { 5449 int i; 5450 fdStream err(defaultStream::error_fd()); 5451 for (i = 0; i < 78; i++) err.print_raw("="); 5452 err.cr(); 5453 err.print_raw_cr(title); 5454 for (i = 0; i < 78; i++) err.print_raw("-"); 5455 err.cr(); 5456 err.print_raw_cr(message); 5457 for (i = 0; i < 78; i++) err.print_raw("="); 5458 err.cr(); 5459 5460 char buf[16]; 5461 // Prevent process from exiting upon "read error" without consuming all CPU 5462 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5463 5464 return buf[0] == 'y' || buf[0] == 'Y'; 5465 } 5466 5467 // Is a (classpath) directory empty? 5468 bool os::dir_is_empty(const char* path) { 5469 DIR *dir = NULL; 5470 struct dirent *ptr; 5471 5472 dir = opendir(path); 5473 if (dir == NULL) return true; 5474 5475 // Scan the directory 5476 bool result = true; 5477 while (result && (ptr = readdir(dir)) != NULL) { 5478 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5479 result = false; 5480 } 5481 } 5482 closedir(dir); 5483 return result; 5484 } 5485 5486 // This code originates from JDK's sysOpen and open64_w 5487 // from src/solaris/hpi/src/system_md.c 5488 5489 int os::open(const char *path, int oflag, int mode) { 5490 if (strlen(path) > MAX_PATH - 1) { 5491 errno = ENAMETOOLONG; 5492 return -1; 5493 } 5494 5495 // All file descriptors that are opened in the Java process and not 5496 // specifically destined for a subprocess should have the close-on-exec 5497 // flag set. If we don't set it, then careless 3rd party native code 5498 // might fork and exec without closing all appropriate file descriptors 5499 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5500 // turn might: 5501 // 5502 // - cause end-of-file to fail to be detected on some file 5503 // descriptors, resulting in mysterious hangs, or 5504 // 5505 // - might cause an fopen in the subprocess to fail on a system 5506 // suffering from bug 1085341. 5507 // 5508 // (Yes, the default setting of the close-on-exec flag is a Unix 5509 // design flaw) 5510 // 5511 // See: 5512 // 1085341: 32-bit stdio routines should support file descriptors >255 5513 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5514 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5515 // 5516 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5517 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5518 // because it saves a system call and removes a small window where the flag 5519 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5520 // and we fall back to using FD_CLOEXEC (see below). 5521 #ifdef O_CLOEXEC 5522 oflag |= O_CLOEXEC; 5523 #endif 5524 5525 int fd = ::open64(path, oflag, mode); 5526 if (fd == -1) return -1; 5527 5528 //If the open succeeded, the file might still be a directory 5529 { 5530 struct stat64 buf64; 5531 int ret = ::fstat64(fd, &buf64); 5532 int st_mode = buf64.st_mode; 5533 5534 if (ret != -1) { 5535 if ((st_mode & S_IFMT) == S_IFDIR) { 5536 errno = EISDIR; 5537 ::close(fd); 5538 return -1; 5539 } 5540 } else { 5541 ::close(fd); 5542 return -1; 5543 } 5544 } 5545 5546 #ifdef FD_CLOEXEC 5547 // Validate that the use of the O_CLOEXEC flag on open above worked. 5548 // With recent kernels, we will perform this check exactly once. 5549 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5550 if (!O_CLOEXEC_is_known_to_work) { 5551 int flags = ::fcntl(fd, F_GETFD); 5552 if (flags != -1) { 5553 if ((flags & FD_CLOEXEC) != 0) 5554 O_CLOEXEC_is_known_to_work = 1; 5555 else 5556 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5557 } 5558 } 5559 #endif 5560 5561 return fd; 5562 } 5563 5564 5565 // create binary file, rewriting existing file if required 5566 int os::create_binary_file(const char* path, bool rewrite_existing) { 5567 int oflags = O_WRONLY | O_CREAT; 5568 if (!rewrite_existing) { 5569 oflags |= O_EXCL; 5570 } 5571 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5572 } 5573 5574 // return current position of file pointer 5575 jlong os::current_file_offset(int fd) { 5576 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5577 } 5578 5579 // move file pointer to the specified offset 5580 jlong os::seek_to_file_offset(int fd, jlong offset) { 5581 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5582 } 5583 5584 // This code originates from JDK's sysAvailable 5585 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5586 5587 int os::available(int fd, jlong *bytes) { 5588 jlong cur, end; 5589 int mode; 5590 struct stat64 buf64; 5591 5592 if (::fstat64(fd, &buf64) >= 0) { 5593 mode = buf64.st_mode; 5594 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5595 int n; 5596 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5597 *bytes = n; 5598 return 1; 5599 } 5600 } 5601 } 5602 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5603 return 0; 5604 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5605 return 0; 5606 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5607 return 0; 5608 } 5609 *bytes = end - cur; 5610 return 1; 5611 } 5612 5613 // Map a block of memory. 5614 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5615 char *addr, size_t bytes, bool read_only, 5616 bool allow_exec) { 5617 int prot; 5618 int flags = MAP_PRIVATE; 5619 5620 if (read_only) { 5621 prot = PROT_READ; 5622 } else { 5623 prot = PROT_READ | PROT_WRITE; 5624 } 5625 5626 if (allow_exec) { 5627 prot |= PROT_EXEC; 5628 } 5629 5630 if (addr != NULL) { 5631 flags |= MAP_FIXED; 5632 } 5633 5634 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5635 fd, file_offset); 5636 if (mapped_address == MAP_FAILED) { 5637 return NULL; 5638 } 5639 return mapped_address; 5640 } 5641 5642 5643 // Remap a block of memory. 5644 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5645 char *addr, size_t bytes, bool read_only, 5646 bool allow_exec) { 5647 // same as map_memory() on this OS 5648 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5649 allow_exec); 5650 } 5651 5652 5653 // Unmap a block of memory. 5654 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5655 return munmap(addr, bytes) == 0; 5656 } 5657 5658 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5659 5660 static jlong fast_cpu_time(Thread *thread) { 5661 clockid_t clockid; 5662 int rc = os::Linux::pthread_getcpuclockid(thread->osthread()->pthread_id(), 5663 &clockid); 5664 if (rc == 0) { 5665 return os::Linux::fast_thread_cpu_time(clockid); 5666 } else { 5667 // It's possible to encounter a terminated native thread that failed 5668 // to detach itself from the VM - which should result in ESRCH. 5669 assert_status(rc == ESRCH, rc, "pthread_getcpuclockid failed"); 5670 return -1; 5671 } 5672 } 5673 5674 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5675 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5676 // of a thread. 5677 // 5678 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5679 // the fast estimate available on the platform. 5680 5681 jlong os::current_thread_cpu_time() { 5682 if (os::Linux::supports_fast_thread_cpu_time()) { 5683 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5684 } else { 5685 // return user + sys since the cost is the same 5686 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5687 } 5688 } 5689 5690 jlong os::thread_cpu_time(Thread* thread) { 5691 // consistent with what current_thread_cpu_time() returns 5692 if (os::Linux::supports_fast_thread_cpu_time()) { 5693 return fast_cpu_time(thread); 5694 } else { 5695 return slow_thread_cpu_time(thread, true /* user + sys */); 5696 } 5697 } 5698 5699 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5700 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5701 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5702 } else { 5703 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5704 } 5705 } 5706 5707 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5708 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5709 return fast_cpu_time(thread); 5710 } else { 5711 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5712 } 5713 } 5714 5715 // -1 on error. 5716 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5717 pid_t tid = thread->osthread()->thread_id(); 5718 char *s; 5719 char stat[2048]; 5720 int statlen; 5721 char proc_name[64]; 5722 int count; 5723 long sys_time, user_time; 5724 char cdummy; 5725 int idummy; 5726 long ldummy; 5727 FILE *fp; 5728 5729 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5730 fp = fopen(proc_name, "r"); 5731 if (fp == NULL) return -1; 5732 statlen = fread(stat, 1, 2047, fp); 5733 stat[statlen] = '\0'; 5734 fclose(fp); 5735 5736 // Skip pid and the command string. Note that we could be dealing with 5737 // weird command names, e.g. user could decide to rename java launcher 5738 // to "java 1.4.2 :)", then the stat file would look like 5739 // 1234 (java 1.4.2 :)) R ... ... 5740 // We don't really need to know the command string, just find the last 5741 // occurrence of ")" and then start parsing from there. See bug 4726580. 5742 s = strrchr(stat, ')'); 5743 if (s == NULL) return -1; 5744 5745 // Skip blank chars 5746 do { s++; } while (s && isspace(*s)); 5747 5748 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5749 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5750 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5751 &user_time, &sys_time); 5752 if (count != 13) return -1; 5753 if (user_sys_cpu_time) { 5754 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5755 } else { 5756 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5757 } 5758 } 5759 5760 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5761 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5762 info_ptr->may_skip_backward = false; // elapsed time not wall time 5763 info_ptr->may_skip_forward = false; // elapsed time not wall time 5764 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5765 } 5766 5767 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5768 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5769 info_ptr->may_skip_backward = false; // elapsed time not wall time 5770 info_ptr->may_skip_forward = false; // elapsed time not wall time 5771 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5772 } 5773 5774 bool os::is_thread_cpu_time_supported() { 5775 return true; 5776 } 5777 5778 // System loadavg support. Returns -1 if load average cannot be obtained. 5779 // Linux doesn't yet have a (official) notion of processor sets, 5780 // so just return the system wide load average. 5781 int os::loadavg(double loadavg[], int nelem) { 5782 return ::getloadavg(loadavg, nelem); 5783 } 5784 5785 void os::pause() { 5786 char filename[MAX_PATH]; 5787 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5788 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5789 } else { 5790 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5791 } 5792 5793 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5794 if (fd != -1) { 5795 struct stat buf; 5796 ::close(fd); 5797 while (::stat(filename, &buf) == 0) { 5798 (void)::poll(NULL, 0, 100); 5799 } 5800 } else { 5801 jio_fprintf(stderr, 5802 "Could not open pause file '%s', continuing immediately.\n", filename); 5803 } 5804 } 5805 5806 extern char** environ; 5807 5808 // Run the specified command in a separate process. Return its exit value, 5809 // or -1 on failure (e.g. can't fork a new process). 5810 // Unlike system(), this function can be called from signal handler. It 5811 // doesn't block SIGINT et al. 5812 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) { 5813 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5814 5815 pid_t pid ; 5816 5817 if (use_vfork_if_available) { 5818 pid = vfork(); 5819 } else { 5820 pid = fork(); 5821 } 5822 5823 if (pid < 0) { 5824 // fork failed 5825 return -1; 5826 5827 } else if (pid == 0) { 5828 // child process 5829 5830 execve("/bin/sh", (char* const*)argv, environ); 5831 5832 // execve failed 5833 _exit(-1); 5834 5835 } else { 5836 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5837 // care about the actual exit code, for now. 5838 5839 int status; 5840 5841 // Wait for the child process to exit. This returns immediately if 5842 // the child has already exited. */ 5843 while (waitpid(pid, &status, 0) < 0) { 5844 switch (errno) { 5845 case ECHILD: return 0; 5846 case EINTR: break; 5847 default: return -1; 5848 } 5849 } 5850 5851 if (WIFEXITED(status)) { 5852 // The child exited normally; get its exit code. 5853 return WEXITSTATUS(status); 5854 } else if (WIFSIGNALED(status)) { 5855 // The child exited because of a signal 5856 // The best value to return is 0x80 + signal number, 5857 // because that is what all Unix shells do, and because 5858 // it allows callers to distinguish between process exit and 5859 // process death by signal. 5860 return 0x80 + WTERMSIG(status); 5861 } else { 5862 // Unknown exit code; pass it through 5863 return status; 5864 } 5865 } 5866 } 5867 5868 // Get the default path to the core file 5869 // Returns the length of the string 5870 int os::get_core_path(char* buffer, size_t bufferSize) { 5871 /* 5872 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 5873 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 5874 */ 5875 const int core_pattern_len = 129; 5876 char core_pattern[core_pattern_len] = {0}; 5877 5878 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 5879 if (core_pattern_file == -1) { 5880 return -1; 5881 } 5882 5883 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 5884 ::close(core_pattern_file); 5885 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 5886 return -1; 5887 } 5888 if (core_pattern[ret-1] == '\n') { 5889 core_pattern[ret-1] = '\0'; 5890 } else { 5891 core_pattern[ret] = '\0'; 5892 } 5893 5894 // Replace the %p in the core pattern with the process id. NOTE: we do this 5895 // only if the pattern doesn't start with "|", and we support only one %p in 5896 // the pattern. 5897 char *pid_pos = strstr(core_pattern, "%p"); 5898 const char* tail = (pid_pos != NULL) ? (pid_pos + 2) : ""; // skip over the "%p" 5899 int written; 5900 5901 if (core_pattern[0] == '/') { 5902 if (pid_pos != NULL) { 5903 *pid_pos = '\0'; 5904 written = jio_snprintf(buffer, bufferSize, "%s%d%s", core_pattern, 5905 current_process_id(), tail); 5906 } else { 5907 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 5908 } 5909 } else { 5910 char cwd[PATH_MAX]; 5911 5912 const char* p = get_current_directory(cwd, PATH_MAX); 5913 if (p == NULL) { 5914 return -1; 5915 } 5916 5917 if (core_pattern[0] == '|') { 5918 written = jio_snprintf(buffer, bufferSize, 5919 "\"%s\" (or dumping to %s/core.%d)", 5920 &core_pattern[1], p, current_process_id()); 5921 } else if (pid_pos != NULL) { 5922 *pid_pos = '\0'; 5923 written = jio_snprintf(buffer, bufferSize, "%s/%s%d%s", p, core_pattern, 5924 current_process_id(), tail); 5925 } else { 5926 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 5927 } 5928 } 5929 5930 if (written < 0) { 5931 return -1; 5932 } 5933 5934 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 5935 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 5936 5937 if (core_uses_pid_file != -1) { 5938 char core_uses_pid = 0; 5939 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 5940 ::close(core_uses_pid_file); 5941 5942 if (core_uses_pid == '1') { 5943 jio_snprintf(buffer + written, bufferSize - written, 5944 ".%d", current_process_id()); 5945 } 5946 } 5947 } 5948 5949 return strlen(buffer); 5950 } 5951 5952 bool os::start_debugging(char *buf, int buflen) { 5953 int len = (int)strlen(buf); 5954 char *p = &buf[len]; 5955 5956 jio_snprintf(p, buflen-len, 5957 "\n\n" 5958 "Do you want to debug the problem?\n\n" 5959 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 5960 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 5961 "Otherwise, press RETURN to abort...", 5962 os::current_process_id(), os::current_process_id(), 5963 os::current_thread_id(), os::current_thread_id()); 5964 5965 bool yes = os::message_box("Unexpected Error", buf); 5966 5967 if (yes) { 5968 // yes, user asked VM to launch debugger 5969 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d", 5970 os::current_process_id(), os::current_process_id()); 5971 5972 os::fork_and_exec(buf); 5973 yes = false; 5974 } 5975 return yes; 5976 } 5977 5978 5979 // Java/Compiler thread: 5980 // 5981 // Low memory addresses 5982 // P0 +------------------------+ 5983 // | |\ Java thread created by VM does not have glibc 5984 // | glibc guard page | - guard page, attached Java thread usually has 5985 // | |/ 1 glibc guard page. 5986 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 5987 // | |\ 5988 // | HotSpot Guard Pages | - red, yellow and reserved pages 5989 // | |/ 5990 // +------------------------+ JavaThread::stack_reserved_zone_base() 5991 // | |\ 5992 // | Normal Stack | - 5993 // | |/ 5994 // P2 +------------------------+ Thread::stack_base() 5995 // 5996 // Non-Java thread: 5997 // 5998 // Low memory addresses 5999 // P0 +------------------------+ 6000 // | |\ 6001 // | glibc guard page | - usually 1 page 6002 // | |/ 6003 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 6004 // | |\ 6005 // | Normal Stack | - 6006 // | |/ 6007 // P2 +------------------------+ Thread::stack_base() 6008 // 6009 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size 6010 // returned from pthread_attr_getstack(). 6011 // ** Due to NPTL implementation error, linux takes the glibc guard page out 6012 // of the stack size given in pthread_attr. We work around this for 6013 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.) 6014 // 6015 #ifndef ZERO 6016 static void current_stack_region(address * bottom, size_t * size) { 6017 if (os::is_primordial_thread()) { 6018 // primordial thread needs special handling because pthread_getattr_np() 6019 // may return bogus value. 6020 *bottom = os::Linux::initial_thread_stack_bottom(); 6021 *size = os::Linux::initial_thread_stack_size(); 6022 } else { 6023 pthread_attr_t attr; 6024 6025 int rslt = pthread_getattr_np(pthread_self(), &attr); 6026 6027 // JVM needs to know exact stack location, abort if it fails 6028 if (rslt != 0) { 6029 if (rslt == ENOMEM) { 6030 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 6031 } else { 6032 fatal("pthread_getattr_np failed with error = %d", rslt); 6033 } 6034 } 6035 6036 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 6037 fatal("Cannot locate current stack attributes!"); 6038 } 6039 6040 // Work around NPTL stack guard error. 6041 size_t guard_size = 0; 6042 rslt = pthread_attr_getguardsize(&attr, &guard_size); 6043 if (rslt != 0) { 6044 fatal("pthread_attr_getguardsize failed with error = %d", rslt); 6045 } 6046 *bottom += guard_size; 6047 *size -= guard_size; 6048 6049 pthread_attr_destroy(&attr); 6050 6051 } 6052 assert(os::current_stack_pointer() >= *bottom && 6053 os::current_stack_pointer() < *bottom + *size, "just checking"); 6054 } 6055 6056 address os::current_stack_base() { 6057 address bottom; 6058 size_t size; 6059 current_stack_region(&bottom, &size); 6060 return (bottom + size); 6061 } 6062 6063 size_t os::current_stack_size() { 6064 // This stack size includes the usable stack and HotSpot guard pages 6065 // (for the threads that have Hotspot guard pages). 6066 address bottom; 6067 size_t size; 6068 current_stack_region(&bottom, &size); 6069 return size; 6070 } 6071 #endif 6072 6073 static inline struct timespec get_mtime(const char* filename) { 6074 struct stat st; 6075 int ret = os::stat(filename, &st); 6076 assert(ret == 0, "failed to stat() file '%s': %s", filename, os::strerror(errno)); 6077 return st.st_mtim; 6078 } 6079 6080 int os::compare_file_modified_times(const char* file1, const char* file2) { 6081 struct timespec filetime1 = get_mtime(file1); 6082 struct timespec filetime2 = get_mtime(file2); 6083 int diff = filetime1.tv_sec - filetime2.tv_sec; 6084 if (diff == 0) { 6085 return filetime1.tv_nsec - filetime2.tv_nsec; 6086 } 6087 return diff; 6088 } 6089 6090 /////////////// Unit tests /////////////// 6091 6092 #ifndef PRODUCT 6093 6094 class TestReserveMemorySpecial : AllStatic { 6095 public: 6096 static void small_page_write(void* addr, size_t size) { 6097 size_t page_size = os::vm_page_size(); 6098 6099 char* end = (char*)addr + size; 6100 for (char* p = (char*)addr; p < end; p += page_size) { 6101 *p = 1; 6102 } 6103 } 6104 6105 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6106 if (!UseHugeTLBFS) { 6107 return; 6108 } 6109 6110 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6111 6112 if (addr != NULL) { 6113 small_page_write(addr, size); 6114 6115 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6116 } 6117 } 6118 6119 static void test_reserve_memory_special_huge_tlbfs_only() { 6120 if (!UseHugeTLBFS) { 6121 return; 6122 } 6123 6124 size_t lp = os::large_page_size(); 6125 6126 for (size_t size = lp; size <= lp * 10; size += lp) { 6127 test_reserve_memory_special_huge_tlbfs_only(size); 6128 } 6129 } 6130 6131 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6132 size_t lp = os::large_page_size(); 6133 size_t ag = os::vm_allocation_granularity(); 6134 6135 // sizes to test 6136 const size_t sizes[] = { 6137 lp, lp + ag, lp + lp / 2, lp * 2, 6138 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6139 lp * 10, lp * 10 + lp / 2 6140 }; 6141 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6142 6143 // For each size/alignment combination, we test three scenarios: 6144 // 1) with req_addr == NULL 6145 // 2) with a non-null req_addr at which we expect to successfully allocate 6146 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6147 // expect the allocation to either fail or to ignore req_addr 6148 6149 // Pre-allocate two areas; they shall be as large as the largest allocation 6150 // and aligned to the largest alignment we will be testing. 6151 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6152 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6153 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6154 -1, 0); 6155 assert(mapping1 != MAP_FAILED, "should work"); 6156 6157 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6158 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6159 -1, 0); 6160 assert(mapping2 != MAP_FAILED, "should work"); 6161 6162 // Unmap the first mapping, but leave the second mapping intact: the first 6163 // mapping will serve as a value for a "good" req_addr (case 2). The second 6164 // mapping, still intact, as "bad" req_addr (case 3). 6165 ::munmap(mapping1, mapping_size); 6166 6167 // Case 1 6168 for (int i = 0; i < num_sizes; i++) { 6169 const size_t size = sizes[i]; 6170 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6171 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6172 if (p != NULL) { 6173 assert(is_aligned(p, alignment), "must be"); 6174 small_page_write(p, size); 6175 os::Linux::release_memory_special_huge_tlbfs(p, size); 6176 } 6177 } 6178 } 6179 6180 // Case 2 6181 for (int i = 0; i < num_sizes; i++) { 6182 const size_t size = sizes[i]; 6183 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6184 char* const req_addr = align_up(mapping1, alignment); 6185 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6186 if (p != NULL) { 6187 assert(p == req_addr, "must be"); 6188 small_page_write(p, size); 6189 os::Linux::release_memory_special_huge_tlbfs(p, size); 6190 } 6191 } 6192 } 6193 6194 // Case 3 6195 for (int i = 0; i < num_sizes; i++) { 6196 const size_t size = sizes[i]; 6197 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6198 char* const req_addr = align_up(mapping2, alignment); 6199 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6200 // as the area around req_addr contains already existing mappings, the API should always 6201 // return NULL (as per contract, it cannot return another address) 6202 assert(p == NULL, "must be"); 6203 } 6204 } 6205 6206 ::munmap(mapping2, mapping_size); 6207 6208 } 6209 6210 static void test_reserve_memory_special_huge_tlbfs() { 6211 if (!UseHugeTLBFS) { 6212 return; 6213 } 6214 6215 test_reserve_memory_special_huge_tlbfs_only(); 6216 test_reserve_memory_special_huge_tlbfs_mixed(); 6217 } 6218 6219 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6220 if (!UseSHM) { 6221 return; 6222 } 6223 6224 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6225 6226 if (addr != NULL) { 6227 assert(is_aligned(addr, alignment), "Check"); 6228 assert(is_aligned(addr, os::large_page_size()), "Check"); 6229 6230 small_page_write(addr, size); 6231 6232 os::Linux::release_memory_special_shm(addr, size); 6233 } 6234 } 6235 6236 static void test_reserve_memory_special_shm() { 6237 size_t lp = os::large_page_size(); 6238 size_t ag = os::vm_allocation_granularity(); 6239 6240 for (size_t size = ag; size < lp * 3; size += ag) { 6241 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6242 test_reserve_memory_special_shm(size, alignment); 6243 } 6244 } 6245 } 6246 6247 static void test() { 6248 test_reserve_memory_special_huge_tlbfs(); 6249 test_reserve_memory_special_shm(); 6250 } 6251 }; 6252 6253 void TestReserveMemorySpecial_test() { 6254 TestReserveMemorySpecial::test(); 6255 } 6256 6257 #endif