1 /* 2 * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 // no precompiled headers 26 #include "jvm.h" 27 #include "classfile/classLoader.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "code/icBuffer.hpp" 31 #include "code/vtableStubs.hpp" 32 #include "compiler/compileBroker.hpp" 33 #include "compiler/disassembler.hpp" 34 #include "interpreter/interpreter.hpp" 35 #include "logging/log.hpp" 36 #include "logging/logStream.hpp" 37 #include "memory/allocation.inline.hpp" 38 #include "memory/filemap.hpp" 39 #include "oops/oop.inline.hpp" 40 #include "os_linux.inline.hpp" 41 #include "os_posix.inline.hpp" 42 #include "os_share_linux.hpp" 43 #include "osContainer_linux.hpp" 44 #include "prims/jniFastGetField.hpp" 45 #include "prims/jvm_misc.hpp" 46 #include "runtime/arguments.hpp" 47 #include "runtime/atomic.hpp" 48 #include "runtime/extendedPC.hpp" 49 #include "runtime/globals.hpp" 50 #include "runtime/interfaceSupport.inline.hpp" 51 #include "runtime/init.hpp" 52 #include "runtime/java.hpp" 53 #include "runtime/javaCalls.hpp" 54 #include "runtime/mutexLocker.hpp" 55 #include "runtime/objectMonitor.hpp" 56 #include "runtime/osThread.hpp" 57 #include "runtime/perfMemory.hpp" 58 #include "runtime/sharedRuntime.hpp" 59 #include "runtime/statSampler.hpp" 60 #include "runtime/stubRoutines.hpp" 61 #include "runtime/thread.inline.hpp" 62 #include "runtime/threadCritical.hpp" 63 #include "runtime/threadSMR.hpp" 64 #include "runtime/timer.hpp" 65 #include "runtime/vm_version.hpp" 66 #include "semaphore_posix.hpp" 67 #include "services/attachListener.hpp" 68 #include "services/memTracker.hpp" 69 #include "services/runtimeService.hpp" 70 #include "utilities/align.hpp" 71 #include "utilities/decoder.hpp" 72 #include "utilities/defaultStream.hpp" 73 #include "utilities/events.hpp" 74 #include "utilities/elfFile.hpp" 75 #include "utilities/growableArray.hpp" 76 #include "utilities/macros.hpp" 77 #include "utilities/powerOfTwo.hpp" 78 #include "utilities/vmError.hpp" 79 80 // put OS-includes here 81 # include <sys/types.h> 82 # include <sys/mman.h> 83 # include <sys/stat.h> 84 # include <sys/select.h> 85 # include <pthread.h> 86 # include <signal.h> 87 # include <endian.h> 88 # include <errno.h> 89 # include <dlfcn.h> 90 # include <stdio.h> 91 # include <unistd.h> 92 # include <sys/resource.h> 93 # include <pthread.h> 94 # include <sys/stat.h> 95 # include <sys/time.h> 96 # include <sys/times.h> 97 # include <sys/utsname.h> 98 # include <sys/socket.h> 99 # include <sys/wait.h> 100 # include <pwd.h> 101 # include <poll.h> 102 # include <fcntl.h> 103 # include <string.h> 104 # include <syscall.h> 105 # include <sys/sysinfo.h> 106 # include <gnu/libc-version.h> 107 # include <sys/ipc.h> 108 # include <sys/shm.h> 109 # include <link.h> 110 # include <stdint.h> 111 # include <inttypes.h> 112 # include <sys/ioctl.h> 113 # include <linux/elf-em.h> 114 115 #ifndef _GNU_SOURCE 116 #define _GNU_SOURCE 117 #include <sched.h> 118 #undef _GNU_SOURCE 119 #else 120 #include <sched.h> 121 #endif 122 123 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 124 // getrusage() is prepared to handle the associated failure. 125 #ifndef RUSAGE_THREAD 126 #define RUSAGE_THREAD (1) /* only the calling thread */ 127 #endif 128 129 #define MAX_PATH (2 * K) 130 131 #define MAX_SECS 100000000 132 133 // for timer info max values which include all bits 134 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 135 136 enum CoredumpFilterBit { 137 FILE_BACKED_PVT_BIT = 1 << 2, 138 FILE_BACKED_SHARED_BIT = 1 << 3, 139 LARGEPAGES_BIT = 1 << 6, 140 DAX_SHARED_BIT = 1 << 8 141 }; 142 143 //////////////////////////////////////////////////////////////////////////////// 144 // global variables 145 julong os::Linux::_physical_memory = 0; 146 147 address os::Linux::_initial_thread_stack_bottom = NULL; 148 uintptr_t os::Linux::_initial_thread_stack_size = 0; 149 150 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 151 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 152 pthread_t os::Linux::_main_thread; 153 int os::Linux::_page_size = -1; 154 bool os::Linux::_supports_fast_thread_cpu_time = false; 155 const char * os::Linux::_glibc_version = NULL; 156 const char * os::Linux::_libpthread_version = NULL; 157 size_t os::Linux::_default_large_page_size = 0; 158 159 static jlong initial_time_count=0; 160 161 static int clock_tics_per_sec = 100; 162 163 // If the VM might have been created on the primordial thread, we need to resolve the 164 // primordial thread stack bounds and check if the current thread might be the 165 // primordial thread in places. If we know that the primordial thread is never used, 166 // such as when the VM was created by one of the standard java launchers, we can 167 // avoid this 168 static bool suppress_primordial_thread_resolution = false; 169 170 // For diagnostics to print a message once. see run_periodic_checks 171 static sigset_t check_signal_done; 172 static bool check_signals = true; 173 174 // Signal number used to suspend/resume a thread 175 176 // do not use any signal number less than SIGSEGV, see 4355769 177 static int SR_signum = SIGUSR2; 178 sigset_t SR_sigset; 179 180 // utility functions 181 182 static int SR_initialize(); 183 184 julong os::available_memory() { 185 return Linux::available_memory(); 186 } 187 188 julong os::Linux::available_memory() { 189 // values in struct sysinfo are "unsigned long" 190 struct sysinfo si; 191 julong avail_mem; 192 193 if (OSContainer::is_containerized()) { 194 jlong mem_limit, mem_usage; 195 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) { 196 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 197 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 198 } 199 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) { 200 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage); 201 } 202 if (mem_limit > 0 && mem_usage > 0 ) { 203 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0; 204 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem); 205 return avail_mem; 206 } 207 } 208 209 sysinfo(&si); 210 avail_mem = (julong)si.freeram * si.mem_unit; 211 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem); 212 return avail_mem; 213 } 214 215 julong os::physical_memory() { 216 jlong phys_mem = 0; 217 if (OSContainer::is_containerized()) { 218 jlong mem_limit; 219 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) { 220 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit); 221 return mem_limit; 222 } 223 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 224 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 225 } 226 227 phys_mem = Linux::physical_memory(); 228 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem); 229 return phys_mem; 230 } 231 232 static uint64_t initial_total_ticks = 0; 233 static uint64_t initial_steal_ticks = 0; 234 static bool has_initial_tick_info = false; 235 236 static void next_line(FILE *f) { 237 int c; 238 do { 239 c = fgetc(f); 240 } while (c != '\n' && c != EOF); 241 } 242 243 bool os::Linux::get_tick_information(CPUPerfTicks* pticks, int which_logical_cpu) { 244 FILE* fh; 245 uint64_t userTicks, niceTicks, systemTicks, idleTicks; 246 // since at least kernel 2.6 : iowait: time waiting for I/O to complete 247 // irq: time servicing interrupts; softirq: time servicing softirqs 248 uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0; 249 // steal (since kernel 2.6.11): time spent in other OS when running in a virtualized environment 250 uint64_t stealTicks = 0; 251 // guest (since kernel 2.6.24): time spent running a virtual CPU for guest OS under the 252 // control of the Linux kernel 253 uint64_t guestNiceTicks = 0; 254 int logical_cpu = -1; 255 const int required_tickinfo_count = (which_logical_cpu == -1) ? 4 : 5; 256 int n; 257 258 memset(pticks, 0, sizeof(CPUPerfTicks)); 259 260 if ((fh = fopen("/proc/stat", "r")) == NULL) { 261 return false; 262 } 263 264 if (which_logical_cpu == -1) { 265 n = fscanf(fh, "cpu " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 266 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 267 UINT64_FORMAT " " UINT64_FORMAT " ", 268 &userTicks, &niceTicks, &systemTicks, &idleTicks, 269 &iowTicks, &irqTicks, &sirqTicks, 270 &stealTicks, &guestNiceTicks); 271 } else { 272 // Move to next line 273 next_line(fh); 274 275 // find the line for requested cpu faster to just iterate linefeeds? 276 for (int i = 0; i < which_logical_cpu; i++) { 277 next_line(fh); 278 } 279 280 n = fscanf(fh, "cpu%u " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 281 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 282 UINT64_FORMAT " " UINT64_FORMAT " ", 283 &logical_cpu, &userTicks, &niceTicks, 284 &systemTicks, &idleTicks, &iowTicks, &irqTicks, &sirqTicks, 285 &stealTicks, &guestNiceTicks); 286 } 287 288 fclose(fh); 289 if (n < required_tickinfo_count || logical_cpu != which_logical_cpu) { 290 return false; 291 } 292 pticks->used = userTicks + niceTicks; 293 pticks->usedKernel = systemTicks + irqTicks + sirqTicks; 294 pticks->total = userTicks + niceTicks + systemTicks + idleTicks + 295 iowTicks + irqTicks + sirqTicks + stealTicks + guestNiceTicks; 296 297 if (n > required_tickinfo_count + 3) { 298 pticks->steal = stealTicks; 299 pticks->has_steal_ticks = true; 300 } else { 301 pticks->steal = 0; 302 pticks->has_steal_ticks = false; 303 } 304 305 return true; 306 } 307 308 // Return true if user is running as root. 309 310 bool os::have_special_privileges() { 311 static bool init = false; 312 static bool privileges = false; 313 if (!init) { 314 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 315 init = true; 316 } 317 return privileges; 318 } 319 320 321 #ifndef SYS_gettid 322 // i386: 224, ia64: 1105, amd64: 186, sparc 143 323 #ifdef __ia64__ 324 #define SYS_gettid 1105 325 #else 326 #ifdef __i386__ 327 #define SYS_gettid 224 328 #else 329 #ifdef __amd64__ 330 #define SYS_gettid 186 331 #else 332 #ifdef __sparc__ 333 #define SYS_gettid 143 334 #else 335 #error define gettid for the arch 336 #endif 337 #endif 338 #endif 339 #endif 340 #endif 341 342 343 // pid_t gettid() 344 // 345 // Returns the kernel thread id of the currently running thread. Kernel 346 // thread id is used to access /proc. 347 pid_t os::Linux::gettid() { 348 int rslt = syscall(SYS_gettid); 349 assert(rslt != -1, "must be."); // old linuxthreads implementation? 350 return (pid_t)rslt; 351 } 352 353 // Most versions of linux have a bug where the number of processors are 354 // determined by looking at the /proc file system. In a chroot environment, 355 // the system call returns 1. 356 static bool unsafe_chroot_detected = false; 357 static const char *unstable_chroot_error = "/proc file system not found.\n" 358 "Java may be unstable running multithreaded in a chroot " 359 "environment on Linux when /proc filesystem is not mounted."; 360 361 void os::Linux::initialize_system_info() { 362 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 363 if (processor_count() == 1) { 364 pid_t pid = os::Linux::gettid(); 365 char fname[32]; 366 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 367 FILE *fp = fopen(fname, "r"); 368 if (fp == NULL) { 369 unsafe_chroot_detected = true; 370 } else { 371 fclose(fp); 372 } 373 } 374 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 375 assert(processor_count() > 0, "linux error"); 376 } 377 378 void os::init_system_properties_values() { 379 // The next steps are taken in the product version: 380 // 381 // Obtain the JAVA_HOME value from the location of libjvm.so. 382 // This library should be located at: 383 // <JAVA_HOME>/lib/{client|server}/libjvm.so. 384 // 385 // If "/jre/lib/" appears at the right place in the path, then we 386 // assume libjvm.so is installed in a JDK and we use this path. 387 // 388 // Otherwise exit with message: "Could not create the Java virtual machine." 389 // 390 // The following extra steps are taken in the debugging version: 391 // 392 // If "/jre/lib/" does NOT appear at the right place in the path 393 // instead of exit check for $JAVA_HOME environment variable. 394 // 395 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 396 // then we append a fake suffix "hotspot/libjvm.so" to this path so 397 // it looks like libjvm.so is installed there 398 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 399 // 400 // Otherwise exit. 401 // 402 // Important note: if the location of libjvm.so changes this 403 // code needs to be changed accordingly. 404 405 // See ld(1): 406 // The linker uses the following search paths to locate required 407 // shared libraries: 408 // 1: ... 409 // ... 410 // 7: The default directories, normally /lib and /usr/lib. 411 #ifndef OVERRIDE_LIBPATH 412 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390) 413 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 414 #else 415 #define DEFAULT_LIBPATH "/lib:/usr/lib" 416 #endif 417 #else 418 #define DEFAULT_LIBPATH OVERRIDE_LIBPATH 419 #endif 420 421 // Base path of extensions installed on the system. 422 #define SYS_EXT_DIR "/usr/java/packages" 423 #define EXTENSIONS_DIR "/lib/ext" 424 425 // Buffer that fits several sprintfs. 426 // Note that the space for the colon and the trailing null are provided 427 // by the nulls included by the sizeof operator. 428 const size_t bufsize = 429 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 430 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 431 char *buf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 432 433 // sysclasspath, java_home, dll_dir 434 { 435 char *pslash; 436 os::jvm_path(buf, bufsize); 437 438 // Found the full path to libjvm.so. 439 // Now cut the path to <java_home>/jre if we can. 440 pslash = strrchr(buf, '/'); 441 if (pslash != NULL) { 442 *pslash = '\0'; // Get rid of /libjvm.so. 443 } 444 pslash = strrchr(buf, '/'); 445 if (pslash != NULL) { 446 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 447 } 448 Arguments::set_dll_dir(buf); 449 450 if (pslash != NULL) { 451 pslash = strrchr(buf, '/'); 452 if (pslash != NULL) { 453 *pslash = '\0'; // Get rid of /lib. 454 } 455 } 456 Arguments::set_java_home(buf); 457 if (!set_boot_path('/', ':')) { 458 vm_exit_during_initialization("Failed setting boot class path.", NULL); 459 } 460 } 461 462 // Where to look for native libraries. 463 // 464 // Note: Due to a legacy implementation, most of the library path 465 // is set in the launcher. This was to accomodate linking restrictions 466 // on legacy Linux implementations (which are no longer supported). 467 // Eventually, all the library path setting will be done here. 468 // 469 // However, to prevent the proliferation of improperly built native 470 // libraries, the new path component /usr/java/packages is added here. 471 // Eventually, all the library path setting will be done here. 472 { 473 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 474 // should always exist (until the legacy problem cited above is 475 // addressed). 476 const char *v = ::getenv("LD_LIBRARY_PATH"); 477 const char *v_colon = ":"; 478 if (v == NULL) { v = ""; v_colon = ""; } 479 // That's +1 for the colon and +1 for the trailing '\0'. 480 char *ld_library_path = NEW_C_HEAP_ARRAY(char, 481 strlen(v) + 1 + 482 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1, 483 mtInternal); 484 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon); 485 Arguments::set_library_path(ld_library_path); 486 FREE_C_HEAP_ARRAY(char, ld_library_path); 487 } 488 489 // Extensions directories. 490 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 491 Arguments::set_ext_dirs(buf); 492 493 FREE_C_HEAP_ARRAY(char, buf); 494 495 #undef DEFAULT_LIBPATH 496 #undef SYS_EXT_DIR 497 #undef EXTENSIONS_DIR 498 } 499 500 //////////////////////////////////////////////////////////////////////////////// 501 // breakpoint support 502 503 void os::breakpoint() { 504 BREAKPOINT; 505 } 506 507 extern "C" void breakpoint() { 508 // use debugger to set breakpoint here 509 } 510 511 //////////////////////////////////////////////////////////////////////////////// 512 // signal support 513 514 debug_only(static bool signal_sets_initialized = false); 515 static sigset_t unblocked_sigs, vm_sigs; 516 517 void os::Linux::signal_sets_init() { 518 // Should also have an assertion stating we are still single-threaded. 519 assert(!signal_sets_initialized, "Already initialized"); 520 // Fill in signals that are necessarily unblocked for all threads in 521 // the VM. Currently, we unblock the following signals: 522 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 523 // by -Xrs (=ReduceSignalUsage)); 524 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 525 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 526 // the dispositions or masks wrt these signals. 527 // Programs embedding the VM that want to use the above signals for their 528 // own purposes must, at this time, use the "-Xrs" option to prevent 529 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 530 // (See bug 4345157, and other related bugs). 531 // In reality, though, unblocking these signals is really a nop, since 532 // these signals are not blocked by default. 533 sigemptyset(&unblocked_sigs); 534 sigaddset(&unblocked_sigs, SIGILL); 535 sigaddset(&unblocked_sigs, SIGSEGV); 536 sigaddset(&unblocked_sigs, SIGBUS); 537 sigaddset(&unblocked_sigs, SIGFPE); 538 #if defined(PPC64) 539 sigaddset(&unblocked_sigs, SIGTRAP); 540 #endif 541 sigaddset(&unblocked_sigs, SR_signum); 542 543 if (!ReduceSignalUsage) { 544 if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 545 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 546 } 547 if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 548 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 549 } 550 if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 551 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 552 } 553 } 554 // Fill in signals that are blocked by all but the VM thread. 555 sigemptyset(&vm_sigs); 556 if (!ReduceSignalUsage) { 557 sigaddset(&vm_sigs, BREAK_SIGNAL); 558 } 559 debug_only(signal_sets_initialized = true); 560 561 } 562 563 // These are signals that are unblocked while a thread is running Java. 564 // (For some reason, they get blocked by default.) 565 sigset_t* os::Linux::unblocked_signals() { 566 assert(signal_sets_initialized, "Not initialized"); 567 return &unblocked_sigs; 568 } 569 570 // These are the signals that are blocked while a (non-VM) thread is 571 // running Java. Only the VM thread handles these signals. 572 sigset_t* os::Linux::vm_signals() { 573 assert(signal_sets_initialized, "Not initialized"); 574 return &vm_sigs; 575 } 576 577 void os::Linux::hotspot_sigmask(Thread* thread) { 578 579 //Save caller's signal mask before setting VM signal mask 580 sigset_t caller_sigmask; 581 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 582 583 OSThread* osthread = thread->osthread(); 584 osthread->set_caller_sigmask(caller_sigmask); 585 586 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 587 588 if (!ReduceSignalUsage) { 589 if (thread->is_VM_thread()) { 590 // Only the VM thread handles BREAK_SIGNAL ... 591 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 592 } else { 593 // ... all other threads block BREAK_SIGNAL 594 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 595 } 596 } 597 } 598 599 ////////////////////////////////////////////////////////////////////////////// 600 // detecting pthread library 601 602 void os::Linux::libpthread_init() { 603 // Save glibc and pthread version strings. 604 #if !defined(_CS_GNU_LIBC_VERSION) || \ 605 !defined(_CS_GNU_LIBPTHREAD_VERSION) 606 #error "glibc too old (< 2.3.2)" 607 #endif 608 609 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 610 assert(n > 0, "cannot retrieve glibc version"); 611 char *str = (char *)malloc(n, mtInternal); 612 confstr(_CS_GNU_LIBC_VERSION, str, n); 613 os::Linux::set_glibc_version(str); 614 615 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 616 assert(n > 0, "cannot retrieve pthread version"); 617 str = (char *)malloc(n, mtInternal); 618 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 619 os::Linux::set_libpthread_version(str); 620 } 621 622 ///////////////////////////////////////////////////////////////////////////// 623 // thread stack expansion 624 625 // os::Linux::manually_expand_stack() takes care of expanding the thread 626 // stack. Note that this is normally not needed: pthread stacks allocate 627 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 628 // committed. Therefore it is not necessary to expand the stack manually. 629 // 630 // Manually expanding the stack was historically needed on LinuxThreads 631 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 632 // it is kept to deal with very rare corner cases: 633 // 634 // For one, user may run the VM on an own implementation of threads 635 // whose stacks are - like the old LinuxThreads - implemented using 636 // mmap(MAP_GROWSDOWN). 637 // 638 // Also, this coding may be needed if the VM is running on the primordial 639 // thread. Normally we avoid running on the primordial thread; however, 640 // user may still invoke the VM on the primordial thread. 641 // 642 // The following historical comment describes the details about running 643 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 644 645 646 // Force Linux kernel to expand current thread stack. If "bottom" is close 647 // to the stack guard, caller should block all signals. 648 // 649 // MAP_GROWSDOWN: 650 // A special mmap() flag that is used to implement thread stacks. It tells 651 // kernel that the memory region should extend downwards when needed. This 652 // allows early versions of LinuxThreads to only mmap the first few pages 653 // when creating a new thread. Linux kernel will automatically expand thread 654 // stack as needed (on page faults). 655 // 656 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 657 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 658 // region, it's hard to tell if the fault is due to a legitimate stack 659 // access or because of reading/writing non-exist memory (e.g. buffer 660 // overrun). As a rule, if the fault happens below current stack pointer, 661 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 662 // application (see Linux kernel fault.c). 663 // 664 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 665 // stack overflow detection. 666 // 667 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 668 // not use MAP_GROWSDOWN. 669 // 670 // To get around the problem and allow stack banging on Linux, we need to 671 // manually expand thread stack after receiving the SIGSEGV. 672 // 673 // There are two ways to expand thread stack to address "bottom", we used 674 // both of them in JVM before 1.5: 675 // 1. adjust stack pointer first so that it is below "bottom", and then 676 // touch "bottom" 677 // 2. mmap() the page in question 678 // 679 // Now alternate signal stack is gone, it's harder to use 2. For instance, 680 // if current sp is already near the lower end of page 101, and we need to 681 // call mmap() to map page 100, it is possible that part of the mmap() frame 682 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 683 // That will destroy the mmap() frame and cause VM to crash. 684 // 685 // The following code works by adjusting sp first, then accessing the "bottom" 686 // page to force a page fault. Linux kernel will then automatically expand the 687 // stack mapping. 688 // 689 // _expand_stack_to() assumes its frame size is less than page size, which 690 // should always be true if the function is not inlined. 691 692 static void NOINLINE _expand_stack_to(address bottom) { 693 address sp; 694 size_t size; 695 volatile char *p; 696 697 // Adjust bottom to point to the largest address within the same page, it 698 // gives us a one-page buffer if alloca() allocates slightly more memory. 699 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size()); 700 bottom += os::Linux::page_size() - 1; 701 702 // sp might be slightly above current stack pointer; if that's the case, we 703 // will alloca() a little more space than necessary, which is OK. Don't use 704 // os::current_stack_pointer(), as its result can be slightly below current 705 // stack pointer, causing us to not alloca enough to reach "bottom". 706 sp = (address)&sp; 707 708 if (sp > bottom) { 709 size = sp - bottom; 710 p = (volatile char *)alloca(size); 711 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 712 p[0] = '\0'; 713 } 714 } 715 716 void os::Linux::expand_stack_to(address bottom) { 717 _expand_stack_to(bottom); 718 } 719 720 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 721 assert(t!=NULL, "just checking"); 722 assert(t->osthread()->expanding_stack(), "expand should be set"); 723 724 if (t->is_in_usable_stack(addr)) { 725 sigset_t mask_all, old_sigset; 726 sigfillset(&mask_all); 727 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 728 _expand_stack_to(addr); 729 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 730 return true; 731 } 732 return false; 733 } 734 735 ////////////////////////////////////////////////////////////////////////////// 736 // create new thread 737 738 // Thread start routine for all newly created threads 739 static void *thread_native_entry(Thread *thread) { 740 741 thread->record_stack_base_and_size(); 742 743 // Try to randomize the cache line index of hot stack frames. 744 // This helps when threads of the same stack traces evict each other's 745 // cache lines. The threads can be either from the same JVM instance, or 746 // from different JVM instances. The benefit is especially true for 747 // processors with hyperthreading technology. 748 static int counter = 0; 749 int pid = os::current_process_id(); 750 alloca(((pid ^ counter++) & 7) * 128); 751 752 thread->initialize_thread_current(); 753 754 OSThread* osthread = thread->osthread(); 755 Monitor* sync = osthread->startThread_lock(); 756 757 osthread->set_thread_id(os::current_thread_id()); 758 759 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 760 os::current_thread_id(), (uintx) pthread_self()); 761 762 if (UseNUMA) { 763 int lgrp_id = os::numa_get_group_id(); 764 if (lgrp_id != -1) { 765 thread->set_lgrp_id(lgrp_id); 766 } 767 } 768 // initialize signal mask for this thread 769 os::Linux::hotspot_sigmask(thread); 770 771 // initialize floating point control register 772 os::Linux::init_thread_fpu_state(); 773 774 // handshaking with parent thread 775 { 776 MutexLocker ml(sync, Mutex::_no_safepoint_check_flag); 777 778 // notify parent thread 779 osthread->set_state(INITIALIZED); 780 sync->notify_all(); 781 782 // wait until os::start_thread() 783 while (osthread->get_state() == INITIALIZED) { 784 sync->wait_without_safepoint_check(); 785 } 786 } 787 788 assert(osthread->pthread_id() != 0, "pthread_id was not set as expected"); 789 790 // call one more level start routine 791 thread->call_run(); 792 793 // Note: at this point the thread object may already have deleted itself. 794 // Prevent dereferencing it from here on out. 795 thread = NULL; 796 797 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 798 os::current_thread_id(), (uintx) pthread_self()); 799 800 return 0; 801 } 802 803 // On Linux, glibc places static TLS blocks (for __thread variables) on 804 // the thread stack. This decreases the stack size actually available 805 // to threads. 806 // 807 // For large static TLS sizes, this may cause threads to malfunction due 808 // to insufficient stack space. This is a well-known issue in glibc: 809 // http://sourceware.org/bugzilla/show_bug.cgi?id=11787. 810 // 811 // As a workaround, we call a private but assumed-stable glibc function, 812 // __pthread_get_minstack() to obtain the minstack size and derive the 813 // static TLS size from it. We then increase the user requested stack 814 // size by this TLS size. 815 // 816 // Due to compatibility concerns, this size adjustment is opt-in and 817 // controlled via AdjustStackSizeForTLS. 818 typedef size_t (*GetMinStack)(const pthread_attr_t *attr); 819 820 GetMinStack _get_minstack_func = NULL; 821 822 static void get_minstack_init() { 823 _get_minstack_func = 824 (GetMinStack)dlsym(RTLD_DEFAULT, "__pthread_get_minstack"); 825 log_info(os, thread)("Lookup of __pthread_get_minstack %s", 826 _get_minstack_func == NULL ? "failed" : "succeeded"); 827 } 828 829 // Returns the size of the static TLS area glibc puts on thread stacks. 830 // The value is cached on first use, which occurs when the first thread 831 // is created during VM initialization. 832 static size_t get_static_tls_area_size(const pthread_attr_t *attr) { 833 size_t tls_size = 0; 834 if (_get_minstack_func != NULL) { 835 // Obtain the pthread minstack size by calling __pthread_get_minstack. 836 size_t minstack_size = _get_minstack_func(attr); 837 838 // Remove non-TLS area size included in minstack size returned 839 // by __pthread_get_minstack() to get the static TLS size. 840 // In glibc before 2.27, minstack size includes guard_size. 841 // In glibc 2.27 and later, guard_size is automatically added 842 // to the stack size by pthread_create and is no longer included 843 // in minstack size. In both cases, the guard_size is taken into 844 // account, so there is no need to adjust the result for that. 845 // 846 // Although __pthread_get_minstack() is a private glibc function, 847 // it is expected to have a stable behavior across future glibc 848 // versions while glibc still allocates the static TLS blocks off 849 // the stack. Following is glibc 2.28 __pthread_get_minstack(): 850 // 851 // size_t 852 // __pthread_get_minstack (const pthread_attr_t *attr) 853 // { 854 // return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN; 855 // } 856 // 857 // 858 // The following 'minstack_size > os::vm_page_size() + PTHREAD_STACK_MIN' 859 // if check is done for precaution. 860 if (minstack_size > (size_t)os::vm_page_size() + PTHREAD_STACK_MIN) { 861 tls_size = minstack_size - os::vm_page_size() - PTHREAD_STACK_MIN; 862 } 863 } 864 865 log_info(os, thread)("Stack size adjustment for TLS is " SIZE_FORMAT, 866 tls_size); 867 return tls_size; 868 } 869 870 bool os::create_thread(Thread* thread, ThreadType thr_type, 871 size_t req_stack_size) { 872 assert(thread->osthread() == NULL, "caller responsible"); 873 874 // Allocate the OSThread object 875 OSThread* osthread = new OSThread(NULL, NULL); 876 if (osthread == NULL) { 877 return false; 878 } 879 880 // set the correct thread state 881 osthread->set_thread_type(thr_type); 882 883 // Initial state is ALLOCATED but not INITIALIZED 884 osthread->set_state(ALLOCATED); 885 886 thread->set_osthread(osthread); 887 888 // init thread attributes 889 pthread_attr_t attr; 890 pthread_attr_init(&attr); 891 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 892 893 // Calculate stack size if it's not specified by caller. 894 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size); 895 // In glibc versions prior to 2.7 the guard size mechanism 896 // is not implemented properly. The posix standard requires adding 897 // the size of the guard pages to the stack size, instead Linux 898 // takes the space out of 'stacksize'. Thus we adapt the requested 899 // stack_size by the size of the guard pages to mimick proper 900 // behaviour. However, be careful not to end up with a size 901 // of zero due to overflow. Don't add the guard page in that case. 902 size_t guard_size = os::Linux::default_guard_size(thr_type); 903 // Configure glibc guard page. Must happen before calling 904 // get_static_tls_area_size(), which uses the guard_size. 905 pthread_attr_setguardsize(&attr, guard_size); 906 907 size_t stack_adjust_size = 0; 908 if (AdjustStackSizeForTLS) { 909 // Adjust the stack_size for on-stack TLS - see get_static_tls_area_size(). 910 stack_adjust_size += get_static_tls_area_size(&attr); 911 } else { 912 stack_adjust_size += guard_size; 913 } 914 915 stack_adjust_size = align_up(stack_adjust_size, os::vm_page_size()); 916 if (stack_size <= SIZE_MAX - stack_adjust_size) { 917 stack_size += stack_adjust_size; 918 } 919 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned"); 920 921 int status = pthread_attr_setstacksize(&attr, stack_size); 922 assert_status(status == 0, status, "pthread_attr_setstacksize"); 923 924 ThreadState state; 925 926 { 927 pthread_t tid; 928 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread); 929 930 char buf[64]; 931 if (ret == 0) { 932 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 933 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 934 } else { 935 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 936 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 937 // Log some OS information which might explain why creating the thread failed. 938 log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads()); 939 LogStream st(Log(os, thread)::info()); 940 os::Posix::print_rlimit_info(&st); 941 os::print_memory_info(&st); 942 os::Linux::print_proc_sys_info(&st); 943 os::Linux::print_container_info(&st); 944 } 945 946 pthread_attr_destroy(&attr); 947 948 if (ret != 0) { 949 // Need to clean up stuff we've allocated so far 950 thread->set_osthread(NULL); 951 delete osthread; 952 return false; 953 } 954 955 // Store pthread info into the OSThread 956 osthread->set_pthread_id(tid); 957 958 // Wait until child thread is either initialized or aborted 959 { 960 Monitor* sync_with_child = osthread->startThread_lock(); 961 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag); 962 while ((state = osthread->get_state()) == ALLOCATED) { 963 sync_with_child->wait_without_safepoint_check(); 964 } 965 } 966 } 967 968 // Aborted due to thread limit being reached 969 if (state == ZOMBIE) { 970 thread->set_osthread(NULL); 971 delete osthread; 972 return false; 973 } 974 975 // The thread is returned suspended (in state INITIALIZED), 976 // and is started higher up in the call chain 977 assert(state == INITIALIZED, "race condition"); 978 return true; 979 } 980 981 ///////////////////////////////////////////////////////////////////////////// 982 // attach existing thread 983 984 // bootstrap the main thread 985 bool os::create_main_thread(JavaThread* thread) { 986 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 987 return create_attached_thread(thread); 988 } 989 990 bool os::create_attached_thread(JavaThread* thread) { 991 #ifdef ASSERT 992 thread->verify_not_published(); 993 #endif 994 995 // Allocate the OSThread object 996 OSThread* osthread = new OSThread(NULL, NULL); 997 998 if (osthread == NULL) { 999 return false; 1000 } 1001 1002 // Store pthread info into the OSThread 1003 osthread->set_thread_id(os::Linux::gettid()); 1004 osthread->set_pthread_id(::pthread_self()); 1005 1006 // initialize floating point control register 1007 os::Linux::init_thread_fpu_state(); 1008 1009 // Initial thread state is RUNNABLE 1010 osthread->set_state(RUNNABLE); 1011 1012 thread->set_osthread(osthread); 1013 1014 if (UseNUMA) { 1015 int lgrp_id = os::numa_get_group_id(); 1016 if (lgrp_id != -1) { 1017 thread->set_lgrp_id(lgrp_id); 1018 } 1019 } 1020 1021 if (os::is_primordial_thread()) { 1022 // If current thread is primordial thread, its stack is mapped on demand, 1023 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 1024 // the entire stack region to avoid SEGV in stack banging. 1025 // It is also useful to get around the heap-stack-gap problem on SuSE 1026 // kernel (see 4821821 for details). We first expand stack to the top 1027 // of yellow zone, then enable stack yellow zone (order is significant, 1028 // enabling yellow zone first will crash JVM on SuSE Linux), so there 1029 // is no gap between the last two virtual memory regions. 1030 1031 JavaThread *jt = (JavaThread *)thread; 1032 address addr = jt->stack_reserved_zone_base(); 1033 assert(addr != NULL, "initialization problem?"); 1034 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 1035 1036 osthread->set_expanding_stack(); 1037 os::Linux::manually_expand_stack(jt, addr); 1038 osthread->clear_expanding_stack(); 1039 } 1040 1041 // initialize signal mask for this thread 1042 // and save the caller's signal mask 1043 os::Linux::hotspot_sigmask(thread); 1044 1045 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 1046 os::current_thread_id(), (uintx) pthread_self()); 1047 1048 return true; 1049 } 1050 1051 void os::pd_start_thread(Thread* thread) { 1052 OSThread * osthread = thread->osthread(); 1053 assert(osthread->get_state() != INITIALIZED, "just checking"); 1054 Monitor* sync_with_child = osthread->startThread_lock(); 1055 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag); 1056 sync_with_child->notify(); 1057 } 1058 1059 // Free Linux resources related to the OSThread 1060 void os::free_thread(OSThread* osthread) { 1061 assert(osthread != NULL, "osthread not set"); 1062 1063 // We are told to free resources of the argument thread, 1064 // but we can only really operate on the current thread. 1065 assert(Thread::current()->osthread() == osthread, 1066 "os::free_thread but not current thread"); 1067 1068 #ifdef ASSERT 1069 sigset_t current; 1070 sigemptyset(¤t); 1071 pthread_sigmask(SIG_SETMASK, NULL, ¤t); 1072 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!"); 1073 #endif 1074 1075 // Restore caller's signal mask 1076 sigset_t sigmask = osthread->caller_sigmask(); 1077 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1078 1079 delete osthread; 1080 } 1081 1082 ////////////////////////////////////////////////////////////////////////////// 1083 // primordial thread 1084 1085 // Check if current thread is the primordial thread, similar to Solaris thr_main. 1086 bool os::is_primordial_thread(void) { 1087 if (suppress_primordial_thread_resolution) { 1088 return false; 1089 } 1090 char dummy; 1091 // If called before init complete, thread stack bottom will be null. 1092 // Can be called if fatal error occurs before initialization. 1093 if (os::Linux::initial_thread_stack_bottom() == NULL) return false; 1094 assert(os::Linux::initial_thread_stack_bottom() != NULL && 1095 os::Linux::initial_thread_stack_size() != 0, 1096 "os::init did not locate primordial thread's stack region"); 1097 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() && 1098 (address)&dummy < os::Linux::initial_thread_stack_bottom() + 1099 os::Linux::initial_thread_stack_size()) { 1100 return true; 1101 } else { 1102 return false; 1103 } 1104 } 1105 1106 // Find the virtual memory area that contains addr 1107 static bool find_vma(address addr, address* vma_low, address* vma_high) { 1108 FILE *fp = fopen("/proc/self/maps", "r"); 1109 if (fp) { 1110 address low, high; 1111 while (!feof(fp)) { 1112 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1113 if (low <= addr && addr < high) { 1114 if (vma_low) *vma_low = low; 1115 if (vma_high) *vma_high = high; 1116 fclose(fp); 1117 return true; 1118 } 1119 } 1120 for (;;) { 1121 int ch = fgetc(fp); 1122 if (ch == EOF || ch == (int)'\n') break; 1123 } 1124 } 1125 fclose(fp); 1126 } 1127 return false; 1128 } 1129 1130 // Locate primordial thread stack. This special handling of primordial thread stack 1131 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 1132 // bogus value for the primordial process thread. While the launcher has created 1133 // the VM in a new thread since JDK 6, we still have to allow for the use of the 1134 // JNI invocation API from a primordial thread. 1135 void os::Linux::capture_initial_stack(size_t max_size) { 1136 1137 // max_size is either 0 (which means accept OS default for thread stacks) or 1138 // a user-specified value known to be at least the minimum needed. If we 1139 // are actually on the primordial thread we can make it appear that we have a 1140 // smaller max_size stack by inserting the guard pages at that location. But we 1141 // cannot do anything to emulate a larger stack than what has been provided by 1142 // the OS or threading library. In fact if we try to use a stack greater than 1143 // what is set by rlimit then we will crash the hosting process. 1144 1145 // Maximum stack size is the easy part, get it from RLIMIT_STACK. 1146 // If this is "unlimited" then it will be a huge value. 1147 struct rlimit rlim; 1148 getrlimit(RLIMIT_STACK, &rlim); 1149 size_t stack_size = rlim.rlim_cur; 1150 1151 // 6308388: a bug in ld.so will relocate its own .data section to the 1152 // lower end of primordial stack; reduce ulimit -s value a little bit 1153 // so we won't install guard page on ld.so's data section. 1154 // But ensure we don't underflow the stack size - allow 1 page spare 1155 if (stack_size >= (size_t)(3 * page_size())) { 1156 stack_size -= 2 * page_size(); 1157 } 1158 1159 // Try to figure out where the stack base (top) is. This is harder. 1160 // 1161 // When an application is started, glibc saves the initial stack pointer in 1162 // a global variable "__libc_stack_end", which is then used by system 1163 // libraries. __libc_stack_end should be pretty close to stack top. The 1164 // variable is available since the very early days. However, because it is 1165 // a private interface, it could disappear in the future. 1166 // 1167 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1168 // to __libc_stack_end, it is very close to stack top, but isn't the real 1169 // stack top. Note that /proc may not exist if VM is running as a chroot 1170 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1171 // /proc/<pid>/stat could change in the future (though unlikely). 1172 // 1173 // We try __libc_stack_end first. If that doesn't work, look for 1174 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1175 // as a hint, which should work well in most cases. 1176 1177 uintptr_t stack_start; 1178 1179 // try __libc_stack_end first 1180 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1181 if (p && *p) { 1182 stack_start = *p; 1183 } else { 1184 // see if we can get the start_stack field from /proc/self/stat 1185 FILE *fp; 1186 int pid; 1187 char state; 1188 int ppid; 1189 int pgrp; 1190 int session; 1191 int nr; 1192 int tpgrp; 1193 unsigned long flags; 1194 unsigned long minflt; 1195 unsigned long cminflt; 1196 unsigned long majflt; 1197 unsigned long cmajflt; 1198 unsigned long utime; 1199 unsigned long stime; 1200 long cutime; 1201 long cstime; 1202 long prio; 1203 long nice; 1204 long junk; 1205 long it_real; 1206 uintptr_t start; 1207 uintptr_t vsize; 1208 intptr_t rss; 1209 uintptr_t rsslim; 1210 uintptr_t scodes; 1211 uintptr_t ecode; 1212 int i; 1213 1214 // Figure what the primordial thread stack base is. Code is inspired 1215 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1216 // followed by command name surrounded by parentheses, state, etc. 1217 char stat[2048]; 1218 int statlen; 1219 1220 fp = fopen("/proc/self/stat", "r"); 1221 if (fp) { 1222 statlen = fread(stat, 1, 2047, fp); 1223 stat[statlen] = '\0'; 1224 fclose(fp); 1225 1226 // Skip pid and the command string. Note that we could be dealing with 1227 // weird command names, e.g. user could decide to rename java launcher 1228 // to "java 1.4.2 :)", then the stat file would look like 1229 // 1234 (java 1.4.2 :)) R ... ... 1230 // We don't really need to know the command string, just find the last 1231 // occurrence of ")" and then start parsing from there. See bug 4726580. 1232 char * s = strrchr(stat, ')'); 1233 1234 i = 0; 1235 if (s) { 1236 // Skip blank chars 1237 do { s++; } while (s && isspace(*s)); 1238 1239 #define _UFM UINTX_FORMAT 1240 #define _DFM INTX_FORMAT 1241 1242 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1243 // 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 1244 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM, 1245 &state, // 3 %c 1246 &ppid, // 4 %d 1247 &pgrp, // 5 %d 1248 &session, // 6 %d 1249 &nr, // 7 %d 1250 &tpgrp, // 8 %d 1251 &flags, // 9 %lu 1252 &minflt, // 10 %lu 1253 &cminflt, // 11 %lu 1254 &majflt, // 12 %lu 1255 &cmajflt, // 13 %lu 1256 &utime, // 14 %lu 1257 &stime, // 15 %lu 1258 &cutime, // 16 %ld 1259 &cstime, // 17 %ld 1260 &prio, // 18 %ld 1261 &nice, // 19 %ld 1262 &junk, // 20 %ld 1263 &it_real, // 21 %ld 1264 &start, // 22 UINTX_FORMAT 1265 &vsize, // 23 UINTX_FORMAT 1266 &rss, // 24 INTX_FORMAT 1267 &rsslim, // 25 UINTX_FORMAT 1268 &scodes, // 26 UINTX_FORMAT 1269 &ecode, // 27 UINTX_FORMAT 1270 &stack_start); // 28 UINTX_FORMAT 1271 } 1272 1273 #undef _UFM 1274 #undef _DFM 1275 1276 if (i != 28 - 2) { 1277 assert(false, "Bad conversion from /proc/self/stat"); 1278 // product mode - assume we are the primordial thread, good luck in the 1279 // embedded case. 1280 warning("Can't detect primordial thread stack location - bad conversion"); 1281 stack_start = (uintptr_t) &rlim; 1282 } 1283 } else { 1284 // For some reason we can't open /proc/self/stat (for example, running on 1285 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1286 // most cases, so don't abort: 1287 warning("Can't detect primordial thread stack location - no /proc/self/stat"); 1288 stack_start = (uintptr_t) &rlim; 1289 } 1290 } 1291 1292 // Now we have a pointer (stack_start) very close to the stack top, the 1293 // next thing to do is to figure out the exact location of stack top. We 1294 // can find out the virtual memory area that contains stack_start by 1295 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1296 // and its upper limit is the real stack top. (again, this would fail if 1297 // running inside chroot, because /proc may not exist.) 1298 1299 uintptr_t stack_top; 1300 address low, high; 1301 if (find_vma((address)stack_start, &low, &high)) { 1302 // success, "high" is the true stack top. (ignore "low", because initial 1303 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1304 stack_top = (uintptr_t)high; 1305 } else { 1306 // failed, likely because /proc/self/maps does not exist 1307 warning("Can't detect primordial thread stack location - find_vma failed"); 1308 // best effort: stack_start is normally within a few pages below the real 1309 // stack top, use it as stack top, and reduce stack size so we won't put 1310 // guard page outside stack. 1311 stack_top = stack_start; 1312 stack_size -= 16 * page_size(); 1313 } 1314 1315 // stack_top could be partially down the page so align it 1316 stack_top = align_up(stack_top, page_size()); 1317 1318 // Allowed stack value is minimum of max_size and what we derived from rlimit 1319 if (max_size > 0) { 1320 _initial_thread_stack_size = MIN2(max_size, stack_size); 1321 } else { 1322 // Accept the rlimit max, but if stack is unlimited then it will be huge, so 1323 // clamp it at 8MB as we do on Solaris 1324 _initial_thread_stack_size = MIN2(stack_size, 8*M); 1325 } 1326 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size()); 1327 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1328 1329 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!"); 1330 1331 if (log_is_enabled(Info, os, thread)) { 1332 // See if we seem to be on primordial process thread 1333 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) && 1334 uintptr_t(&rlim) < stack_top; 1335 1336 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: " 1337 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT, 1338 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K, 1339 stack_top, intptr_t(_initial_thread_stack_bottom)); 1340 } 1341 } 1342 1343 //////////////////////////////////////////////////////////////////////////////// 1344 // time support 1345 1346 #ifndef SUPPORTS_CLOCK_MONOTONIC 1347 #error "Build platform doesn't support clock_gettime and related functionality" 1348 #endif 1349 1350 // Time since start-up in seconds to a fine granularity. 1351 // Used by VMSelfDestructTimer and the MemProfiler. 1352 double os::elapsedTime() { 1353 1354 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1355 } 1356 1357 jlong os::elapsed_counter() { 1358 return javaTimeNanos() - initial_time_count; 1359 } 1360 1361 jlong os::elapsed_frequency() { 1362 return NANOSECS_PER_SEC; // nanosecond resolution 1363 } 1364 1365 bool os::supports_vtime() { return true; } 1366 1367 double os::elapsedVTime() { 1368 struct rusage usage; 1369 int retval = getrusage(RUSAGE_THREAD, &usage); 1370 if (retval == 0) { 1371 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000); 1372 } else { 1373 // better than nothing, but not much 1374 return elapsedTime(); 1375 } 1376 } 1377 1378 jlong os::javaTimeMillis() { 1379 if (os::Posix::supports_clock_gettime()) { 1380 struct timespec ts; 1381 int status = os::Posix::clock_gettime(CLOCK_REALTIME, &ts); 1382 assert_status(status == 0, status, "gettime error"); 1383 return jlong(ts.tv_sec) * MILLIUNITS + 1384 jlong(ts.tv_nsec) / NANOUNITS_PER_MILLIUNIT; 1385 } else { 1386 timeval time; 1387 int status = gettimeofday(&time, NULL); 1388 assert(status != -1, "linux error"); 1389 return jlong(time.tv_sec) * MILLIUNITS + 1390 jlong(time.tv_usec) / (MICROUNITS / MILLIUNITS); 1391 } 1392 } 1393 1394 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1395 if (os::Posix::supports_clock_gettime()) { 1396 struct timespec ts; 1397 int status = os::Posix::clock_gettime(CLOCK_REALTIME, &ts); 1398 assert_status(status == 0, status, "gettime error"); 1399 seconds = jlong(ts.tv_sec); 1400 nanos = jlong(ts.tv_nsec); 1401 } else { 1402 timeval time; 1403 int status = gettimeofday(&time, NULL); 1404 assert(status != -1, "linux error"); 1405 seconds = jlong(time.tv_sec); 1406 nanos = jlong(time.tv_usec) * (NANOUNITS / MICROUNITS); 1407 } 1408 } 1409 1410 void os::Linux::fast_thread_clock_init() { 1411 if (!UseLinuxPosixThreadCPUClocks) { 1412 return; 1413 } 1414 clockid_t clockid; 1415 struct timespec tp; 1416 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1417 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1418 1419 // Switch to using fast clocks for thread cpu time if 1420 // the clock_getres() returns 0 error code. 1421 // Note, that some kernels may support the current thread 1422 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1423 // returned by the pthread_getcpuclockid(). 1424 // If the fast Posix clocks are supported then the clock_getres() 1425 // must return at least tp.tv_sec == 0 which means a resolution 1426 // better than 1 sec. This is extra check for reliability. 1427 1428 if (pthread_getcpuclockid_func && 1429 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1430 os::Posix::clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1431 _supports_fast_thread_cpu_time = true; 1432 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1433 } 1434 } 1435 1436 jlong os::javaTimeNanos() { 1437 if (os::supports_monotonic_clock()) { 1438 struct timespec tp; 1439 int status = os::Posix::clock_gettime(CLOCK_MONOTONIC, &tp); 1440 assert(status == 0, "gettime error"); 1441 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1442 return result; 1443 } else { 1444 timeval time; 1445 int status = gettimeofday(&time, NULL); 1446 assert(status != -1, "linux error"); 1447 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1448 return 1000 * usecs; 1449 } 1450 } 1451 1452 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1453 if (os::supports_monotonic_clock()) { 1454 info_ptr->max_value = ALL_64_BITS; 1455 1456 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1457 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1458 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1459 } else { 1460 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1461 info_ptr->max_value = ALL_64_BITS; 1462 1463 // gettimeofday is a real time clock so it skips 1464 info_ptr->may_skip_backward = true; 1465 info_ptr->may_skip_forward = true; 1466 } 1467 1468 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1469 } 1470 1471 // Return the real, user, and system times in seconds from an 1472 // arbitrary fixed point in the past. 1473 bool os::getTimesSecs(double* process_real_time, 1474 double* process_user_time, 1475 double* process_system_time) { 1476 struct tms ticks; 1477 clock_t real_ticks = times(&ticks); 1478 1479 if (real_ticks == (clock_t) (-1)) { 1480 return false; 1481 } else { 1482 double ticks_per_second = (double) clock_tics_per_sec; 1483 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1484 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1485 *process_real_time = ((double) real_ticks) / ticks_per_second; 1486 1487 return true; 1488 } 1489 } 1490 1491 1492 char * os::local_time_string(char *buf, size_t buflen) { 1493 struct tm t; 1494 time_t long_time; 1495 time(&long_time); 1496 localtime_r(&long_time, &t); 1497 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1498 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1499 t.tm_hour, t.tm_min, t.tm_sec); 1500 return buf; 1501 } 1502 1503 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1504 return localtime_r(clock, res); 1505 } 1506 1507 //////////////////////////////////////////////////////////////////////////////// 1508 // runtime exit support 1509 1510 // Note: os::shutdown() might be called very early during initialization, or 1511 // called from signal handler. Before adding something to os::shutdown(), make 1512 // sure it is async-safe and can handle partially initialized VM. 1513 void os::shutdown() { 1514 1515 // allow PerfMemory to attempt cleanup of any persistent resources 1516 perfMemory_exit(); 1517 1518 // needs to remove object in file system 1519 AttachListener::abort(); 1520 1521 // flush buffered output, finish log files 1522 ostream_abort(); 1523 1524 // Check for abort hook 1525 abort_hook_t abort_hook = Arguments::abort_hook(); 1526 if (abort_hook != NULL) { 1527 abort_hook(); 1528 } 1529 1530 } 1531 1532 // Note: os::abort() might be called very early during initialization, or 1533 // called from signal handler. Before adding something to os::abort(), make 1534 // sure it is async-safe and can handle partially initialized VM. 1535 void os::abort(bool dump_core, void* siginfo, const void* context) { 1536 os::shutdown(); 1537 if (dump_core) { 1538 if (DumpPrivateMappingsInCore) { 1539 ClassLoader::close_jrt_image(); 1540 } 1541 ::abort(); // dump core 1542 } 1543 1544 ::exit(1); 1545 } 1546 1547 // Die immediately, no exit hook, no abort hook, no cleanup. 1548 // Dump a core file, if possible, for debugging. 1549 void os::die() { 1550 if (TestUnresponsiveErrorHandler && !CreateCoredumpOnCrash) { 1551 // For TimeoutInErrorHandlingTest.java, we just kill the VM 1552 // and don't take the time to generate a core file. 1553 os::signal_raise(SIGKILL); 1554 } else { 1555 ::abort(); 1556 } 1557 } 1558 1559 // thread_id is kernel thread id (similar to Solaris LWP id) 1560 intx os::current_thread_id() { return os::Linux::gettid(); } 1561 int os::current_process_id() { 1562 return ::getpid(); 1563 } 1564 1565 // DLL functions 1566 1567 const char* os::dll_file_extension() { return ".so"; } 1568 1569 // This must be hard coded because it's the system's temporary 1570 // directory not the java application's temp directory, ala java.io.tmpdir. 1571 const char* os::get_temp_directory() { return "/tmp"; } 1572 1573 static bool file_exists(const char* filename) { 1574 struct stat statbuf; 1575 if (filename == NULL || strlen(filename) == 0) { 1576 return false; 1577 } 1578 return os::stat(filename, &statbuf) == 0; 1579 } 1580 1581 // check if addr is inside libjvm.so 1582 bool os::address_is_in_vm(address addr) { 1583 static address libjvm_base_addr; 1584 Dl_info dlinfo; 1585 1586 if (libjvm_base_addr == NULL) { 1587 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1588 libjvm_base_addr = (address)dlinfo.dli_fbase; 1589 } 1590 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1591 } 1592 1593 if (dladdr((void *)addr, &dlinfo) != 0) { 1594 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1595 } 1596 1597 return false; 1598 } 1599 1600 bool os::dll_address_to_function_name(address addr, char *buf, 1601 int buflen, int *offset, 1602 bool demangle) { 1603 // buf is not optional, but offset is optional 1604 assert(buf != NULL, "sanity check"); 1605 1606 Dl_info dlinfo; 1607 1608 if (dladdr((void*)addr, &dlinfo) != 0) { 1609 // see if we have a matching symbol 1610 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1611 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1612 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1613 } 1614 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1615 return true; 1616 } 1617 // no matching symbol so try for just file info 1618 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1619 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1620 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1621 return true; 1622 } 1623 } 1624 } 1625 1626 buf[0] = '\0'; 1627 if (offset != NULL) *offset = -1; 1628 return false; 1629 } 1630 1631 struct _address_to_library_name { 1632 address addr; // input : memory address 1633 size_t buflen; // size of fname 1634 char* fname; // output: library name 1635 address base; // library base addr 1636 }; 1637 1638 static int address_to_library_name_callback(struct dl_phdr_info *info, 1639 size_t size, void *data) { 1640 int i; 1641 bool found = false; 1642 address libbase = NULL; 1643 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1644 1645 // iterate through all loadable segments 1646 for (i = 0; i < info->dlpi_phnum; i++) { 1647 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1648 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1649 // base address of a library is the lowest address of its loaded 1650 // segments. 1651 if (libbase == NULL || libbase > segbase) { 1652 libbase = segbase; 1653 } 1654 // see if 'addr' is within current segment 1655 if (segbase <= d->addr && 1656 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1657 found = true; 1658 } 1659 } 1660 } 1661 1662 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1663 // so dll_address_to_library_name() can fall through to use dladdr() which 1664 // can figure out executable name from argv[0]. 1665 if (found && info->dlpi_name && info->dlpi_name[0]) { 1666 d->base = libbase; 1667 if (d->fname) { 1668 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1669 } 1670 return 1; 1671 } 1672 return 0; 1673 } 1674 1675 bool os::dll_address_to_library_name(address addr, char* buf, 1676 int buflen, int* offset) { 1677 // buf is not optional, but offset is optional 1678 assert(buf != NULL, "sanity check"); 1679 1680 Dl_info dlinfo; 1681 struct _address_to_library_name data; 1682 1683 // There is a bug in old glibc dladdr() implementation that it could resolve 1684 // to wrong library name if the .so file has a base address != NULL. Here 1685 // we iterate through the program headers of all loaded libraries to find 1686 // out which library 'addr' really belongs to. This workaround can be 1687 // removed once the minimum requirement for glibc is moved to 2.3.x. 1688 data.addr = addr; 1689 data.fname = buf; 1690 data.buflen = buflen; 1691 data.base = NULL; 1692 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1693 1694 if (rslt) { 1695 // buf already contains library name 1696 if (offset) *offset = addr - data.base; 1697 return true; 1698 } 1699 if (dladdr((void*)addr, &dlinfo) != 0) { 1700 if (dlinfo.dli_fname != NULL) { 1701 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1702 } 1703 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1704 *offset = addr - (address)dlinfo.dli_fbase; 1705 } 1706 return true; 1707 } 1708 1709 buf[0] = '\0'; 1710 if (offset) *offset = -1; 1711 return false; 1712 } 1713 1714 // Loads .dll/.so and 1715 // in case of error it checks if .dll/.so was built for the 1716 // same architecture as Hotspot is running on 1717 1718 1719 // Remember the stack's state. The Linux dynamic linker will change 1720 // the stack to 'executable' at most once, so we must safepoint only once. 1721 bool os::Linux::_stack_is_executable = false; 1722 1723 // VM operation that loads a library. This is necessary if stack protection 1724 // of the Java stacks can be lost during loading the library. If we 1725 // do not stop the Java threads, they can stack overflow before the stacks 1726 // are protected again. 1727 class VM_LinuxDllLoad: public VM_Operation { 1728 private: 1729 const char *_filename; 1730 char *_ebuf; 1731 int _ebuflen; 1732 void *_lib; 1733 public: 1734 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1735 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1736 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1737 void doit() { 1738 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1739 os::Linux::_stack_is_executable = true; 1740 } 1741 void* loaded_library() { return _lib; } 1742 }; 1743 1744 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1745 void * result = NULL; 1746 bool load_attempted = false; 1747 1748 log_info(os)("attempting shared library load of %s", filename); 1749 1750 // Check whether the library to load might change execution rights 1751 // of the stack. If they are changed, the protection of the stack 1752 // guard pages will be lost. We need a safepoint to fix this. 1753 // 1754 // See Linux man page execstack(8) for more info. 1755 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1756 if (!ElfFile::specifies_noexecstack(filename)) { 1757 if (!is_init_completed()) { 1758 os::Linux::_stack_is_executable = true; 1759 // This is OK - No Java threads have been created yet, and hence no 1760 // stack guard pages to fix. 1761 // 1762 // Dynamic loader will make all stacks executable after 1763 // this function returns, and will not do that again. 1764 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet."); 1765 } else { 1766 warning("You have loaded library %s which might have disabled stack guard. " 1767 "The VM will try to fix the stack guard now.\n" 1768 "It's highly recommended that you fix the library with " 1769 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1770 filename); 1771 1772 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1773 JavaThread *jt = JavaThread::current(); 1774 if (jt->thread_state() != _thread_in_native) { 1775 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1776 // that requires ExecStack. Cannot enter safe point. Let's give up. 1777 warning("Unable to fix stack guard. Giving up."); 1778 } else { 1779 if (!LoadExecStackDllInVMThread) { 1780 // This is for the case where the DLL has an static 1781 // constructor function that executes JNI code. We cannot 1782 // load such DLLs in the VMThread. 1783 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1784 } 1785 1786 ThreadInVMfromNative tiv(jt); 1787 debug_only(VMNativeEntryWrapper vew;) 1788 1789 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1790 VMThread::execute(&op); 1791 if (LoadExecStackDllInVMThread) { 1792 result = op.loaded_library(); 1793 } 1794 load_attempted = true; 1795 } 1796 } 1797 } 1798 } 1799 1800 if (!load_attempted) { 1801 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1802 } 1803 1804 if (result != NULL) { 1805 // Successful loading 1806 return result; 1807 } 1808 1809 Elf32_Ehdr elf_head; 1810 int diag_msg_max_length=ebuflen-strlen(ebuf); 1811 char* diag_msg_buf=ebuf+strlen(ebuf); 1812 1813 if (diag_msg_max_length==0) { 1814 // No more space in ebuf for additional diagnostics message 1815 return NULL; 1816 } 1817 1818 1819 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1820 1821 if (file_descriptor < 0) { 1822 // Can't open library, report dlerror() message 1823 return NULL; 1824 } 1825 1826 bool failed_to_read_elf_head= 1827 (sizeof(elf_head)!= 1828 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1829 1830 ::close(file_descriptor); 1831 if (failed_to_read_elf_head) { 1832 // file i/o error - report dlerror() msg 1833 return NULL; 1834 } 1835 1836 if (elf_head.e_ident[EI_DATA] != LITTLE_ENDIAN_ONLY(ELFDATA2LSB) BIG_ENDIAN_ONLY(ELFDATA2MSB)) { 1837 // handle invalid/out of range endianness values 1838 if (elf_head.e_ident[EI_DATA] == 0 || elf_head.e_ident[EI_DATA] > 2) { 1839 return NULL; 1840 } 1841 1842 #if defined(VM_LITTLE_ENDIAN) 1843 // VM is LE, shared object BE 1844 elf_head.e_machine = be16toh(elf_head.e_machine); 1845 #else 1846 // VM is BE, shared object LE 1847 elf_head.e_machine = le16toh(elf_head.e_machine); 1848 #endif 1849 } 1850 1851 typedef struct { 1852 Elf32_Half code; // Actual value as defined in elf.h 1853 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1854 unsigned char elf_class; // 32 or 64 bit 1855 unsigned char endianness; // MSB or LSB 1856 char* name; // String representation 1857 } arch_t; 1858 1859 #ifndef EM_AARCH64 1860 #define EM_AARCH64 183 /* ARM AARCH64 */ 1861 #endif 1862 #ifndef EM_RISCV 1863 #define EM_RISCV 243 /* RISC-V */ 1864 #endif 1865 1866 static const arch_t arch_array[]={ 1867 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1868 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1869 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1870 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1871 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1872 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1873 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1874 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1875 #if defined(VM_LITTLE_ENDIAN) 1876 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"}, 1877 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"}, 1878 #else 1879 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1880 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"}, 1881 #endif 1882 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1883 // we only support 64 bit z architecture 1884 {EM_S390, EM_S390, ELFCLASS64, ELFDATA2MSB, (char*)"IBM System/390"}, 1885 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1886 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1887 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1888 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1889 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1890 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1891 {EM_RISCV, EM_RISCV, ELFCLASS64, ELFDATA2LSB, (char*)"RISC-V"}, 1892 }; 1893 1894 #if (defined IA32) 1895 static Elf32_Half running_arch_code=EM_386; 1896 #elif (defined AMD64) || (defined X32) 1897 static Elf32_Half running_arch_code=EM_X86_64; 1898 #elif (defined IA64) 1899 static Elf32_Half running_arch_code=EM_IA_64; 1900 #elif (defined __sparc) && (defined _LP64) 1901 static Elf32_Half running_arch_code=EM_SPARCV9; 1902 #elif (defined __sparc) && (!defined _LP64) 1903 static Elf32_Half running_arch_code=EM_SPARC; 1904 #elif (defined __powerpc64__) 1905 static Elf32_Half running_arch_code=EM_PPC64; 1906 #elif (defined __powerpc__) 1907 static Elf32_Half running_arch_code=EM_PPC; 1908 #elif (defined AARCH64) 1909 static Elf32_Half running_arch_code=EM_AARCH64; 1910 #elif (defined ARM) 1911 static Elf32_Half running_arch_code=EM_ARM; 1912 #elif (defined S390) 1913 static Elf32_Half running_arch_code=EM_S390; 1914 #elif (defined ALPHA) 1915 static Elf32_Half running_arch_code=EM_ALPHA; 1916 #elif (defined MIPSEL) 1917 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1918 #elif (defined PARISC) 1919 static Elf32_Half running_arch_code=EM_PARISC; 1920 #elif (defined MIPS) 1921 static Elf32_Half running_arch_code=EM_MIPS; 1922 #elif (defined M68K) 1923 static Elf32_Half running_arch_code=EM_68K; 1924 #elif (defined SH) 1925 static Elf32_Half running_arch_code=EM_SH; 1926 #elif (defined RISCV) 1927 static Elf32_Half running_arch_code=EM_RISCV; 1928 #else 1929 #error Method os::dll_load requires that one of following is defined:\ 1930 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, RISCV, S390, SH, __sparc 1931 #endif 1932 1933 // Identify compatibility class for VM's architecture and library's architecture 1934 // Obtain string descriptions for architectures 1935 1936 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1937 int running_arch_index=-1; 1938 1939 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1940 if (running_arch_code == arch_array[i].code) { 1941 running_arch_index = i; 1942 } 1943 if (lib_arch.code == arch_array[i].code) { 1944 lib_arch.compat_class = arch_array[i].compat_class; 1945 lib_arch.name = arch_array[i].name; 1946 } 1947 } 1948 1949 assert(running_arch_index != -1, 1950 "Didn't find running architecture code (running_arch_code) in arch_array"); 1951 if (running_arch_index == -1) { 1952 // Even though running architecture detection failed 1953 // we may still continue with reporting dlerror() message 1954 return NULL; 1955 } 1956 1957 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1958 if (lib_arch.name != NULL) { 1959 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1960 " (Possible cause: can't load %s .so on a %s platform)", 1961 lib_arch.name, arch_array[running_arch_index].name); 1962 } else { 1963 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1964 " (Possible cause: can't load this .so (machine code=0x%x) on a %s platform)", 1965 lib_arch.code, arch_array[running_arch_index].name); 1966 } 1967 return NULL; 1968 } 1969 1970 if (lib_arch.endianness != arch_array[running_arch_index].endianness) { 1971 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: endianness mismatch)"); 1972 return NULL; 1973 } 1974 1975 // ELF file class/capacity : 0 - invalid, 1 - 32bit, 2 - 64bit 1976 if (lib_arch.elf_class > 2 || lib_arch.elf_class < 1) { 1977 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: invalid ELF file class)"); 1978 return NULL; 1979 } 1980 1981 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1982 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1983 " (Possible cause: architecture word width mismatch, can't load %d-bit .so on a %d-bit platform)", 1984 (int) lib_arch.elf_class * 32, arch_array[running_arch_index].elf_class * 32); 1985 return NULL; 1986 } 1987 1988 return NULL; 1989 } 1990 1991 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1992 int ebuflen) { 1993 void * result = ::dlopen(filename, RTLD_LAZY); 1994 if (result == NULL) { 1995 const char* error_report = ::dlerror(); 1996 if (error_report == NULL) { 1997 error_report = "dlerror returned no error description"; 1998 } 1999 if (ebuf != NULL && ebuflen > 0) { 2000 ::strncpy(ebuf, error_report, ebuflen-1); 2001 ebuf[ebuflen-1]='\0'; 2002 } 2003 Events::log(NULL, "Loading shared library %s failed, %s", filename, error_report); 2004 log_info(os)("shared library load of %s failed, %s", filename, error_report); 2005 } else { 2006 Events::log(NULL, "Loaded shared library %s", filename); 2007 log_info(os)("shared library load of %s was successful", filename); 2008 } 2009 return result; 2010 } 2011 2012 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 2013 int ebuflen) { 2014 void * result = NULL; 2015 if (LoadExecStackDllInVMThread) { 2016 result = dlopen_helper(filename, ebuf, ebuflen); 2017 } 2018 2019 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 2020 // library that requires an executable stack, or which does not have this 2021 // stack attribute set, dlopen changes the stack attribute to executable. The 2022 // read protection of the guard pages gets lost. 2023 // 2024 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 2025 // may have been queued at the same time. 2026 2027 if (!_stack_is_executable) { 2028 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) { 2029 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 2030 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 2031 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 2032 warning("Attempt to reguard stack yellow zone failed."); 2033 } 2034 } 2035 } 2036 } 2037 2038 return result; 2039 } 2040 2041 void* os::dll_lookup(void* handle, const char* name) { 2042 void* res = dlsym(handle, name); 2043 return res; 2044 } 2045 2046 void* os::get_default_process_handle() { 2047 return (void*)::dlopen(NULL, RTLD_LAZY); 2048 } 2049 2050 static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) { 2051 int fd = ::open(filename, O_RDONLY); 2052 if (fd == -1) { 2053 return false; 2054 } 2055 2056 if (hdr != NULL) { 2057 st->print_cr("%s", hdr); 2058 } 2059 2060 char buf[33]; 2061 int bytes; 2062 buf[32] = '\0'; 2063 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) { 2064 st->print_raw(buf, bytes); 2065 } 2066 2067 ::close(fd); 2068 2069 return true; 2070 } 2071 2072 static void _print_ascii_file_h(const char* header, const char* filename, outputStream* st) { 2073 st->print_cr("%s:", header); 2074 if (!_print_ascii_file(filename, st)) { 2075 st->print_cr("<Not Available>"); 2076 } 2077 } 2078 2079 void os::print_dll_info(outputStream *st) { 2080 st->print_cr("Dynamic libraries:"); 2081 2082 char fname[32]; 2083 pid_t pid = os::Linux::gettid(); 2084 2085 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 2086 2087 if (!_print_ascii_file(fname, st)) { 2088 st->print("Can not get library information for pid = %d\n", pid); 2089 } 2090 } 2091 2092 struct loaded_modules_info_param { 2093 os::LoadedModulesCallbackFunc callback; 2094 void *param; 2095 }; 2096 2097 static int dl_iterate_callback(struct dl_phdr_info *info, size_t size, void *data) { 2098 if ((info->dlpi_name == NULL) || (*info->dlpi_name == '\0')) { 2099 return 0; 2100 } 2101 2102 struct loaded_modules_info_param *callback_param = reinterpret_cast<struct loaded_modules_info_param *>(data); 2103 address base = NULL; 2104 address top = NULL; 2105 for (int idx = 0; idx < info->dlpi_phnum; idx++) { 2106 const ElfW(Phdr) *phdr = info->dlpi_phdr + idx; 2107 if (phdr->p_type == PT_LOAD) { 2108 address raw_phdr_base = reinterpret_cast<address>(info->dlpi_addr + phdr->p_vaddr); 2109 2110 address phdr_base = align_down(raw_phdr_base, phdr->p_align); 2111 if ((base == NULL) || (base > phdr_base)) { 2112 base = phdr_base; 2113 } 2114 2115 address phdr_top = align_up(raw_phdr_base + phdr->p_memsz, phdr->p_align); 2116 if ((top == NULL) || (top < phdr_top)) { 2117 top = phdr_top; 2118 } 2119 } 2120 } 2121 2122 return callback_param->callback(info->dlpi_name, base, top, callback_param->param); 2123 } 2124 2125 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 2126 struct loaded_modules_info_param callback_param = {callback, param}; 2127 return dl_iterate_phdr(&dl_iterate_callback, &callback_param); 2128 } 2129 2130 void os::print_os_info_brief(outputStream* st) { 2131 os::Linux::print_distro_info(st); 2132 2133 os::Posix::print_uname_info(st); 2134 2135 os::Linux::print_libversion_info(st); 2136 2137 } 2138 2139 void os::print_os_info(outputStream* st) { 2140 st->print("OS:"); 2141 2142 os::Linux::print_distro_info(st); 2143 2144 os::Posix::print_uname_info(st); 2145 2146 os::Linux::print_uptime_info(st); 2147 2148 // Print warning if unsafe chroot environment detected 2149 if (unsafe_chroot_detected) { 2150 st->print("WARNING!! "); 2151 st->print_cr("%s", unstable_chroot_error); 2152 } 2153 2154 os::Linux::print_libversion_info(st); 2155 2156 os::Posix::print_rlimit_info(st); 2157 2158 os::Posix::print_load_average(st); 2159 2160 os::Linux::print_full_memory_info(st); 2161 2162 os::Linux::print_proc_sys_info(st); 2163 2164 os::Linux::print_ld_preload_file(st); 2165 2166 os::Linux::print_container_info(st); 2167 2168 VM_Version::print_platform_virtualization_info(st); 2169 2170 os::Linux::print_steal_info(st); 2171 } 2172 2173 // Try to identify popular distros. 2174 // Most Linux distributions have a /etc/XXX-release file, which contains 2175 // the OS version string. Newer Linux distributions have a /etc/lsb-release 2176 // file that also contains the OS version string. Some have more than one 2177 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2178 // /etc/redhat-release.), so the order is important. 2179 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2180 // their own specific XXX-release file as well as a redhat-release file. 2181 // Because of this the XXX-release file needs to be searched for before the 2182 // redhat-release file. 2183 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the 2184 // search for redhat-release / SuSE-release needs to be before lsb-release. 2185 // Since the lsb-release file is the new standard it needs to be searched 2186 // before the older style release files. 2187 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 2188 // next to last resort. The os-release file is a new standard that contains 2189 // distribution information and the system-release file seems to be an old 2190 // standard that has been replaced by the lsb-release and os-release files. 2191 // Searching for the debian_version file is the last resort. It contains 2192 // an informative string like "6.0.6" or "wheezy/sid". Because of this 2193 // "Debian " is printed before the contents of the debian_version file. 2194 2195 const char* distro_files[] = { 2196 "/etc/oracle-release", 2197 "/etc/mandriva-release", 2198 "/etc/mandrake-release", 2199 "/etc/sun-release", 2200 "/etc/redhat-release", 2201 "/etc/SuSE-release", 2202 "/etc/lsb-release", 2203 "/etc/turbolinux-release", 2204 "/etc/gentoo-release", 2205 "/etc/ltib-release", 2206 "/etc/angstrom-version", 2207 "/etc/system-release", 2208 "/etc/os-release", 2209 NULL }; 2210 2211 void os::Linux::print_distro_info(outputStream* st) { 2212 for (int i = 0;; i++) { 2213 const char* file = distro_files[i]; 2214 if (file == NULL) { 2215 break; // done 2216 } 2217 // If file prints, we found it. 2218 if (_print_ascii_file(file, st)) { 2219 return; 2220 } 2221 } 2222 2223 if (file_exists("/etc/debian_version")) { 2224 st->print("Debian "); 2225 _print_ascii_file("/etc/debian_version", st); 2226 } else { 2227 st->print("Linux"); 2228 } 2229 st->cr(); 2230 } 2231 2232 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) { 2233 char buf[256]; 2234 while (fgets(buf, sizeof(buf), fp)) { 2235 // Edit out extra stuff in expected format 2236 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) { 2237 char* ptr = strstr(buf, "\""); // the name is in quotes 2238 if (ptr != NULL) { 2239 ptr++; // go beyond first quote 2240 char* nl = strchr(ptr, '\"'); 2241 if (nl != NULL) *nl = '\0'; 2242 strncpy(distro, ptr, length); 2243 } else { 2244 ptr = strstr(buf, "="); 2245 ptr++; // go beyond equals then 2246 char* nl = strchr(ptr, '\n'); 2247 if (nl != NULL) *nl = '\0'; 2248 strncpy(distro, ptr, length); 2249 } 2250 return; 2251 } else if (get_first_line) { 2252 char* nl = strchr(buf, '\n'); 2253 if (nl != NULL) *nl = '\0'; 2254 strncpy(distro, buf, length); 2255 return; 2256 } 2257 } 2258 // print last line and close 2259 char* nl = strchr(buf, '\n'); 2260 if (nl != NULL) *nl = '\0'; 2261 strncpy(distro, buf, length); 2262 } 2263 2264 static void parse_os_info(char* distro, size_t length, const char* file) { 2265 FILE* fp = fopen(file, "r"); 2266 if (fp != NULL) { 2267 // if suse format, print out first line 2268 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0); 2269 parse_os_info_helper(fp, distro, length, get_first_line); 2270 fclose(fp); 2271 } 2272 } 2273 2274 void os::get_summary_os_info(char* buf, size_t buflen) { 2275 for (int i = 0;; i++) { 2276 const char* file = distro_files[i]; 2277 if (file == NULL) { 2278 break; // ran out of distro_files 2279 } 2280 if (file_exists(file)) { 2281 parse_os_info(buf, buflen, file); 2282 return; 2283 } 2284 } 2285 // special case for debian 2286 if (file_exists("/etc/debian_version")) { 2287 strncpy(buf, "Debian ", buflen); 2288 if (buflen > 7) { 2289 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2290 } 2291 } else { 2292 strncpy(buf, "Linux", buflen); 2293 } 2294 } 2295 2296 void os::Linux::print_libversion_info(outputStream* st) { 2297 // libc, pthread 2298 st->print("libc:"); 2299 st->print("%s ", os::Linux::glibc_version()); 2300 st->print("%s ", os::Linux::libpthread_version()); 2301 st->cr(); 2302 } 2303 2304 void os::Linux::print_proc_sys_info(outputStream* st) { 2305 st->cr(); 2306 _print_ascii_file_h("/proc/sys/kernel/threads-max (system-wide limit on the number of threads)", 2307 "/proc/sys/kernel/threads-max", st); 2308 _print_ascii_file_h("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have)", 2309 "/proc/sys/vm/max_map_count", st); 2310 _print_ascii_file_h("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers)", 2311 "/proc/sys/kernel/pid_max", st); 2312 } 2313 2314 void os::Linux::print_full_memory_info(outputStream* st) { 2315 _print_ascii_file_h("\n/proc/meminfo", "/proc/meminfo", st); 2316 st->cr(); 2317 2318 // some information regarding THPs; for details see 2319 // https://www.kernel.org/doc/Documentation/vm/transhuge.txt 2320 _print_ascii_file_h("/sys/kernel/mm/transparent_hugepage/enabled", 2321 "/sys/kernel/mm/transparent_hugepage/enabled", st); 2322 _print_ascii_file_h("/sys/kernel/mm/transparent_hugepage/defrag (defrag/compaction efforts parameter)", 2323 "/sys/kernel/mm/transparent_hugepage/defrag", st); 2324 } 2325 2326 void os::Linux::print_ld_preload_file(outputStream* st) { 2327 _print_ascii_file("/etc/ld.so.preload", st, "\n/etc/ld.so.preload:"); 2328 st->cr(); 2329 } 2330 2331 void os::Linux::print_uptime_info(outputStream* st) { 2332 struct sysinfo sinfo; 2333 int ret = sysinfo(&sinfo); 2334 if (ret == 0) { 2335 os::print_dhm(st, "OS uptime:", (long) sinfo.uptime); 2336 } 2337 } 2338 2339 2340 void os::Linux::print_container_info(outputStream* st) { 2341 if (!OSContainer::is_containerized()) { 2342 return; 2343 } 2344 2345 st->print("container (cgroup) information:\n"); 2346 2347 const char *p_ct = OSContainer::container_type(); 2348 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "not supported"); 2349 2350 char *p = OSContainer::cpu_cpuset_cpus(); 2351 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "not supported"); 2352 free(p); 2353 2354 p = OSContainer::cpu_cpuset_memory_nodes(); 2355 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "not supported"); 2356 free(p); 2357 2358 int i = OSContainer::active_processor_count(); 2359 st->print("active_processor_count: "); 2360 if (i > 0) { 2361 st->print("%d\n", i); 2362 } else { 2363 st->print("not supported\n"); 2364 } 2365 2366 i = OSContainer::cpu_quota(); 2367 st->print("cpu_quota: "); 2368 if (i > 0) { 2369 st->print("%d\n", i); 2370 } else { 2371 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no quota"); 2372 } 2373 2374 i = OSContainer::cpu_period(); 2375 st->print("cpu_period: "); 2376 if (i > 0) { 2377 st->print("%d\n", i); 2378 } else { 2379 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no period"); 2380 } 2381 2382 i = OSContainer::cpu_shares(); 2383 st->print("cpu_shares: "); 2384 if (i > 0) { 2385 st->print("%d\n", i); 2386 } else { 2387 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no shares"); 2388 } 2389 2390 jlong j = OSContainer::memory_limit_in_bytes(); 2391 st->print("memory_limit_in_bytes: "); 2392 if (j > 0) { 2393 st->print(JLONG_FORMAT "\n", j); 2394 } else { 2395 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2396 } 2397 2398 j = OSContainer::memory_and_swap_limit_in_bytes(); 2399 st->print("memory_and_swap_limit_in_bytes: "); 2400 if (j > 0) { 2401 st->print(JLONG_FORMAT "\n", j); 2402 } else { 2403 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2404 } 2405 2406 j = OSContainer::memory_soft_limit_in_bytes(); 2407 st->print("memory_soft_limit_in_bytes: "); 2408 if (j > 0) { 2409 st->print(JLONG_FORMAT "\n", j); 2410 } else { 2411 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2412 } 2413 2414 j = OSContainer::OSContainer::memory_usage_in_bytes(); 2415 st->print("memory_usage_in_bytes: "); 2416 if (j > 0) { 2417 st->print(JLONG_FORMAT "\n", j); 2418 } else { 2419 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2420 } 2421 2422 j = OSContainer::OSContainer::memory_max_usage_in_bytes(); 2423 st->print("memory_max_usage_in_bytes: "); 2424 if (j > 0) { 2425 st->print(JLONG_FORMAT "\n", j); 2426 } else { 2427 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited"); 2428 } 2429 st->cr(); 2430 } 2431 2432 void os::Linux::print_steal_info(outputStream* st) { 2433 if (has_initial_tick_info) { 2434 CPUPerfTicks pticks; 2435 bool res = os::Linux::get_tick_information(&pticks, -1); 2436 2437 if (res && pticks.has_steal_ticks) { 2438 uint64_t steal_ticks_difference = pticks.steal - initial_steal_ticks; 2439 uint64_t total_ticks_difference = pticks.total - initial_total_ticks; 2440 double steal_ticks_perc = 0.0; 2441 if (total_ticks_difference != 0) { 2442 steal_ticks_perc = (double) steal_ticks_difference / total_ticks_difference; 2443 } 2444 st->print_cr("Steal ticks since vm start: " UINT64_FORMAT, steal_ticks_difference); 2445 st->print_cr("Steal ticks percentage since vm start:%7.3f", steal_ticks_perc); 2446 } 2447 } 2448 } 2449 2450 void os::print_memory_info(outputStream* st) { 2451 2452 st->print("Memory:"); 2453 st->print(" %dk page", os::vm_page_size()>>10); 2454 2455 // values in struct sysinfo are "unsigned long" 2456 struct sysinfo si; 2457 sysinfo(&si); 2458 2459 st->print(", physical " UINT64_FORMAT "k", 2460 os::physical_memory() >> 10); 2461 st->print("(" UINT64_FORMAT "k free)", 2462 os::available_memory() >> 10); 2463 st->print(", swap " UINT64_FORMAT "k", 2464 ((jlong)si.totalswap * si.mem_unit) >> 10); 2465 st->print("(" UINT64_FORMAT "k free)", 2466 ((jlong)si.freeswap * si.mem_unit) >> 10); 2467 st->cr(); 2468 } 2469 2470 // Print the first "model name" line and the first "flags" line 2471 // that we find and nothing more. We assume "model name" comes 2472 // before "flags" so if we find a second "model name", then the 2473 // "flags" field is considered missing. 2474 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2475 #if defined(IA32) || defined(AMD64) 2476 // Other platforms have less repetitive cpuinfo files 2477 FILE *fp = fopen("/proc/cpuinfo", "r"); 2478 if (fp) { 2479 while (!feof(fp)) { 2480 if (fgets(buf, buflen, fp)) { 2481 // Assume model name comes before flags 2482 bool model_name_printed = false; 2483 if (strstr(buf, "model name") != NULL) { 2484 if (!model_name_printed) { 2485 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n"); 2486 st->print_raw(buf); 2487 model_name_printed = true; 2488 } else { 2489 // model name printed but not flags? Odd, just return 2490 fclose(fp); 2491 return true; 2492 } 2493 } 2494 // print the flags line too 2495 if (strstr(buf, "flags") != NULL) { 2496 st->print_raw(buf); 2497 fclose(fp); 2498 return true; 2499 } 2500 } 2501 } 2502 fclose(fp); 2503 } 2504 #endif // x86 platforms 2505 return false; 2506 } 2507 2508 // additional information about CPU e.g. available frequency ranges 2509 static void print_sys_devices_cpu_info(outputStream* st, char* buf, size_t buflen) { 2510 _print_ascii_file_h("Online cpus", "/sys/devices/system/cpu/online", st); 2511 _print_ascii_file_h("Offline cpus", "/sys/devices/system/cpu/offline", st); 2512 2513 if (ExtensiveErrorReports) { 2514 // cache related info (cpu 0, should be similar for other CPUs) 2515 for (unsigned int i=0; i < 10; i++) { // handle max. 10 cache entries 2516 char hbuf_level[60]; 2517 char hbuf_type[60]; 2518 char hbuf_size[60]; 2519 char hbuf_coherency_line_size[80]; 2520 snprintf(hbuf_level, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/level", i); 2521 snprintf(hbuf_type, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/type", i); 2522 snprintf(hbuf_size, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/size", i); 2523 snprintf(hbuf_coherency_line_size, 80, "/sys/devices/system/cpu/cpu0/cache/index%u/coherency_line_size", i); 2524 if (file_exists(hbuf_level)) { 2525 _print_ascii_file_h("cache level", hbuf_level, st); 2526 _print_ascii_file_h("cache type", hbuf_type, st); 2527 _print_ascii_file_h("cache size", hbuf_size, st); 2528 _print_ascii_file_h("cache coherency line size", hbuf_coherency_line_size, st); 2529 } 2530 } 2531 } 2532 2533 // we miss the cpufreq entries on Power and s390x 2534 #if defined(IA32) || defined(AMD64) 2535 _print_ascii_file_h("BIOS frequency limitation", "/sys/devices/system/cpu/cpu0/cpufreq/bios_limit", st); 2536 _print_ascii_file_h("Frequency switch latency (ns)", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_transition_latency", st); 2537 _print_ascii_file_h("Available cpu frequencies", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies", st); 2538 // min and max should be in the Available range but still print them (not all info might be available for all kernels) 2539 if (ExtensiveErrorReports) { 2540 _print_ascii_file_h("Maximum cpu frequency", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq", st); 2541 _print_ascii_file_h("Minimum cpu frequency", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq", st); 2542 _print_ascii_file_h("Current cpu frequency", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq", st); 2543 } 2544 // governors are power schemes, see https://wiki.archlinux.org/index.php/CPU_frequency_scaling 2545 if (ExtensiveErrorReports) { 2546 _print_ascii_file_h("Available governors", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors", st); 2547 } 2548 _print_ascii_file_h("Current governor", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor", st); 2549 // Core performance boost, see https://www.kernel.org/doc/Documentation/cpu-freq/boost.txt 2550 // Raise operating frequency of some cores in a multi-core package if certain conditions apply, e.g. 2551 // whole chip is not fully utilized 2552 _print_ascii_file_h("Core performance/turbo boost", "/sys/devices/system/cpu/cpufreq/boost", st); 2553 #endif 2554 } 2555 2556 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2557 // Only print the model name if the platform provides this as a summary 2558 if (!print_model_name_and_flags(st, buf, buflen)) { 2559 _print_ascii_file_h("\n/proc/cpuinfo", "/proc/cpuinfo", st); 2560 } 2561 print_sys_devices_cpu_info(st, buf, buflen); 2562 } 2563 2564 #if defined(AMD64) || defined(IA32) || defined(X32) 2565 const char* search_string = "model name"; 2566 #elif defined(M68K) 2567 const char* search_string = "CPU"; 2568 #elif defined(PPC64) 2569 const char* search_string = "cpu"; 2570 #elif defined(S390) 2571 const char* search_string = "machine ="; 2572 #elif defined(SPARC) 2573 const char* search_string = "cpu"; 2574 #else 2575 const char* search_string = "Processor"; 2576 #endif 2577 2578 // Parses the cpuinfo file for string representing the model name. 2579 void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2580 FILE* fp = fopen("/proc/cpuinfo", "r"); 2581 if (fp != NULL) { 2582 while (!feof(fp)) { 2583 char buf[256]; 2584 if (fgets(buf, sizeof(buf), fp)) { 2585 char* start = strstr(buf, search_string); 2586 if (start != NULL) { 2587 char *ptr = start + strlen(search_string); 2588 char *end = buf + strlen(buf); 2589 while (ptr != end) { 2590 // skip whitespace and colon for the rest of the name. 2591 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2592 break; 2593 } 2594 ptr++; 2595 } 2596 if (ptr != end) { 2597 // reasonable string, get rid of newline and keep the rest 2598 char* nl = strchr(buf, '\n'); 2599 if (nl != NULL) *nl = '\0'; 2600 strncpy(cpuinfo, ptr, length); 2601 fclose(fp); 2602 return; 2603 } 2604 } 2605 } 2606 } 2607 fclose(fp); 2608 } 2609 // cpuinfo not found or parsing failed, just print generic string. The entire 2610 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2611 #if defined(AARCH64) 2612 strncpy(cpuinfo, "AArch64", length); 2613 #elif defined(AMD64) 2614 strncpy(cpuinfo, "x86_64", length); 2615 #elif defined(ARM) // Order wrt. AARCH64 is relevant! 2616 strncpy(cpuinfo, "ARM", length); 2617 #elif defined(IA32) 2618 strncpy(cpuinfo, "x86_32", length); 2619 #elif defined(IA64) 2620 strncpy(cpuinfo, "IA64", length); 2621 #elif defined(PPC) 2622 strncpy(cpuinfo, "PPC64", length); 2623 #elif defined(S390) 2624 strncpy(cpuinfo, "S390", length); 2625 #elif defined(SPARC) 2626 strncpy(cpuinfo, "sparcv9", length); 2627 #elif defined(ZERO_LIBARCH) 2628 strncpy(cpuinfo, ZERO_LIBARCH, length); 2629 #else 2630 strncpy(cpuinfo, "unknown", length); 2631 #endif 2632 } 2633 2634 static void print_signal_handler(outputStream* st, int sig, 2635 char* buf, size_t buflen); 2636 2637 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2638 st->print_cr("Signal Handlers:"); 2639 print_signal_handler(st, SIGSEGV, buf, buflen); 2640 print_signal_handler(st, SIGBUS , buf, buflen); 2641 print_signal_handler(st, SIGFPE , buf, buflen); 2642 print_signal_handler(st, SIGPIPE, buf, buflen); 2643 print_signal_handler(st, SIGXFSZ, buf, buflen); 2644 print_signal_handler(st, SIGILL , buf, buflen); 2645 print_signal_handler(st, SR_signum, buf, buflen); 2646 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2647 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2648 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2649 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2650 #if defined(PPC64) 2651 print_signal_handler(st, SIGTRAP, buf, buflen); 2652 #endif 2653 } 2654 2655 static char saved_jvm_path[MAXPATHLEN] = {0}; 2656 2657 // Find the full path to the current module, libjvm.so 2658 void os::jvm_path(char *buf, jint buflen) { 2659 // Error checking. 2660 if (buflen < MAXPATHLEN) { 2661 assert(false, "must use a large-enough buffer"); 2662 buf[0] = '\0'; 2663 return; 2664 } 2665 // Lazy resolve the path to current module. 2666 if (saved_jvm_path[0] != 0) { 2667 strcpy(buf, saved_jvm_path); 2668 return; 2669 } 2670 2671 char dli_fname[MAXPATHLEN]; 2672 bool ret = dll_address_to_library_name( 2673 CAST_FROM_FN_PTR(address, os::jvm_path), 2674 dli_fname, sizeof(dli_fname), NULL); 2675 assert(ret, "cannot locate libjvm"); 2676 char *rp = NULL; 2677 if (ret && dli_fname[0] != '\0') { 2678 rp = os::Posix::realpath(dli_fname, buf, buflen); 2679 } 2680 if (rp == NULL) { 2681 return; 2682 } 2683 2684 if (Arguments::sun_java_launcher_is_altjvm()) { 2685 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2686 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so". 2687 // If "/jre/lib/" appears at the right place in the string, then 2688 // assume we are installed in a JDK and we're done. Otherwise, check 2689 // for a JAVA_HOME environment variable and fix up the path so it 2690 // looks like libjvm.so is installed there (append a fake suffix 2691 // hotspot/libjvm.so). 2692 const char *p = buf + strlen(buf) - 1; 2693 for (int count = 0; p > buf && count < 5; ++count) { 2694 for (--p; p > buf && *p != '/'; --p) 2695 /* empty */ ; 2696 } 2697 2698 if (strncmp(p, "/jre/lib/", 9) != 0) { 2699 // Look for JAVA_HOME in the environment. 2700 char* java_home_var = ::getenv("JAVA_HOME"); 2701 if (java_home_var != NULL && java_home_var[0] != 0) { 2702 char* jrelib_p; 2703 int len; 2704 2705 // Check the current module name "libjvm.so". 2706 p = strrchr(buf, '/'); 2707 if (p == NULL) { 2708 return; 2709 } 2710 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2711 2712 rp = os::Posix::realpath(java_home_var, buf, buflen); 2713 if (rp == NULL) { 2714 return; 2715 } 2716 2717 // determine if this is a legacy image or modules image 2718 // modules image doesn't have "jre" subdirectory 2719 len = strlen(buf); 2720 assert(len < buflen, "Ran out of buffer room"); 2721 jrelib_p = buf + len; 2722 snprintf(jrelib_p, buflen-len, "/jre/lib"); 2723 if (0 != access(buf, F_OK)) { 2724 snprintf(jrelib_p, buflen-len, "/lib"); 2725 } 2726 2727 if (0 == access(buf, F_OK)) { 2728 // Use current module name "libjvm.so" 2729 len = strlen(buf); 2730 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2731 } else { 2732 // Go back to path of .so 2733 rp = os::Posix::realpath(dli_fname, buf, buflen); 2734 if (rp == NULL) { 2735 return; 2736 } 2737 } 2738 } 2739 } 2740 } 2741 2742 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2743 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2744 } 2745 2746 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2747 // no prefix required, not even "_" 2748 } 2749 2750 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2751 // no suffix required 2752 } 2753 2754 //////////////////////////////////////////////////////////////////////////////// 2755 // sun.misc.Signal support 2756 2757 static void UserHandler(int sig, void *siginfo, void *context) { 2758 // Ctrl-C is pressed during error reporting, likely because the error 2759 // handler fails to abort. Let VM die immediately. 2760 if (sig == SIGINT && VMError::is_error_reported()) { 2761 os::die(); 2762 } 2763 2764 os::signal_notify(sig); 2765 } 2766 2767 void* os::user_handler() { 2768 return CAST_FROM_FN_PTR(void*, UserHandler); 2769 } 2770 2771 extern "C" { 2772 typedef void (*sa_handler_t)(int); 2773 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2774 } 2775 2776 void* os::signal(int signal_number, void* handler) { 2777 struct sigaction sigAct, oldSigAct; 2778 2779 sigfillset(&(sigAct.sa_mask)); 2780 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2781 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2782 2783 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2784 // -1 means registration failed 2785 return (void *)-1; 2786 } 2787 2788 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2789 } 2790 2791 void os::signal_raise(int signal_number) { 2792 ::raise(signal_number); 2793 } 2794 2795 // The following code is moved from os.cpp for making this 2796 // code platform specific, which it is by its very nature. 2797 2798 // Will be modified when max signal is changed to be dynamic 2799 int os::sigexitnum_pd() { 2800 return NSIG; 2801 } 2802 2803 // a counter for each possible signal value 2804 static volatile jint pending_signals[NSIG+1] = { 0 }; 2805 2806 // Linux(POSIX) specific hand shaking semaphore. 2807 static Semaphore* sig_sem = NULL; 2808 static PosixSemaphore sr_semaphore; 2809 2810 static void jdk_misc_signal_init() { 2811 // Initialize signal structures 2812 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2813 2814 // Initialize signal semaphore 2815 sig_sem = new Semaphore(); 2816 } 2817 2818 void os::signal_notify(int sig) { 2819 if (sig_sem != NULL) { 2820 Atomic::inc(&pending_signals[sig]); 2821 sig_sem->signal(); 2822 } else { 2823 // Signal thread is not created with ReduceSignalUsage and jdk_misc_signal_init 2824 // initialization isn't called. 2825 assert(ReduceSignalUsage, "signal semaphore should be created"); 2826 } 2827 } 2828 2829 static int check_pending_signals() { 2830 for (;;) { 2831 for (int i = 0; i < NSIG + 1; i++) { 2832 jint n = pending_signals[i]; 2833 if (n > 0 && n == Atomic::cmpxchg(&pending_signals[i], n, n - 1)) { 2834 return i; 2835 } 2836 } 2837 JavaThread *thread = JavaThread::current(); 2838 ThreadBlockInVM tbivm(thread); 2839 2840 bool threadIsSuspended; 2841 do { 2842 thread->set_suspend_equivalent(); 2843 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2844 sig_sem->wait(); 2845 2846 // were we externally suspended while we were waiting? 2847 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2848 if (threadIsSuspended) { 2849 // The semaphore has been incremented, but while we were waiting 2850 // another thread suspended us. We don't want to continue running 2851 // while suspended because that would surprise the thread that 2852 // suspended us. 2853 sig_sem->signal(); 2854 2855 thread->java_suspend_self(); 2856 } 2857 } while (threadIsSuspended); 2858 } 2859 } 2860 2861 int os::signal_wait() { 2862 return check_pending_signals(); 2863 } 2864 2865 //////////////////////////////////////////////////////////////////////////////// 2866 // Virtual Memory 2867 2868 int os::vm_page_size() { 2869 // Seems redundant as all get out 2870 assert(os::Linux::page_size() != -1, "must call os::init"); 2871 return os::Linux::page_size(); 2872 } 2873 2874 // Solaris allocates memory by pages. 2875 int os::vm_allocation_granularity() { 2876 assert(os::Linux::page_size() != -1, "must call os::init"); 2877 return os::Linux::page_size(); 2878 } 2879 2880 // Rationale behind this function: 2881 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2882 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2883 // samples for JITted code. Here we create private executable mapping over the code cache 2884 // and then we can use standard (well, almost, as mapping can change) way to provide 2885 // info for the reporting script by storing timestamp and location of symbol 2886 void linux_wrap_code(char* base, size_t size) { 2887 static volatile jint cnt = 0; 2888 2889 if (!UseOprofile) { 2890 return; 2891 } 2892 2893 char buf[PATH_MAX+1]; 2894 int num = Atomic::add(&cnt, 1); 2895 2896 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2897 os::get_temp_directory(), os::current_process_id(), num); 2898 unlink(buf); 2899 2900 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2901 2902 if (fd != -1) { 2903 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2904 if (rv != (off_t)-1) { 2905 if (::write(fd, "", 1) == 1) { 2906 mmap(base, size, 2907 PROT_READ|PROT_WRITE|PROT_EXEC, 2908 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2909 } 2910 } 2911 ::close(fd); 2912 unlink(buf); 2913 } 2914 } 2915 2916 static bool recoverable_mmap_error(int err) { 2917 // See if the error is one we can let the caller handle. This 2918 // list of errno values comes from JBS-6843484. I can't find a 2919 // Linux man page that documents this specific set of errno 2920 // values so while this list currently matches Solaris, it may 2921 // change as we gain experience with this failure mode. 2922 switch (err) { 2923 case EBADF: 2924 case EINVAL: 2925 case ENOTSUP: 2926 // let the caller deal with these errors 2927 return true; 2928 2929 default: 2930 // Any remaining errors on this OS can cause our reserved mapping 2931 // to be lost. That can cause confusion where different data 2932 // structures think they have the same memory mapped. The worst 2933 // scenario is if both the VM and a library think they have the 2934 // same memory mapped. 2935 return false; 2936 } 2937 } 2938 2939 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2940 int err) { 2941 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2942 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2943 os::strerror(err), err); 2944 } 2945 2946 static void warn_fail_commit_memory(char* addr, size_t size, 2947 size_t alignment_hint, bool exec, 2948 int err) { 2949 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2950 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2951 alignment_hint, exec, os::strerror(err), err); 2952 } 2953 2954 // NOTE: Linux kernel does not really reserve the pages for us. 2955 // All it does is to check if there are enough free pages 2956 // left at the time of mmap(). This could be a potential 2957 // problem. 2958 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2959 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2960 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2961 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2962 if (res != (uintptr_t) MAP_FAILED) { 2963 if (UseNUMAInterleaving) { 2964 numa_make_global(addr, size); 2965 } 2966 return 0; 2967 } 2968 2969 int err = errno; // save errno from mmap() call above 2970 2971 if (!recoverable_mmap_error(err)) { 2972 warn_fail_commit_memory(addr, size, exec, err); 2973 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2974 } 2975 2976 return err; 2977 } 2978 2979 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2980 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2981 } 2982 2983 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2984 const char* mesg) { 2985 assert(mesg != NULL, "mesg must be specified"); 2986 int err = os::Linux::commit_memory_impl(addr, size, exec); 2987 if (err != 0) { 2988 // the caller wants all commit errors to exit with the specified mesg: 2989 warn_fail_commit_memory(addr, size, exec, err); 2990 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2991 } 2992 } 2993 2994 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2995 #ifndef MAP_HUGETLB 2996 #define MAP_HUGETLB 0x40000 2997 #endif 2998 2999 // If mmap flags are set with MAP_HUGETLB and the system supports multiple 3000 // huge page sizes, flag bits [26:31] can be used to encode the log2 of the 3001 // desired huge page size. Otherwise, the system's default huge page size will be used. 3002 // See mmap(2) man page for more info (since Linux 3.8). 3003 // https://lwn.net/Articles/533499/ 3004 #ifndef MAP_HUGE_SHIFT 3005 #define MAP_HUGE_SHIFT 26 3006 #endif 3007 3008 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 3009 #ifndef MADV_HUGEPAGE 3010 #define MADV_HUGEPAGE 14 3011 #endif 3012 3013 int os::Linux::commit_memory_impl(char* addr, size_t size, 3014 size_t alignment_hint, bool exec) { 3015 int err = os::Linux::commit_memory_impl(addr, size, exec); 3016 if (err == 0) { 3017 realign_memory(addr, size, alignment_hint); 3018 } 3019 return err; 3020 } 3021 3022 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 3023 bool exec) { 3024 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 3025 } 3026 3027 void os::pd_commit_memory_or_exit(char* addr, size_t size, 3028 size_t alignment_hint, bool exec, 3029 const char* mesg) { 3030 assert(mesg != NULL, "mesg must be specified"); 3031 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 3032 if (err != 0) { 3033 // the caller wants all commit errors to exit with the specified mesg: 3034 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 3035 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 3036 } 3037 } 3038 3039 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 3040 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 3041 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 3042 // be supported or the memory may already be backed by huge pages. 3043 ::madvise(addr, bytes, MADV_HUGEPAGE); 3044 } 3045 } 3046 3047 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 3048 // This method works by doing an mmap over an existing mmaping and effectively discarding 3049 // the existing pages. However it won't work for SHM-based large pages that cannot be 3050 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 3051 // small pages on top of the SHM segment. This method always works for small pages, so we 3052 // allow that in any case. 3053 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 3054 commit_memory(addr, bytes, alignment_hint, !ExecMem); 3055 } 3056 } 3057 3058 void os::numa_make_global(char *addr, size_t bytes) { 3059 Linux::numa_interleave_memory(addr, bytes); 3060 } 3061 3062 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 3063 // bind policy to MPOL_PREFERRED for the current thread. 3064 #define USE_MPOL_PREFERRED 0 3065 3066 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 3067 // To make NUMA and large pages more robust when both enabled, we need to ease 3068 // the requirements on where the memory should be allocated. MPOL_BIND is the 3069 // default policy and it will force memory to be allocated on the specified 3070 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 3071 // the specified node, but will not force it. Using this policy will prevent 3072 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 3073 // free large pages. 3074 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 3075 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 3076 } 3077 3078 bool os::numa_topology_changed() { return false; } 3079 3080 size_t os::numa_get_groups_num() { 3081 // Return just the number of nodes in which it's possible to allocate memory 3082 // (in numa terminology, configured nodes). 3083 return Linux::numa_num_configured_nodes(); 3084 } 3085 3086 int os::numa_get_group_id() { 3087 int cpu_id = Linux::sched_getcpu(); 3088 if (cpu_id != -1) { 3089 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 3090 if (lgrp_id != -1) { 3091 return lgrp_id; 3092 } 3093 } 3094 return 0; 3095 } 3096 3097 int os::numa_get_group_id_for_address(const void* address) { 3098 void** pages = const_cast<void**>(&address); 3099 int id = -1; 3100 3101 if (os::Linux::numa_move_pages(0, 1, pages, NULL, &id, 0) == -1) { 3102 return -1; 3103 } 3104 if (id < 0) { 3105 return -1; 3106 } 3107 return id; 3108 } 3109 3110 int os::Linux::get_existing_num_nodes() { 3111 int node; 3112 int highest_node_number = Linux::numa_max_node(); 3113 int num_nodes = 0; 3114 3115 // Get the total number of nodes in the system including nodes without memory. 3116 for (node = 0; node <= highest_node_number; node++) { 3117 if (is_node_in_existing_nodes(node)) { 3118 num_nodes++; 3119 } 3120 } 3121 return num_nodes; 3122 } 3123 3124 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 3125 int highest_node_number = Linux::numa_max_node(); 3126 size_t i = 0; 3127 3128 // Map all node ids in which it is possible to allocate memory. Also nodes are 3129 // not always consecutively available, i.e. available from 0 to the highest 3130 // node number. If the nodes have been bound explicitly using numactl membind, 3131 // then allocate memory from those nodes only. 3132 for (int node = 0; node <= highest_node_number; node++) { 3133 if (Linux::is_node_in_bound_nodes((unsigned int)node)) { 3134 ids[i++] = node; 3135 } 3136 } 3137 return i; 3138 } 3139 3140 bool os::get_page_info(char *start, page_info* info) { 3141 return false; 3142 } 3143 3144 char *os::scan_pages(char *start, char* end, page_info* page_expected, 3145 page_info* page_found) { 3146 return end; 3147 } 3148 3149 3150 int os::Linux::sched_getcpu_syscall(void) { 3151 unsigned int cpu = 0; 3152 int retval = -1; 3153 3154 #if defined(IA32) 3155 #ifndef SYS_getcpu 3156 #define SYS_getcpu 318 3157 #endif 3158 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 3159 #elif defined(AMD64) 3160 // Unfortunately we have to bring all these macros here from vsyscall.h 3161 // to be able to compile on old linuxes. 3162 #define __NR_vgetcpu 2 3163 #define VSYSCALL_START (-10UL << 20) 3164 #define VSYSCALL_SIZE 1024 3165 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 3166 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 3167 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 3168 retval = vgetcpu(&cpu, NULL, NULL); 3169 #endif 3170 3171 return (retval == -1) ? retval : cpu; 3172 } 3173 3174 void os::Linux::sched_getcpu_init() { 3175 // sched_getcpu() should be in libc. 3176 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 3177 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 3178 3179 // If it's not, try a direct syscall. 3180 if (sched_getcpu() == -1) { 3181 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 3182 (void*)&sched_getcpu_syscall)); 3183 } 3184 3185 if (sched_getcpu() == -1) { 3186 vm_exit_during_initialization("getcpu(2) system call not supported by kernel"); 3187 } 3188 } 3189 3190 // Something to do with the numa-aware allocator needs these symbols 3191 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 3192 extern "C" JNIEXPORT void numa_error(char *where) { } 3193 3194 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails 3195 // load symbol from base version instead. 3196 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 3197 void *f = dlvsym(handle, name, "libnuma_1.1"); 3198 if (f == NULL) { 3199 f = dlsym(handle, name); 3200 } 3201 return f; 3202 } 3203 3204 // Handle request to load libnuma symbol version 1.2 (API v2) only. 3205 // Return NULL if the symbol is not defined in this particular version. 3206 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) { 3207 return dlvsym(handle, name, "libnuma_1.2"); 3208 } 3209 3210 bool os::Linux::libnuma_init() { 3211 if (sched_getcpu() != -1) { // Requires sched_getcpu() support 3212 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 3213 if (handle != NULL) { 3214 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 3215 libnuma_dlsym(handle, "numa_node_to_cpus"))); 3216 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 3217 libnuma_dlsym(handle, "numa_max_node"))); 3218 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t, 3219 libnuma_dlsym(handle, "numa_num_configured_nodes"))); 3220 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 3221 libnuma_dlsym(handle, "numa_available"))); 3222 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 3223 libnuma_dlsym(handle, "numa_tonode_memory"))); 3224 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 3225 libnuma_dlsym(handle, "numa_interleave_memory"))); 3226 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t, 3227 libnuma_v2_dlsym(handle, "numa_interleave_memory"))); 3228 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 3229 libnuma_dlsym(handle, "numa_set_bind_policy"))); 3230 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t, 3231 libnuma_dlsym(handle, "numa_bitmask_isbitset"))); 3232 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t, 3233 libnuma_dlsym(handle, "numa_distance"))); 3234 set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t, 3235 libnuma_v2_dlsym(handle, "numa_get_membind"))); 3236 set_numa_get_interleave_mask(CAST_TO_FN_PTR(numa_get_interleave_mask_func_t, 3237 libnuma_v2_dlsym(handle, "numa_get_interleave_mask"))); 3238 set_numa_move_pages(CAST_TO_FN_PTR(numa_move_pages_func_t, 3239 libnuma_dlsym(handle, "numa_move_pages"))); 3240 set_numa_set_preferred(CAST_TO_FN_PTR(numa_set_preferred_func_t, 3241 libnuma_dlsym(handle, "numa_set_preferred"))); 3242 3243 if (numa_available() != -1) { 3244 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 3245 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr")); 3246 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr")); 3247 set_numa_interleave_bitmask(_numa_get_interleave_mask()); 3248 set_numa_membind_bitmask(_numa_get_membind()); 3249 // Create an index -> node mapping, since nodes are not always consecutive 3250 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 3251 rebuild_nindex_to_node_map(); 3252 // Create a cpu -> node mapping 3253 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 3254 rebuild_cpu_to_node_map(); 3255 return true; 3256 } 3257 } 3258 } 3259 return false; 3260 } 3261 3262 size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 3263 // Creating guard page is very expensive. Java thread has HotSpot 3264 // guard pages, only enable glibc guard page for non-Java threads. 3265 // (Remember: compiler thread is a Java thread, too!) 3266 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size()); 3267 } 3268 3269 void os::Linux::rebuild_nindex_to_node_map() { 3270 int highest_node_number = Linux::numa_max_node(); 3271 3272 nindex_to_node()->clear(); 3273 for (int node = 0; node <= highest_node_number; node++) { 3274 if (Linux::is_node_in_existing_nodes(node)) { 3275 nindex_to_node()->append(node); 3276 } 3277 } 3278 } 3279 3280 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 3281 // The table is later used in get_node_by_cpu(). 3282 void os::Linux::rebuild_cpu_to_node_map() { 3283 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 3284 // in libnuma (possible values are starting from 16, 3285 // and continuing up with every other power of 2, but less 3286 // than the maximum number of CPUs supported by kernel), and 3287 // is a subject to change (in libnuma version 2 the requirements 3288 // are more reasonable) we'll just hardcode the number they use 3289 // in the library. 3290 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 3291 3292 size_t cpu_num = processor_count(); 3293 size_t cpu_map_size = NCPUS / BitsPerCLong; 3294 size_t cpu_map_valid_size = 3295 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 3296 3297 cpu_to_node()->clear(); 3298 cpu_to_node()->at_grow(cpu_num - 1); 3299 3300 size_t node_num = get_existing_num_nodes(); 3301 3302 int distance = 0; 3303 int closest_distance = INT_MAX; 3304 int closest_node = 0; 3305 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 3306 for (size_t i = 0; i < node_num; i++) { 3307 // Check if node is configured (not a memory-less node). If it is not, find 3308 // the closest configured node. Check also if node is bound, i.e. it's allowed 3309 // to allocate memory from the node. If it's not allowed, map cpus in that node 3310 // to the closest node from which memory allocation is allowed. 3311 if (!is_node_in_configured_nodes(nindex_to_node()->at(i)) || 3312 !is_node_in_bound_nodes(nindex_to_node()->at(i))) { 3313 closest_distance = INT_MAX; 3314 // Check distance from all remaining nodes in the system. Ignore distance 3315 // from itself, from another non-configured node, and from another non-bound 3316 // node. 3317 for (size_t m = 0; m < node_num; m++) { 3318 if (m != i && 3319 is_node_in_configured_nodes(nindex_to_node()->at(m)) && 3320 is_node_in_bound_nodes(nindex_to_node()->at(m))) { 3321 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m)); 3322 // If a closest node is found, update. There is always at least one 3323 // configured and bound node in the system so there is always at least 3324 // one node close. 3325 if (distance != 0 && distance < closest_distance) { 3326 closest_distance = distance; 3327 closest_node = nindex_to_node()->at(m); 3328 } 3329 } 3330 } 3331 } else { 3332 // Current node is already a configured node. 3333 closest_node = nindex_to_node()->at(i); 3334 } 3335 3336 // Get cpus from the original node and map them to the closest node. If node 3337 // is a configured node (not a memory-less node), then original node and 3338 // closest node are the same. 3339 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 3340 for (size_t j = 0; j < cpu_map_valid_size; j++) { 3341 if (cpu_map[j] != 0) { 3342 for (size_t k = 0; k < BitsPerCLong; k++) { 3343 if (cpu_map[j] & (1UL << k)) { 3344 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node); 3345 } 3346 } 3347 } 3348 } 3349 } 3350 } 3351 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 3352 } 3353 3354 int os::Linux::get_node_by_cpu(int cpu_id) { 3355 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 3356 return cpu_to_node()->at(cpu_id); 3357 } 3358 return -1; 3359 } 3360 3361 GrowableArray<int>* os::Linux::_cpu_to_node; 3362 GrowableArray<int>* os::Linux::_nindex_to_node; 3363 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 3364 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 3365 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 3366 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes; 3367 os::Linux::numa_available_func_t os::Linux::_numa_available; 3368 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 3369 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 3370 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2; 3371 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 3372 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset; 3373 os::Linux::numa_distance_func_t os::Linux::_numa_distance; 3374 os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind; 3375 os::Linux::numa_get_interleave_mask_func_t os::Linux::_numa_get_interleave_mask; 3376 os::Linux::numa_move_pages_func_t os::Linux::_numa_move_pages; 3377 os::Linux::numa_set_preferred_func_t os::Linux::_numa_set_preferred; 3378 os::Linux::NumaAllocationPolicy os::Linux::_current_numa_policy; 3379 unsigned long* os::Linux::_numa_all_nodes; 3380 struct bitmask* os::Linux::_numa_all_nodes_ptr; 3381 struct bitmask* os::Linux::_numa_nodes_ptr; 3382 struct bitmask* os::Linux::_numa_interleave_bitmask; 3383 struct bitmask* os::Linux::_numa_membind_bitmask; 3384 3385 bool os::pd_uncommit_memory(char* addr, size_t size) { 3386 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 3387 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 3388 return res != (uintptr_t) MAP_FAILED; 3389 } 3390 3391 static address get_stack_commited_bottom(address bottom, size_t size) { 3392 address nbot = bottom; 3393 address ntop = bottom + size; 3394 3395 size_t page_sz = os::vm_page_size(); 3396 unsigned pages = size / page_sz; 3397 3398 unsigned char vec[1]; 3399 unsigned imin = 1, imax = pages + 1, imid; 3400 int mincore_return_value = 0; 3401 3402 assert(imin <= imax, "Unexpected page size"); 3403 3404 while (imin < imax) { 3405 imid = (imax + imin) / 2; 3406 nbot = ntop - (imid * page_sz); 3407 3408 // Use a trick with mincore to check whether the page is mapped or not. 3409 // mincore sets vec to 1 if page resides in memory and to 0 if page 3410 // is swapped output but if page we are asking for is unmapped 3411 // it returns -1,ENOMEM 3412 mincore_return_value = mincore(nbot, page_sz, vec); 3413 3414 if (mincore_return_value == -1) { 3415 // Page is not mapped go up 3416 // to find first mapped page 3417 if (errno != EAGAIN) { 3418 assert(errno == ENOMEM, "Unexpected mincore errno"); 3419 imax = imid; 3420 } 3421 } else { 3422 // Page is mapped go down 3423 // to find first not mapped page 3424 imin = imid + 1; 3425 } 3426 } 3427 3428 nbot = nbot + page_sz; 3429 3430 // Adjust stack bottom one page up if last checked page is not mapped 3431 if (mincore_return_value == -1) { 3432 nbot = nbot + page_sz; 3433 } 3434 3435 return nbot; 3436 } 3437 3438 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) { 3439 int mincore_return_value; 3440 const size_t stripe = 1024; // query this many pages each time 3441 unsigned char vec[stripe + 1]; 3442 // set a guard 3443 vec[stripe] = 'X'; 3444 3445 const size_t page_sz = os::vm_page_size(); 3446 size_t pages = size / page_sz; 3447 3448 assert(is_aligned(start, page_sz), "Start address must be page aligned"); 3449 assert(is_aligned(size, page_sz), "Size must be page aligned"); 3450 3451 committed_start = NULL; 3452 3453 int loops = (pages + stripe - 1) / stripe; 3454 int committed_pages = 0; 3455 address loop_base = start; 3456 bool found_range = false; 3457 3458 for (int index = 0; index < loops && !found_range; index ++) { 3459 assert(pages > 0, "Nothing to do"); 3460 int pages_to_query = (pages >= stripe) ? stripe : pages; 3461 pages -= pages_to_query; 3462 3463 // Get stable read 3464 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN); 3465 3466 // During shutdown, some memory goes away without properly notifying NMT, 3467 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object. 3468 // Bailout and return as not committed for now. 3469 if (mincore_return_value == -1 && errno == ENOMEM) { 3470 return false; 3471 } 3472 3473 assert(vec[stripe] == 'X', "overflow guard"); 3474 assert(mincore_return_value == 0, "Range must be valid"); 3475 // Process this stripe 3476 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) { 3477 if ((vec[vecIdx] & 0x01) == 0) { // not committed 3478 // End of current contiguous region 3479 if (committed_start != NULL) { 3480 found_range = true; 3481 break; 3482 } 3483 } else { // committed 3484 // Start of region 3485 if (committed_start == NULL) { 3486 committed_start = loop_base + page_sz * vecIdx; 3487 } 3488 committed_pages ++; 3489 } 3490 } 3491 3492 loop_base += pages_to_query * page_sz; 3493 } 3494 3495 if (committed_start != NULL) { 3496 assert(committed_pages > 0, "Must have committed region"); 3497 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has"); 3498 assert(committed_start >= start && committed_start < start + size, "Out of range"); 3499 committed_size = page_sz * committed_pages; 3500 return true; 3501 } else { 3502 assert(committed_pages == 0, "Should not have committed region"); 3503 return false; 3504 } 3505 } 3506 3507 3508 // Linux uses a growable mapping for the stack, and if the mapping for 3509 // the stack guard pages is not removed when we detach a thread the 3510 // stack cannot grow beyond the pages where the stack guard was 3511 // mapped. If at some point later in the process the stack expands to 3512 // that point, the Linux kernel cannot expand the stack any further 3513 // because the guard pages are in the way, and a segfault occurs. 3514 // 3515 // However, it's essential not to split the stack region by unmapping 3516 // a region (leaving a hole) that's already part of the stack mapping, 3517 // so if the stack mapping has already grown beyond the guard pages at 3518 // the time we create them, we have to truncate the stack mapping. 3519 // So, we need to know the extent of the stack mapping when 3520 // create_stack_guard_pages() is called. 3521 3522 // We only need this for stacks that are growable: at the time of 3523 // writing thread stacks don't use growable mappings (i.e. those 3524 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 3525 // only applies to the main thread. 3526 3527 // If the (growable) stack mapping already extends beyond the point 3528 // where we're going to put our guard pages, truncate the mapping at 3529 // that point by munmap()ping it. This ensures that when we later 3530 // munmap() the guard pages we don't leave a hole in the stack 3531 // mapping. This only affects the main/primordial thread 3532 3533 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3534 if (os::is_primordial_thread()) { 3535 // As we manually grow stack up to bottom inside create_attached_thread(), 3536 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3537 // we don't need to do anything special. 3538 // Check it first, before calling heavy function. 3539 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3540 unsigned char vec[1]; 3541 3542 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3543 // Fallback to slow path on all errors, including EAGAIN 3544 stack_extent = (uintptr_t) get_stack_commited_bottom( 3545 os::Linux::initial_thread_stack_bottom(), 3546 (size_t)addr - stack_extent); 3547 } 3548 3549 if (stack_extent < (uintptr_t)addr) { 3550 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3551 } 3552 } 3553 3554 return os::commit_memory(addr, size, !ExecMem); 3555 } 3556 3557 // If this is a growable mapping, remove the guard pages entirely by 3558 // munmap()ping them. If not, just call uncommit_memory(). This only 3559 // affects the main/primordial thread, but guard against future OS changes. 3560 // It's safe to always unmap guard pages for primordial thread because we 3561 // always place it right after end of the mapped region. 3562 3563 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3564 uintptr_t stack_extent, stack_base; 3565 3566 if (os::is_primordial_thread()) { 3567 return ::munmap(addr, size) == 0; 3568 } 3569 3570 return os::uncommit_memory(addr, size); 3571 } 3572 3573 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3574 // at 'requested_addr'. If there are existing memory mappings at the same 3575 // location, however, they will be overwritten. If 'fixed' is false, 3576 // 'requested_addr' is only treated as a hint, the return value may or 3577 // may not start from the requested address. Unlike Linux mmap(), this 3578 // function returns NULL to indicate failure. 3579 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3580 char * addr; 3581 int flags; 3582 3583 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3584 if (fixed) { 3585 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3586 flags |= MAP_FIXED; 3587 } 3588 3589 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3590 // touch an uncommitted page. Otherwise, the read/write might 3591 // succeed if we have enough swap space to back the physical page. 3592 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3593 flags, -1, 0); 3594 3595 return addr == MAP_FAILED ? NULL : addr; 3596 } 3597 3598 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3599 // (req_addr != NULL) or with a given alignment. 3600 // - bytes shall be a multiple of alignment. 3601 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3602 // - alignment sets the alignment at which memory shall be allocated. 3603 // It must be a multiple of allocation granularity. 3604 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3605 // req_addr or NULL. 3606 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3607 3608 size_t extra_size = bytes; 3609 if (req_addr == NULL && alignment > 0) { 3610 extra_size += alignment; 3611 } 3612 3613 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3614 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3615 -1, 0); 3616 if (start == MAP_FAILED) { 3617 start = NULL; 3618 } else { 3619 if (req_addr != NULL) { 3620 if (start != req_addr) { 3621 ::munmap(start, extra_size); 3622 start = NULL; 3623 } 3624 } else { 3625 char* const start_aligned = align_up(start, alignment); 3626 char* const end_aligned = start_aligned + bytes; 3627 char* const end = start + extra_size; 3628 if (start_aligned > start) { 3629 ::munmap(start, start_aligned - start); 3630 } 3631 if (end_aligned < end) { 3632 ::munmap(end_aligned, end - end_aligned); 3633 } 3634 start = start_aligned; 3635 } 3636 } 3637 return start; 3638 } 3639 3640 static int anon_munmap(char * addr, size_t size) { 3641 return ::munmap(addr, size) == 0; 3642 } 3643 3644 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3645 size_t alignment_hint) { 3646 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3647 } 3648 3649 bool os::pd_release_memory(char* addr, size_t size) { 3650 return anon_munmap(addr, size); 3651 } 3652 3653 static bool linux_mprotect(char* addr, size_t size, int prot) { 3654 // Linux wants the mprotect address argument to be page aligned. 3655 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size()); 3656 3657 // According to SUSv3, mprotect() should only be used with mappings 3658 // established by mmap(), and mmap() always maps whole pages. Unaligned 3659 // 'addr' likely indicates problem in the VM (e.g. trying to change 3660 // protection of malloc'ed or statically allocated memory). Check the 3661 // caller if you hit this assert. 3662 assert(addr == bottom, "sanity check"); 3663 3664 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3665 Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with protection modes %x", p2i(bottom), p2i(bottom+size), prot); 3666 return ::mprotect(bottom, size, prot) == 0; 3667 } 3668 3669 // Set protections specified 3670 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3671 bool is_committed) { 3672 unsigned int p = 0; 3673 switch (prot) { 3674 case MEM_PROT_NONE: p = PROT_NONE; break; 3675 case MEM_PROT_READ: p = PROT_READ; break; 3676 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3677 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3678 default: 3679 ShouldNotReachHere(); 3680 } 3681 // is_committed is unused. 3682 return linux_mprotect(addr, bytes, p); 3683 } 3684 3685 bool os::guard_memory(char* addr, size_t size) { 3686 return linux_mprotect(addr, size, PROT_NONE); 3687 } 3688 3689 bool os::unguard_memory(char* addr, size_t size) { 3690 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3691 } 3692 3693 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3694 size_t page_size) { 3695 bool result = false; 3696 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3697 MAP_ANONYMOUS|MAP_PRIVATE, 3698 -1, 0); 3699 if (p != MAP_FAILED) { 3700 void *aligned_p = align_up(p, page_size); 3701 3702 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3703 3704 munmap(p, page_size * 2); 3705 } 3706 3707 if (warn && !result) { 3708 warning("TransparentHugePages is not supported by the operating system."); 3709 } 3710 3711 return result; 3712 } 3713 3714 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3715 bool result = false; 3716 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3717 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3718 -1, 0); 3719 3720 if (p != MAP_FAILED) { 3721 // We don't know if this really is a huge page or not. 3722 FILE *fp = fopen("/proc/self/maps", "r"); 3723 if (fp) { 3724 while (!feof(fp)) { 3725 char chars[257]; 3726 long x = 0; 3727 if (fgets(chars, sizeof(chars), fp)) { 3728 if (sscanf(chars, "%lx-%*x", &x) == 1 3729 && x == (long)p) { 3730 if (strstr (chars, "hugepage")) { 3731 result = true; 3732 break; 3733 } 3734 } 3735 } 3736 } 3737 fclose(fp); 3738 } 3739 munmap(p, page_size); 3740 } 3741 3742 if (warn && !result) { 3743 warning("HugeTLBFS is not supported by the operating system."); 3744 } 3745 3746 return result; 3747 } 3748 3749 // From the coredump_filter documentation: 3750 // 3751 // - (bit 0) anonymous private memory 3752 // - (bit 1) anonymous shared memory 3753 // - (bit 2) file-backed private memory 3754 // - (bit 3) file-backed shared memory 3755 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3756 // effective only if the bit 2 is cleared) 3757 // - (bit 5) hugetlb private memory 3758 // - (bit 6) hugetlb shared memory 3759 // - (bit 7) dax private memory 3760 // - (bit 8) dax shared memory 3761 // 3762 static void set_coredump_filter(CoredumpFilterBit bit) { 3763 FILE *f; 3764 long cdm; 3765 3766 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3767 return; 3768 } 3769 3770 if (fscanf(f, "%lx", &cdm) != 1) { 3771 fclose(f); 3772 return; 3773 } 3774 3775 long saved_cdm = cdm; 3776 rewind(f); 3777 cdm |= bit; 3778 3779 if (cdm != saved_cdm) { 3780 fprintf(f, "%#lx", cdm); 3781 } 3782 3783 fclose(f); 3784 } 3785 3786 // Large page support 3787 3788 static size_t _large_page_size = 0; 3789 3790 size_t os::Linux::find_default_large_page_size() { 3791 if (_default_large_page_size != 0) { 3792 return _default_large_page_size; 3793 } 3794 size_t large_page_size = 0; 3795 3796 // large_page_size on Linux is used to round up heap size. x86 uses either 3797 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3798 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3799 // page as large as 256M. 3800 // 3801 // Here we try to figure out page size by parsing /proc/meminfo and looking 3802 // for a line with the following format: 3803 // Hugepagesize: 2048 kB 3804 // 3805 // If we can't determine the value (e.g. /proc is not mounted, or the text 3806 // format has been changed), we'll use the largest page size supported by 3807 // the processor. 3808 3809 #ifndef ZERO 3810 large_page_size = 3811 AARCH64_ONLY(2 * M) 3812 AMD64_ONLY(2 * M) 3813 ARM32_ONLY(2 * M) 3814 IA32_ONLY(4 * M) 3815 IA64_ONLY(256 * M) 3816 PPC_ONLY(4 * M) 3817 S390_ONLY(1 * M); 3818 #endif // ZERO 3819 3820 FILE *fp = fopen("/proc/meminfo", "r"); 3821 if (fp) { 3822 while (!feof(fp)) { 3823 int x = 0; 3824 char buf[16]; 3825 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3826 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3827 large_page_size = x * K; 3828 break; 3829 } 3830 } else { 3831 // skip to next line 3832 for (;;) { 3833 int ch = fgetc(fp); 3834 if (ch == EOF || ch == (int)'\n') break; 3835 } 3836 } 3837 } 3838 fclose(fp); 3839 } 3840 return large_page_size; 3841 } 3842 3843 size_t os::Linux::find_large_page_size(size_t large_page_size) { 3844 if (_default_large_page_size == 0) { 3845 _default_large_page_size = Linux::find_default_large_page_size(); 3846 } 3847 // We need to scan /sys/kernel/mm/hugepages 3848 // to discover the available page sizes 3849 const char* sys_hugepages = "/sys/kernel/mm/hugepages"; 3850 3851 DIR *dir = opendir(sys_hugepages); 3852 if (dir == NULL) { 3853 return _default_large_page_size; 3854 } 3855 3856 struct dirent *entry; 3857 size_t page_size; 3858 while ((entry = readdir(dir)) != NULL) { 3859 if (entry->d_type == DT_DIR && 3860 sscanf(entry->d_name, "hugepages-%zukB", &page_size) == 1) { 3861 // The kernel is using kB, hotspot uses bytes 3862 if (large_page_size == page_size * K) { 3863 closedir(dir); 3864 return large_page_size; 3865 } 3866 } 3867 } 3868 closedir(dir); 3869 return _default_large_page_size; 3870 } 3871 3872 size_t os::Linux::setup_large_page_size() { 3873 _default_large_page_size = Linux::find_default_large_page_size(); 3874 3875 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != _default_large_page_size ) { 3876 _large_page_size = find_large_page_size(LargePageSizeInBytes); 3877 if (_large_page_size == _default_large_page_size) { 3878 warning("Setting LargePageSizeInBytes=" SIZE_FORMAT " has no effect on this OS. Using the default large page size " 3879 SIZE_FORMAT "%s.", 3880 LargePageSizeInBytes, 3881 byte_size_in_proper_unit(_large_page_size), proper_unit_for_byte_size(_large_page_size)); 3882 } 3883 } else { 3884 _large_page_size = _default_large_page_size; 3885 } 3886 3887 const size_t default_page_size = (size_t)Linux::page_size(); 3888 if (_large_page_size > default_page_size) { 3889 _page_sizes[0] = _large_page_size; 3890 _page_sizes[1] = default_page_size; 3891 _page_sizes[2] = 0; 3892 } 3893 3894 return _large_page_size; 3895 } 3896 3897 size_t os::Linux::default_large_page_size() { 3898 return _default_large_page_size; 3899 } 3900 3901 bool os::Linux::setup_large_page_type(size_t page_size) { 3902 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3903 FLAG_IS_DEFAULT(UseSHM) && 3904 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3905 3906 // The type of large pages has not been specified by the user. 3907 3908 // Try UseHugeTLBFS and then UseSHM. 3909 UseHugeTLBFS = UseSHM = true; 3910 3911 // Don't try UseTransparentHugePages since there are known 3912 // performance issues with it turned on. This might change in the future. 3913 UseTransparentHugePages = false; 3914 } 3915 3916 if (UseTransparentHugePages) { 3917 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3918 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3919 UseHugeTLBFS = false; 3920 UseSHM = false; 3921 return true; 3922 } 3923 UseTransparentHugePages = false; 3924 } 3925 3926 if (UseHugeTLBFS) { 3927 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3928 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3929 UseSHM = false; 3930 return true; 3931 } 3932 UseHugeTLBFS = false; 3933 } 3934 3935 return UseSHM; 3936 } 3937 3938 void os::large_page_init() { 3939 if (!UseLargePages && 3940 !UseTransparentHugePages && 3941 !UseHugeTLBFS && 3942 !UseSHM) { 3943 // Not using large pages. 3944 return; 3945 } 3946 3947 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3948 // The user explicitly turned off large pages. 3949 // Ignore the rest of the large pages flags. 3950 UseTransparentHugePages = false; 3951 UseHugeTLBFS = false; 3952 UseSHM = false; 3953 return; 3954 } 3955 3956 size_t large_page_size = Linux::setup_large_page_size(); 3957 UseLargePages = Linux::setup_large_page_type(large_page_size); 3958 3959 set_coredump_filter(LARGEPAGES_BIT); 3960 } 3961 3962 #ifndef SHM_HUGETLB 3963 #define SHM_HUGETLB 04000 3964 #endif 3965 3966 #define shm_warning_format(format, ...) \ 3967 do { \ 3968 if (UseLargePages && \ 3969 (!FLAG_IS_DEFAULT(UseLargePages) || \ 3970 !FLAG_IS_DEFAULT(UseSHM) || \ 3971 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \ 3972 warning(format, __VA_ARGS__); \ 3973 } \ 3974 } while (0) 3975 3976 #define shm_warning(str) shm_warning_format("%s", str) 3977 3978 #define shm_warning_with_errno(str) \ 3979 do { \ 3980 int err = errno; \ 3981 shm_warning_format(str " (error = %d)", err); \ 3982 } while (0) 3983 3984 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) { 3985 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment"); 3986 3987 if (!is_aligned(alignment, SHMLBA)) { 3988 assert(false, "Code below assumes that alignment is at least SHMLBA aligned"); 3989 return NULL; 3990 } 3991 3992 // To ensure that we get 'alignment' aligned memory from shmat, 3993 // we pre-reserve aligned virtual memory and then attach to that. 3994 3995 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL); 3996 if (pre_reserved_addr == NULL) { 3997 // Couldn't pre-reserve aligned memory. 3998 shm_warning("Failed to pre-reserve aligned memory for shmat."); 3999 return NULL; 4000 } 4001 4002 // SHM_REMAP is needed to allow shmat to map over an existing mapping. 4003 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP); 4004 4005 if ((intptr_t)addr == -1) { 4006 int err = errno; 4007 shm_warning_with_errno("Failed to attach shared memory."); 4008 4009 assert(err != EACCES, "Unexpected error"); 4010 assert(err != EIDRM, "Unexpected error"); 4011 assert(err != EINVAL, "Unexpected error"); 4012 4013 // Since we don't know if the kernel unmapped the pre-reserved memory area 4014 // we can't unmap it, since that would potentially unmap memory that was 4015 // mapped from other threads. 4016 return NULL; 4017 } 4018 4019 return addr; 4020 } 4021 4022 static char* shmat_at_address(int shmid, char* req_addr) { 4023 if (!is_aligned(req_addr, SHMLBA)) { 4024 assert(false, "Requested address needs to be SHMLBA aligned"); 4025 return NULL; 4026 } 4027 4028 char* addr = (char*)shmat(shmid, req_addr, 0); 4029 4030 if ((intptr_t)addr == -1) { 4031 shm_warning_with_errno("Failed to attach shared memory."); 4032 return NULL; 4033 } 4034 4035 return addr; 4036 } 4037 4038 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) { 4039 // If a req_addr has been provided, we assume that the caller has already aligned the address. 4040 if (req_addr != NULL) { 4041 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size"); 4042 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment"); 4043 return shmat_at_address(shmid, req_addr); 4044 } 4045 4046 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically 4047 // return large page size aligned memory addresses when req_addr == NULL. 4048 // However, if the alignment is larger than the large page size, we have 4049 // to manually ensure that the memory returned is 'alignment' aligned. 4050 if (alignment > os::large_page_size()) { 4051 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size"); 4052 return shmat_with_alignment(shmid, bytes, alignment); 4053 } else { 4054 return shmat_at_address(shmid, NULL); 4055 } 4056 } 4057 4058 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 4059 char* req_addr, bool exec) { 4060 // "exec" is passed in but not used. Creating the shared image for 4061 // the code cache doesn't have an SHM_X executable permission to check. 4062 assert(UseLargePages && UseSHM, "only for SHM large pages"); 4063 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 4064 assert(is_aligned(req_addr, alignment), "Unaligned address"); 4065 4066 if (!is_aligned(bytes, os::large_page_size())) { 4067 return NULL; // Fallback to small pages. 4068 } 4069 4070 // Create a large shared memory region to attach to based on size. 4071 // Currently, size is the total size of the heap. 4072 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 4073 if (shmid == -1) { 4074 // Possible reasons for shmget failure: 4075 // 1. shmmax is too small for Java heap. 4076 // > check shmmax value: cat /proc/sys/kernel/shmmax 4077 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 4078 // 2. not enough large page memory. 4079 // > check available large pages: cat /proc/meminfo 4080 // > increase amount of large pages: 4081 // echo new_value > /proc/sys/vm/nr_hugepages 4082 // Note 1: different Linux may use different name for this property, 4083 // e.g. on Redhat AS-3 it is "hugetlb_pool". 4084 // Note 2: it's possible there's enough physical memory available but 4085 // they are so fragmented after a long run that they can't 4086 // coalesce into large pages. Try to reserve large pages when 4087 // the system is still "fresh". 4088 shm_warning_with_errno("Failed to reserve shared memory."); 4089 return NULL; 4090 } 4091 4092 // Attach to the region. 4093 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr); 4094 4095 // Remove shmid. If shmat() is successful, the actual shared memory segment 4096 // will be deleted when it's detached by shmdt() or when the process 4097 // terminates. If shmat() is not successful this will remove the shared 4098 // segment immediately. 4099 shmctl(shmid, IPC_RMID, NULL); 4100 4101 return addr; 4102 } 4103 4104 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 4105 int error) { 4106 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 4107 4108 bool warn_on_failure = UseLargePages && 4109 (!FLAG_IS_DEFAULT(UseLargePages) || 4110 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 4111 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 4112 4113 if (warn_on_failure) { 4114 char msg[128]; 4115 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 4116 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 4117 warning("%s", msg); 4118 } 4119 } 4120 4121 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 4122 char* req_addr, 4123 bool exec) { 4124 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 4125 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size"); 4126 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 4127 4128 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 4129 int flags = MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB; 4130 4131 if (os::large_page_size() != default_large_page_size()) { 4132 flags |= (exact_log2(os::large_page_size()) << MAP_HUGE_SHIFT); 4133 } 4134 char* addr = (char*)::mmap(req_addr, bytes, prot, flags, -1, 0); 4135 4136 if (addr == MAP_FAILED) { 4137 warn_on_large_pages_failure(req_addr, bytes, errno); 4138 return NULL; 4139 } 4140 4141 assert(is_aligned(addr, os::large_page_size()), "Must be"); 4142 4143 return addr; 4144 } 4145 4146 // Reserve memory using mmap(MAP_HUGETLB). 4147 // - bytes shall be a multiple of alignment. 4148 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 4149 // - alignment sets the alignment at which memory shall be allocated. 4150 // It must be a multiple of allocation granularity. 4151 // Returns address of memory or NULL. If req_addr was not NULL, will only return 4152 // req_addr or NULL. 4153 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 4154 size_t alignment, 4155 char* req_addr, 4156 bool exec) { 4157 size_t large_page_size = os::large_page_size(); 4158 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 4159 4160 assert(is_aligned(req_addr, alignment), "Must be"); 4161 assert(is_aligned(bytes, alignment), "Must be"); 4162 4163 // First reserve - but not commit - the address range in small pages. 4164 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 4165 4166 if (start == NULL) { 4167 return NULL; 4168 } 4169 4170 assert(is_aligned(start, alignment), "Must be"); 4171 4172 char* end = start + bytes; 4173 4174 // Find the regions of the allocated chunk that can be promoted to large pages. 4175 char* lp_start = align_up(start, large_page_size); 4176 char* lp_end = align_down(end, large_page_size); 4177 4178 size_t lp_bytes = lp_end - lp_start; 4179 4180 assert(is_aligned(lp_bytes, large_page_size), "Must be"); 4181 4182 if (lp_bytes == 0) { 4183 // The mapped region doesn't even span the start and the end of a large page. 4184 // Fall back to allocate a non-special area. 4185 ::munmap(start, end - start); 4186 return NULL; 4187 } 4188 4189 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 4190 int flags = MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED; 4191 void* result; 4192 4193 // Commit small-paged leading area. 4194 if (start != lp_start) { 4195 result = ::mmap(start, lp_start - start, prot, flags, -1, 0); 4196 if (result == MAP_FAILED) { 4197 ::munmap(lp_start, end - lp_start); 4198 return NULL; 4199 } 4200 } 4201 4202 // Commit large-paged area. 4203 flags |= MAP_HUGETLB; 4204 4205 if (os::large_page_size() != default_large_page_size()) { 4206 flags |= (exact_log2(os::large_page_size()) << MAP_HUGE_SHIFT); 4207 } 4208 4209 result = ::mmap(lp_start, lp_bytes, prot, flags, -1, 0); 4210 if (result == MAP_FAILED) { 4211 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 4212 // If the mmap above fails, the large pages region will be unmapped and we 4213 // have regions before and after with small pages. Release these regions. 4214 // 4215 // | mapped | unmapped | mapped | 4216 // ^ ^ ^ ^ 4217 // start lp_start lp_end end 4218 // 4219 ::munmap(start, lp_start - start); 4220 ::munmap(lp_end, end - lp_end); 4221 return NULL; 4222 } 4223 4224 // Commit small-paged trailing area. 4225 if (lp_end != end) { 4226 result = ::mmap(lp_end, end - lp_end, prot, 4227 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 4228 -1, 0); 4229 if (result == MAP_FAILED) { 4230 ::munmap(start, lp_end - start); 4231 return NULL; 4232 } 4233 } 4234 4235 return start; 4236 } 4237 4238 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 4239 size_t alignment, 4240 char* req_addr, 4241 bool exec) { 4242 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 4243 assert(is_aligned(req_addr, alignment), "Must be"); 4244 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 4245 assert(is_power_of_2(os::large_page_size()), "Must be"); 4246 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 4247 4248 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 4249 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 4250 } else { 4251 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 4252 } 4253 } 4254 4255 char* os::pd_reserve_memory_special(size_t bytes, size_t alignment, 4256 char* req_addr, bool exec) { 4257 assert(UseLargePages, "only for large pages"); 4258 4259 char* addr; 4260 if (UseSHM) { 4261 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 4262 } else { 4263 assert(UseHugeTLBFS, "must be"); 4264 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 4265 } 4266 4267 if (addr != NULL) { 4268 if (UseNUMAInterleaving) { 4269 numa_make_global(addr, bytes); 4270 } 4271 } 4272 4273 return addr; 4274 } 4275 4276 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 4277 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 4278 return shmdt(base) == 0; 4279 } 4280 4281 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 4282 return pd_release_memory(base, bytes); 4283 } 4284 4285 bool os::pd_release_memory_special(char* base, size_t bytes) { 4286 assert(UseLargePages, "only for large pages"); 4287 bool res; 4288 4289 if (UseSHM) { 4290 res = os::Linux::release_memory_special_shm(base, bytes); 4291 } else { 4292 assert(UseHugeTLBFS, "must be"); 4293 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 4294 } 4295 return res; 4296 } 4297 4298 size_t os::large_page_size() { 4299 return _large_page_size; 4300 } 4301 4302 // With SysV SHM the entire memory region must be allocated as shared 4303 // memory. 4304 // HugeTLBFS allows application to commit large page memory on demand. 4305 // However, when committing memory with HugeTLBFS fails, the region 4306 // that was supposed to be committed will lose the old reservation 4307 // and allow other threads to steal that memory region. Because of this 4308 // behavior we can't commit HugeTLBFS memory. 4309 bool os::can_commit_large_page_memory() { 4310 return UseTransparentHugePages; 4311 } 4312 4313 bool os::can_execute_large_page_memory() { 4314 return UseTransparentHugePages || UseHugeTLBFS; 4315 } 4316 4317 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) { 4318 assert(file_desc >= 0, "file_desc is not valid"); 4319 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr); 4320 if (result != NULL) { 4321 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) { 4322 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory")); 4323 } 4324 } 4325 return result; 4326 } 4327 4328 // Reserve memory at an arbitrary address, only if that area is 4329 // available (and not reserved for something else). 4330 4331 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 4332 // Assert only that the size is a multiple of the page size, since 4333 // that's all that mmap requires, and since that's all we really know 4334 // about at this low abstraction level. If we need higher alignment, 4335 // we can either pass an alignment to this method or verify alignment 4336 // in one of the methods further up the call chain. See bug 5044738. 4337 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 4338 4339 // Repeatedly allocate blocks until the block is allocated at the 4340 // right spot. 4341 4342 // Linux mmap allows caller to pass an address as hint; give it a try first, 4343 // if kernel honors the hint then we can return immediately. 4344 char * addr = anon_mmap(requested_addr, bytes, false); 4345 if (addr == requested_addr) { 4346 return requested_addr; 4347 } 4348 4349 if (addr != NULL) { 4350 // mmap() is successful but it fails to reserve at the requested address 4351 anon_munmap(addr, bytes); 4352 } 4353 4354 return NULL; 4355 } 4356 4357 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 4358 void os::infinite_sleep() { 4359 while (true) { // sleep forever ... 4360 ::sleep(100); // ... 100 seconds at a time 4361 } 4362 } 4363 4364 // Used to convert frequent JVM_Yield() to nops 4365 bool os::dont_yield() { 4366 return DontYieldALot; 4367 } 4368 4369 // Linux CFS scheduler (since 2.6.23) does not guarantee sched_yield(2) will 4370 // actually give up the CPU. Since skip buddy (v2.6.28): 4371 // 4372 // * Sets the yielding task as skip buddy for current CPU's run queue. 4373 // * Picks next from run queue, if empty, picks a skip buddy (can be the yielding task). 4374 // * Clears skip buddies for this run queue (yielding task no longer a skip buddy). 4375 // 4376 // An alternative is calling os::naked_short_nanosleep with a small number to avoid 4377 // getting re-scheduled immediately. 4378 // 4379 void os::naked_yield() { 4380 sched_yield(); 4381 } 4382 4383 //////////////////////////////////////////////////////////////////////////////// 4384 // thread priority support 4385 4386 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 4387 // only supports dynamic priority, static priority must be zero. For real-time 4388 // applications, Linux supports SCHED_RR which allows static priority (1-99). 4389 // However, for large multi-threaded applications, SCHED_RR is not only slower 4390 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 4391 // of 5 runs - Sep 2005). 4392 // 4393 // The following code actually changes the niceness of kernel-thread/LWP. It 4394 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 4395 // not the entire user process, and user level threads are 1:1 mapped to kernel 4396 // threads. It has always been the case, but could change in the future. For 4397 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 4398 // It is only used when ThreadPriorityPolicy=1 and may require system level permission 4399 // (e.g., root privilege or CAP_SYS_NICE capability). 4400 4401 int os::java_to_os_priority[CriticalPriority + 1] = { 4402 19, // 0 Entry should never be used 4403 4404 4, // 1 MinPriority 4405 3, // 2 4406 2, // 3 4407 4408 1, // 4 4409 0, // 5 NormPriority 4410 -1, // 6 4411 4412 -2, // 7 4413 -3, // 8 4414 -4, // 9 NearMaxPriority 4415 4416 -5, // 10 MaxPriority 4417 4418 -5 // 11 CriticalPriority 4419 }; 4420 4421 static int prio_init() { 4422 if (ThreadPriorityPolicy == 1) { 4423 if (geteuid() != 0) { 4424 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy) && !FLAG_IS_JIMAGE_RESOURCE(ThreadPriorityPolicy)) { 4425 warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \ 4426 "e.g., being the root user. If the necessary permission is not " \ 4427 "possessed, changes to priority will be silently ignored."); 4428 } 4429 } 4430 } 4431 if (UseCriticalJavaThreadPriority) { 4432 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 4433 } 4434 return 0; 4435 } 4436 4437 OSReturn os::set_native_priority(Thread* thread, int newpri) { 4438 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 4439 4440 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 4441 return (ret == 0) ? OS_OK : OS_ERR; 4442 } 4443 4444 OSReturn os::get_native_priority(const Thread* const thread, 4445 int *priority_ptr) { 4446 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 4447 *priority_ptr = java_to_os_priority[NormPriority]; 4448 return OS_OK; 4449 } 4450 4451 errno = 0; 4452 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 4453 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 4454 } 4455 4456 //////////////////////////////////////////////////////////////////////////////// 4457 // suspend/resume support 4458 4459 // The low-level signal-based suspend/resume support is a remnant from the 4460 // old VM-suspension that used to be for java-suspension, safepoints etc, 4461 // within hotspot. Currently used by JFR's OSThreadSampler 4462 // 4463 // The remaining code is greatly simplified from the more general suspension 4464 // code that used to be used. 4465 // 4466 // The protocol is quite simple: 4467 // - suspend: 4468 // - sends a signal to the target thread 4469 // - polls the suspend state of the osthread using a yield loop 4470 // - target thread signal handler (SR_handler) sets suspend state 4471 // and blocks in sigsuspend until continued 4472 // - resume: 4473 // - sets target osthread state to continue 4474 // - sends signal to end the sigsuspend loop in the SR_handler 4475 // 4476 // Note that the SR_lock plays no role in this suspend/resume protocol, 4477 // but is checked for NULL in SR_handler as a thread termination indicator. 4478 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs. 4479 // 4480 // Note that resume_clear_context() and suspend_save_context() are needed 4481 // by SR_handler(), so that fetch_frame_from_ucontext() works, 4482 // which in part is used by: 4483 // - Forte Analyzer: AsyncGetCallTrace() 4484 // - StackBanging: get_frame_at_stack_banging_point() 4485 4486 static void resume_clear_context(OSThread *osthread) { 4487 osthread->set_ucontext(NULL); 4488 osthread->set_siginfo(NULL); 4489 } 4490 4491 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 4492 ucontext_t* context) { 4493 osthread->set_ucontext(context); 4494 osthread->set_siginfo(siginfo); 4495 } 4496 4497 // Handler function invoked when a thread's execution is suspended or 4498 // resumed. We have to be careful that only async-safe functions are 4499 // called here (Note: most pthread functions are not async safe and 4500 // should be avoided.) 4501 // 4502 // Note: sigwait() is a more natural fit than sigsuspend() from an 4503 // interface point of view, but sigwait() prevents the signal hander 4504 // from being run. libpthread would get very confused by not having 4505 // its signal handlers run and prevents sigwait()'s use with the 4506 // mutex granting granting signal. 4507 // 4508 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 4509 // 4510 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 4511 // Save and restore errno to avoid confusing native code with EINTR 4512 // after sigsuspend. 4513 int old_errno = errno; 4514 4515 Thread* thread = Thread::current_or_null_safe(); 4516 assert(thread != NULL, "Missing current thread in SR_handler"); 4517 4518 // On some systems we have seen signal delivery get "stuck" until the signal 4519 // mask is changed as part of thread termination. Check that the current thread 4520 // has not already terminated (via SR_lock()) - else the following assertion 4521 // will fail because the thread is no longer a JavaThread as the ~JavaThread 4522 // destructor has completed. 4523 4524 if (thread->SR_lock() == NULL) { 4525 return; 4526 } 4527 4528 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 4529 4530 OSThread* osthread = thread->osthread(); 4531 4532 os::SuspendResume::State current = osthread->sr.state(); 4533 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 4534 suspend_save_context(osthread, siginfo, context); 4535 4536 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 4537 os::SuspendResume::State state = osthread->sr.suspended(); 4538 if (state == os::SuspendResume::SR_SUSPENDED) { 4539 sigset_t suspend_set; // signals for sigsuspend() 4540 sigemptyset(&suspend_set); 4541 // get current set of blocked signals and unblock resume signal 4542 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 4543 sigdelset(&suspend_set, SR_signum); 4544 4545 sr_semaphore.signal(); 4546 // wait here until we are resumed 4547 while (1) { 4548 sigsuspend(&suspend_set); 4549 4550 os::SuspendResume::State result = osthread->sr.running(); 4551 if (result == os::SuspendResume::SR_RUNNING) { 4552 sr_semaphore.signal(); 4553 break; 4554 } 4555 } 4556 4557 } else if (state == os::SuspendResume::SR_RUNNING) { 4558 // request was cancelled, continue 4559 } else { 4560 ShouldNotReachHere(); 4561 } 4562 4563 resume_clear_context(osthread); 4564 } else if (current == os::SuspendResume::SR_RUNNING) { 4565 // request was cancelled, continue 4566 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 4567 // ignore 4568 } else { 4569 // ignore 4570 } 4571 4572 errno = old_errno; 4573 } 4574 4575 static int SR_initialize() { 4576 struct sigaction act; 4577 char *s; 4578 4579 // Get signal number to use for suspend/resume 4580 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4581 int sig = ::strtol(s, 0, 10); 4582 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 4583 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 4584 SR_signum = sig; 4585 } else { 4586 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 4587 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 4588 } 4589 } 4590 4591 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4592 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4593 4594 sigemptyset(&SR_sigset); 4595 sigaddset(&SR_sigset, SR_signum); 4596 4597 // Set up signal handler for suspend/resume 4598 act.sa_flags = SA_RESTART|SA_SIGINFO; 4599 act.sa_handler = (void (*)(int)) SR_handler; 4600 4601 // SR_signum is blocked by default. 4602 // 4528190 - We also need to block pthread restart signal (32 on all 4603 // supported Linux platforms). Note that LinuxThreads need to block 4604 // this signal for all threads to work properly. So we don't have 4605 // to use hard-coded signal number when setting up the mask. 4606 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4607 4608 if (sigaction(SR_signum, &act, 0) == -1) { 4609 return -1; 4610 } 4611 4612 // Save signal flag 4613 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4614 return 0; 4615 } 4616 4617 static int sr_notify(OSThread* osthread) { 4618 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4619 assert_status(status == 0, status, "pthread_kill"); 4620 return status; 4621 } 4622 4623 // "Randomly" selected value for how long we want to spin 4624 // before bailing out on suspending a thread, also how often 4625 // we send a signal to a thread we want to resume 4626 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4627 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4628 4629 // returns true on success and false on error - really an error is fatal 4630 // but this seems the normal response to library errors 4631 static bool do_suspend(OSThread* osthread) { 4632 assert(osthread->sr.is_running(), "thread should be running"); 4633 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4634 4635 // mark as suspended and send signal 4636 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4637 // failed to switch, state wasn't running? 4638 ShouldNotReachHere(); 4639 return false; 4640 } 4641 4642 if (sr_notify(osthread) != 0) { 4643 ShouldNotReachHere(); 4644 } 4645 4646 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4647 while (true) { 4648 if (sr_semaphore.timedwait(2)) { 4649 break; 4650 } else { 4651 // timeout 4652 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4653 if (cancelled == os::SuspendResume::SR_RUNNING) { 4654 return false; 4655 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4656 // make sure that we consume the signal on the semaphore as well 4657 sr_semaphore.wait(); 4658 break; 4659 } else { 4660 ShouldNotReachHere(); 4661 return false; 4662 } 4663 } 4664 } 4665 4666 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4667 return true; 4668 } 4669 4670 static void do_resume(OSThread* osthread) { 4671 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4672 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4673 4674 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4675 // failed to switch to WAKEUP_REQUEST 4676 ShouldNotReachHere(); 4677 return; 4678 } 4679 4680 while (true) { 4681 if (sr_notify(osthread) == 0) { 4682 if (sr_semaphore.timedwait(2)) { 4683 if (osthread->sr.is_running()) { 4684 return; 4685 } 4686 } 4687 } else { 4688 ShouldNotReachHere(); 4689 } 4690 } 4691 4692 guarantee(osthread->sr.is_running(), "Must be running!"); 4693 } 4694 4695 /////////////////////////////////////////////////////////////////////////////////// 4696 // signal handling (except suspend/resume) 4697 4698 // This routine may be used by user applications as a "hook" to catch signals. 4699 // The user-defined signal handler must pass unrecognized signals to this 4700 // routine, and if it returns true (non-zero), then the signal handler must 4701 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4702 // routine will never retun false (zero), but instead will execute a VM panic 4703 // routine kill the process. 4704 // 4705 // If this routine returns false, it is OK to call it again. This allows 4706 // the user-defined signal handler to perform checks either before or after 4707 // the VM performs its own checks. Naturally, the user code would be making 4708 // a serious error if it tried to handle an exception (such as a null check 4709 // or breakpoint) that the VM was generating for its own correct operation. 4710 // 4711 // This routine may recognize any of the following kinds of signals: 4712 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4713 // It should be consulted by handlers for any of those signals. 4714 // 4715 // The caller of this routine must pass in the three arguments supplied 4716 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4717 // field of the structure passed to sigaction(). This routine assumes that 4718 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4719 // 4720 // Note that the VM will print warnings if it detects conflicting signal 4721 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4722 // 4723 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4724 siginfo_t* siginfo, 4725 void* ucontext, 4726 int abort_if_unrecognized); 4727 4728 static void signalHandler(int sig, siginfo_t* info, void* uc) { 4729 assert(info != NULL && uc != NULL, "it must be old kernel"); 4730 int orig_errno = errno; // Preserve errno value over signal handler. 4731 JVM_handle_linux_signal(sig, info, uc, true); 4732 errno = orig_errno; 4733 } 4734 4735 4736 // This boolean allows users to forward their own non-matching signals 4737 // to JVM_handle_linux_signal, harmlessly. 4738 bool os::Linux::signal_handlers_are_installed = false; 4739 4740 // For signal-chaining 4741 bool os::Linux::libjsig_is_loaded = false; 4742 typedef struct sigaction *(*get_signal_t)(int); 4743 get_signal_t os::Linux::get_signal_action = NULL; 4744 4745 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4746 struct sigaction *actp = NULL; 4747 4748 if (libjsig_is_loaded) { 4749 // Retrieve the old signal handler from libjsig 4750 actp = (*get_signal_action)(sig); 4751 } 4752 if (actp == NULL) { 4753 // Retrieve the preinstalled signal handler from jvm 4754 actp = os::Posix::get_preinstalled_handler(sig); 4755 } 4756 4757 return actp; 4758 } 4759 4760 static bool call_chained_handler(struct sigaction *actp, int sig, 4761 siginfo_t *siginfo, void *context) { 4762 // Call the old signal handler 4763 if (actp->sa_handler == SIG_DFL) { 4764 // It's more reasonable to let jvm treat it as an unexpected exception 4765 // instead of taking the default action. 4766 return false; 4767 } else if (actp->sa_handler != SIG_IGN) { 4768 if ((actp->sa_flags & SA_NODEFER) == 0) { 4769 // automaticlly block the signal 4770 sigaddset(&(actp->sa_mask), sig); 4771 } 4772 4773 sa_handler_t hand = NULL; 4774 sa_sigaction_t sa = NULL; 4775 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4776 // retrieve the chained handler 4777 if (siginfo_flag_set) { 4778 sa = actp->sa_sigaction; 4779 } else { 4780 hand = actp->sa_handler; 4781 } 4782 4783 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4784 actp->sa_handler = SIG_DFL; 4785 } 4786 4787 // try to honor the signal mask 4788 sigset_t oset; 4789 sigemptyset(&oset); 4790 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4791 4792 // call into the chained handler 4793 if (siginfo_flag_set) { 4794 (*sa)(sig, siginfo, context); 4795 } else { 4796 (*hand)(sig); 4797 } 4798 4799 // restore the signal mask 4800 pthread_sigmask(SIG_SETMASK, &oset, NULL); 4801 } 4802 // Tell jvm's signal handler the signal is taken care of. 4803 return true; 4804 } 4805 4806 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4807 bool chained = false; 4808 // signal-chaining 4809 if (UseSignalChaining) { 4810 struct sigaction *actp = get_chained_signal_action(sig); 4811 if (actp != NULL) { 4812 chained = call_chained_handler(actp, sig, siginfo, context); 4813 } 4814 } 4815 return chained; 4816 } 4817 4818 // for diagnostic 4819 int sigflags[NSIG]; 4820 4821 int os::Linux::get_our_sigflags(int sig) { 4822 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4823 return sigflags[sig]; 4824 } 4825 4826 void os::Linux::set_our_sigflags(int sig, int flags) { 4827 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4828 if (sig > 0 && sig < NSIG) { 4829 sigflags[sig] = flags; 4830 } 4831 } 4832 4833 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4834 // Check for overwrite. 4835 struct sigaction oldAct; 4836 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4837 4838 void* oldhand = oldAct.sa_sigaction 4839 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4840 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4841 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4842 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4843 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4844 if (AllowUserSignalHandlers || !set_installed) { 4845 // Do not overwrite; user takes responsibility to forward to us. 4846 return; 4847 } else if (UseSignalChaining) { 4848 // save the old handler in jvm 4849 os::Posix::save_preinstalled_handler(sig, oldAct); 4850 // libjsig also interposes the sigaction() call below and saves the 4851 // old sigaction on it own. 4852 } else { 4853 fatal("Encountered unexpected pre-existing sigaction handler " 4854 "%#lx for signal %d.", (long)oldhand, sig); 4855 } 4856 } 4857 4858 struct sigaction sigAct; 4859 sigfillset(&(sigAct.sa_mask)); 4860 sigAct.sa_handler = SIG_DFL; 4861 if (!set_installed) { 4862 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4863 } else { 4864 sigAct.sa_sigaction = signalHandler; 4865 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4866 } 4867 // Save flags, which are set by ours 4868 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4869 sigflags[sig] = sigAct.sa_flags; 4870 4871 int ret = sigaction(sig, &sigAct, &oldAct); 4872 assert(ret == 0, "check"); 4873 4874 void* oldhand2 = oldAct.sa_sigaction 4875 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4876 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4877 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4878 } 4879 4880 // install signal handlers for signals that HotSpot needs to 4881 // handle in order to support Java-level exception handling. 4882 4883 void os::Linux::install_signal_handlers() { 4884 if (!signal_handlers_are_installed) { 4885 signal_handlers_are_installed = true; 4886 4887 // signal-chaining 4888 typedef void (*signal_setting_t)(); 4889 signal_setting_t begin_signal_setting = NULL; 4890 signal_setting_t end_signal_setting = NULL; 4891 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4892 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4893 if (begin_signal_setting != NULL) { 4894 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4895 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4896 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4897 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4898 libjsig_is_loaded = true; 4899 assert(UseSignalChaining, "should enable signal-chaining"); 4900 } 4901 if (libjsig_is_loaded) { 4902 // Tell libjsig jvm is setting signal handlers 4903 (*begin_signal_setting)(); 4904 } 4905 4906 set_signal_handler(SIGSEGV, true); 4907 set_signal_handler(SIGPIPE, true); 4908 set_signal_handler(SIGBUS, true); 4909 set_signal_handler(SIGILL, true); 4910 set_signal_handler(SIGFPE, true); 4911 #if defined(PPC64) 4912 set_signal_handler(SIGTRAP, true); 4913 #endif 4914 set_signal_handler(SIGXFSZ, true); 4915 4916 if (libjsig_is_loaded) { 4917 // Tell libjsig jvm finishes setting signal handlers 4918 (*end_signal_setting)(); 4919 } 4920 4921 // We don't activate signal checker if libjsig is in place, we trust ourselves 4922 // and if UserSignalHandler is installed all bets are off. 4923 // Log that signal checking is off only if -verbose:jni is specified. 4924 if (CheckJNICalls) { 4925 if (libjsig_is_loaded) { 4926 log_debug(jni, resolve)("Info: libjsig is activated, all active signal checking is disabled"); 4927 check_signals = false; 4928 } 4929 if (AllowUserSignalHandlers) { 4930 log_debug(jni, resolve)("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4931 check_signals = false; 4932 } 4933 } 4934 } 4935 } 4936 4937 // This is the fastest way to get thread cpu time on Linux. 4938 // Returns cpu time (user+sys) for any thread, not only for current. 4939 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4940 // It might work on 2.6.10+ with a special kernel/glibc patch. 4941 // For reference, please, see IEEE Std 1003.1-2004: 4942 // http://www.unix.org/single_unix_specification 4943 4944 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4945 struct timespec tp; 4946 int rc = os::Posix::clock_gettime(clockid, &tp); 4947 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4948 4949 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4950 } 4951 4952 ///// 4953 // glibc on Linux platform uses non-documented flag 4954 // to indicate, that some special sort of signal 4955 // trampoline is used. 4956 // We will never set this flag, and we should 4957 // ignore this flag in our diagnostic 4958 #ifdef SIGNIFICANT_SIGNAL_MASK 4959 #undef SIGNIFICANT_SIGNAL_MASK 4960 #endif 4961 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4962 4963 static const char* get_signal_handler_name(address handler, 4964 char* buf, int buflen) { 4965 int offset = 0; 4966 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4967 if (found) { 4968 // skip directory names 4969 const char *p1, *p2; 4970 p1 = buf; 4971 size_t len = strlen(os::file_separator()); 4972 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4973 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4974 } else { 4975 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4976 } 4977 return buf; 4978 } 4979 4980 static void print_signal_handler(outputStream* st, int sig, 4981 char* buf, size_t buflen) { 4982 struct sigaction sa; 4983 4984 sigaction(sig, NULL, &sa); 4985 4986 // See comment for SIGNIFICANT_SIGNAL_MASK define 4987 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4988 4989 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4990 4991 address handler = (sa.sa_flags & SA_SIGINFO) 4992 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4993 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4994 4995 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4996 st->print("SIG_DFL"); 4997 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4998 st->print("SIG_IGN"); 4999 } else { 5000 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 5001 } 5002 5003 st->print(", sa_mask[0]="); 5004 os::Posix::print_signal_set_short(st, &sa.sa_mask); 5005 5006 address rh = VMError::get_resetted_sighandler(sig); 5007 // May be, handler was resetted by VMError? 5008 if (rh != NULL) { 5009 handler = rh; 5010 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 5011 } 5012 5013 st->print(", sa_flags="); 5014 os::Posix::print_sa_flags(st, sa.sa_flags); 5015 5016 // Check: is it our handler? 5017 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 5018 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 5019 // It is our signal handler 5020 // check for flags, reset system-used one! 5021 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 5022 st->print( 5023 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 5024 os::Linux::get_our_sigflags(sig)); 5025 } 5026 } 5027 st->cr(); 5028 } 5029 5030 5031 #define DO_SIGNAL_CHECK(sig) \ 5032 do { \ 5033 if (!sigismember(&check_signal_done, sig)) { \ 5034 os::Linux::check_signal_handler(sig); \ 5035 } \ 5036 } while (0) 5037 5038 // This method is a periodic task to check for misbehaving JNI applications 5039 // under CheckJNI, we can add any periodic checks here 5040 5041 void os::run_periodic_checks() { 5042 if (check_signals == false) return; 5043 5044 // SEGV and BUS if overridden could potentially prevent 5045 // generation of hs*.log in the event of a crash, debugging 5046 // such a case can be very challenging, so we absolutely 5047 // check the following for a good measure: 5048 DO_SIGNAL_CHECK(SIGSEGV); 5049 DO_SIGNAL_CHECK(SIGILL); 5050 DO_SIGNAL_CHECK(SIGFPE); 5051 DO_SIGNAL_CHECK(SIGBUS); 5052 DO_SIGNAL_CHECK(SIGPIPE); 5053 DO_SIGNAL_CHECK(SIGXFSZ); 5054 #if defined(PPC64) 5055 DO_SIGNAL_CHECK(SIGTRAP); 5056 #endif 5057 5058 // ReduceSignalUsage allows the user to override these handlers 5059 // see comments at the very top and jvm_md.h 5060 if (!ReduceSignalUsage) { 5061 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 5062 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 5063 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 5064 DO_SIGNAL_CHECK(BREAK_SIGNAL); 5065 } 5066 5067 DO_SIGNAL_CHECK(SR_signum); 5068 } 5069 5070 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 5071 5072 static os_sigaction_t os_sigaction = NULL; 5073 5074 void os::Linux::check_signal_handler(int sig) { 5075 char buf[O_BUFLEN]; 5076 address jvmHandler = NULL; 5077 5078 5079 struct sigaction act; 5080 if (os_sigaction == NULL) { 5081 // only trust the default sigaction, in case it has been interposed 5082 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 5083 if (os_sigaction == NULL) return; 5084 } 5085 5086 os_sigaction(sig, (struct sigaction*)NULL, &act); 5087 5088 5089 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 5090 5091 address thisHandler = (act.sa_flags & SA_SIGINFO) 5092 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 5093 : CAST_FROM_FN_PTR(address, act.sa_handler); 5094 5095 5096 switch (sig) { 5097 case SIGSEGV: 5098 case SIGBUS: 5099 case SIGFPE: 5100 case SIGPIPE: 5101 case SIGILL: 5102 case SIGXFSZ: 5103 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 5104 break; 5105 5106 case SHUTDOWN1_SIGNAL: 5107 case SHUTDOWN2_SIGNAL: 5108 case SHUTDOWN3_SIGNAL: 5109 case BREAK_SIGNAL: 5110 jvmHandler = (address)user_handler(); 5111 break; 5112 5113 default: 5114 if (sig == SR_signum) { 5115 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 5116 } else { 5117 return; 5118 } 5119 break; 5120 } 5121 5122 if (thisHandler != jvmHandler) { 5123 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 5124 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 5125 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 5126 // No need to check this sig any longer 5127 sigaddset(&check_signal_done, sig); 5128 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 5129 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 5130 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 5131 exception_name(sig, buf, O_BUFLEN)); 5132 } 5133 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 5134 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 5135 tty->print("expected:"); 5136 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 5137 tty->cr(); 5138 tty->print(" found:"); 5139 os::Posix::print_sa_flags(tty, act.sa_flags); 5140 tty->cr(); 5141 // No need to check this sig any longer 5142 sigaddset(&check_signal_done, sig); 5143 } 5144 5145 // Dump all the signal 5146 if (sigismember(&check_signal_done, sig)) { 5147 print_signal_handlers(tty, buf, O_BUFLEN); 5148 } 5149 } 5150 5151 extern void report_error(char* file_name, int line_no, char* title, 5152 char* format, ...); 5153 5154 // this is called _before_ most of the global arguments have been parsed 5155 void os::init(void) { 5156 char dummy; // used to get a guess on initial stack address 5157 5158 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 5159 5160 init_random(1234567); 5161 5162 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 5163 if (Linux::page_size() == -1) { 5164 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 5165 os::strerror(errno)); 5166 } 5167 init_page_sizes((size_t) Linux::page_size()); 5168 5169 Linux::initialize_system_info(); 5170 5171 os::Linux::CPUPerfTicks pticks; 5172 bool res = os::Linux::get_tick_information(&pticks, -1); 5173 5174 if (res && pticks.has_steal_ticks) { 5175 has_initial_tick_info = true; 5176 initial_total_ticks = pticks.total; 5177 initial_steal_ticks = pticks.steal; 5178 } 5179 5180 // _main_thread points to the thread that created/loaded the JVM. 5181 Linux::_main_thread = pthread_self(); 5182 5183 // retrieve entry point for pthread_setname_np 5184 Linux::_pthread_setname_np = 5185 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 5186 5187 os::Posix::init(); 5188 5189 initial_time_count = javaTimeNanos(); 5190 5191 // Always warn if no monotonic clock available 5192 if (!os::Posix::supports_monotonic_clock()) { 5193 warning("No monotonic clock was available - timed services may " \ 5194 "be adversely affected if the time-of-day clock changes"); 5195 } 5196 } 5197 5198 // To install functions for atexit system call 5199 extern "C" { 5200 static void perfMemory_exit_helper() { 5201 perfMemory_exit(); 5202 } 5203 } 5204 5205 void os::pd_init_container_support() { 5206 OSContainer::init(); 5207 } 5208 5209 void os::Linux::numa_init() { 5210 5211 // Java can be invoked as 5212 // 1. Without numactl and heap will be allocated/configured on all nodes as 5213 // per the system policy. 5214 // 2. With numactl --interleave: 5215 // Use numa_get_interleave_mask(v2) API to get nodes bitmask. The same 5216 // API for membind case bitmask is reset. 5217 // Interleave is only hint and Kernel can fallback to other nodes if 5218 // no memory is available on the target nodes. 5219 // 3. With numactl --membind: 5220 // Use numa_get_membind(v2) API to get nodes bitmask. The same API for 5221 // interleave case returns bitmask of all nodes. 5222 // numa_all_nodes_ptr holds bitmask of all nodes. 5223 // numa_get_interleave_mask(v2) and numa_get_membind(v2) APIs returns correct 5224 // bitmask when externally configured to run on all or fewer nodes. 5225 5226 if (!Linux::libnuma_init()) { 5227 FLAG_SET_ERGO(UseNUMA, false); 5228 FLAG_SET_ERGO(UseNUMAInterleaving, false); // Also depends on libnuma. 5229 } else { 5230 if ((Linux::numa_max_node() < 1) || Linux::is_bound_to_single_node()) { 5231 // If there's only one node (they start from 0) or if the process 5232 // is bound explicitly to a single node using membind, disable NUMA unless 5233 // user explicilty forces NUMA optimizations on single-node/UMA systems 5234 UseNUMA = ForceNUMA; 5235 } else { 5236 5237 LogTarget(Info,os) log; 5238 LogStream ls(log); 5239 5240 Linux::set_configured_numa_policy(Linux::identify_numa_policy()); 5241 5242 struct bitmask* bmp = Linux::_numa_membind_bitmask; 5243 const char* numa_mode = "membind"; 5244 5245 if (Linux::is_running_in_interleave_mode()) { 5246 bmp = Linux::_numa_interleave_bitmask; 5247 numa_mode = "interleave"; 5248 } 5249 5250 ls.print("UseNUMA is enabled and invoked in '%s' mode." 5251 " Heap will be configured using NUMA memory nodes:", numa_mode); 5252 5253 for (int node = 0; node <= Linux::numa_max_node(); node++) { 5254 if (Linux::_numa_bitmask_isbitset(bmp, node)) { 5255 ls.print(" %d", node); 5256 } 5257 } 5258 } 5259 } 5260 5261 // When NUMA requested, not-NUMA-aware allocations default to interleaving. 5262 if (UseNUMA && !UseNUMAInterleaving) { 5263 FLAG_SET_ERGO_IF_DEFAULT(UseNUMAInterleaving, true); 5264 } 5265 5266 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 5267 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 5268 // we can make the adaptive lgrp chunk resizing work. If the user specified both 5269 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn 5270 // and disable adaptive resizing. 5271 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 5272 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, " 5273 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 5274 UseAdaptiveSizePolicy = false; 5275 UseAdaptiveNUMAChunkSizing = false; 5276 } 5277 } 5278 } 5279 5280 // this is called _after_ the global arguments have been parsed 5281 jint os::init_2(void) { 5282 5283 // This could be set after os::Posix::init() but all platforms 5284 // have to set it the same so we have to mirror Solaris. 5285 DEBUG_ONLY(os::set_mutex_init_done();) 5286 5287 os::Posix::init_2(); 5288 5289 Linux::fast_thread_clock_init(); 5290 5291 // initialize suspend/resume support - must do this before signal_sets_init() 5292 if (SR_initialize() != 0) { 5293 perror("SR_initialize failed"); 5294 return JNI_ERR; 5295 } 5296 5297 Linux::signal_sets_init(); 5298 Linux::install_signal_handlers(); 5299 // Initialize data for jdk.internal.misc.Signal 5300 if (!ReduceSignalUsage) { 5301 jdk_misc_signal_init(); 5302 } 5303 5304 if (AdjustStackSizeForTLS) { 5305 get_minstack_init(); 5306 } 5307 5308 // Check and sets minimum stack sizes against command line options 5309 if (Posix::set_minimum_stack_sizes() == JNI_ERR) { 5310 return JNI_ERR; 5311 } 5312 5313 #if defined(IA32) 5314 // Need to ensure we've determined the process's initial stack to 5315 // perform the workaround 5316 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 5317 workaround_expand_exec_shield_cs_limit(); 5318 #else 5319 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher(); 5320 if (!suppress_primordial_thread_resolution) { 5321 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 5322 } 5323 #endif 5324 5325 Linux::libpthread_init(); 5326 Linux::sched_getcpu_init(); 5327 log_info(os)("HotSpot is running with %s, %s", 5328 Linux::glibc_version(), Linux::libpthread_version()); 5329 5330 if (UseNUMA || UseNUMAInterleaving) { 5331 Linux::numa_init(); 5332 } 5333 5334 if (MaxFDLimit) { 5335 // set the number of file descriptors to max. print out error 5336 // if getrlimit/setrlimit fails but continue regardless. 5337 struct rlimit nbr_files; 5338 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 5339 if (status != 0) { 5340 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno)); 5341 } else { 5342 nbr_files.rlim_cur = nbr_files.rlim_max; 5343 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 5344 if (status != 0) { 5345 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno)); 5346 } 5347 } 5348 } 5349 5350 // at-exit methods are called in the reverse order of their registration. 5351 // atexit functions are called on return from main or as a result of a 5352 // call to exit(3C). There can be only 32 of these functions registered 5353 // and atexit() does not set errno. 5354 5355 if (PerfAllowAtExitRegistration) { 5356 // only register atexit functions if PerfAllowAtExitRegistration is set. 5357 // atexit functions can be delayed until process exit time, which 5358 // can be problematic for embedded VM situations. Embedded VMs should 5359 // call DestroyJavaVM() to assure that VM resources are released. 5360 5361 // note: perfMemory_exit_helper atexit function may be removed in 5362 // the future if the appropriate cleanup code can be added to the 5363 // VM_Exit VMOperation's doit method. 5364 if (atexit(perfMemory_exit_helper) != 0) { 5365 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 5366 } 5367 } 5368 5369 // initialize thread priority policy 5370 prio_init(); 5371 5372 if (!FLAG_IS_DEFAULT(AllocateHeapAt) || !FLAG_IS_DEFAULT(AllocateOldGenAt)) { 5373 set_coredump_filter(DAX_SHARED_BIT); 5374 } 5375 5376 if (DumpPrivateMappingsInCore) { 5377 set_coredump_filter(FILE_BACKED_PVT_BIT); 5378 } 5379 5380 if (DumpSharedMappingsInCore) { 5381 set_coredump_filter(FILE_BACKED_SHARED_BIT); 5382 } 5383 5384 return JNI_OK; 5385 } 5386 5387 // older glibc versions don't have this macro (which expands to 5388 // an optimized bit-counting function) so we have to roll our own 5389 #ifndef CPU_COUNT 5390 5391 static int _cpu_count(const cpu_set_t* cpus) { 5392 int count = 0; 5393 // only look up to the number of configured processors 5394 for (int i = 0; i < os::processor_count(); i++) { 5395 if (CPU_ISSET(i, cpus)) { 5396 count++; 5397 } 5398 } 5399 return count; 5400 } 5401 5402 #define CPU_COUNT(cpus) _cpu_count(cpus) 5403 5404 #endif // CPU_COUNT 5405 5406 // Get the current number of available processors for this process. 5407 // This value can change at any time during a process's lifetime. 5408 // sched_getaffinity gives an accurate answer as it accounts for cpusets. 5409 // If it appears there may be more than 1024 processors then we do a 5410 // dynamic check - see 6515172 for details. 5411 // If anything goes wrong we fallback to returning the number of online 5412 // processors - which can be greater than the number available to the process. 5413 int os::Linux::active_processor_count() { 5414 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 5415 cpu_set_t* cpus_p = &cpus; 5416 int cpus_size = sizeof(cpu_set_t); 5417 5418 int configured_cpus = os::processor_count(); // upper bound on available cpus 5419 int cpu_count = 0; 5420 5421 // old build platforms may not support dynamic cpu sets 5422 #ifdef CPU_ALLOC 5423 5424 // To enable easy testing of the dynamic path on different platforms we 5425 // introduce a diagnostic flag: UseCpuAllocPath 5426 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 5427 // kernel may use a mask bigger than cpu_set_t 5428 log_trace(os)("active_processor_count: using dynamic path %s" 5429 "- configured processors: %d", 5430 UseCpuAllocPath ? "(forced) " : "", 5431 configured_cpus); 5432 cpus_p = CPU_ALLOC(configured_cpus); 5433 if (cpus_p != NULL) { 5434 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 5435 // zero it just to be safe 5436 CPU_ZERO_S(cpus_size, cpus_p); 5437 } 5438 else { 5439 // failed to allocate so fallback to online cpus 5440 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 5441 log_trace(os)("active_processor_count: " 5442 "CPU_ALLOC failed (%s) - using " 5443 "online processor count: %d", 5444 os::strerror(errno), online_cpus); 5445 return online_cpus; 5446 } 5447 } 5448 else { 5449 log_trace(os)("active_processor_count: using static path - configured processors: %d", 5450 configured_cpus); 5451 } 5452 #else // CPU_ALLOC 5453 // these stubs won't be executed 5454 #define CPU_COUNT_S(size, cpus) -1 5455 #define CPU_FREE(cpus) 5456 5457 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 5458 configured_cpus); 5459 #endif // CPU_ALLOC 5460 5461 // pid 0 means the current thread - which we have to assume represents the process 5462 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 5463 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5464 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 5465 } 5466 else { 5467 cpu_count = CPU_COUNT(cpus_p); 5468 } 5469 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 5470 } 5471 else { 5472 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 5473 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 5474 "which may exceed available processors", os::strerror(errno), cpu_count); 5475 } 5476 5477 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5478 CPU_FREE(cpus_p); 5479 } 5480 5481 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check"); 5482 return cpu_count; 5483 } 5484 5485 // Determine the active processor count from one of 5486 // three different sources: 5487 // 5488 // 1. User option -XX:ActiveProcessorCount 5489 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN) 5490 // 3. extracted from cgroup cpu subsystem (shares and quotas) 5491 // 5492 // Option 1, if specified, will always override. 5493 // If the cgroup subsystem is active and configured, we 5494 // will return the min of the cgroup and option 2 results. 5495 // This is required since tools, such as numactl, that 5496 // alter cpu affinity do not update cgroup subsystem 5497 // cpuset configuration files. 5498 int os::active_processor_count() { 5499 // User has overridden the number of active processors 5500 if (ActiveProcessorCount > 0) { 5501 log_trace(os)("active_processor_count: " 5502 "active processor count set by user : %d", 5503 ActiveProcessorCount); 5504 return ActiveProcessorCount; 5505 } 5506 5507 int active_cpus; 5508 if (OSContainer::is_containerized()) { 5509 active_cpus = OSContainer::active_processor_count(); 5510 log_trace(os)("active_processor_count: determined by OSContainer: %d", 5511 active_cpus); 5512 } else { 5513 active_cpus = os::Linux::active_processor_count(); 5514 } 5515 5516 return active_cpus; 5517 } 5518 5519 uint os::processor_id() { 5520 const int id = Linux::sched_getcpu(); 5521 assert(id >= 0 && id < _processor_count, "Invalid processor id"); 5522 return (uint)id; 5523 } 5524 5525 void os::set_native_thread_name(const char *name) { 5526 if (Linux::_pthread_setname_np) { 5527 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 5528 snprintf(buf, sizeof(buf), "%s", name); 5529 buf[sizeof(buf) - 1] = '\0'; 5530 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 5531 // ERANGE should not happen; all other errors should just be ignored. 5532 assert(rc != ERANGE, "pthread_setname_np failed"); 5533 } 5534 } 5535 5536 bool os::bind_to_processor(uint processor_id) { 5537 // Not yet implemented. 5538 return false; 5539 } 5540 5541 /// 5542 5543 void os::SuspendedThreadTask::internal_do_task() { 5544 if (do_suspend(_thread->osthread())) { 5545 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 5546 do_task(context); 5547 do_resume(_thread->osthread()); 5548 } 5549 } 5550 5551 //////////////////////////////////////////////////////////////////////////////// 5552 // debug support 5553 5554 bool os::find(address addr, outputStream* st) { 5555 Dl_info dlinfo; 5556 memset(&dlinfo, 0, sizeof(dlinfo)); 5557 if (dladdr(addr, &dlinfo) != 0) { 5558 st->print(PTR_FORMAT ": ", p2i(addr)); 5559 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5560 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 5561 p2i(addr) - p2i(dlinfo.dli_saddr)); 5562 } else if (dlinfo.dli_fbase != NULL) { 5563 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 5564 } else { 5565 st->print("<absolute address>"); 5566 } 5567 if (dlinfo.dli_fname != NULL) { 5568 st->print(" in %s", dlinfo.dli_fname); 5569 } 5570 if (dlinfo.dli_fbase != NULL) { 5571 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 5572 } 5573 st->cr(); 5574 5575 if (Verbose) { 5576 // decode some bytes around the PC 5577 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5578 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5579 address lowest = (address) dlinfo.dli_sname; 5580 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5581 if (begin < lowest) begin = lowest; 5582 Dl_info dlinfo2; 5583 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5584 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 5585 end = (address) dlinfo2.dli_saddr; 5586 } 5587 Disassembler::decode(begin, end, st); 5588 } 5589 return true; 5590 } 5591 return false; 5592 } 5593 5594 //////////////////////////////////////////////////////////////////////////////// 5595 // misc 5596 5597 // This does not do anything on Linux. This is basically a hook for being 5598 // able to use structured exception handling (thread-local exception filters) 5599 // on, e.g., Win32. 5600 void 5601 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5602 JavaCallArguments* args, Thread* thread) { 5603 f(value, method, args, thread); 5604 } 5605 5606 void os::print_statistics() { 5607 } 5608 5609 bool os::message_box(const char* title, const char* message) { 5610 int i; 5611 fdStream err(defaultStream::error_fd()); 5612 for (i = 0; i < 78; i++) err.print_raw("="); 5613 err.cr(); 5614 err.print_raw_cr(title); 5615 for (i = 0; i < 78; i++) err.print_raw("-"); 5616 err.cr(); 5617 err.print_raw_cr(message); 5618 for (i = 0; i < 78; i++) err.print_raw("="); 5619 err.cr(); 5620 5621 char buf[16]; 5622 // Prevent process from exiting upon "read error" without consuming all CPU 5623 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5624 5625 return buf[0] == 'y' || buf[0] == 'Y'; 5626 } 5627 5628 // Is a (classpath) directory empty? 5629 bool os::dir_is_empty(const char* path) { 5630 DIR *dir = NULL; 5631 struct dirent *ptr; 5632 5633 dir = opendir(path); 5634 if (dir == NULL) return true; 5635 5636 // Scan the directory 5637 bool result = true; 5638 while (result && (ptr = readdir(dir)) != NULL) { 5639 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5640 result = false; 5641 } 5642 } 5643 closedir(dir); 5644 return result; 5645 } 5646 5647 // This code originates from JDK's sysOpen and open64_w 5648 // from src/solaris/hpi/src/system_md.c 5649 5650 int os::open(const char *path, int oflag, int mode) { 5651 if (strlen(path) > MAX_PATH - 1) { 5652 errno = ENAMETOOLONG; 5653 return -1; 5654 } 5655 5656 // All file descriptors that are opened in the Java process and not 5657 // specifically destined for a subprocess should have the close-on-exec 5658 // flag set. If we don't set it, then careless 3rd party native code 5659 // might fork and exec without closing all appropriate file descriptors 5660 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5661 // turn might: 5662 // 5663 // - cause end-of-file to fail to be detected on some file 5664 // descriptors, resulting in mysterious hangs, or 5665 // 5666 // - might cause an fopen in the subprocess to fail on a system 5667 // suffering from bug 1085341. 5668 // 5669 // (Yes, the default setting of the close-on-exec flag is a Unix 5670 // design flaw) 5671 // 5672 // See: 5673 // 1085341: 32-bit stdio routines should support file descriptors >255 5674 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5675 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5676 // 5677 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5678 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5679 // because it saves a system call and removes a small window where the flag 5680 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5681 // and we fall back to using FD_CLOEXEC (see below). 5682 #ifdef O_CLOEXEC 5683 oflag |= O_CLOEXEC; 5684 #endif 5685 5686 int fd = ::open64(path, oflag, mode); 5687 if (fd == -1) return -1; 5688 5689 //If the open succeeded, the file might still be a directory 5690 { 5691 struct stat64 buf64; 5692 int ret = ::fstat64(fd, &buf64); 5693 int st_mode = buf64.st_mode; 5694 5695 if (ret != -1) { 5696 if ((st_mode & S_IFMT) == S_IFDIR) { 5697 errno = EISDIR; 5698 ::close(fd); 5699 return -1; 5700 } 5701 } else { 5702 ::close(fd); 5703 return -1; 5704 } 5705 } 5706 5707 #ifdef FD_CLOEXEC 5708 // Validate that the use of the O_CLOEXEC flag on open above worked. 5709 // With recent kernels, we will perform this check exactly once. 5710 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5711 if (!O_CLOEXEC_is_known_to_work) { 5712 int flags = ::fcntl(fd, F_GETFD); 5713 if (flags != -1) { 5714 if ((flags & FD_CLOEXEC) != 0) 5715 O_CLOEXEC_is_known_to_work = 1; 5716 else 5717 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5718 } 5719 } 5720 #endif 5721 5722 return fd; 5723 } 5724 5725 5726 // create binary file, rewriting existing file if required 5727 int os::create_binary_file(const char* path, bool rewrite_existing) { 5728 int oflags = O_WRONLY | O_CREAT; 5729 if (!rewrite_existing) { 5730 oflags |= O_EXCL; 5731 } 5732 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5733 } 5734 5735 // return current position of file pointer 5736 jlong os::current_file_offset(int fd) { 5737 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5738 } 5739 5740 // move file pointer to the specified offset 5741 jlong os::seek_to_file_offset(int fd, jlong offset) { 5742 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5743 } 5744 5745 // This code originates from JDK's sysAvailable 5746 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5747 5748 int os::available(int fd, jlong *bytes) { 5749 jlong cur, end; 5750 int mode; 5751 struct stat64 buf64; 5752 5753 if (::fstat64(fd, &buf64) >= 0) { 5754 mode = buf64.st_mode; 5755 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5756 int n; 5757 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5758 *bytes = n; 5759 return 1; 5760 } 5761 } 5762 } 5763 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5764 return 0; 5765 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5766 return 0; 5767 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5768 return 0; 5769 } 5770 *bytes = end - cur; 5771 return 1; 5772 } 5773 5774 // Map a block of memory. 5775 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5776 char *addr, size_t bytes, bool read_only, 5777 bool allow_exec) { 5778 int prot; 5779 int flags = MAP_PRIVATE; 5780 5781 if (read_only) { 5782 prot = PROT_READ; 5783 } else { 5784 prot = PROT_READ | PROT_WRITE; 5785 } 5786 5787 if (allow_exec) { 5788 prot |= PROT_EXEC; 5789 } 5790 5791 if (addr != NULL) { 5792 flags |= MAP_FIXED; 5793 } 5794 5795 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5796 fd, file_offset); 5797 if (mapped_address == MAP_FAILED) { 5798 return NULL; 5799 } 5800 return mapped_address; 5801 } 5802 5803 5804 // Remap a block of memory. 5805 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5806 char *addr, size_t bytes, bool read_only, 5807 bool allow_exec) { 5808 // same as map_memory() on this OS 5809 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5810 allow_exec); 5811 } 5812 5813 5814 // Unmap a block of memory. 5815 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5816 return munmap(addr, bytes) == 0; 5817 } 5818 5819 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5820 5821 static jlong fast_cpu_time(Thread *thread) { 5822 clockid_t clockid; 5823 int rc = os::Linux::pthread_getcpuclockid(thread->osthread()->pthread_id(), 5824 &clockid); 5825 if (rc == 0) { 5826 return os::Linux::fast_thread_cpu_time(clockid); 5827 } else { 5828 // It's possible to encounter a terminated native thread that failed 5829 // to detach itself from the VM - which should result in ESRCH. 5830 assert_status(rc == ESRCH, rc, "pthread_getcpuclockid failed"); 5831 return -1; 5832 } 5833 } 5834 5835 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5836 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5837 // of a thread. 5838 // 5839 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5840 // the fast estimate available on the platform. 5841 5842 jlong os::current_thread_cpu_time() { 5843 if (os::Linux::supports_fast_thread_cpu_time()) { 5844 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5845 } else { 5846 // return user + sys since the cost is the same 5847 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5848 } 5849 } 5850 5851 jlong os::thread_cpu_time(Thread* thread) { 5852 // consistent with what current_thread_cpu_time() returns 5853 if (os::Linux::supports_fast_thread_cpu_time()) { 5854 return fast_cpu_time(thread); 5855 } else { 5856 return slow_thread_cpu_time(thread, true /* user + sys */); 5857 } 5858 } 5859 5860 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5861 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5862 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5863 } else { 5864 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5865 } 5866 } 5867 5868 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5869 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5870 return fast_cpu_time(thread); 5871 } else { 5872 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5873 } 5874 } 5875 5876 // -1 on error. 5877 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5878 pid_t tid = thread->osthread()->thread_id(); 5879 char *s; 5880 char stat[2048]; 5881 int statlen; 5882 char proc_name[64]; 5883 int count; 5884 long sys_time, user_time; 5885 char cdummy; 5886 int idummy; 5887 long ldummy; 5888 FILE *fp; 5889 5890 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5891 fp = fopen(proc_name, "r"); 5892 if (fp == NULL) return -1; 5893 statlen = fread(stat, 1, 2047, fp); 5894 stat[statlen] = '\0'; 5895 fclose(fp); 5896 5897 // Skip pid and the command string. Note that we could be dealing with 5898 // weird command names, e.g. user could decide to rename java launcher 5899 // to "java 1.4.2 :)", then the stat file would look like 5900 // 1234 (java 1.4.2 :)) R ... ... 5901 // We don't really need to know the command string, just find the last 5902 // occurrence of ")" and then start parsing from there. See bug 4726580. 5903 s = strrchr(stat, ')'); 5904 if (s == NULL) return -1; 5905 5906 // Skip blank chars 5907 do { s++; } while (s && isspace(*s)); 5908 5909 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5910 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5911 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5912 &user_time, &sys_time); 5913 if (count != 13) return -1; 5914 if (user_sys_cpu_time) { 5915 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5916 } else { 5917 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5918 } 5919 } 5920 5921 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5922 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5923 info_ptr->may_skip_backward = false; // elapsed time not wall time 5924 info_ptr->may_skip_forward = false; // elapsed time not wall time 5925 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5926 } 5927 5928 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5929 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5930 info_ptr->may_skip_backward = false; // elapsed time not wall time 5931 info_ptr->may_skip_forward = false; // elapsed time not wall time 5932 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5933 } 5934 5935 bool os::is_thread_cpu_time_supported() { 5936 return true; 5937 } 5938 5939 // System loadavg support. Returns -1 if load average cannot be obtained. 5940 // Linux doesn't yet have a (official) notion of processor sets, 5941 // so just return the system wide load average. 5942 int os::loadavg(double loadavg[], int nelem) { 5943 return ::getloadavg(loadavg, nelem); 5944 } 5945 5946 void os::pause() { 5947 char filename[MAX_PATH]; 5948 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5949 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5950 } else { 5951 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5952 } 5953 5954 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5955 if (fd != -1) { 5956 struct stat buf; 5957 ::close(fd); 5958 while (::stat(filename, &buf) == 0) { 5959 (void)::poll(NULL, 0, 100); 5960 } 5961 } else { 5962 jio_fprintf(stderr, 5963 "Could not open pause file '%s', continuing immediately.\n", filename); 5964 } 5965 } 5966 5967 extern char** environ; 5968 5969 // Run the specified command in a separate process. Return its exit value, 5970 // or -1 on failure (e.g. can't fork a new process). 5971 // Unlike system(), this function can be called from signal handler. It 5972 // doesn't block SIGINT et al. 5973 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) { 5974 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5975 5976 pid_t pid ; 5977 5978 if (use_vfork_if_available) { 5979 pid = vfork(); 5980 } else { 5981 pid = fork(); 5982 } 5983 5984 if (pid < 0) { 5985 // fork failed 5986 return -1; 5987 5988 } else if (pid == 0) { 5989 // child process 5990 5991 execve("/bin/sh", (char* const*)argv, environ); 5992 5993 // execve failed 5994 _exit(-1); 5995 5996 } else { 5997 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5998 // care about the actual exit code, for now. 5999 6000 int status; 6001 6002 // Wait for the child process to exit. This returns immediately if 6003 // the child has already exited. */ 6004 while (waitpid(pid, &status, 0) < 0) { 6005 switch (errno) { 6006 case ECHILD: return 0; 6007 case EINTR: break; 6008 default: return -1; 6009 } 6010 } 6011 6012 if (WIFEXITED(status)) { 6013 // The child exited normally; get its exit code. 6014 return WEXITSTATUS(status); 6015 } else if (WIFSIGNALED(status)) { 6016 // The child exited because of a signal 6017 // The best value to return is 0x80 + signal number, 6018 // because that is what all Unix shells do, and because 6019 // it allows callers to distinguish between process exit and 6020 // process death by signal. 6021 return 0x80 + WTERMSIG(status); 6022 } else { 6023 // Unknown exit code; pass it through 6024 return status; 6025 } 6026 } 6027 } 6028 6029 // Get the default path to the core file 6030 // Returns the length of the string 6031 int os::get_core_path(char* buffer, size_t bufferSize) { 6032 /* 6033 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 6034 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 6035 */ 6036 const int core_pattern_len = 129; 6037 char core_pattern[core_pattern_len] = {0}; 6038 6039 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 6040 if (core_pattern_file == -1) { 6041 return -1; 6042 } 6043 6044 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 6045 ::close(core_pattern_file); 6046 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 6047 return -1; 6048 } 6049 if (core_pattern[ret-1] == '\n') { 6050 core_pattern[ret-1] = '\0'; 6051 } else { 6052 core_pattern[ret] = '\0'; 6053 } 6054 6055 // Replace the %p in the core pattern with the process id. NOTE: we do this 6056 // only if the pattern doesn't start with "|", and we support only one %p in 6057 // the pattern. 6058 char *pid_pos = strstr(core_pattern, "%p"); 6059 const char* tail = (pid_pos != NULL) ? (pid_pos + 2) : ""; // skip over the "%p" 6060 int written; 6061 6062 if (core_pattern[0] == '/') { 6063 if (pid_pos != NULL) { 6064 *pid_pos = '\0'; 6065 written = jio_snprintf(buffer, bufferSize, "%s%d%s", core_pattern, 6066 current_process_id(), tail); 6067 } else { 6068 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 6069 } 6070 } else { 6071 char cwd[PATH_MAX]; 6072 6073 const char* p = get_current_directory(cwd, PATH_MAX); 6074 if (p == NULL) { 6075 return -1; 6076 } 6077 6078 if (core_pattern[0] == '|') { 6079 written = jio_snprintf(buffer, bufferSize, 6080 "\"%s\" (or dumping to %s/core.%d)", 6081 &core_pattern[1], p, current_process_id()); 6082 } else if (pid_pos != NULL) { 6083 *pid_pos = '\0'; 6084 written = jio_snprintf(buffer, bufferSize, "%s/%s%d%s", p, core_pattern, 6085 current_process_id(), tail); 6086 } else { 6087 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 6088 } 6089 } 6090 6091 if (written < 0) { 6092 return -1; 6093 } 6094 6095 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 6096 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 6097 6098 if (core_uses_pid_file != -1) { 6099 char core_uses_pid = 0; 6100 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 6101 ::close(core_uses_pid_file); 6102 6103 if (core_uses_pid == '1') { 6104 jio_snprintf(buffer + written, bufferSize - written, 6105 ".%d", current_process_id()); 6106 } 6107 } 6108 } 6109 6110 return strlen(buffer); 6111 } 6112 6113 bool os::start_debugging(char *buf, int buflen) { 6114 int len = (int)strlen(buf); 6115 char *p = &buf[len]; 6116 6117 jio_snprintf(p, buflen-len, 6118 "\n\n" 6119 "Do you want to debug the problem?\n\n" 6120 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 6121 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 6122 "Otherwise, press RETURN to abort...", 6123 os::current_process_id(), os::current_process_id(), 6124 os::current_thread_id(), os::current_thread_id()); 6125 6126 bool yes = os::message_box("Unexpected Error", buf); 6127 6128 if (yes) { 6129 // yes, user asked VM to launch debugger 6130 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d", 6131 os::current_process_id(), os::current_process_id()); 6132 6133 os::fork_and_exec(buf); 6134 yes = false; 6135 } 6136 return yes; 6137 } 6138 6139 6140 // Java/Compiler thread: 6141 // 6142 // Low memory addresses 6143 // P0 +------------------------+ 6144 // | |\ Java thread created by VM does not have glibc 6145 // | glibc guard page | - guard page, attached Java thread usually has 6146 // | |/ 1 glibc guard page. 6147 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 6148 // | |\ 6149 // | HotSpot Guard Pages | - red, yellow and reserved pages 6150 // | |/ 6151 // +------------------------+ JavaThread::stack_reserved_zone_base() 6152 // | |\ 6153 // | Normal Stack | - 6154 // | |/ 6155 // P2 +------------------------+ Thread::stack_base() 6156 // 6157 // Non-Java thread: 6158 // 6159 // Low memory addresses 6160 // P0 +------------------------+ 6161 // | |\ 6162 // | glibc guard page | - usually 1 page 6163 // | |/ 6164 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 6165 // | |\ 6166 // | Normal Stack | - 6167 // | |/ 6168 // P2 +------------------------+ Thread::stack_base() 6169 // 6170 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size 6171 // returned from pthread_attr_getstack(). 6172 // ** Due to NPTL implementation error, linux takes the glibc guard page out 6173 // of the stack size given in pthread_attr. We work around this for 6174 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.) 6175 // 6176 #ifndef ZERO 6177 static void current_stack_region(address * bottom, size_t * size) { 6178 if (os::is_primordial_thread()) { 6179 // primordial thread needs special handling because pthread_getattr_np() 6180 // may return bogus value. 6181 *bottom = os::Linux::initial_thread_stack_bottom(); 6182 *size = os::Linux::initial_thread_stack_size(); 6183 } else { 6184 pthread_attr_t attr; 6185 6186 int rslt = pthread_getattr_np(pthread_self(), &attr); 6187 6188 // JVM needs to know exact stack location, abort if it fails 6189 if (rslt != 0) { 6190 if (rslt == ENOMEM) { 6191 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 6192 } else { 6193 fatal("pthread_getattr_np failed with error = %d", rslt); 6194 } 6195 } 6196 6197 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 6198 fatal("Cannot locate current stack attributes!"); 6199 } 6200 6201 // Work around NPTL stack guard error. 6202 size_t guard_size = 0; 6203 rslt = pthread_attr_getguardsize(&attr, &guard_size); 6204 if (rslt != 0) { 6205 fatal("pthread_attr_getguardsize failed with error = %d", rslt); 6206 } 6207 *bottom += guard_size; 6208 *size -= guard_size; 6209 6210 pthread_attr_destroy(&attr); 6211 6212 } 6213 assert(os::current_stack_pointer() >= *bottom && 6214 os::current_stack_pointer() < *bottom + *size, "just checking"); 6215 } 6216 6217 address os::current_stack_base() { 6218 address bottom; 6219 size_t size; 6220 current_stack_region(&bottom, &size); 6221 return (bottom + size); 6222 } 6223 6224 size_t os::current_stack_size() { 6225 // This stack size includes the usable stack and HotSpot guard pages 6226 // (for the threads that have Hotspot guard pages). 6227 address bottom; 6228 size_t size; 6229 current_stack_region(&bottom, &size); 6230 return size; 6231 } 6232 #endif 6233 6234 static inline struct timespec get_mtime(const char* filename) { 6235 struct stat st; 6236 int ret = os::stat(filename, &st); 6237 assert(ret == 0, "failed to stat() file '%s': %s", filename, os::strerror(errno)); 6238 return st.st_mtim; 6239 } 6240 6241 int os::compare_file_modified_times(const char* file1, const char* file2) { 6242 struct timespec filetime1 = get_mtime(file1); 6243 struct timespec filetime2 = get_mtime(file2); 6244 int diff = filetime1.tv_sec - filetime2.tv_sec; 6245 if (diff == 0) { 6246 return filetime1.tv_nsec - filetime2.tv_nsec; 6247 } 6248 return diff; 6249 } 6250 6251 bool os::supports_map_sync() { 6252 return true; 6253 } 6254 6255 /////////////// Unit tests /////////////// 6256 6257 #ifndef PRODUCT 6258 6259 class TestReserveMemorySpecial : AllStatic { 6260 public: 6261 static void small_page_write(void* addr, size_t size) { 6262 size_t page_size = os::vm_page_size(); 6263 6264 char* end = (char*)addr + size; 6265 for (char* p = (char*)addr; p < end; p += page_size) { 6266 *p = 1; 6267 } 6268 } 6269 6270 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6271 if (!UseHugeTLBFS) { 6272 return; 6273 } 6274 6275 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6276 6277 if (addr != NULL) { 6278 small_page_write(addr, size); 6279 6280 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6281 } 6282 } 6283 6284 static void test_reserve_memory_special_huge_tlbfs_only() { 6285 if (!UseHugeTLBFS) { 6286 return; 6287 } 6288 6289 size_t lp = os::large_page_size(); 6290 6291 for (size_t size = lp; size <= lp * 10; size += lp) { 6292 test_reserve_memory_special_huge_tlbfs_only(size); 6293 } 6294 } 6295 6296 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6297 size_t lp = os::large_page_size(); 6298 size_t ag = os::vm_allocation_granularity(); 6299 6300 // sizes to test 6301 const size_t sizes[] = { 6302 lp, lp + ag, lp + lp / 2, lp * 2, 6303 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6304 lp * 10, lp * 10 + lp / 2 6305 }; 6306 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6307 6308 // For each size/alignment combination, we test three scenarios: 6309 // 1) with req_addr == NULL 6310 // 2) with a non-null req_addr at which we expect to successfully allocate 6311 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6312 // expect the allocation to either fail or to ignore req_addr 6313 6314 // Pre-allocate two areas; they shall be as large as the largest allocation 6315 // and aligned to the largest alignment we will be testing. 6316 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6317 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6318 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6319 -1, 0); 6320 assert(mapping1 != MAP_FAILED, "should work"); 6321 6322 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6323 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6324 -1, 0); 6325 assert(mapping2 != MAP_FAILED, "should work"); 6326 6327 // Unmap the first mapping, but leave the second mapping intact: the first 6328 // mapping will serve as a value for a "good" req_addr (case 2). The second 6329 // mapping, still intact, as "bad" req_addr (case 3). 6330 ::munmap(mapping1, mapping_size); 6331 6332 // Case 1 6333 for (int i = 0; i < num_sizes; i++) { 6334 const size_t size = sizes[i]; 6335 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6336 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6337 if (p != NULL) { 6338 assert(is_aligned(p, alignment), "must be"); 6339 small_page_write(p, size); 6340 os::Linux::release_memory_special_huge_tlbfs(p, size); 6341 } 6342 } 6343 } 6344 6345 // Case 2 6346 for (int i = 0; i < num_sizes; i++) { 6347 const size_t size = sizes[i]; 6348 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6349 char* const req_addr = align_up(mapping1, alignment); 6350 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6351 if (p != NULL) { 6352 assert(p == req_addr, "must be"); 6353 small_page_write(p, size); 6354 os::Linux::release_memory_special_huge_tlbfs(p, size); 6355 } 6356 } 6357 } 6358 6359 // Case 3 6360 for (int i = 0; i < num_sizes; i++) { 6361 const size_t size = sizes[i]; 6362 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6363 char* const req_addr = align_up(mapping2, alignment); 6364 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6365 // as the area around req_addr contains already existing mappings, the API should always 6366 // return NULL (as per contract, it cannot return another address) 6367 assert(p == NULL, "must be"); 6368 } 6369 } 6370 6371 ::munmap(mapping2, mapping_size); 6372 6373 } 6374 6375 static void test_reserve_memory_special_huge_tlbfs() { 6376 if (!UseHugeTLBFS) { 6377 return; 6378 } 6379 6380 test_reserve_memory_special_huge_tlbfs_only(); 6381 test_reserve_memory_special_huge_tlbfs_mixed(); 6382 } 6383 6384 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6385 if (!UseSHM) { 6386 return; 6387 } 6388 6389 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6390 6391 if (addr != NULL) { 6392 assert(is_aligned(addr, alignment), "Check"); 6393 assert(is_aligned(addr, os::large_page_size()), "Check"); 6394 6395 small_page_write(addr, size); 6396 6397 os::Linux::release_memory_special_shm(addr, size); 6398 } 6399 } 6400 6401 static void test_reserve_memory_special_shm() { 6402 size_t lp = os::large_page_size(); 6403 size_t ag = os::vm_allocation_granularity(); 6404 6405 for (size_t size = ag; size < lp * 3; size += ag) { 6406 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6407 test_reserve_memory_special_shm(size, alignment); 6408 } 6409 } 6410 } 6411 6412 static void test() { 6413 test_reserve_memory_special_huge_tlbfs(); 6414 test_reserve_memory_special_shm(); 6415 } 6416 }; 6417 6418 void TestReserveMemorySpecial_test() { 6419 TestReserveMemorySpecial::test(); 6420 } 6421 6422 #endif