1 /* 2 * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 // no precompiled headers 26 #include "jvm.h" 27 #include "classfile/classLoader.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "code/icBuffer.hpp" 31 #include "code/vtableStubs.hpp" 32 #include "compiler/compileBroker.hpp" 33 #include "compiler/disassembler.hpp" 34 #include "interpreter/interpreter.hpp" 35 #include "logging/log.hpp" 36 #include "logging/logStream.hpp" 37 #include "memory/allocation.inline.hpp" 38 #include "memory/filemap.hpp" 39 #include "oops/oop.inline.hpp" 40 #include "os_linux.inline.hpp" 41 #include "os_posix.inline.hpp" 42 #include "os_share_linux.hpp" 43 #include "osContainer_linux.hpp" 44 #include "prims/jniFastGetField.hpp" 45 #include "prims/jvm_misc.hpp" 46 #include "runtime/arguments.hpp" 47 #include "runtime/atomic.hpp" 48 #include "runtime/extendedPC.hpp" 49 #include "runtime/globals.hpp" 50 #include "runtime/interfaceSupport.inline.hpp" 51 #include "runtime/init.hpp" 52 #include "runtime/java.hpp" 53 #include "runtime/javaCalls.hpp" 54 #include "runtime/mutexLocker.hpp" 55 #include "runtime/objectMonitor.hpp" 56 #include "runtime/orderAccess.hpp" 57 #include "runtime/osThread.hpp" 58 #include "runtime/perfMemory.hpp" 59 #include "runtime/sharedRuntime.hpp" 60 #include "runtime/statSampler.hpp" 61 #include "runtime/stubRoutines.hpp" 62 #include "runtime/thread.inline.hpp" 63 #include "runtime/threadCritical.hpp" 64 #include "runtime/threadSMR.hpp" 65 #include "runtime/timer.hpp" 66 #include "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/vmError.hpp" 78 79 // put OS-includes here 80 # include <sys/types.h> 81 # include <sys/mman.h> 82 # include <sys/stat.h> 83 # include <sys/select.h> 84 # include <pthread.h> 85 # include <signal.h> 86 # include <errno.h> 87 # include <dlfcn.h> 88 # include <stdio.h> 89 # include <unistd.h> 90 # include <sys/resource.h> 91 # include <pthread.h> 92 # include <sys/stat.h> 93 # include <sys/time.h> 94 # include <sys/times.h> 95 # include <sys/utsname.h> 96 # include <sys/socket.h> 97 # include <sys/wait.h> 98 # include <pwd.h> 99 # include <poll.h> 100 # include <fcntl.h> 101 # include <string.h> 102 # include <syscall.h> 103 # include <sys/sysinfo.h> 104 # include <gnu/libc-version.h> 105 # include <sys/ipc.h> 106 # include <sys/shm.h> 107 # include <link.h> 108 # include <stdint.h> 109 # include <inttypes.h> 110 # include <sys/ioctl.h> 111 112 #ifndef _GNU_SOURCE 113 #define _GNU_SOURCE 114 #include <sched.h> 115 #undef _GNU_SOURCE 116 #else 117 #include <sched.h> 118 #endif 119 120 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 121 // getrusage() is prepared to handle the associated failure. 122 #ifndef RUSAGE_THREAD 123 #define RUSAGE_THREAD (1) /* only the calling thread */ 124 #endif 125 126 #define MAX_PATH (2 * K) 127 128 #define MAX_SECS 100000000 129 130 // for timer info max values which include all bits 131 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 132 133 enum CoredumpFilterBit { 134 FILE_BACKED_PVT_BIT = 1 << 2, 135 FILE_BACKED_SHARED_BIT = 1 << 3, 136 LARGEPAGES_BIT = 1 << 6, 137 DAX_SHARED_BIT = 1 << 8 138 }; 139 140 //////////////////////////////////////////////////////////////////////////////// 141 // global variables 142 julong os::Linux::_physical_memory = 0; 143 144 address os::Linux::_initial_thread_stack_bottom = NULL; 145 uintptr_t os::Linux::_initial_thread_stack_size = 0; 146 147 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 148 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 149 Mutex* os::Linux::_createThread_lock = NULL; 150 pthread_t os::Linux::_main_thread; 151 int os::Linux::_page_size = -1; 152 bool os::Linux::_supports_fast_thread_cpu_time = false; 153 uint32_t os::Linux::_os_version = 0; 154 const char * os::Linux::_glibc_version = NULL; 155 const char * os::Linux::_libpthread_version = NULL; 156 157 static jlong initial_time_count=0; 158 159 static int clock_tics_per_sec = 100; 160 161 // If the VM might have been created on the primordial thread, we need to resolve the 162 // primordial thread stack bounds and check if the current thread might be the 163 // primordial thread in places. If we know that the primordial thread is never used, 164 // such as when the VM was created by one of the standard java launchers, we can 165 // avoid this 166 static bool suppress_primordial_thread_resolution = false; 167 168 // For diagnostics to print a message once. see run_periodic_checks 169 static sigset_t check_signal_done; 170 static bool check_signals = true; 171 172 // Signal number used to suspend/resume a thread 173 174 // do not use any signal number less than SIGSEGV, see 4355769 175 static int SR_signum = SIGUSR2; 176 sigset_t SR_sigset; 177 178 // utility functions 179 180 static int SR_initialize(); 181 182 julong os::available_memory() { 183 return Linux::available_memory(); 184 } 185 186 julong os::Linux::available_memory() { 187 // values in struct sysinfo are "unsigned long" 188 struct sysinfo si; 189 julong avail_mem; 190 191 if (OSContainer::is_containerized()) { 192 jlong mem_limit, mem_usage; 193 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) { 194 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 195 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 196 } 197 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) { 198 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage); 199 } 200 if (mem_limit > 0 && mem_usage > 0 ) { 201 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0; 202 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem); 203 return avail_mem; 204 } 205 } 206 207 sysinfo(&si); 208 avail_mem = (julong)si.freeram * si.mem_unit; 209 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem); 210 return avail_mem; 211 } 212 213 julong os::physical_memory() { 214 jlong phys_mem = 0; 215 if (OSContainer::is_containerized()) { 216 jlong mem_limit; 217 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) { 218 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit); 219 return mem_limit; 220 } 221 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 222 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 223 } 224 225 phys_mem = Linux::physical_memory(); 226 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem); 227 return phys_mem; 228 } 229 230 // Return true if user is running as root. 231 232 bool os::have_special_privileges() { 233 static bool init = false; 234 static bool privileges = false; 235 if (!init) { 236 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 237 init = true; 238 } 239 return privileges; 240 } 241 242 243 #ifndef SYS_gettid 244 // i386: 224, ia64: 1105, amd64: 186, sparc 143 245 #ifdef __ia64__ 246 #define SYS_gettid 1105 247 #else 248 #ifdef __i386__ 249 #define SYS_gettid 224 250 #else 251 #ifdef __amd64__ 252 #define SYS_gettid 186 253 #else 254 #ifdef __sparc__ 255 #define SYS_gettid 143 256 #else 257 #error define gettid for the arch 258 #endif 259 #endif 260 #endif 261 #endif 262 #endif 263 264 265 // pid_t gettid() 266 // 267 // Returns the kernel thread id of the currently running thread. Kernel 268 // thread id is used to access /proc. 269 pid_t os::Linux::gettid() { 270 int rslt = syscall(SYS_gettid); 271 assert(rslt != -1, "must be."); // old linuxthreads implementation? 272 return (pid_t)rslt; 273 } 274 275 // Most versions of linux have a bug where the number of processors are 276 // determined by looking at the /proc file system. In a chroot environment, 277 // the system call returns 1. 278 static bool unsafe_chroot_detected = false; 279 static const char *unstable_chroot_error = "/proc file system not found.\n" 280 "Java may be unstable running multithreaded in a chroot " 281 "environment on Linux when /proc filesystem is not mounted."; 282 283 void os::Linux::initialize_system_info() { 284 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 285 if (processor_count() == 1) { 286 pid_t pid = os::Linux::gettid(); 287 char fname[32]; 288 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 289 FILE *fp = fopen(fname, "r"); 290 if (fp == NULL) { 291 unsafe_chroot_detected = true; 292 } else { 293 fclose(fp); 294 } 295 } 296 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 297 assert(processor_count() > 0, "linux error"); 298 } 299 300 void os::init_system_properties_values() { 301 // The next steps are taken in the product version: 302 // 303 // Obtain the JAVA_HOME value from the location of libjvm.so. 304 // This library should be located at: 305 // <JAVA_HOME>/lib/{client|server}/libjvm.so. 306 // 307 // If "/jre/lib/" appears at the right place in the path, then we 308 // assume libjvm.so is installed in a JDK and we use this path. 309 // 310 // Otherwise exit with message: "Could not create the Java virtual machine." 311 // 312 // The following extra steps are taken in the debugging version: 313 // 314 // If "/jre/lib/" does NOT appear at the right place in the path 315 // instead of exit check for $JAVA_HOME environment variable. 316 // 317 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 318 // then we append a fake suffix "hotspot/libjvm.so" to this path so 319 // it looks like libjvm.so is installed there 320 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 321 // 322 // Otherwise exit. 323 // 324 // Important note: if the location of libjvm.so changes this 325 // code needs to be changed accordingly. 326 327 // See ld(1): 328 // The linker uses the following search paths to locate required 329 // shared libraries: 330 // 1: ... 331 // ... 332 // 7: The default directories, normally /lib and /usr/lib. 333 #ifndef OVERRIDE_LIBPATH 334 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390) 335 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 336 #else 337 #define DEFAULT_LIBPATH "/lib:/usr/lib" 338 #endif 339 #else 340 #define DEFAULT_LIBPATH OVERRIDE_LIBPATH 341 #endif 342 343 // Base path of extensions installed on the system. 344 #define SYS_EXT_DIR "/usr/java/packages" 345 #define EXTENSIONS_DIR "/lib/ext" 346 347 // Buffer that fits several sprintfs. 348 // Note that the space for the colon and the trailing null are provided 349 // by the nulls included by the sizeof operator. 350 const size_t bufsize = 351 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 352 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 353 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 354 355 // sysclasspath, java_home, dll_dir 356 { 357 char *pslash; 358 os::jvm_path(buf, bufsize); 359 360 // Found the full path to libjvm.so. 361 // Now cut the path to <java_home>/jre if we can. 362 pslash = strrchr(buf, '/'); 363 if (pslash != NULL) { 364 *pslash = '\0'; // Get rid of /libjvm.so. 365 } 366 pslash = strrchr(buf, '/'); 367 if (pslash != NULL) { 368 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 369 } 370 Arguments::set_dll_dir(buf); 371 372 if (pslash != NULL) { 373 pslash = strrchr(buf, '/'); 374 if (pslash != NULL) { 375 *pslash = '\0'; // Get rid of /lib. 376 } 377 } 378 Arguments::set_java_home(buf); 379 if (!set_boot_path('/', ':')) { 380 vm_exit_during_initialization("Failed setting boot class path.", NULL); 381 } 382 } 383 384 // Where to look for native libraries. 385 // 386 // Note: Due to a legacy implementation, most of the library path 387 // is set in the launcher. This was to accomodate linking restrictions 388 // on legacy Linux implementations (which are no longer supported). 389 // Eventually, all the library path setting will be done here. 390 // 391 // However, to prevent the proliferation of improperly built native 392 // libraries, the new path component /usr/java/packages is added here. 393 // Eventually, all the library path setting will be done here. 394 { 395 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 396 // should always exist (until the legacy problem cited above is 397 // addressed). 398 const char *v = ::getenv("LD_LIBRARY_PATH"); 399 const char *v_colon = ":"; 400 if (v == NULL) { v = ""; v_colon = ""; } 401 // That's +1 for the colon and +1 for the trailing '\0'. 402 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 403 strlen(v) + 1 + 404 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1, 405 mtInternal); 406 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon); 407 Arguments::set_library_path(ld_library_path); 408 FREE_C_HEAP_ARRAY(char, ld_library_path); 409 } 410 411 // Extensions directories. 412 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 413 Arguments::set_ext_dirs(buf); 414 415 FREE_C_HEAP_ARRAY(char, buf); 416 417 #undef DEFAULT_LIBPATH 418 #undef SYS_EXT_DIR 419 #undef EXTENSIONS_DIR 420 } 421 422 //////////////////////////////////////////////////////////////////////////////// 423 // breakpoint support 424 425 void os::breakpoint() { 426 BREAKPOINT; 427 } 428 429 extern "C" void breakpoint() { 430 // use debugger to set breakpoint here 431 } 432 433 //////////////////////////////////////////////////////////////////////////////// 434 // signal support 435 436 debug_only(static bool signal_sets_initialized = false); 437 static sigset_t unblocked_sigs, vm_sigs; 438 439 void os::Linux::signal_sets_init() { 440 // Should also have an assertion stating we are still single-threaded. 441 assert(!signal_sets_initialized, "Already initialized"); 442 // Fill in signals that are necessarily unblocked for all threads in 443 // the VM. Currently, we unblock the following signals: 444 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 445 // by -Xrs (=ReduceSignalUsage)); 446 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 447 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 448 // the dispositions or masks wrt these signals. 449 // Programs embedding the VM that want to use the above signals for their 450 // own purposes must, at this time, use the "-Xrs" option to prevent 451 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 452 // (See bug 4345157, and other related bugs). 453 // In reality, though, unblocking these signals is really a nop, since 454 // these signals are not blocked by default. 455 sigemptyset(&unblocked_sigs); 456 sigaddset(&unblocked_sigs, SIGILL); 457 sigaddset(&unblocked_sigs, SIGSEGV); 458 sigaddset(&unblocked_sigs, SIGBUS); 459 sigaddset(&unblocked_sigs, SIGFPE); 460 #if defined(PPC64) 461 sigaddset(&unblocked_sigs, SIGTRAP); 462 #endif 463 sigaddset(&unblocked_sigs, SR_signum); 464 465 if (!ReduceSignalUsage) { 466 if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 467 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 468 } 469 if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 470 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 471 } 472 if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 473 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 474 } 475 } 476 // Fill in signals that are blocked by all but the VM thread. 477 sigemptyset(&vm_sigs); 478 if (!ReduceSignalUsage) { 479 sigaddset(&vm_sigs, BREAK_SIGNAL); 480 } 481 debug_only(signal_sets_initialized = true); 482 483 } 484 485 // These are signals that are unblocked while a thread is running Java. 486 // (For some reason, they get blocked by default.) 487 sigset_t* os::Linux::unblocked_signals() { 488 assert(signal_sets_initialized, "Not initialized"); 489 return &unblocked_sigs; 490 } 491 492 // These are the signals that are blocked while a (non-VM) thread is 493 // running Java. Only the VM thread handles these signals. 494 sigset_t* os::Linux::vm_signals() { 495 assert(signal_sets_initialized, "Not initialized"); 496 return &vm_sigs; 497 } 498 499 void os::Linux::hotspot_sigmask(Thread* thread) { 500 501 //Save caller's signal mask before setting VM signal mask 502 sigset_t caller_sigmask; 503 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 504 505 OSThread* osthread = thread->osthread(); 506 osthread->set_caller_sigmask(caller_sigmask); 507 508 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 509 510 if (!ReduceSignalUsage) { 511 if (thread->is_VM_thread()) { 512 // Only the VM thread handles BREAK_SIGNAL ... 513 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 514 } else { 515 // ... all other threads block BREAK_SIGNAL 516 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 517 } 518 } 519 } 520 521 ////////////////////////////////////////////////////////////////////////////// 522 // detecting pthread library 523 524 void os::Linux::libpthread_init() { 525 // Save glibc and pthread version strings. 526 #if !defined(_CS_GNU_LIBC_VERSION) || \ 527 !defined(_CS_GNU_LIBPTHREAD_VERSION) 528 #error "glibc too old (< 2.3.2)" 529 #endif 530 531 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 532 assert(n > 0, "cannot retrieve glibc version"); 533 char *str = (char *)malloc(n, mtInternal); 534 confstr(_CS_GNU_LIBC_VERSION, str, n); 535 os::Linux::set_glibc_version(str); 536 537 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 538 assert(n > 0, "cannot retrieve pthread version"); 539 str = (char *)malloc(n, mtInternal); 540 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 541 os::Linux::set_libpthread_version(str); 542 } 543 544 ///////////////////////////////////////////////////////////////////////////// 545 // thread stack expansion 546 547 // os::Linux::manually_expand_stack() takes care of expanding the thread 548 // stack. Note that this is normally not needed: pthread stacks allocate 549 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 550 // committed. Therefore it is not necessary to expand the stack manually. 551 // 552 // Manually expanding the stack was historically needed on LinuxThreads 553 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 554 // it is kept to deal with very rare corner cases: 555 // 556 // For one, user may run the VM on an own implementation of threads 557 // whose stacks are - like the old LinuxThreads - implemented using 558 // mmap(MAP_GROWSDOWN). 559 // 560 // Also, this coding may be needed if the VM is running on the primordial 561 // thread. Normally we avoid running on the primordial thread; however, 562 // user may still invoke the VM on the primordial thread. 563 // 564 // The following historical comment describes the details about running 565 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 566 567 568 // Force Linux kernel to expand current thread stack. If "bottom" is close 569 // to the stack guard, caller should block all signals. 570 // 571 // MAP_GROWSDOWN: 572 // A special mmap() flag that is used to implement thread stacks. It tells 573 // kernel that the memory region should extend downwards when needed. This 574 // allows early versions of LinuxThreads to only mmap the first few pages 575 // when creating a new thread. Linux kernel will automatically expand thread 576 // stack as needed (on page faults). 577 // 578 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 579 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 580 // region, it's hard to tell if the fault is due to a legitimate stack 581 // access or because of reading/writing non-exist memory (e.g. buffer 582 // overrun). As a rule, if the fault happens below current stack pointer, 583 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 584 // application (see Linux kernel fault.c). 585 // 586 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 587 // stack overflow detection. 588 // 589 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 590 // not use MAP_GROWSDOWN. 591 // 592 // To get around the problem and allow stack banging on Linux, we need to 593 // manually expand thread stack after receiving the SIGSEGV. 594 // 595 // There are two ways to expand thread stack to address "bottom", we used 596 // both of them in JVM before 1.5: 597 // 1. adjust stack pointer first so that it is below "bottom", and then 598 // touch "bottom" 599 // 2. mmap() the page in question 600 // 601 // Now alternate signal stack is gone, it's harder to use 2. For instance, 602 // if current sp is already near the lower end of page 101, and we need to 603 // call mmap() to map page 100, it is possible that part of the mmap() frame 604 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 605 // That will destroy the mmap() frame and cause VM to crash. 606 // 607 // The following code works by adjusting sp first, then accessing the "bottom" 608 // page to force a page fault. Linux kernel will then automatically expand the 609 // stack mapping. 610 // 611 // _expand_stack_to() assumes its frame size is less than page size, which 612 // should always be true if the function is not inlined. 613 614 static void NOINLINE _expand_stack_to(address bottom) { 615 address sp; 616 size_t size; 617 volatile char *p; 618 619 // Adjust bottom to point to the largest address within the same page, it 620 // gives us a one-page buffer if alloca() allocates slightly more memory. 621 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size()); 622 bottom += os::Linux::page_size() - 1; 623 624 // sp might be slightly above current stack pointer; if that's the case, we 625 // will alloca() a little more space than necessary, which is OK. Don't use 626 // os::current_stack_pointer(), as its result can be slightly below current 627 // stack pointer, causing us to not alloca enough to reach "bottom". 628 sp = (address)&sp; 629 630 if (sp > bottom) { 631 size = sp - bottom; 632 p = (volatile char *)alloca(size); 633 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 634 p[0] = '\0'; 635 } 636 } 637 638 void os::Linux::expand_stack_to(address bottom) { 639 _expand_stack_to(bottom); 640 } 641 642 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 643 assert(t!=NULL, "just checking"); 644 assert(t->osthread()->expanding_stack(), "expand should be set"); 645 assert(t->stack_base() != NULL, "stack_base was not initialized"); 646 647 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) { 648 sigset_t mask_all, old_sigset; 649 sigfillset(&mask_all); 650 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 651 _expand_stack_to(addr); 652 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 653 return true; 654 } 655 return false; 656 } 657 658 ////////////////////////////////////////////////////////////////////////////// 659 // create new thread 660 661 // Thread start routine for all newly created threads 662 static void *thread_native_entry(Thread *thread) { 663 664 thread->record_stack_base_and_size(); 665 666 // Try to randomize the cache line index of hot stack frames. 667 // This helps when threads of the same stack traces evict each other's 668 // cache lines. The threads can be either from the same JVM instance, or 669 // from different JVM instances. The benefit is especially true for 670 // processors with hyperthreading technology. 671 static int counter = 0; 672 int pid = os::current_process_id(); 673 alloca(((pid ^ counter++) & 7) * 128); 674 675 thread->initialize_thread_current(); 676 677 OSThread* osthread = thread->osthread(); 678 Monitor* sync = osthread->startThread_lock(); 679 680 osthread->set_thread_id(os::current_thread_id()); 681 682 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 683 os::current_thread_id(), (uintx) pthread_self()); 684 685 if (UseNUMA) { 686 int lgrp_id = os::numa_get_group_id(); 687 if (lgrp_id != -1) { 688 thread->set_lgrp_id(lgrp_id); 689 } 690 } 691 // initialize signal mask for this thread 692 os::Linux::hotspot_sigmask(thread); 693 694 // initialize floating point control register 695 os::Linux::init_thread_fpu_state(); 696 697 // handshaking with parent thread 698 { 699 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 700 701 // notify parent thread 702 osthread->set_state(INITIALIZED); 703 sync->notify_all(); 704 705 // wait until os::start_thread() 706 while (osthread->get_state() == INITIALIZED) { 707 sync->wait(Mutex::_no_safepoint_check_flag); 708 } 709 } 710 711 assert(osthread->pthread_id() != 0, "pthread_id was not set as expected"); 712 713 // call one more level start routine 714 thread->call_run(); 715 716 // Note: at this point the thread object may already have deleted itself. 717 // Prevent dereferencing it from here on out. 718 thread = NULL; 719 720 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 721 os::current_thread_id(), (uintx) pthread_self()); 722 723 return 0; 724 } 725 726 bool os::create_thread(Thread* thread, ThreadType thr_type, 727 size_t req_stack_size) { 728 assert(thread->osthread() == NULL, "caller responsible"); 729 730 // Allocate the OSThread object 731 OSThread* osthread = new OSThread(NULL, NULL); 732 if (osthread == NULL) { 733 return false; 734 } 735 736 // set the correct thread state 737 osthread->set_thread_type(thr_type); 738 739 // Initial state is ALLOCATED but not INITIALIZED 740 osthread->set_state(ALLOCATED); 741 742 thread->set_osthread(osthread); 743 744 // init thread attributes 745 pthread_attr_t attr; 746 pthread_attr_init(&attr); 747 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 748 749 // Calculate stack size if it's not specified by caller. 750 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size); 751 // In the Linux NPTL pthread implementation the guard size mechanism 752 // is not implemented properly. The posix standard requires adding 753 // the size of the guard pages to the stack size, instead Linux 754 // takes the space out of 'stacksize'. Thus we adapt the requested 755 // stack_size by the size of the guard pages to mimick proper 756 // behaviour. However, be careful not to end up with a size 757 // of zero due to overflow. Don't add the guard page in that case. 758 size_t guard_size = os::Linux::default_guard_size(thr_type); 759 if (stack_size <= SIZE_MAX - guard_size) { 760 stack_size += guard_size; 761 } 762 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned"); 763 764 int status = pthread_attr_setstacksize(&attr, stack_size); 765 assert_status(status == 0, status, "pthread_attr_setstacksize"); 766 767 // Configure glibc guard page. 768 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 769 770 ThreadState state; 771 772 { 773 pthread_t tid; 774 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread); 775 776 char buf[64]; 777 if (ret == 0) { 778 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 779 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 780 } else { 781 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 782 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 783 } 784 785 pthread_attr_destroy(&attr); 786 787 if (ret != 0) { 788 // Need to clean up stuff we've allocated so far 789 thread->set_osthread(NULL); 790 delete osthread; 791 return false; 792 } 793 794 // Store pthread info into the OSThread 795 osthread->set_pthread_id(tid); 796 797 // Wait until child thread is either initialized or aborted 798 { 799 Monitor* sync_with_child = osthread->startThread_lock(); 800 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 801 while ((state = osthread->get_state()) == ALLOCATED) { 802 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 803 } 804 } 805 } 806 807 // Aborted due to thread limit being reached 808 if (state == ZOMBIE) { 809 thread->set_osthread(NULL); 810 delete osthread; 811 return false; 812 } 813 814 // The thread is returned suspended (in state INITIALIZED), 815 // and is started higher up in the call chain 816 assert(state == INITIALIZED, "race condition"); 817 return true; 818 } 819 820 ///////////////////////////////////////////////////////////////////////////// 821 // attach existing thread 822 823 // bootstrap the main thread 824 bool os::create_main_thread(JavaThread* thread) { 825 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 826 return create_attached_thread(thread); 827 } 828 829 bool os::create_attached_thread(JavaThread* thread) { 830 #ifdef ASSERT 831 thread->verify_not_published(); 832 #endif 833 834 // Allocate the OSThread object 835 OSThread* osthread = new OSThread(NULL, NULL); 836 837 if (osthread == NULL) { 838 return false; 839 } 840 841 // Store pthread info into the OSThread 842 osthread->set_thread_id(os::Linux::gettid()); 843 osthread->set_pthread_id(::pthread_self()); 844 845 // initialize floating point control register 846 os::Linux::init_thread_fpu_state(); 847 848 // Initial thread state is RUNNABLE 849 osthread->set_state(RUNNABLE); 850 851 thread->set_osthread(osthread); 852 853 if (UseNUMA) { 854 int lgrp_id = os::numa_get_group_id(); 855 if (lgrp_id != -1) { 856 thread->set_lgrp_id(lgrp_id); 857 } 858 } 859 860 if (os::is_primordial_thread()) { 861 // If current thread is primordial thread, its stack is mapped on demand, 862 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 863 // the entire stack region to avoid SEGV in stack banging. 864 // It is also useful to get around the heap-stack-gap problem on SuSE 865 // kernel (see 4821821 for details). We first expand stack to the top 866 // of yellow zone, then enable stack yellow zone (order is significant, 867 // enabling yellow zone first will crash JVM on SuSE Linux), so there 868 // is no gap between the last two virtual memory regions. 869 870 JavaThread *jt = (JavaThread *)thread; 871 address addr = jt->stack_reserved_zone_base(); 872 assert(addr != NULL, "initialization problem?"); 873 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 874 875 osthread->set_expanding_stack(); 876 os::Linux::manually_expand_stack(jt, addr); 877 osthread->clear_expanding_stack(); 878 } 879 880 // initialize signal mask for this thread 881 // and save the caller's signal mask 882 os::Linux::hotspot_sigmask(thread); 883 884 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 885 os::current_thread_id(), (uintx) pthread_self()); 886 887 return true; 888 } 889 890 void os::pd_start_thread(Thread* thread) { 891 OSThread * osthread = thread->osthread(); 892 assert(osthread->get_state() != INITIALIZED, "just checking"); 893 Monitor* sync_with_child = osthread->startThread_lock(); 894 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 895 sync_with_child->notify(); 896 } 897 898 // Free Linux resources related to the OSThread 899 void os::free_thread(OSThread* osthread) { 900 assert(osthread != NULL, "osthread not set"); 901 902 // We are told to free resources of the argument thread, 903 // but we can only really operate on the current thread. 904 assert(Thread::current()->osthread() == osthread, 905 "os::free_thread but not current thread"); 906 907 #ifdef ASSERT 908 sigset_t current; 909 sigemptyset(¤t); 910 pthread_sigmask(SIG_SETMASK, NULL, ¤t); 911 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!"); 912 #endif 913 914 // Restore caller's signal mask 915 sigset_t sigmask = osthread->caller_sigmask(); 916 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 917 918 delete osthread; 919 } 920 921 ////////////////////////////////////////////////////////////////////////////// 922 // primordial thread 923 924 // Check if current thread is the primordial thread, similar to Solaris thr_main. 925 bool os::is_primordial_thread(void) { 926 if (suppress_primordial_thread_resolution) { 927 return false; 928 } 929 char dummy; 930 // If called before init complete, thread stack bottom will be null. 931 // Can be called if fatal error occurs before initialization. 932 if (os::Linux::initial_thread_stack_bottom() == NULL) return false; 933 assert(os::Linux::initial_thread_stack_bottom() != NULL && 934 os::Linux::initial_thread_stack_size() != 0, 935 "os::init did not locate primordial thread's stack region"); 936 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() && 937 (address)&dummy < os::Linux::initial_thread_stack_bottom() + 938 os::Linux::initial_thread_stack_size()) { 939 return true; 940 } else { 941 return false; 942 } 943 } 944 945 // Find the virtual memory area that contains addr 946 static bool find_vma(address addr, address* vma_low, address* vma_high) { 947 FILE *fp = fopen("/proc/self/maps", "r"); 948 if (fp) { 949 address low, high; 950 while (!feof(fp)) { 951 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 952 if (low <= addr && addr < high) { 953 if (vma_low) *vma_low = low; 954 if (vma_high) *vma_high = high; 955 fclose(fp); 956 return true; 957 } 958 } 959 for (;;) { 960 int ch = fgetc(fp); 961 if (ch == EOF || ch == (int)'\n') break; 962 } 963 } 964 fclose(fp); 965 } 966 return false; 967 } 968 969 // Locate primordial thread stack. This special handling of primordial thread stack 970 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 971 // bogus value for the primordial process thread. While the launcher has created 972 // the VM in a new thread since JDK 6, we still have to allow for the use of the 973 // JNI invocation API from a primordial thread. 974 void os::Linux::capture_initial_stack(size_t max_size) { 975 976 // max_size is either 0 (which means accept OS default for thread stacks) or 977 // a user-specified value known to be at least the minimum needed. If we 978 // are actually on the primordial thread we can make it appear that we have a 979 // smaller max_size stack by inserting the guard pages at that location. But we 980 // cannot do anything to emulate a larger stack than what has been provided by 981 // the OS or threading library. In fact if we try to use a stack greater than 982 // what is set by rlimit then we will crash the hosting process. 983 984 // Maximum stack size is the easy part, get it from RLIMIT_STACK. 985 // If this is "unlimited" then it will be a huge value. 986 struct rlimit rlim; 987 getrlimit(RLIMIT_STACK, &rlim); 988 size_t stack_size = rlim.rlim_cur; 989 990 // 6308388: a bug in ld.so will relocate its own .data section to the 991 // lower end of primordial stack; reduce ulimit -s value a little bit 992 // so we won't install guard page on ld.so's data section. 993 // But ensure we don't underflow the stack size - allow 1 page spare 994 if (stack_size >= (size_t)(3 * page_size())) { 995 stack_size -= 2 * page_size(); 996 } 997 998 // Try to figure out where the stack base (top) is. This is harder. 999 // 1000 // When an application is started, glibc saves the initial stack pointer in 1001 // a global variable "__libc_stack_end", which is then used by system 1002 // libraries. __libc_stack_end should be pretty close to stack top. The 1003 // variable is available since the very early days. However, because it is 1004 // a private interface, it could disappear in the future. 1005 // 1006 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1007 // to __libc_stack_end, it is very close to stack top, but isn't the real 1008 // stack top. Note that /proc may not exist if VM is running as a chroot 1009 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1010 // /proc/<pid>/stat could change in the future (though unlikely). 1011 // 1012 // We try __libc_stack_end first. If that doesn't work, look for 1013 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1014 // as a hint, which should work well in most cases. 1015 1016 uintptr_t stack_start; 1017 1018 // try __libc_stack_end first 1019 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1020 if (p && *p) { 1021 stack_start = *p; 1022 } else { 1023 // see if we can get the start_stack field from /proc/self/stat 1024 FILE *fp; 1025 int pid; 1026 char state; 1027 int ppid; 1028 int pgrp; 1029 int session; 1030 int nr; 1031 int tpgrp; 1032 unsigned long flags; 1033 unsigned long minflt; 1034 unsigned long cminflt; 1035 unsigned long majflt; 1036 unsigned long cmajflt; 1037 unsigned long utime; 1038 unsigned long stime; 1039 long cutime; 1040 long cstime; 1041 long prio; 1042 long nice; 1043 long junk; 1044 long it_real; 1045 uintptr_t start; 1046 uintptr_t vsize; 1047 intptr_t rss; 1048 uintptr_t rsslim; 1049 uintptr_t scodes; 1050 uintptr_t ecode; 1051 int i; 1052 1053 // Figure what the primordial thread stack base is. Code is inspired 1054 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1055 // followed by command name surrounded by parentheses, state, etc. 1056 char stat[2048]; 1057 int statlen; 1058 1059 fp = fopen("/proc/self/stat", "r"); 1060 if (fp) { 1061 statlen = fread(stat, 1, 2047, fp); 1062 stat[statlen] = '\0'; 1063 fclose(fp); 1064 1065 // Skip pid and the command string. Note that we could be dealing with 1066 // weird command names, e.g. user could decide to rename java launcher 1067 // to "java 1.4.2 :)", then the stat file would look like 1068 // 1234 (java 1.4.2 :)) R ... ... 1069 // We don't really need to know the command string, just find the last 1070 // occurrence of ")" and then start parsing from there. See bug 4726580. 1071 char * s = strrchr(stat, ')'); 1072 1073 i = 0; 1074 if (s) { 1075 // Skip blank chars 1076 do { s++; } while (s && isspace(*s)); 1077 1078 #define _UFM UINTX_FORMAT 1079 #define _DFM INTX_FORMAT 1080 1081 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1082 // 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 1083 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, 1084 &state, // 3 %c 1085 &ppid, // 4 %d 1086 &pgrp, // 5 %d 1087 &session, // 6 %d 1088 &nr, // 7 %d 1089 &tpgrp, // 8 %d 1090 &flags, // 9 %lu 1091 &minflt, // 10 %lu 1092 &cminflt, // 11 %lu 1093 &majflt, // 12 %lu 1094 &cmajflt, // 13 %lu 1095 &utime, // 14 %lu 1096 &stime, // 15 %lu 1097 &cutime, // 16 %ld 1098 &cstime, // 17 %ld 1099 &prio, // 18 %ld 1100 &nice, // 19 %ld 1101 &junk, // 20 %ld 1102 &it_real, // 21 %ld 1103 &start, // 22 UINTX_FORMAT 1104 &vsize, // 23 UINTX_FORMAT 1105 &rss, // 24 INTX_FORMAT 1106 &rsslim, // 25 UINTX_FORMAT 1107 &scodes, // 26 UINTX_FORMAT 1108 &ecode, // 27 UINTX_FORMAT 1109 &stack_start); // 28 UINTX_FORMAT 1110 } 1111 1112 #undef _UFM 1113 #undef _DFM 1114 1115 if (i != 28 - 2) { 1116 assert(false, "Bad conversion from /proc/self/stat"); 1117 // product mode - assume we are the primordial thread, good luck in the 1118 // embedded case. 1119 warning("Can't detect primordial thread stack location - bad conversion"); 1120 stack_start = (uintptr_t) &rlim; 1121 } 1122 } else { 1123 // For some reason we can't open /proc/self/stat (for example, running on 1124 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1125 // most cases, so don't abort: 1126 warning("Can't detect primordial thread stack location - no /proc/self/stat"); 1127 stack_start = (uintptr_t) &rlim; 1128 } 1129 } 1130 1131 // Now we have a pointer (stack_start) very close to the stack top, the 1132 // next thing to do is to figure out the exact location of stack top. We 1133 // can find out the virtual memory area that contains stack_start by 1134 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1135 // and its upper limit is the real stack top. (again, this would fail if 1136 // running inside chroot, because /proc may not exist.) 1137 1138 uintptr_t stack_top; 1139 address low, high; 1140 if (find_vma((address)stack_start, &low, &high)) { 1141 // success, "high" is the true stack top. (ignore "low", because initial 1142 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1143 stack_top = (uintptr_t)high; 1144 } else { 1145 // failed, likely because /proc/self/maps does not exist 1146 warning("Can't detect primordial thread stack location - find_vma failed"); 1147 // best effort: stack_start is normally within a few pages below the real 1148 // stack top, use it as stack top, and reduce stack size so we won't put 1149 // guard page outside stack. 1150 stack_top = stack_start; 1151 stack_size -= 16 * page_size(); 1152 } 1153 1154 // stack_top could be partially down the page so align it 1155 stack_top = align_up(stack_top, page_size()); 1156 1157 // Allowed stack value is minimum of max_size and what we derived from rlimit 1158 if (max_size > 0) { 1159 _initial_thread_stack_size = MIN2(max_size, stack_size); 1160 } else { 1161 // Accept the rlimit max, but if stack is unlimited then it will be huge, so 1162 // clamp it at 8MB as we do on Solaris 1163 _initial_thread_stack_size = MIN2(stack_size, 8*M); 1164 } 1165 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size()); 1166 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1167 1168 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!"); 1169 1170 if (log_is_enabled(Info, os, thread)) { 1171 // See if we seem to be on primordial process thread 1172 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) && 1173 uintptr_t(&rlim) < stack_top; 1174 1175 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: " 1176 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT, 1177 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K, 1178 stack_top, intptr_t(_initial_thread_stack_bottom)); 1179 } 1180 } 1181 1182 //////////////////////////////////////////////////////////////////////////////// 1183 // time support 1184 1185 #ifndef SUPPORTS_CLOCK_MONOTONIC 1186 #error "Build platform doesn't support clock_gettime and related functionality" 1187 #endif 1188 1189 // Time since start-up in seconds to a fine granularity. 1190 // Used by VMSelfDestructTimer and the MemProfiler. 1191 double os::elapsedTime() { 1192 1193 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1194 } 1195 1196 jlong os::elapsed_counter() { 1197 return javaTimeNanos() - initial_time_count; 1198 } 1199 1200 jlong os::elapsed_frequency() { 1201 return NANOSECS_PER_SEC; // nanosecond resolution 1202 } 1203 1204 bool os::supports_vtime() { return true; } 1205 bool os::enable_vtime() { return false; } 1206 bool os::vtime_enabled() { return false; } 1207 1208 double os::elapsedVTime() { 1209 struct rusage usage; 1210 int retval = getrusage(RUSAGE_THREAD, &usage); 1211 if (retval == 0) { 1212 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); 1213 } else { 1214 // better than nothing, but not much 1215 return elapsedTime(); 1216 } 1217 } 1218 1219 jlong os::javaTimeMillis() { 1220 timeval time; 1221 int status = gettimeofday(&time, NULL); 1222 assert(status != -1, "linux error"); 1223 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1224 } 1225 1226 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1227 timeval time; 1228 int status = gettimeofday(&time, NULL); 1229 assert(status != -1, "linux error"); 1230 seconds = jlong(time.tv_sec); 1231 nanos = jlong(time.tv_usec) * 1000; 1232 } 1233 1234 void os::Linux::fast_thread_clock_init() { 1235 if (!UseLinuxPosixThreadCPUClocks) { 1236 return; 1237 } 1238 clockid_t clockid; 1239 struct timespec tp; 1240 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1241 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1242 1243 // Switch to using fast clocks for thread cpu time if 1244 // the clock_getres() returns 0 error code. 1245 // Note, that some kernels may support the current thread 1246 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1247 // returned by the pthread_getcpuclockid(). 1248 // If the fast Posix clocks are supported then the clock_getres() 1249 // must return at least tp.tv_sec == 0 which means a resolution 1250 // better than 1 sec. This is extra check for reliability. 1251 1252 if (pthread_getcpuclockid_func && 1253 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1254 os::Posix::clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1255 _supports_fast_thread_cpu_time = true; 1256 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1257 } 1258 } 1259 1260 jlong os::javaTimeNanos() { 1261 if (os::supports_monotonic_clock()) { 1262 struct timespec tp; 1263 int status = os::Posix::clock_gettime(CLOCK_MONOTONIC, &tp); 1264 assert(status == 0, "gettime error"); 1265 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1266 return result; 1267 } else { 1268 timeval time; 1269 int status = gettimeofday(&time, NULL); 1270 assert(status != -1, "linux error"); 1271 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1272 return 1000 * usecs; 1273 } 1274 } 1275 1276 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1277 if (os::supports_monotonic_clock()) { 1278 info_ptr->max_value = ALL_64_BITS; 1279 1280 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1281 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1282 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1283 } else { 1284 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1285 info_ptr->max_value = ALL_64_BITS; 1286 1287 // gettimeofday is a real time clock so it skips 1288 info_ptr->may_skip_backward = true; 1289 info_ptr->may_skip_forward = true; 1290 } 1291 1292 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1293 } 1294 1295 // Return the real, user, and system times in seconds from an 1296 // arbitrary fixed point in the past. 1297 bool os::getTimesSecs(double* process_real_time, 1298 double* process_user_time, 1299 double* process_system_time) { 1300 struct tms ticks; 1301 clock_t real_ticks = times(&ticks); 1302 1303 if (real_ticks == (clock_t) (-1)) { 1304 return false; 1305 } else { 1306 double ticks_per_second = (double) clock_tics_per_sec; 1307 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1308 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1309 *process_real_time = ((double) real_ticks) / ticks_per_second; 1310 1311 return true; 1312 } 1313 } 1314 1315 1316 char * os::local_time_string(char *buf, size_t buflen) { 1317 struct tm t; 1318 time_t long_time; 1319 time(&long_time); 1320 localtime_r(&long_time, &t); 1321 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1322 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1323 t.tm_hour, t.tm_min, t.tm_sec); 1324 return buf; 1325 } 1326 1327 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1328 return localtime_r(clock, res); 1329 } 1330 1331 //////////////////////////////////////////////////////////////////////////////// 1332 // runtime exit support 1333 1334 // Note: os::shutdown() might be called very early during initialization, or 1335 // called from signal handler. Before adding something to os::shutdown(), make 1336 // sure it is async-safe and can handle partially initialized VM. 1337 void os::shutdown() { 1338 1339 // allow PerfMemory to attempt cleanup of any persistent resources 1340 perfMemory_exit(); 1341 1342 // needs to remove object in file system 1343 AttachListener::abort(); 1344 1345 // flush buffered output, finish log files 1346 ostream_abort(); 1347 1348 // Check for abort hook 1349 abort_hook_t abort_hook = Arguments::abort_hook(); 1350 if (abort_hook != NULL) { 1351 abort_hook(); 1352 } 1353 1354 } 1355 1356 // Note: os::abort() might be called very early during initialization, or 1357 // called from signal handler. Before adding something to os::abort(), make 1358 // sure it is async-safe and can handle partially initialized VM. 1359 void os::abort(bool dump_core, void* siginfo, const void* context) { 1360 os::shutdown(); 1361 if (dump_core) { 1362 if (DumpPrivateMappingsInCore) { 1363 ClassLoader::close_jrt_image(); 1364 } 1365 #ifndef PRODUCT 1366 fdStream out(defaultStream::output_fd()); 1367 out.print_raw("Current thread is "); 1368 char buf[16]; 1369 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1370 out.print_raw_cr(buf); 1371 out.print_raw_cr("Dumping core ..."); 1372 #endif 1373 ::abort(); // dump core 1374 } 1375 1376 ::exit(1); 1377 } 1378 1379 // Die immediately, no exit hook, no abort hook, no cleanup. 1380 void os::die() { 1381 ::abort(); 1382 } 1383 1384 // thread_id is kernel thread id (similar to Solaris LWP id) 1385 intx os::current_thread_id() { return os::Linux::gettid(); } 1386 int os::current_process_id() { 1387 return ::getpid(); 1388 } 1389 1390 // DLL functions 1391 1392 const char* os::dll_file_extension() { return ".so"; } 1393 1394 // This must be hard coded because it's the system's temporary 1395 // directory not the java application's temp directory, ala java.io.tmpdir. 1396 const char* os::get_temp_directory() { return "/tmp"; } 1397 1398 static bool file_exists(const char* filename) { 1399 struct stat statbuf; 1400 if (filename == NULL || strlen(filename) == 0) { 1401 return false; 1402 } 1403 return os::stat(filename, &statbuf) == 0; 1404 } 1405 1406 // check if addr is inside libjvm.so 1407 bool os::address_is_in_vm(address addr) { 1408 static address libjvm_base_addr; 1409 Dl_info dlinfo; 1410 1411 if (libjvm_base_addr == NULL) { 1412 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1413 libjvm_base_addr = (address)dlinfo.dli_fbase; 1414 } 1415 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1416 } 1417 1418 if (dladdr((void *)addr, &dlinfo) != 0) { 1419 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1420 } 1421 1422 return false; 1423 } 1424 1425 bool os::dll_address_to_function_name(address addr, char *buf, 1426 int buflen, int *offset, 1427 bool demangle) { 1428 // buf is not optional, but offset is optional 1429 assert(buf != NULL, "sanity check"); 1430 1431 Dl_info dlinfo; 1432 1433 if (dladdr((void*)addr, &dlinfo) != 0) { 1434 // see if we have a matching symbol 1435 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1436 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1437 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1438 } 1439 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1440 return true; 1441 } 1442 // no matching symbol so try for just file info 1443 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1444 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1445 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1446 return true; 1447 } 1448 } 1449 } 1450 1451 buf[0] = '\0'; 1452 if (offset != NULL) *offset = -1; 1453 return false; 1454 } 1455 1456 struct _address_to_library_name { 1457 address addr; // input : memory address 1458 size_t buflen; // size of fname 1459 char* fname; // output: library name 1460 address base; // library base addr 1461 }; 1462 1463 static int address_to_library_name_callback(struct dl_phdr_info *info, 1464 size_t size, void *data) { 1465 int i; 1466 bool found = false; 1467 address libbase = NULL; 1468 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1469 1470 // iterate through all loadable segments 1471 for (i = 0; i < info->dlpi_phnum; i++) { 1472 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1473 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1474 // base address of a library is the lowest address of its loaded 1475 // segments. 1476 if (libbase == NULL || libbase > segbase) { 1477 libbase = segbase; 1478 } 1479 // see if 'addr' is within current segment 1480 if (segbase <= d->addr && 1481 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1482 found = true; 1483 } 1484 } 1485 } 1486 1487 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1488 // so dll_address_to_library_name() can fall through to use dladdr() which 1489 // can figure out executable name from argv[0]. 1490 if (found && info->dlpi_name && info->dlpi_name[0]) { 1491 d->base = libbase; 1492 if (d->fname) { 1493 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1494 } 1495 return 1; 1496 } 1497 return 0; 1498 } 1499 1500 bool os::dll_address_to_library_name(address addr, char* buf, 1501 int buflen, int* offset) { 1502 // buf is not optional, but offset is optional 1503 assert(buf != NULL, "sanity check"); 1504 1505 Dl_info dlinfo; 1506 struct _address_to_library_name data; 1507 1508 // There is a bug in old glibc dladdr() implementation that it could resolve 1509 // to wrong library name if the .so file has a base address != NULL. Here 1510 // we iterate through the program headers of all loaded libraries to find 1511 // out which library 'addr' really belongs to. This workaround can be 1512 // removed once the minimum requirement for glibc is moved to 2.3.x. 1513 data.addr = addr; 1514 data.fname = buf; 1515 data.buflen = buflen; 1516 data.base = NULL; 1517 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1518 1519 if (rslt) { 1520 // buf already contains library name 1521 if (offset) *offset = addr - data.base; 1522 return true; 1523 } 1524 if (dladdr((void*)addr, &dlinfo) != 0) { 1525 if (dlinfo.dli_fname != NULL) { 1526 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1527 } 1528 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1529 *offset = addr - (address)dlinfo.dli_fbase; 1530 } 1531 return true; 1532 } 1533 1534 buf[0] = '\0'; 1535 if (offset) *offset = -1; 1536 return false; 1537 } 1538 1539 // Loads .dll/.so and 1540 // in case of error it checks if .dll/.so was built for the 1541 // same architecture as Hotspot is running on 1542 1543 1544 // Remember the stack's state. The Linux dynamic linker will change 1545 // the stack to 'executable' at most once, so we must safepoint only once. 1546 bool os::Linux::_stack_is_executable = false; 1547 1548 // VM operation that loads a library. This is necessary if stack protection 1549 // of the Java stacks can be lost during loading the library. If we 1550 // do not stop the Java threads, they can stack overflow before the stacks 1551 // are protected again. 1552 class VM_LinuxDllLoad: public VM_Operation { 1553 private: 1554 const char *_filename; 1555 char *_ebuf; 1556 int _ebuflen; 1557 void *_lib; 1558 public: 1559 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1560 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1561 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1562 void doit() { 1563 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1564 os::Linux::_stack_is_executable = true; 1565 } 1566 void* loaded_library() { return _lib; } 1567 }; 1568 1569 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1570 void * result = NULL; 1571 bool load_attempted = false; 1572 1573 // Check whether the library to load might change execution rights 1574 // of the stack. If they are changed, the protection of the stack 1575 // guard pages will be lost. We need a safepoint to fix this. 1576 // 1577 // See Linux man page execstack(8) for more info. 1578 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1579 if (!ElfFile::specifies_noexecstack(filename)) { 1580 if (!is_init_completed()) { 1581 os::Linux::_stack_is_executable = true; 1582 // This is OK - No Java threads have been created yet, and hence no 1583 // stack guard pages to fix. 1584 // 1585 // Dynamic loader will make all stacks executable after 1586 // this function returns, and will not do that again. 1587 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet."); 1588 } else { 1589 warning("You have loaded library %s which might have disabled stack guard. " 1590 "The VM will try to fix the stack guard now.\n" 1591 "It's highly recommended that you fix the library with " 1592 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1593 filename); 1594 1595 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1596 JavaThread *jt = JavaThread::current(); 1597 if (jt->thread_state() != _thread_in_native) { 1598 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1599 // that requires ExecStack. Cannot enter safe point. Let's give up. 1600 warning("Unable to fix stack guard. Giving up."); 1601 } else { 1602 if (!LoadExecStackDllInVMThread) { 1603 // This is for the case where the DLL has an static 1604 // constructor function that executes JNI code. We cannot 1605 // load such DLLs in the VMThread. 1606 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1607 } 1608 1609 ThreadInVMfromNative tiv(jt); 1610 debug_only(VMNativeEntryWrapper vew;) 1611 1612 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1613 VMThread::execute(&op); 1614 if (LoadExecStackDllInVMThread) { 1615 result = op.loaded_library(); 1616 } 1617 load_attempted = true; 1618 } 1619 } 1620 } 1621 } 1622 1623 if (!load_attempted) { 1624 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1625 } 1626 1627 if (result != NULL) { 1628 // Successful loading 1629 return result; 1630 } 1631 1632 Elf32_Ehdr elf_head; 1633 int diag_msg_max_length=ebuflen-strlen(ebuf); 1634 char* diag_msg_buf=ebuf+strlen(ebuf); 1635 1636 if (diag_msg_max_length==0) { 1637 // No more space in ebuf for additional diagnostics message 1638 return NULL; 1639 } 1640 1641 1642 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1643 1644 if (file_descriptor < 0) { 1645 // Can't open library, report dlerror() message 1646 return NULL; 1647 } 1648 1649 bool failed_to_read_elf_head= 1650 (sizeof(elf_head)!= 1651 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1652 1653 ::close(file_descriptor); 1654 if (failed_to_read_elf_head) { 1655 // file i/o error - report dlerror() msg 1656 return NULL; 1657 } 1658 1659 typedef struct { 1660 Elf32_Half code; // Actual value as defined in elf.h 1661 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1662 unsigned char elf_class; // 32 or 64 bit 1663 unsigned char endianess; // MSB or LSB 1664 char* name; // String representation 1665 } arch_t; 1666 1667 #ifndef EM_486 1668 #define EM_486 6 /* Intel 80486 */ 1669 #endif 1670 #ifndef EM_AARCH64 1671 #define EM_AARCH64 183 /* ARM AARCH64 */ 1672 #endif 1673 1674 static const arch_t arch_array[]={ 1675 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1676 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1677 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1678 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1679 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1680 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1681 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1682 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1683 #if defined(VM_LITTLE_ENDIAN) 1684 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"}, 1685 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"}, 1686 #else 1687 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1688 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"}, 1689 #endif 1690 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1691 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1692 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1693 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1694 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1695 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1696 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1697 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1698 }; 1699 1700 #if (defined IA32) 1701 static Elf32_Half running_arch_code=EM_386; 1702 #elif (defined AMD64) || (defined X32) 1703 static Elf32_Half running_arch_code=EM_X86_64; 1704 #elif (defined IA64) 1705 static Elf32_Half running_arch_code=EM_IA_64; 1706 #elif (defined __sparc) && (defined _LP64) 1707 static Elf32_Half running_arch_code=EM_SPARCV9; 1708 #elif (defined __sparc) && (!defined _LP64) 1709 static Elf32_Half running_arch_code=EM_SPARC; 1710 #elif (defined __powerpc64__) 1711 static Elf32_Half running_arch_code=EM_PPC64; 1712 #elif (defined __powerpc__) 1713 static Elf32_Half running_arch_code=EM_PPC; 1714 #elif (defined AARCH64) 1715 static Elf32_Half running_arch_code=EM_AARCH64; 1716 #elif (defined ARM) 1717 static Elf32_Half running_arch_code=EM_ARM; 1718 #elif (defined S390) 1719 static Elf32_Half running_arch_code=EM_S390; 1720 #elif (defined ALPHA) 1721 static Elf32_Half running_arch_code=EM_ALPHA; 1722 #elif (defined MIPSEL) 1723 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1724 #elif (defined PARISC) 1725 static Elf32_Half running_arch_code=EM_PARISC; 1726 #elif (defined MIPS) 1727 static Elf32_Half running_arch_code=EM_MIPS; 1728 #elif (defined M68K) 1729 static Elf32_Half running_arch_code=EM_68K; 1730 #elif (defined SH) 1731 static Elf32_Half running_arch_code=EM_SH; 1732 #else 1733 #error Method os::dll_load requires that one of following is defined:\ 1734 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, SH, __sparc 1735 #endif 1736 1737 // Identify compatability class for VM's architecture and library's architecture 1738 // Obtain string descriptions for architectures 1739 1740 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1741 int running_arch_index=-1; 1742 1743 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1744 if (running_arch_code == arch_array[i].code) { 1745 running_arch_index = i; 1746 } 1747 if (lib_arch.code == arch_array[i].code) { 1748 lib_arch.compat_class = arch_array[i].compat_class; 1749 lib_arch.name = arch_array[i].name; 1750 } 1751 } 1752 1753 assert(running_arch_index != -1, 1754 "Didn't find running architecture code (running_arch_code) in arch_array"); 1755 if (running_arch_index == -1) { 1756 // Even though running architecture detection failed 1757 // we may still continue with reporting dlerror() message 1758 return NULL; 1759 } 1760 1761 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1762 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1763 return NULL; 1764 } 1765 1766 #ifndef S390 1767 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1768 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1769 return NULL; 1770 } 1771 #endif // !S390 1772 1773 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1774 if (lib_arch.name!=NULL) { 1775 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1776 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1777 lib_arch.name, arch_array[running_arch_index].name); 1778 } else { 1779 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1780 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1781 lib_arch.code, 1782 arch_array[running_arch_index].name); 1783 } 1784 } 1785 1786 return NULL; 1787 } 1788 1789 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1790 int ebuflen) { 1791 void * result = ::dlopen(filename, RTLD_LAZY); 1792 if (result == NULL) { 1793 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1794 ebuf[ebuflen-1] = '\0'; 1795 } 1796 return result; 1797 } 1798 1799 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1800 int ebuflen) { 1801 void * result = NULL; 1802 if (LoadExecStackDllInVMThread) { 1803 result = dlopen_helper(filename, ebuf, ebuflen); 1804 } 1805 1806 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1807 // library that requires an executable stack, or which does not have this 1808 // stack attribute set, dlopen changes the stack attribute to executable. The 1809 // read protection of the guard pages gets lost. 1810 // 1811 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1812 // may have been queued at the same time. 1813 1814 if (!_stack_is_executable) { 1815 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) { 1816 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1817 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 1818 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 1819 warning("Attempt to reguard stack yellow zone failed."); 1820 } 1821 } 1822 } 1823 } 1824 1825 return result; 1826 } 1827 1828 void* os::dll_lookup(void* handle, const char* name) { 1829 void* res = dlsym(handle, name); 1830 return res; 1831 } 1832 1833 void* os::get_default_process_handle() { 1834 return (void*)::dlopen(NULL, RTLD_LAZY); 1835 } 1836 1837 static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) { 1838 int fd = ::open(filename, O_RDONLY); 1839 if (fd == -1) { 1840 return false; 1841 } 1842 1843 if (hdr != NULL) { 1844 st->print_cr("%s", hdr); 1845 } 1846 1847 char buf[33]; 1848 int bytes; 1849 buf[32] = '\0'; 1850 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) { 1851 st->print_raw(buf, bytes); 1852 } 1853 1854 ::close(fd); 1855 1856 return true; 1857 } 1858 1859 #if defined(S390) 1860 // keywords_to_match - NULL terminated array of keywords 1861 static bool print_matching_lines_from_sysinfo_file(outputStream* st, const char* keywords_to_match[]) { 1862 const char* filename = "/proc/sysinfo"; 1863 char* line = NULL; 1864 size_t length = 0; 1865 FILE* fp = fopen(filename, "r"); 1866 if (fp == NULL) { 1867 return false; 1868 } 1869 1870 st->print_cr("Virtualization information:"); 1871 while (getline(&line, &length, fp) != -1) { 1872 int i = 0; 1873 while (keywords_to_match[i] != NULL) { 1874 if (strncmp(line, keywords_to_match[i], strlen(keywords_to_match[i])) == 0) { 1875 st->print("%s", line); 1876 break; 1877 } 1878 i++; 1879 } 1880 } 1881 1882 free(line); 1883 fclose(fp); 1884 1885 return true; 1886 } 1887 #endif 1888 1889 void os::print_dll_info(outputStream *st) { 1890 st->print_cr("Dynamic libraries:"); 1891 1892 char fname[32]; 1893 pid_t pid = os::Linux::gettid(); 1894 1895 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1896 1897 if (!_print_ascii_file(fname, st)) { 1898 st->print("Can not get library information for pid = %d\n", pid); 1899 } 1900 } 1901 1902 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1903 FILE *procmapsFile = NULL; 1904 1905 // Open the procfs maps file for the current process 1906 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1907 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1908 char line[PATH_MAX + 100]; 1909 1910 // Read line by line from 'file' 1911 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1912 u8 base, top, offset, inode; 1913 char permissions[5]; 1914 char device[6]; 1915 char name[PATH_MAX + 1]; 1916 1917 // Parse fields from line 1918 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %7s " INT64_FORMAT " %s", 1919 &base, &top, permissions, &offset, device, &inode, name); 1920 1921 // Filter by device id '00:00' so that we only get file system mapped files. 1922 if (strcmp(device, "00:00") != 0) { 1923 1924 // Call callback with the fields of interest 1925 if(callback(name, (address)base, (address)top, param)) { 1926 // Oops abort, callback aborted 1927 fclose(procmapsFile); 1928 return 1; 1929 } 1930 } 1931 } 1932 fclose(procmapsFile); 1933 } 1934 return 0; 1935 } 1936 1937 void os::print_os_info_brief(outputStream* st) { 1938 os::Linux::print_distro_info(st); 1939 1940 os::Posix::print_uname_info(st); 1941 1942 os::Linux::print_libversion_info(st); 1943 1944 } 1945 1946 void os::print_os_info(outputStream* st) { 1947 st->print("OS:"); 1948 1949 os::Linux::print_distro_info(st); 1950 1951 os::Posix::print_uname_info(st); 1952 1953 // Print warning if unsafe chroot environment detected 1954 if (unsafe_chroot_detected) { 1955 st->print("WARNING!! "); 1956 st->print_cr("%s", unstable_chroot_error); 1957 } 1958 1959 os::Linux::print_libversion_info(st); 1960 1961 os::Posix::print_rlimit_info(st); 1962 1963 os::Posix::print_load_average(st); 1964 1965 os::Linux::print_full_memory_info(st); 1966 1967 os::Linux::print_proc_sys_info(st); 1968 1969 os::Linux::print_ld_preload_file(st); 1970 1971 os::Linux::print_container_info(st); 1972 1973 os::Linux::print_virtualization_info(st); 1974 } 1975 1976 // Try to identify popular distros. 1977 // Most Linux distributions have a /etc/XXX-release file, which contains 1978 // the OS version string. Newer Linux distributions have a /etc/lsb-release 1979 // file that also contains the OS version string. Some have more than one 1980 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 1981 // /etc/redhat-release.), so the order is important. 1982 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 1983 // their own specific XXX-release file as well as a redhat-release file. 1984 // Because of this the XXX-release file needs to be searched for before the 1985 // redhat-release file. 1986 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the 1987 // search for redhat-release / SuSE-release needs to be before lsb-release. 1988 // Since the lsb-release file is the new standard it needs to be searched 1989 // before the older style release files. 1990 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 1991 // next to last resort. The os-release file is a new standard that contains 1992 // distribution information and the system-release file seems to be an old 1993 // standard that has been replaced by the lsb-release and os-release files. 1994 // Searching for the debian_version file is the last resort. It contains 1995 // an informative string like "6.0.6" or "wheezy/sid". Because of this 1996 // "Debian " is printed before the contents of the debian_version file. 1997 1998 const char* distro_files[] = { 1999 "/etc/oracle-release", 2000 "/etc/mandriva-release", 2001 "/etc/mandrake-release", 2002 "/etc/sun-release", 2003 "/etc/redhat-release", 2004 "/etc/SuSE-release", 2005 "/etc/lsb-release", 2006 "/etc/turbolinux-release", 2007 "/etc/gentoo-release", 2008 "/etc/ltib-release", 2009 "/etc/angstrom-version", 2010 "/etc/system-release", 2011 "/etc/os-release", 2012 NULL }; 2013 2014 void os::Linux::print_distro_info(outputStream* st) { 2015 for (int i = 0;; i++) { 2016 const char* file = distro_files[i]; 2017 if (file == NULL) { 2018 break; // done 2019 } 2020 // If file prints, we found it. 2021 if (_print_ascii_file(file, st)) { 2022 return; 2023 } 2024 } 2025 2026 if (file_exists("/etc/debian_version")) { 2027 st->print("Debian "); 2028 _print_ascii_file("/etc/debian_version", st); 2029 } else { 2030 st->print("Linux"); 2031 } 2032 st->cr(); 2033 } 2034 2035 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) { 2036 char buf[256]; 2037 while (fgets(buf, sizeof(buf), fp)) { 2038 // Edit out extra stuff in expected format 2039 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) { 2040 char* ptr = strstr(buf, "\""); // the name is in quotes 2041 if (ptr != NULL) { 2042 ptr++; // go beyond first quote 2043 char* nl = strchr(ptr, '\"'); 2044 if (nl != NULL) *nl = '\0'; 2045 strncpy(distro, ptr, length); 2046 } else { 2047 ptr = strstr(buf, "="); 2048 ptr++; // go beyond equals then 2049 char* nl = strchr(ptr, '\n'); 2050 if (nl != NULL) *nl = '\0'; 2051 strncpy(distro, ptr, length); 2052 } 2053 return; 2054 } else if (get_first_line) { 2055 char* nl = strchr(buf, '\n'); 2056 if (nl != NULL) *nl = '\0'; 2057 strncpy(distro, buf, length); 2058 return; 2059 } 2060 } 2061 // print last line and close 2062 char* nl = strchr(buf, '\n'); 2063 if (nl != NULL) *nl = '\0'; 2064 strncpy(distro, buf, length); 2065 } 2066 2067 static void parse_os_info(char* distro, size_t length, const char* file) { 2068 FILE* fp = fopen(file, "r"); 2069 if (fp != NULL) { 2070 // if suse format, print out first line 2071 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0); 2072 parse_os_info_helper(fp, distro, length, get_first_line); 2073 fclose(fp); 2074 } 2075 } 2076 2077 void os::get_summary_os_info(char* buf, size_t buflen) { 2078 for (int i = 0;; i++) { 2079 const char* file = distro_files[i]; 2080 if (file == NULL) { 2081 break; // ran out of distro_files 2082 } 2083 if (file_exists(file)) { 2084 parse_os_info(buf, buflen, file); 2085 return; 2086 } 2087 } 2088 // special case for debian 2089 if (file_exists("/etc/debian_version")) { 2090 strncpy(buf, "Debian ", buflen); 2091 if (buflen > 7) { 2092 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2093 } 2094 } else { 2095 strncpy(buf, "Linux", buflen); 2096 } 2097 } 2098 2099 void os::Linux::print_libversion_info(outputStream* st) { 2100 // libc, pthread 2101 st->print("libc:"); 2102 st->print("%s ", os::Linux::glibc_version()); 2103 st->print("%s ", os::Linux::libpthread_version()); 2104 st->cr(); 2105 } 2106 2107 void os::Linux::print_proc_sys_info(outputStream* st) { 2108 st->cr(); 2109 st->print_cr("/proc/sys/kernel/threads-max (system-wide limit on the number of threads):"); 2110 _print_ascii_file("/proc/sys/kernel/threads-max", st); 2111 st->cr(); 2112 st->cr(); 2113 2114 st->print_cr("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have):"); 2115 _print_ascii_file("/proc/sys/vm/max_map_count", st); 2116 st->cr(); 2117 st->cr(); 2118 2119 st->print_cr("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers):"); 2120 _print_ascii_file("/proc/sys/kernel/pid_max", st); 2121 st->cr(); 2122 st->cr(); 2123 } 2124 2125 void os::Linux::print_full_memory_info(outputStream* st) { 2126 st->print("\n/proc/meminfo:\n"); 2127 _print_ascii_file("/proc/meminfo", st); 2128 st->cr(); 2129 } 2130 2131 void os::Linux::print_ld_preload_file(outputStream* st) { 2132 _print_ascii_file("/etc/ld.so.preload", st, "\n/etc/ld.so.preload:"); 2133 st->cr(); 2134 } 2135 2136 void os::Linux::print_container_info(outputStream* st) { 2137 if (!OSContainer::is_containerized()) { 2138 return; 2139 } 2140 2141 st->print("container (cgroup) information:\n"); 2142 2143 const char *p_ct = OSContainer::container_type(); 2144 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "failed"); 2145 2146 char *p = OSContainer::cpu_cpuset_cpus(); 2147 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "failed"); 2148 free(p); 2149 2150 p = OSContainer::cpu_cpuset_memory_nodes(); 2151 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "failed"); 2152 free(p); 2153 2154 int i = OSContainer::active_processor_count(); 2155 if (i > 0) { 2156 st->print("active_processor_count: %d\n", i); 2157 } else { 2158 st->print("active_processor_count: failed\n"); 2159 } 2160 2161 i = OSContainer::cpu_quota(); 2162 st->print("cpu_quota: %d\n", i); 2163 2164 i = OSContainer::cpu_period(); 2165 st->print("cpu_period: %d\n", i); 2166 2167 i = OSContainer::cpu_shares(); 2168 st->print("cpu_shares: %d\n", i); 2169 2170 jlong j = OSContainer::memory_limit_in_bytes(); 2171 st->print("memory_limit_in_bytes: " JLONG_FORMAT "\n", j); 2172 2173 j = OSContainer::memory_and_swap_limit_in_bytes(); 2174 st->print("memory_and_swap_limit_in_bytes: " JLONG_FORMAT "\n", j); 2175 2176 j = OSContainer::memory_soft_limit_in_bytes(); 2177 st->print("memory_soft_limit_in_bytes: " JLONG_FORMAT "\n", j); 2178 2179 j = OSContainer::OSContainer::memory_usage_in_bytes(); 2180 st->print("memory_usage_in_bytes: " JLONG_FORMAT "\n", j); 2181 2182 j = OSContainer::OSContainer::memory_max_usage_in_bytes(); 2183 st->print("memory_max_usage_in_bytes: " JLONG_FORMAT "\n", j); 2184 st->cr(); 2185 } 2186 2187 void os::Linux::print_virtualization_info(outputStream* st) { 2188 #if defined(S390) 2189 // /proc/sysinfo contains interesting information about 2190 // - LPAR 2191 // - whole "Box" (CPUs ) 2192 // - z/VM / KVM (VM<nn>); this is not available in an LPAR-only setup 2193 const char* kw[] = { "LPAR", "CPUs", "VM", NULL }; 2194 2195 if (! print_matching_lines_from_sysinfo_file(st, kw)) { 2196 st->print_cr(" </proc/sysinfo Not Available>"); 2197 } 2198 #endif 2199 } 2200 2201 void os::print_memory_info(outputStream* st) { 2202 2203 st->print("Memory:"); 2204 st->print(" %dk page", os::vm_page_size()>>10); 2205 2206 // values in struct sysinfo are "unsigned long" 2207 struct sysinfo si; 2208 sysinfo(&si); 2209 2210 st->print(", physical " UINT64_FORMAT "k", 2211 os::physical_memory() >> 10); 2212 st->print("(" UINT64_FORMAT "k free)", 2213 os::available_memory() >> 10); 2214 st->print(", swap " UINT64_FORMAT "k", 2215 ((jlong)si.totalswap * si.mem_unit) >> 10); 2216 st->print("(" UINT64_FORMAT "k free)", 2217 ((jlong)si.freeswap * si.mem_unit) >> 10); 2218 st->cr(); 2219 } 2220 2221 // Print the first "model name" line and the first "flags" line 2222 // that we find and nothing more. We assume "model name" comes 2223 // before "flags" so if we find a second "model name", then the 2224 // "flags" field is considered missing. 2225 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2226 #if defined(IA32) || defined(AMD64) 2227 // Other platforms have less repetitive cpuinfo files 2228 FILE *fp = fopen("/proc/cpuinfo", "r"); 2229 if (fp) { 2230 while (!feof(fp)) { 2231 if (fgets(buf, buflen, fp)) { 2232 // Assume model name comes before flags 2233 bool model_name_printed = false; 2234 if (strstr(buf, "model name") != NULL) { 2235 if (!model_name_printed) { 2236 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n"); 2237 st->print_raw(buf); 2238 model_name_printed = true; 2239 } else { 2240 // model name printed but not flags? Odd, just return 2241 fclose(fp); 2242 return true; 2243 } 2244 } 2245 // print the flags line too 2246 if (strstr(buf, "flags") != NULL) { 2247 st->print_raw(buf); 2248 fclose(fp); 2249 return true; 2250 } 2251 } 2252 } 2253 fclose(fp); 2254 } 2255 #endif // x86 platforms 2256 return false; 2257 } 2258 2259 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2260 // Only print the model name if the platform provides this as a summary 2261 if (!print_model_name_and_flags(st, buf, buflen)) { 2262 st->print("\n/proc/cpuinfo:\n"); 2263 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2264 st->print_cr(" <Not Available>"); 2265 } 2266 } 2267 } 2268 2269 #if defined(AMD64) || defined(IA32) || defined(X32) 2270 const char* search_string = "model name"; 2271 #elif defined(M68K) 2272 const char* search_string = "CPU"; 2273 #elif defined(PPC64) 2274 const char* search_string = "cpu"; 2275 #elif defined(S390) 2276 const char* search_string = "processor"; 2277 #elif defined(SPARC) 2278 const char* search_string = "cpu"; 2279 #else 2280 const char* search_string = "Processor"; 2281 #endif 2282 2283 // Parses the cpuinfo file for string representing the model name. 2284 void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2285 FILE* fp = fopen("/proc/cpuinfo", "r"); 2286 if (fp != NULL) { 2287 while (!feof(fp)) { 2288 char buf[256]; 2289 if (fgets(buf, sizeof(buf), fp)) { 2290 char* start = strstr(buf, search_string); 2291 if (start != NULL) { 2292 char *ptr = start + strlen(search_string); 2293 char *end = buf + strlen(buf); 2294 while (ptr != end) { 2295 // skip whitespace and colon for the rest of the name. 2296 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2297 break; 2298 } 2299 ptr++; 2300 } 2301 if (ptr != end) { 2302 // reasonable string, get rid of newline and keep the rest 2303 char* nl = strchr(buf, '\n'); 2304 if (nl != NULL) *nl = '\0'; 2305 strncpy(cpuinfo, ptr, length); 2306 fclose(fp); 2307 return; 2308 } 2309 } 2310 } 2311 } 2312 fclose(fp); 2313 } 2314 // cpuinfo not found or parsing failed, just print generic string. The entire 2315 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2316 #if defined(AARCH64) 2317 strncpy(cpuinfo, "AArch64", length); 2318 #elif defined(AMD64) 2319 strncpy(cpuinfo, "x86_64", length); 2320 #elif defined(ARM) // Order wrt. AARCH64 is relevant! 2321 strncpy(cpuinfo, "ARM", length); 2322 #elif defined(IA32) 2323 strncpy(cpuinfo, "x86_32", length); 2324 #elif defined(IA64) 2325 strncpy(cpuinfo, "IA64", length); 2326 #elif defined(PPC) 2327 strncpy(cpuinfo, "PPC64", length); 2328 #elif defined(S390) 2329 strncpy(cpuinfo, "S390", length); 2330 #elif defined(SPARC) 2331 strncpy(cpuinfo, "sparcv9", length); 2332 #elif defined(ZERO_LIBARCH) 2333 strncpy(cpuinfo, ZERO_LIBARCH, length); 2334 #else 2335 strncpy(cpuinfo, "unknown", length); 2336 #endif 2337 } 2338 2339 static void print_signal_handler(outputStream* st, int sig, 2340 char* buf, size_t buflen); 2341 2342 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2343 st->print_cr("Signal Handlers:"); 2344 print_signal_handler(st, SIGSEGV, buf, buflen); 2345 print_signal_handler(st, SIGBUS , buf, buflen); 2346 print_signal_handler(st, SIGFPE , buf, buflen); 2347 print_signal_handler(st, SIGPIPE, buf, buflen); 2348 print_signal_handler(st, SIGXFSZ, buf, buflen); 2349 print_signal_handler(st, SIGILL , buf, buflen); 2350 print_signal_handler(st, SR_signum, buf, buflen); 2351 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2352 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2353 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2354 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2355 #if defined(PPC64) 2356 print_signal_handler(st, SIGTRAP, buf, buflen); 2357 #endif 2358 } 2359 2360 static char saved_jvm_path[MAXPATHLEN] = {0}; 2361 2362 // Find the full path to the current module, libjvm.so 2363 void os::jvm_path(char *buf, jint buflen) { 2364 // Error checking. 2365 if (buflen < MAXPATHLEN) { 2366 assert(false, "must use a large-enough buffer"); 2367 buf[0] = '\0'; 2368 return; 2369 } 2370 // Lazy resolve the path to current module. 2371 if (saved_jvm_path[0] != 0) { 2372 strcpy(buf, saved_jvm_path); 2373 return; 2374 } 2375 2376 char dli_fname[MAXPATHLEN]; 2377 bool ret = dll_address_to_library_name( 2378 CAST_FROM_FN_PTR(address, os::jvm_path), 2379 dli_fname, sizeof(dli_fname), NULL); 2380 assert(ret, "cannot locate libjvm"); 2381 char *rp = NULL; 2382 if (ret && dli_fname[0] != '\0') { 2383 rp = os::Posix::realpath(dli_fname, buf, buflen); 2384 } 2385 if (rp == NULL) { 2386 return; 2387 } 2388 2389 if (Arguments::sun_java_launcher_is_altjvm()) { 2390 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2391 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so". 2392 // If "/jre/lib/" appears at the right place in the string, then 2393 // assume we are installed in a JDK and we're done. Otherwise, check 2394 // for a JAVA_HOME environment variable and fix up the path so it 2395 // looks like libjvm.so is installed there (append a fake suffix 2396 // hotspot/libjvm.so). 2397 const char *p = buf + strlen(buf) - 1; 2398 for (int count = 0; p > buf && count < 5; ++count) { 2399 for (--p; p > buf && *p != '/'; --p) 2400 /* empty */ ; 2401 } 2402 2403 if (strncmp(p, "/jre/lib/", 9) != 0) { 2404 // Look for JAVA_HOME in the environment. 2405 char* java_home_var = ::getenv("JAVA_HOME"); 2406 if (java_home_var != NULL && java_home_var[0] != 0) { 2407 char* jrelib_p; 2408 int len; 2409 2410 // Check the current module name "libjvm.so". 2411 p = strrchr(buf, '/'); 2412 if (p == NULL) { 2413 return; 2414 } 2415 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2416 2417 rp = os::Posix::realpath(java_home_var, buf, buflen); 2418 if (rp == NULL) { 2419 return; 2420 } 2421 2422 // determine if this is a legacy image or modules image 2423 // modules image doesn't have "jre" subdirectory 2424 len = strlen(buf); 2425 assert(len < buflen, "Ran out of buffer room"); 2426 jrelib_p = buf + len; 2427 snprintf(jrelib_p, buflen-len, "/jre/lib"); 2428 if (0 != access(buf, F_OK)) { 2429 snprintf(jrelib_p, buflen-len, "/lib"); 2430 } 2431 2432 if (0 == access(buf, F_OK)) { 2433 // Use current module name "libjvm.so" 2434 len = strlen(buf); 2435 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2436 } else { 2437 // Go back to path of .so 2438 rp = os::Posix::realpath(dli_fname, buf, buflen); 2439 if (rp == NULL) { 2440 return; 2441 } 2442 } 2443 } 2444 } 2445 } 2446 2447 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2448 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2449 } 2450 2451 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2452 // no prefix required, not even "_" 2453 } 2454 2455 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2456 // no suffix required 2457 } 2458 2459 //////////////////////////////////////////////////////////////////////////////// 2460 // sun.misc.Signal support 2461 2462 static volatile jint sigint_count = 0; 2463 2464 static void UserHandler(int sig, void *siginfo, void *context) { 2465 // 4511530 - sem_post is serialized and handled by the manager thread. When 2466 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2467 // don't want to flood the manager thread with sem_post requests. 2468 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2469 return; 2470 } 2471 2472 // Ctrl-C is pressed during error reporting, likely because the error 2473 // handler fails to abort. Let VM die immediately. 2474 if (sig == SIGINT && VMError::is_error_reported()) { 2475 os::die(); 2476 } 2477 2478 os::signal_notify(sig); 2479 } 2480 2481 void* os::user_handler() { 2482 return CAST_FROM_FN_PTR(void*, UserHandler); 2483 } 2484 2485 extern "C" { 2486 typedef void (*sa_handler_t)(int); 2487 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2488 } 2489 2490 void* os::signal(int signal_number, void* handler) { 2491 struct sigaction sigAct, oldSigAct; 2492 2493 sigfillset(&(sigAct.sa_mask)); 2494 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2495 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2496 2497 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2498 // -1 means registration failed 2499 return (void *)-1; 2500 } 2501 2502 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2503 } 2504 2505 void os::signal_raise(int signal_number) { 2506 ::raise(signal_number); 2507 } 2508 2509 // The following code is moved from os.cpp for making this 2510 // code platform specific, which it is by its very nature. 2511 2512 // Will be modified when max signal is changed to be dynamic 2513 int os::sigexitnum_pd() { 2514 return NSIG; 2515 } 2516 2517 // a counter for each possible signal value 2518 static volatile jint pending_signals[NSIG+1] = { 0 }; 2519 2520 // Linux(POSIX) specific hand shaking semaphore. 2521 static Semaphore* sig_sem = NULL; 2522 static PosixSemaphore sr_semaphore; 2523 2524 static void jdk_misc_signal_init() { 2525 // Initialize signal structures 2526 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2527 2528 // Initialize signal semaphore 2529 sig_sem = new Semaphore(); 2530 } 2531 2532 void os::signal_notify(int sig) { 2533 if (sig_sem != NULL) { 2534 Atomic::inc(&pending_signals[sig]); 2535 sig_sem->signal(); 2536 } else { 2537 // Signal thread is not created with ReduceSignalUsage and jdk_misc_signal_init 2538 // initialization isn't called. 2539 assert(ReduceSignalUsage, "signal semaphore should be created"); 2540 } 2541 } 2542 2543 static int check_pending_signals() { 2544 Atomic::store(0, &sigint_count); 2545 for (;;) { 2546 for (int i = 0; i < NSIG + 1; i++) { 2547 jint n = pending_signals[i]; 2548 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2549 return i; 2550 } 2551 } 2552 JavaThread *thread = JavaThread::current(); 2553 ThreadBlockInVM tbivm(thread); 2554 2555 bool threadIsSuspended; 2556 do { 2557 thread->set_suspend_equivalent(); 2558 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2559 sig_sem->wait(); 2560 2561 // were we externally suspended while we were waiting? 2562 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2563 if (threadIsSuspended) { 2564 // The semaphore has been incremented, but while we were waiting 2565 // another thread suspended us. We don't want to continue running 2566 // while suspended because that would surprise the thread that 2567 // suspended us. 2568 sig_sem->signal(); 2569 2570 thread->java_suspend_self(); 2571 } 2572 } while (threadIsSuspended); 2573 } 2574 } 2575 2576 int os::signal_wait() { 2577 return check_pending_signals(); 2578 } 2579 2580 //////////////////////////////////////////////////////////////////////////////// 2581 // Virtual Memory 2582 2583 int os::vm_page_size() { 2584 // Seems redundant as all get out 2585 assert(os::Linux::page_size() != -1, "must call os::init"); 2586 return os::Linux::page_size(); 2587 } 2588 2589 // Solaris allocates memory by pages. 2590 int os::vm_allocation_granularity() { 2591 assert(os::Linux::page_size() != -1, "must call os::init"); 2592 return os::Linux::page_size(); 2593 } 2594 2595 // Rationale behind this function: 2596 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2597 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2598 // samples for JITted code. Here we create private executable mapping over the code cache 2599 // and then we can use standard (well, almost, as mapping can change) way to provide 2600 // info for the reporting script by storing timestamp and location of symbol 2601 void linux_wrap_code(char* base, size_t size) { 2602 static volatile jint cnt = 0; 2603 2604 if (!UseOprofile) { 2605 return; 2606 } 2607 2608 char buf[PATH_MAX+1]; 2609 int num = Atomic::add(1, &cnt); 2610 2611 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2612 os::get_temp_directory(), os::current_process_id(), num); 2613 unlink(buf); 2614 2615 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2616 2617 if (fd != -1) { 2618 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2619 if (rv != (off_t)-1) { 2620 if (::write(fd, "", 1) == 1) { 2621 mmap(base, size, 2622 PROT_READ|PROT_WRITE|PROT_EXEC, 2623 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2624 } 2625 } 2626 ::close(fd); 2627 unlink(buf); 2628 } 2629 } 2630 2631 static bool recoverable_mmap_error(int err) { 2632 // See if the error is one we can let the caller handle. This 2633 // list of errno values comes from JBS-6843484. I can't find a 2634 // Linux man page that documents this specific set of errno 2635 // values so while this list currently matches Solaris, it may 2636 // change as we gain experience with this failure mode. 2637 switch (err) { 2638 case EBADF: 2639 case EINVAL: 2640 case ENOTSUP: 2641 // let the caller deal with these errors 2642 return true; 2643 2644 default: 2645 // Any remaining errors on this OS can cause our reserved mapping 2646 // to be lost. That can cause confusion where different data 2647 // structures think they have the same memory mapped. The worst 2648 // scenario is if both the VM and a library think they have the 2649 // same memory mapped. 2650 return false; 2651 } 2652 } 2653 2654 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2655 int err) { 2656 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2657 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2658 os::strerror(err), err); 2659 } 2660 2661 static void warn_fail_commit_memory(char* addr, size_t size, 2662 size_t alignment_hint, bool exec, 2663 int err) { 2664 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2665 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2666 alignment_hint, exec, os::strerror(err), err); 2667 } 2668 2669 // NOTE: Linux kernel does not really reserve the pages for us. 2670 // All it does is to check if there are enough free pages 2671 // left at the time of mmap(). This could be a potential 2672 // problem. 2673 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2674 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2675 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2676 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2677 if (res != (uintptr_t) MAP_FAILED) { 2678 if (UseNUMAInterleaving) { 2679 numa_make_global(addr, size); 2680 } 2681 return 0; 2682 } 2683 2684 int err = errno; // save errno from mmap() call above 2685 2686 if (!recoverable_mmap_error(err)) { 2687 warn_fail_commit_memory(addr, size, exec, err); 2688 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2689 } 2690 2691 return err; 2692 } 2693 2694 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2695 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2696 } 2697 2698 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2699 const char* mesg) { 2700 assert(mesg != NULL, "mesg must be specified"); 2701 int err = os::Linux::commit_memory_impl(addr, size, exec); 2702 if (err != 0) { 2703 // the caller wants all commit errors to exit with the specified mesg: 2704 warn_fail_commit_memory(addr, size, exec, err); 2705 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2706 } 2707 } 2708 2709 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2710 #ifndef MAP_HUGETLB 2711 #define MAP_HUGETLB 0x40000 2712 #endif 2713 2714 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2715 #ifndef MADV_HUGEPAGE 2716 #define MADV_HUGEPAGE 14 2717 #endif 2718 2719 int os::Linux::commit_memory_impl(char* addr, size_t size, 2720 size_t alignment_hint, bool exec) { 2721 int err = os::Linux::commit_memory_impl(addr, size, exec); 2722 if (err == 0) { 2723 realign_memory(addr, size, alignment_hint); 2724 } 2725 return err; 2726 } 2727 2728 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2729 bool exec) { 2730 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2731 } 2732 2733 void os::pd_commit_memory_or_exit(char* addr, size_t size, 2734 size_t alignment_hint, bool exec, 2735 const char* mesg) { 2736 assert(mesg != NULL, "mesg must be specified"); 2737 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2738 if (err != 0) { 2739 // the caller wants all commit errors to exit with the specified mesg: 2740 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2741 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2742 } 2743 } 2744 2745 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2746 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2747 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2748 // be supported or the memory may already be backed by huge pages. 2749 ::madvise(addr, bytes, MADV_HUGEPAGE); 2750 } 2751 } 2752 2753 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2754 // This method works by doing an mmap over an existing mmaping and effectively discarding 2755 // the existing pages. However it won't work for SHM-based large pages that cannot be 2756 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2757 // small pages on top of the SHM segment. This method always works for small pages, so we 2758 // allow that in any case. 2759 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2760 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2761 } 2762 } 2763 2764 void os::numa_make_global(char *addr, size_t bytes) { 2765 Linux::numa_interleave_memory(addr, bytes); 2766 } 2767 2768 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2769 // bind policy to MPOL_PREFERRED for the current thread. 2770 #define USE_MPOL_PREFERRED 0 2771 2772 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2773 // To make NUMA and large pages more robust when both enabled, we need to ease 2774 // the requirements on where the memory should be allocated. MPOL_BIND is the 2775 // default policy and it will force memory to be allocated on the specified 2776 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2777 // the specified node, but will not force it. Using this policy will prevent 2778 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2779 // free large pages. 2780 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2781 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2782 } 2783 2784 bool os::numa_topology_changed() { return false; } 2785 2786 size_t os::numa_get_groups_num() { 2787 // Return just the number of nodes in which it's possible to allocate memory 2788 // (in numa terminology, configured nodes). 2789 return Linux::numa_num_configured_nodes(); 2790 } 2791 2792 int os::numa_get_group_id() { 2793 int cpu_id = Linux::sched_getcpu(); 2794 if (cpu_id != -1) { 2795 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2796 if (lgrp_id != -1) { 2797 return lgrp_id; 2798 } 2799 } 2800 return 0; 2801 } 2802 2803 int os::Linux::get_existing_num_nodes() { 2804 int node; 2805 int highest_node_number = Linux::numa_max_node(); 2806 int num_nodes = 0; 2807 2808 // Get the total number of nodes in the system including nodes without memory. 2809 for (node = 0; node <= highest_node_number; node++) { 2810 if (is_node_in_existing_nodes(node)) { 2811 num_nodes++; 2812 } 2813 } 2814 return num_nodes; 2815 } 2816 2817 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2818 int highest_node_number = Linux::numa_max_node(); 2819 size_t i = 0; 2820 2821 // Map all node ids in which it is possible to allocate memory. Also nodes are 2822 // not always consecutively available, i.e. available from 0 to the highest 2823 // node number. If the nodes have been bound explicitly using numactl membind, 2824 // then allocate memory from those nodes only. 2825 for (int node = 0; node <= highest_node_number; node++) { 2826 if (Linux::is_node_in_bound_nodes((unsigned int)node)) { 2827 ids[i++] = node; 2828 } 2829 } 2830 return i; 2831 } 2832 2833 bool os::get_page_info(char *start, page_info* info) { 2834 return false; 2835 } 2836 2837 char *os::scan_pages(char *start, char* end, page_info* page_expected, 2838 page_info* page_found) { 2839 return end; 2840 } 2841 2842 2843 int os::Linux::sched_getcpu_syscall(void) { 2844 unsigned int cpu = 0; 2845 int retval = -1; 2846 2847 #if defined(IA32) 2848 #ifndef SYS_getcpu 2849 #define SYS_getcpu 318 2850 #endif 2851 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2852 #elif defined(AMD64) 2853 // Unfortunately we have to bring all these macros here from vsyscall.h 2854 // to be able to compile on old linuxes. 2855 #define __NR_vgetcpu 2 2856 #define VSYSCALL_START (-10UL << 20) 2857 #define VSYSCALL_SIZE 1024 2858 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2859 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2860 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2861 retval = vgetcpu(&cpu, NULL, NULL); 2862 #endif 2863 2864 return (retval == -1) ? retval : cpu; 2865 } 2866 2867 void os::Linux::sched_getcpu_init() { 2868 // sched_getcpu() should be in libc. 2869 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2870 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2871 2872 // If it's not, try a direct syscall. 2873 if (sched_getcpu() == -1) { 2874 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2875 (void*)&sched_getcpu_syscall)); 2876 } 2877 2878 if (sched_getcpu() == -1) { 2879 vm_exit_during_initialization("getcpu(2) system call not supported by kernel"); 2880 } 2881 } 2882 2883 // Something to do with the numa-aware allocator needs these symbols 2884 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2885 extern "C" JNIEXPORT void numa_error(char *where) { } 2886 2887 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails 2888 // load symbol from base version instead. 2889 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2890 void *f = dlvsym(handle, name, "libnuma_1.1"); 2891 if (f == NULL) { 2892 f = dlsym(handle, name); 2893 } 2894 return f; 2895 } 2896 2897 // Handle request to load libnuma symbol version 1.2 (API v2) only. 2898 // Return NULL if the symbol is not defined in this particular version. 2899 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) { 2900 return dlvsym(handle, name, "libnuma_1.2"); 2901 } 2902 2903 bool os::Linux::libnuma_init() { 2904 if (sched_getcpu() != -1) { // Requires sched_getcpu() support 2905 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2906 if (handle != NULL) { 2907 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2908 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2909 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2910 libnuma_dlsym(handle, "numa_max_node"))); 2911 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t, 2912 libnuma_dlsym(handle, "numa_num_configured_nodes"))); 2913 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2914 libnuma_dlsym(handle, "numa_available"))); 2915 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2916 libnuma_dlsym(handle, "numa_tonode_memory"))); 2917 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2918 libnuma_dlsym(handle, "numa_interleave_memory"))); 2919 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t, 2920 libnuma_v2_dlsym(handle, "numa_interleave_memory"))); 2921 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2922 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2923 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t, 2924 libnuma_dlsym(handle, "numa_bitmask_isbitset"))); 2925 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t, 2926 libnuma_dlsym(handle, "numa_distance"))); 2927 set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t, 2928 libnuma_v2_dlsym(handle, "numa_get_membind"))); 2929 set_numa_get_interleave_mask(CAST_TO_FN_PTR(numa_get_interleave_mask_func_t, 2930 libnuma_v2_dlsym(handle, "numa_get_interleave_mask"))); 2931 2932 if (numa_available() != -1) { 2933 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2934 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr")); 2935 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr")); 2936 set_numa_interleave_bitmask(_numa_get_interleave_mask()); 2937 set_numa_membind_bitmask(_numa_get_membind()); 2938 // Create an index -> node mapping, since nodes are not always consecutive 2939 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2940 rebuild_nindex_to_node_map(); 2941 // Create a cpu -> node mapping 2942 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2943 rebuild_cpu_to_node_map(); 2944 return true; 2945 } 2946 } 2947 } 2948 return false; 2949 } 2950 2951 size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 2952 // Creating guard page is very expensive. Java thread has HotSpot 2953 // guard pages, only enable glibc guard page for non-Java threads. 2954 // (Remember: compiler thread is a Java thread, too!) 2955 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size()); 2956 } 2957 2958 void os::Linux::rebuild_nindex_to_node_map() { 2959 int highest_node_number = Linux::numa_max_node(); 2960 2961 nindex_to_node()->clear(); 2962 for (int node = 0; node <= highest_node_number; node++) { 2963 if (Linux::is_node_in_existing_nodes(node)) { 2964 nindex_to_node()->append(node); 2965 } 2966 } 2967 } 2968 2969 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2970 // The table is later used in get_node_by_cpu(). 2971 void os::Linux::rebuild_cpu_to_node_map() { 2972 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2973 // in libnuma (possible values are starting from 16, 2974 // and continuing up with every other power of 2, but less 2975 // than the maximum number of CPUs supported by kernel), and 2976 // is a subject to change (in libnuma version 2 the requirements 2977 // are more reasonable) we'll just hardcode the number they use 2978 // in the library. 2979 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2980 2981 size_t cpu_num = processor_count(); 2982 size_t cpu_map_size = NCPUS / BitsPerCLong; 2983 size_t cpu_map_valid_size = 2984 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2985 2986 cpu_to_node()->clear(); 2987 cpu_to_node()->at_grow(cpu_num - 1); 2988 2989 size_t node_num = get_existing_num_nodes(); 2990 2991 int distance = 0; 2992 int closest_distance = INT_MAX; 2993 int closest_node = 0; 2994 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2995 for (size_t i = 0; i < node_num; i++) { 2996 // Check if node is configured (not a memory-less node). If it is not, find 2997 // the closest configured node. Check also if node is bound, i.e. it's allowed 2998 // to allocate memory from the node. If it's not allowed, map cpus in that node 2999 // to the closest node from which memory allocation is allowed. 3000 if (!is_node_in_configured_nodes(nindex_to_node()->at(i)) || 3001 !is_node_in_bound_nodes(nindex_to_node()->at(i))) { 3002 closest_distance = INT_MAX; 3003 // Check distance from all remaining nodes in the system. Ignore distance 3004 // from itself, from another non-configured node, and from another non-bound 3005 // node. 3006 for (size_t m = 0; m < node_num; m++) { 3007 if (m != i && 3008 is_node_in_configured_nodes(nindex_to_node()->at(m)) && 3009 is_node_in_bound_nodes(nindex_to_node()->at(m))) { 3010 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m)); 3011 // If a closest node is found, update. There is always at least one 3012 // configured and bound node in the system so there is always at least 3013 // one node close. 3014 if (distance != 0 && distance < closest_distance) { 3015 closest_distance = distance; 3016 closest_node = nindex_to_node()->at(m); 3017 } 3018 } 3019 } 3020 } else { 3021 // Current node is already a configured node. 3022 closest_node = nindex_to_node()->at(i); 3023 } 3024 3025 // Get cpus from the original node and map them to the closest node. If node 3026 // is a configured node (not a memory-less node), then original node and 3027 // closest node are the same. 3028 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 3029 for (size_t j = 0; j < cpu_map_valid_size; j++) { 3030 if (cpu_map[j] != 0) { 3031 for (size_t k = 0; k < BitsPerCLong; k++) { 3032 if (cpu_map[j] & (1UL << k)) { 3033 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node); 3034 } 3035 } 3036 } 3037 } 3038 } 3039 } 3040 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 3041 } 3042 3043 int os::Linux::get_node_by_cpu(int cpu_id) { 3044 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 3045 return cpu_to_node()->at(cpu_id); 3046 } 3047 return -1; 3048 } 3049 3050 GrowableArray<int>* os::Linux::_cpu_to_node; 3051 GrowableArray<int>* os::Linux::_nindex_to_node; 3052 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 3053 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 3054 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 3055 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes; 3056 os::Linux::numa_available_func_t os::Linux::_numa_available; 3057 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 3058 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 3059 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2; 3060 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 3061 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset; 3062 os::Linux::numa_distance_func_t os::Linux::_numa_distance; 3063 os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind; 3064 os::Linux::numa_get_interleave_mask_func_t os::Linux::_numa_get_interleave_mask; 3065 os::Linux::NumaAllocationPolicy os::Linux::_current_numa_policy; 3066 unsigned long* os::Linux::_numa_all_nodes; 3067 struct bitmask* os::Linux::_numa_all_nodes_ptr; 3068 struct bitmask* os::Linux::_numa_nodes_ptr; 3069 struct bitmask* os::Linux::_numa_interleave_bitmask; 3070 struct bitmask* os::Linux::_numa_membind_bitmask; 3071 3072 bool os::pd_uncommit_memory(char* addr, size_t size) { 3073 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 3074 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 3075 return res != (uintptr_t) MAP_FAILED; 3076 } 3077 3078 static address get_stack_commited_bottom(address bottom, size_t size) { 3079 address nbot = bottom; 3080 address ntop = bottom + size; 3081 3082 size_t page_sz = os::vm_page_size(); 3083 unsigned pages = size / page_sz; 3084 3085 unsigned char vec[1]; 3086 unsigned imin = 1, imax = pages + 1, imid; 3087 int mincore_return_value = 0; 3088 3089 assert(imin <= imax, "Unexpected page size"); 3090 3091 while (imin < imax) { 3092 imid = (imax + imin) / 2; 3093 nbot = ntop - (imid * page_sz); 3094 3095 // Use a trick with mincore to check whether the page is mapped or not. 3096 // mincore sets vec to 1 if page resides in memory and to 0 if page 3097 // is swapped output but if page we are asking for is unmapped 3098 // it returns -1,ENOMEM 3099 mincore_return_value = mincore(nbot, page_sz, vec); 3100 3101 if (mincore_return_value == -1) { 3102 // Page is not mapped go up 3103 // to find first mapped page 3104 if (errno != EAGAIN) { 3105 assert(errno == ENOMEM, "Unexpected mincore errno"); 3106 imax = imid; 3107 } 3108 } else { 3109 // Page is mapped go down 3110 // to find first not mapped page 3111 imin = imid + 1; 3112 } 3113 } 3114 3115 nbot = nbot + page_sz; 3116 3117 // Adjust stack bottom one page up if last checked page is not mapped 3118 if (mincore_return_value == -1) { 3119 nbot = nbot + page_sz; 3120 } 3121 3122 return nbot; 3123 } 3124 3125 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) { 3126 int mincore_return_value; 3127 const size_t stripe = 1024; // query this many pages each time 3128 unsigned char vec[stripe + 1]; 3129 // set a guard 3130 vec[stripe] = 'X'; 3131 3132 const size_t page_sz = os::vm_page_size(); 3133 size_t pages = size / page_sz; 3134 3135 assert(is_aligned(start, page_sz), "Start address must be page aligned"); 3136 assert(is_aligned(size, page_sz), "Size must be page aligned"); 3137 3138 committed_start = NULL; 3139 3140 int loops = (pages + stripe - 1) / stripe; 3141 int committed_pages = 0; 3142 address loop_base = start; 3143 bool found_range = false; 3144 3145 for (int index = 0; index < loops && !found_range; index ++) { 3146 assert(pages > 0, "Nothing to do"); 3147 int pages_to_query = (pages >= stripe) ? stripe : pages; 3148 pages -= pages_to_query; 3149 3150 // Get stable read 3151 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN); 3152 3153 // During shutdown, some memory goes away without properly notifying NMT, 3154 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object. 3155 // Bailout and return as not committed for now. 3156 if (mincore_return_value == -1 && errno == ENOMEM) { 3157 return false; 3158 } 3159 3160 assert(vec[stripe] == 'X', "overflow guard"); 3161 assert(mincore_return_value == 0, "Range must be valid"); 3162 // Process this stripe 3163 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) { 3164 if ((vec[vecIdx] & 0x01) == 0) { // not committed 3165 // End of current contiguous region 3166 if (committed_start != NULL) { 3167 found_range = true; 3168 break; 3169 } 3170 } else { // committed 3171 // Start of region 3172 if (committed_start == NULL) { 3173 committed_start = loop_base + page_sz * vecIdx; 3174 } 3175 committed_pages ++; 3176 } 3177 } 3178 3179 loop_base += pages_to_query * page_sz; 3180 } 3181 3182 if (committed_start != NULL) { 3183 assert(committed_pages > 0, "Must have committed region"); 3184 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has"); 3185 assert(committed_start >= start && committed_start < start + size, "Out of range"); 3186 committed_size = page_sz * committed_pages; 3187 return true; 3188 } else { 3189 assert(committed_pages == 0, "Should not have committed region"); 3190 return false; 3191 } 3192 } 3193 3194 3195 // Linux uses a growable mapping for the stack, and if the mapping for 3196 // the stack guard pages is not removed when we detach a thread the 3197 // stack cannot grow beyond the pages where the stack guard was 3198 // mapped. If at some point later in the process the stack expands to 3199 // that point, the Linux kernel cannot expand the stack any further 3200 // because the guard pages are in the way, and a segfault occurs. 3201 // 3202 // However, it's essential not to split the stack region by unmapping 3203 // a region (leaving a hole) that's already part of the stack mapping, 3204 // so if the stack mapping has already grown beyond the guard pages at 3205 // the time we create them, we have to truncate the stack mapping. 3206 // So, we need to know the extent of the stack mapping when 3207 // create_stack_guard_pages() is called. 3208 3209 // We only need this for stacks that are growable: at the time of 3210 // writing thread stacks don't use growable mappings (i.e. those 3211 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 3212 // only applies to the main thread. 3213 3214 // If the (growable) stack mapping already extends beyond the point 3215 // where we're going to put our guard pages, truncate the mapping at 3216 // that point by munmap()ping it. This ensures that when we later 3217 // munmap() the guard pages we don't leave a hole in the stack 3218 // mapping. This only affects the main/primordial thread 3219 3220 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3221 if (os::is_primordial_thread()) { 3222 // As we manually grow stack up to bottom inside create_attached_thread(), 3223 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3224 // we don't need to do anything special. 3225 // Check it first, before calling heavy function. 3226 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3227 unsigned char vec[1]; 3228 3229 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3230 // Fallback to slow path on all errors, including EAGAIN 3231 stack_extent = (uintptr_t) get_stack_commited_bottom( 3232 os::Linux::initial_thread_stack_bottom(), 3233 (size_t)addr - stack_extent); 3234 } 3235 3236 if (stack_extent < (uintptr_t)addr) { 3237 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3238 } 3239 } 3240 3241 return os::commit_memory(addr, size, !ExecMem); 3242 } 3243 3244 // If this is a growable mapping, remove the guard pages entirely by 3245 // munmap()ping them. If not, just call uncommit_memory(). This only 3246 // affects the main/primordial thread, but guard against future OS changes. 3247 // It's safe to always unmap guard pages for primordial thread because we 3248 // always place it right after end of the mapped region. 3249 3250 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3251 uintptr_t stack_extent, stack_base; 3252 3253 if (os::is_primordial_thread()) { 3254 return ::munmap(addr, size) == 0; 3255 } 3256 3257 return os::uncommit_memory(addr, size); 3258 } 3259 3260 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3261 // at 'requested_addr'. If there are existing memory mappings at the same 3262 // location, however, they will be overwritten. If 'fixed' is false, 3263 // 'requested_addr' is only treated as a hint, the return value may or 3264 // may not start from the requested address. Unlike Linux mmap(), this 3265 // function returns NULL to indicate failure. 3266 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3267 char * addr; 3268 int flags; 3269 3270 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3271 if (fixed) { 3272 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3273 flags |= MAP_FIXED; 3274 } 3275 3276 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3277 // touch an uncommitted page. Otherwise, the read/write might 3278 // succeed if we have enough swap space to back the physical page. 3279 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3280 flags, -1, 0); 3281 3282 return addr == MAP_FAILED ? NULL : addr; 3283 } 3284 3285 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3286 // (req_addr != NULL) or with a given alignment. 3287 // - bytes shall be a multiple of alignment. 3288 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3289 // - alignment sets the alignment at which memory shall be allocated. 3290 // It must be a multiple of allocation granularity. 3291 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3292 // req_addr or NULL. 3293 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3294 3295 size_t extra_size = bytes; 3296 if (req_addr == NULL && alignment > 0) { 3297 extra_size += alignment; 3298 } 3299 3300 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3301 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3302 -1, 0); 3303 if (start == MAP_FAILED) { 3304 start = NULL; 3305 } else { 3306 if (req_addr != NULL) { 3307 if (start != req_addr) { 3308 ::munmap(start, extra_size); 3309 start = NULL; 3310 } 3311 } else { 3312 char* const start_aligned = align_up(start, alignment); 3313 char* const end_aligned = start_aligned + bytes; 3314 char* const end = start + extra_size; 3315 if (start_aligned > start) { 3316 ::munmap(start, start_aligned - start); 3317 } 3318 if (end_aligned < end) { 3319 ::munmap(end_aligned, end - end_aligned); 3320 } 3321 start = start_aligned; 3322 } 3323 } 3324 return start; 3325 } 3326 3327 static int anon_munmap(char * addr, size_t size) { 3328 return ::munmap(addr, size) == 0; 3329 } 3330 3331 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3332 size_t alignment_hint) { 3333 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3334 } 3335 3336 bool os::pd_release_memory(char* addr, size_t size) { 3337 return anon_munmap(addr, size); 3338 } 3339 3340 static bool linux_mprotect(char* addr, size_t size, int prot) { 3341 // Linux wants the mprotect address argument to be page aligned. 3342 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size()); 3343 3344 // According to SUSv3, mprotect() should only be used with mappings 3345 // established by mmap(), and mmap() always maps whole pages. Unaligned 3346 // 'addr' likely indicates problem in the VM (e.g. trying to change 3347 // protection of malloc'ed or statically allocated memory). Check the 3348 // caller if you hit this assert. 3349 assert(addr == bottom, "sanity check"); 3350 3351 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3352 return ::mprotect(bottom, size, prot) == 0; 3353 } 3354 3355 // Set protections specified 3356 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3357 bool is_committed) { 3358 unsigned int p = 0; 3359 switch (prot) { 3360 case MEM_PROT_NONE: p = PROT_NONE; break; 3361 case MEM_PROT_READ: p = PROT_READ; break; 3362 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3363 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3364 default: 3365 ShouldNotReachHere(); 3366 } 3367 // is_committed is unused. 3368 return linux_mprotect(addr, bytes, p); 3369 } 3370 3371 bool os::guard_memory(char* addr, size_t size) { 3372 return linux_mprotect(addr, size, PROT_NONE); 3373 } 3374 3375 bool os::unguard_memory(char* addr, size_t size) { 3376 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3377 } 3378 3379 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3380 size_t page_size) { 3381 bool result = false; 3382 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3383 MAP_ANONYMOUS|MAP_PRIVATE, 3384 -1, 0); 3385 if (p != MAP_FAILED) { 3386 void *aligned_p = align_up(p, page_size); 3387 3388 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3389 3390 munmap(p, page_size * 2); 3391 } 3392 3393 if (warn && !result) { 3394 warning("TransparentHugePages is not supported by the operating system."); 3395 } 3396 3397 return result; 3398 } 3399 3400 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3401 bool result = false; 3402 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3403 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3404 -1, 0); 3405 3406 if (p != MAP_FAILED) { 3407 // We don't know if this really is a huge page or not. 3408 FILE *fp = fopen("/proc/self/maps", "r"); 3409 if (fp) { 3410 while (!feof(fp)) { 3411 char chars[257]; 3412 long x = 0; 3413 if (fgets(chars, sizeof(chars), fp)) { 3414 if (sscanf(chars, "%lx-%*x", &x) == 1 3415 && x == (long)p) { 3416 if (strstr (chars, "hugepage")) { 3417 result = true; 3418 break; 3419 } 3420 } 3421 } 3422 } 3423 fclose(fp); 3424 } 3425 munmap(p, page_size); 3426 } 3427 3428 if (warn && !result) { 3429 warning("HugeTLBFS is not supported by the operating system."); 3430 } 3431 3432 return result; 3433 } 3434 3435 // From the coredump_filter documentation: 3436 // 3437 // - (bit 0) anonymous private memory 3438 // - (bit 1) anonymous shared memory 3439 // - (bit 2) file-backed private memory 3440 // - (bit 3) file-backed shared memory 3441 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3442 // effective only if the bit 2 is cleared) 3443 // - (bit 5) hugetlb private memory 3444 // - (bit 6) hugetlb shared memory 3445 // - (bit 7) dax private memory 3446 // - (bit 8) dax shared memory 3447 // 3448 static void set_coredump_filter(CoredumpFilterBit bit) { 3449 FILE *f; 3450 long cdm; 3451 3452 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3453 return; 3454 } 3455 3456 if (fscanf(f, "%lx", &cdm) != 1) { 3457 fclose(f); 3458 return; 3459 } 3460 3461 long saved_cdm = cdm; 3462 rewind(f); 3463 cdm |= bit; 3464 3465 if (cdm != saved_cdm) { 3466 fprintf(f, "%#lx", cdm); 3467 } 3468 3469 fclose(f); 3470 } 3471 3472 // Large page support 3473 3474 static size_t _large_page_size = 0; 3475 3476 size_t os::Linux::find_large_page_size() { 3477 size_t large_page_size = 0; 3478 3479 // large_page_size on Linux is used to round up heap size. x86 uses either 3480 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3481 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3482 // page as large as 256M. 3483 // 3484 // Here we try to figure out page size by parsing /proc/meminfo and looking 3485 // for a line with the following format: 3486 // Hugepagesize: 2048 kB 3487 // 3488 // If we can't determine the value (e.g. /proc is not mounted, or the text 3489 // format has been changed), we'll use the largest page size supported by 3490 // the processor. 3491 3492 #ifndef ZERO 3493 large_page_size = 3494 AARCH64_ONLY(2 * M) 3495 AMD64_ONLY(2 * M) 3496 ARM32_ONLY(2 * M) 3497 IA32_ONLY(4 * M) 3498 IA64_ONLY(256 * M) 3499 PPC_ONLY(4 * M) 3500 S390_ONLY(1 * M) 3501 SPARC_ONLY(4 * M); 3502 #endif // ZERO 3503 3504 FILE *fp = fopen("/proc/meminfo", "r"); 3505 if (fp) { 3506 while (!feof(fp)) { 3507 int x = 0; 3508 char buf[16]; 3509 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3510 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3511 large_page_size = x * K; 3512 break; 3513 } 3514 } else { 3515 // skip to next line 3516 for (;;) { 3517 int ch = fgetc(fp); 3518 if (ch == EOF || ch == (int)'\n') break; 3519 } 3520 } 3521 } 3522 fclose(fp); 3523 } 3524 3525 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3526 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3527 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3528 proper_unit_for_byte_size(large_page_size)); 3529 } 3530 3531 return large_page_size; 3532 } 3533 3534 size_t os::Linux::setup_large_page_size() { 3535 _large_page_size = Linux::find_large_page_size(); 3536 const size_t default_page_size = (size_t)Linux::page_size(); 3537 if (_large_page_size > default_page_size) { 3538 _page_sizes[0] = _large_page_size; 3539 _page_sizes[1] = default_page_size; 3540 _page_sizes[2] = 0; 3541 } 3542 3543 return _large_page_size; 3544 } 3545 3546 bool os::Linux::setup_large_page_type(size_t page_size) { 3547 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3548 FLAG_IS_DEFAULT(UseSHM) && 3549 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3550 3551 // The type of large pages has not been specified by the user. 3552 3553 // Try UseHugeTLBFS and then UseSHM. 3554 UseHugeTLBFS = UseSHM = true; 3555 3556 // Don't try UseTransparentHugePages since there are known 3557 // performance issues with it turned on. This might change in the future. 3558 UseTransparentHugePages = false; 3559 } 3560 3561 if (UseTransparentHugePages) { 3562 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3563 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3564 UseHugeTLBFS = false; 3565 UseSHM = false; 3566 return true; 3567 } 3568 UseTransparentHugePages = false; 3569 } 3570 3571 if (UseHugeTLBFS) { 3572 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3573 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3574 UseSHM = false; 3575 return true; 3576 } 3577 UseHugeTLBFS = false; 3578 } 3579 3580 return UseSHM; 3581 } 3582 3583 void os::large_page_init() { 3584 if (!UseLargePages && 3585 !UseTransparentHugePages && 3586 !UseHugeTLBFS && 3587 !UseSHM) { 3588 // Not using large pages. 3589 return; 3590 } 3591 3592 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3593 // The user explicitly turned off large pages. 3594 // Ignore the rest of the large pages flags. 3595 UseTransparentHugePages = false; 3596 UseHugeTLBFS = false; 3597 UseSHM = false; 3598 return; 3599 } 3600 3601 size_t large_page_size = Linux::setup_large_page_size(); 3602 UseLargePages = Linux::setup_large_page_type(large_page_size); 3603 3604 set_coredump_filter(LARGEPAGES_BIT); 3605 } 3606 3607 #ifndef SHM_HUGETLB 3608 #define SHM_HUGETLB 04000 3609 #endif 3610 3611 #define shm_warning_format(format, ...) \ 3612 do { \ 3613 if (UseLargePages && \ 3614 (!FLAG_IS_DEFAULT(UseLargePages) || \ 3615 !FLAG_IS_DEFAULT(UseSHM) || \ 3616 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \ 3617 warning(format, __VA_ARGS__); \ 3618 } \ 3619 } while (0) 3620 3621 #define shm_warning(str) shm_warning_format("%s", str) 3622 3623 #define shm_warning_with_errno(str) \ 3624 do { \ 3625 int err = errno; \ 3626 shm_warning_format(str " (error = %d)", err); \ 3627 } while (0) 3628 3629 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) { 3630 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment"); 3631 3632 if (!is_aligned(alignment, SHMLBA)) { 3633 assert(false, "Code below assumes that alignment is at least SHMLBA aligned"); 3634 return NULL; 3635 } 3636 3637 // To ensure that we get 'alignment' aligned memory from shmat, 3638 // we pre-reserve aligned virtual memory and then attach to that. 3639 3640 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL); 3641 if (pre_reserved_addr == NULL) { 3642 // Couldn't pre-reserve aligned memory. 3643 shm_warning("Failed to pre-reserve aligned memory for shmat."); 3644 return NULL; 3645 } 3646 3647 // SHM_REMAP is needed to allow shmat to map over an existing mapping. 3648 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP); 3649 3650 if ((intptr_t)addr == -1) { 3651 int err = errno; 3652 shm_warning_with_errno("Failed to attach shared memory."); 3653 3654 assert(err != EACCES, "Unexpected error"); 3655 assert(err != EIDRM, "Unexpected error"); 3656 assert(err != EINVAL, "Unexpected error"); 3657 3658 // Since we don't know if the kernel unmapped the pre-reserved memory area 3659 // we can't unmap it, since that would potentially unmap memory that was 3660 // mapped from other threads. 3661 return NULL; 3662 } 3663 3664 return addr; 3665 } 3666 3667 static char* shmat_at_address(int shmid, char* req_addr) { 3668 if (!is_aligned(req_addr, SHMLBA)) { 3669 assert(false, "Requested address needs to be SHMLBA aligned"); 3670 return NULL; 3671 } 3672 3673 char* addr = (char*)shmat(shmid, req_addr, 0); 3674 3675 if ((intptr_t)addr == -1) { 3676 shm_warning_with_errno("Failed to attach shared memory."); 3677 return NULL; 3678 } 3679 3680 return addr; 3681 } 3682 3683 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) { 3684 // If a req_addr has been provided, we assume that the caller has already aligned the address. 3685 if (req_addr != NULL) { 3686 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size"); 3687 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment"); 3688 return shmat_at_address(shmid, req_addr); 3689 } 3690 3691 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically 3692 // return large page size aligned memory addresses when req_addr == NULL. 3693 // However, if the alignment is larger than the large page size, we have 3694 // to manually ensure that the memory returned is 'alignment' aligned. 3695 if (alignment > os::large_page_size()) { 3696 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size"); 3697 return shmat_with_alignment(shmid, bytes, alignment); 3698 } else { 3699 return shmat_at_address(shmid, NULL); 3700 } 3701 } 3702 3703 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3704 char* req_addr, bool exec) { 3705 // "exec" is passed in but not used. Creating the shared image for 3706 // the code cache doesn't have an SHM_X executable permission to check. 3707 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3708 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3709 assert(is_aligned(req_addr, alignment), "Unaligned address"); 3710 3711 if (!is_aligned(bytes, os::large_page_size())) { 3712 return NULL; // Fallback to small pages. 3713 } 3714 3715 // Create a large shared memory region to attach to based on size. 3716 // Currently, size is the total size of the heap. 3717 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3718 if (shmid == -1) { 3719 // Possible reasons for shmget failure: 3720 // 1. shmmax is too small for Java heap. 3721 // > check shmmax value: cat /proc/sys/kernel/shmmax 3722 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3723 // 2. not enough large page memory. 3724 // > check available large pages: cat /proc/meminfo 3725 // > increase amount of large pages: 3726 // echo new_value > /proc/sys/vm/nr_hugepages 3727 // Note 1: different Linux may use different name for this property, 3728 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3729 // Note 2: it's possible there's enough physical memory available but 3730 // they are so fragmented after a long run that they can't 3731 // coalesce into large pages. Try to reserve large pages when 3732 // the system is still "fresh". 3733 shm_warning_with_errno("Failed to reserve shared memory."); 3734 return NULL; 3735 } 3736 3737 // Attach to the region. 3738 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr); 3739 3740 // Remove shmid. If shmat() is successful, the actual shared memory segment 3741 // will be deleted when it's detached by shmdt() or when the process 3742 // terminates. If shmat() is not successful this will remove the shared 3743 // segment immediately. 3744 shmctl(shmid, IPC_RMID, NULL); 3745 3746 return addr; 3747 } 3748 3749 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3750 int error) { 3751 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3752 3753 bool warn_on_failure = UseLargePages && 3754 (!FLAG_IS_DEFAULT(UseLargePages) || 3755 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3756 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3757 3758 if (warn_on_failure) { 3759 char msg[128]; 3760 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3761 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3762 warning("%s", msg); 3763 } 3764 } 3765 3766 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3767 char* req_addr, 3768 bool exec) { 3769 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3770 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size"); 3771 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3772 3773 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3774 char* addr = (char*)::mmap(req_addr, bytes, prot, 3775 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3776 -1, 0); 3777 3778 if (addr == MAP_FAILED) { 3779 warn_on_large_pages_failure(req_addr, bytes, errno); 3780 return NULL; 3781 } 3782 3783 assert(is_aligned(addr, os::large_page_size()), "Must be"); 3784 3785 return addr; 3786 } 3787 3788 // Reserve memory using mmap(MAP_HUGETLB). 3789 // - bytes shall be a multiple of alignment. 3790 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3791 // - alignment sets the alignment at which memory shall be allocated. 3792 // It must be a multiple of allocation granularity. 3793 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3794 // req_addr or NULL. 3795 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3796 size_t alignment, 3797 char* req_addr, 3798 bool exec) { 3799 size_t large_page_size = os::large_page_size(); 3800 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3801 3802 assert(is_aligned(req_addr, alignment), "Must be"); 3803 assert(is_aligned(bytes, alignment), "Must be"); 3804 3805 // First reserve - but not commit - the address range in small pages. 3806 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3807 3808 if (start == NULL) { 3809 return NULL; 3810 } 3811 3812 assert(is_aligned(start, alignment), "Must be"); 3813 3814 char* end = start + bytes; 3815 3816 // Find the regions of the allocated chunk that can be promoted to large pages. 3817 char* lp_start = align_up(start, large_page_size); 3818 char* lp_end = align_down(end, large_page_size); 3819 3820 size_t lp_bytes = lp_end - lp_start; 3821 3822 assert(is_aligned(lp_bytes, large_page_size), "Must be"); 3823 3824 if (lp_bytes == 0) { 3825 // The mapped region doesn't even span the start and the end of a large page. 3826 // Fall back to allocate a non-special area. 3827 ::munmap(start, end - start); 3828 return NULL; 3829 } 3830 3831 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3832 3833 void* result; 3834 3835 // Commit small-paged leading area. 3836 if (start != lp_start) { 3837 result = ::mmap(start, lp_start - start, prot, 3838 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3839 -1, 0); 3840 if (result == MAP_FAILED) { 3841 ::munmap(lp_start, end - lp_start); 3842 return NULL; 3843 } 3844 } 3845 3846 // Commit large-paged area. 3847 result = ::mmap(lp_start, lp_bytes, prot, 3848 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3849 -1, 0); 3850 if (result == MAP_FAILED) { 3851 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3852 // If the mmap above fails, the large pages region will be unmapped and we 3853 // have regions before and after with small pages. Release these regions. 3854 // 3855 // | mapped | unmapped | mapped | 3856 // ^ ^ ^ ^ 3857 // start lp_start lp_end end 3858 // 3859 ::munmap(start, lp_start - start); 3860 ::munmap(lp_end, end - lp_end); 3861 return NULL; 3862 } 3863 3864 // Commit small-paged trailing area. 3865 if (lp_end != end) { 3866 result = ::mmap(lp_end, end - lp_end, prot, 3867 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3868 -1, 0); 3869 if (result == MAP_FAILED) { 3870 ::munmap(start, lp_end - start); 3871 return NULL; 3872 } 3873 } 3874 3875 return start; 3876 } 3877 3878 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3879 size_t alignment, 3880 char* req_addr, 3881 bool exec) { 3882 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3883 assert(is_aligned(req_addr, alignment), "Must be"); 3884 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 3885 assert(is_power_of_2(os::large_page_size()), "Must be"); 3886 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3887 3888 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3889 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3890 } else { 3891 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3892 } 3893 } 3894 3895 char* os::reserve_memory_special(size_t bytes, size_t alignment, 3896 char* req_addr, bool exec) { 3897 assert(UseLargePages, "only for large pages"); 3898 3899 char* addr; 3900 if (UseSHM) { 3901 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3902 } else { 3903 assert(UseHugeTLBFS, "must be"); 3904 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3905 } 3906 3907 if (addr != NULL) { 3908 if (UseNUMAInterleaving) { 3909 numa_make_global(addr, bytes); 3910 } 3911 3912 // The memory is committed 3913 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3914 } 3915 3916 return addr; 3917 } 3918 3919 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3920 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3921 return shmdt(base) == 0; 3922 } 3923 3924 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3925 return pd_release_memory(base, bytes); 3926 } 3927 3928 bool os::release_memory_special(char* base, size_t bytes) { 3929 bool res; 3930 if (MemTracker::tracking_level() > NMT_minimal) { 3931 Tracker tkr(Tracker::release); 3932 res = os::Linux::release_memory_special_impl(base, bytes); 3933 if (res) { 3934 tkr.record((address)base, bytes); 3935 } 3936 3937 } else { 3938 res = os::Linux::release_memory_special_impl(base, bytes); 3939 } 3940 return res; 3941 } 3942 3943 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3944 assert(UseLargePages, "only for large pages"); 3945 bool res; 3946 3947 if (UseSHM) { 3948 res = os::Linux::release_memory_special_shm(base, bytes); 3949 } else { 3950 assert(UseHugeTLBFS, "must be"); 3951 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3952 } 3953 return res; 3954 } 3955 3956 size_t os::large_page_size() { 3957 return _large_page_size; 3958 } 3959 3960 // With SysV SHM the entire memory region must be allocated as shared 3961 // memory. 3962 // HugeTLBFS allows application to commit large page memory on demand. 3963 // However, when committing memory with HugeTLBFS fails, the region 3964 // that was supposed to be committed will lose the old reservation 3965 // and allow other threads to steal that memory region. Because of this 3966 // behavior we can't commit HugeTLBFS memory. 3967 bool os::can_commit_large_page_memory() { 3968 return UseTransparentHugePages; 3969 } 3970 3971 bool os::can_execute_large_page_memory() { 3972 return UseTransparentHugePages || UseHugeTLBFS; 3973 } 3974 3975 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) { 3976 assert(file_desc >= 0, "file_desc is not valid"); 3977 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr); 3978 if (result != NULL) { 3979 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) { 3980 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory")); 3981 } 3982 } 3983 return result; 3984 } 3985 3986 // Reserve memory at an arbitrary address, only if that area is 3987 // available (and not reserved for something else). 3988 3989 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3990 const int max_tries = 10; 3991 char* base[max_tries]; 3992 size_t size[max_tries]; 3993 const size_t gap = 0x000000; 3994 3995 // Assert only that the size is a multiple of the page size, since 3996 // that's all that mmap requires, and since that's all we really know 3997 // about at this low abstraction level. If we need higher alignment, 3998 // we can either pass an alignment to this method or verify alignment 3999 // in one of the methods further up the call chain. See bug 5044738. 4000 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 4001 4002 // Repeatedly allocate blocks until the block is allocated at the 4003 // right spot. 4004 4005 // Linux mmap allows caller to pass an address as hint; give it a try first, 4006 // if kernel honors the hint then we can return immediately. 4007 char * addr = anon_mmap(requested_addr, bytes, false); 4008 if (addr == requested_addr) { 4009 return requested_addr; 4010 } 4011 4012 if (addr != NULL) { 4013 // mmap() is successful but it fails to reserve at the requested address 4014 anon_munmap(addr, bytes); 4015 } 4016 4017 int i; 4018 for (i = 0; i < max_tries; ++i) { 4019 base[i] = reserve_memory(bytes); 4020 4021 if (base[i] != NULL) { 4022 // Is this the block we wanted? 4023 if (base[i] == requested_addr) { 4024 size[i] = bytes; 4025 break; 4026 } 4027 4028 // Does this overlap the block we wanted? Give back the overlapped 4029 // parts and try again. 4030 4031 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 4032 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 4033 unmap_memory(base[i], top_overlap); 4034 base[i] += top_overlap; 4035 size[i] = bytes - top_overlap; 4036 } else { 4037 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 4038 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 4039 unmap_memory(requested_addr, bottom_overlap); 4040 size[i] = bytes - bottom_overlap; 4041 } else { 4042 size[i] = bytes; 4043 } 4044 } 4045 } 4046 } 4047 4048 // Give back the unused reserved pieces. 4049 4050 for (int j = 0; j < i; ++j) { 4051 if (base[j] != NULL) { 4052 unmap_memory(base[j], size[j]); 4053 } 4054 } 4055 4056 if (i < max_tries) { 4057 return requested_addr; 4058 } else { 4059 return NULL; 4060 } 4061 } 4062 4063 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 4064 void os::infinite_sleep() { 4065 while (true) { // sleep forever ... 4066 ::sleep(100); // ... 100 seconds at a time 4067 } 4068 } 4069 4070 // Used to convert frequent JVM_Yield() to nops 4071 bool os::dont_yield() { 4072 return DontYieldALot; 4073 } 4074 4075 // Linux CFS scheduler (since 2.6.23) does not guarantee sched_yield(2) will 4076 // actually give up the CPU. Since skip buddy (v2.6.28): 4077 // 4078 // * Sets the yielding task as skip buddy for current CPU's run queue. 4079 // * Picks next from run queue, if empty, picks a skip buddy (can be the yielding task). 4080 // * Clears skip buddies for this run queue (yielding task no longer a skip buddy). 4081 // 4082 // An alternative is calling os::naked_short_nanosleep with a small number to avoid 4083 // getting re-scheduled immediately. 4084 // 4085 void os::naked_yield() { 4086 sched_yield(); 4087 } 4088 4089 //////////////////////////////////////////////////////////////////////////////// 4090 // thread priority support 4091 4092 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 4093 // only supports dynamic priority, static priority must be zero. For real-time 4094 // applications, Linux supports SCHED_RR which allows static priority (1-99). 4095 // However, for large multi-threaded applications, SCHED_RR is not only slower 4096 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 4097 // of 5 runs - Sep 2005). 4098 // 4099 // The following code actually changes the niceness of kernel-thread/LWP. It 4100 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 4101 // not the entire user process, and user level threads are 1:1 mapped to kernel 4102 // threads. It has always been the case, but could change in the future. For 4103 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 4104 // It is only used when ThreadPriorityPolicy=1 and may require system level permission 4105 // (e.g., root privilege or CAP_SYS_NICE capability). 4106 4107 int os::java_to_os_priority[CriticalPriority + 1] = { 4108 19, // 0 Entry should never be used 4109 4110 4, // 1 MinPriority 4111 3, // 2 4112 2, // 3 4113 4114 1, // 4 4115 0, // 5 NormPriority 4116 -1, // 6 4117 4118 -2, // 7 4119 -3, // 8 4120 -4, // 9 NearMaxPriority 4121 4122 -5, // 10 MaxPriority 4123 4124 -5 // 11 CriticalPriority 4125 }; 4126 4127 static int prio_init() { 4128 if (ThreadPriorityPolicy == 1) { 4129 if (geteuid() != 0) { 4130 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 4131 warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \ 4132 "e.g., being the root user. If the necessary permission is not " \ 4133 "possessed, changes to priority will be silently ignored."); 4134 } 4135 } 4136 } 4137 if (UseCriticalJavaThreadPriority) { 4138 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 4139 } 4140 return 0; 4141 } 4142 4143 OSReturn os::set_native_priority(Thread* thread, int newpri) { 4144 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 4145 4146 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 4147 return (ret == 0) ? OS_OK : OS_ERR; 4148 } 4149 4150 OSReturn os::get_native_priority(const Thread* const thread, 4151 int *priority_ptr) { 4152 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 4153 *priority_ptr = java_to_os_priority[NormPriority]; 4154 return OS_OK; 4155 } 4156 4157 errno = 0; 4158 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 4159 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 4160 } 4161 4162 //////////////////////////////////////////////////////////////////////////////// 4163 // suspend/resume support 4164 4165 // The low-level signal-based suspend/resume support is a remnant from the 4166 // old VM-suspension that used to be for java-suspension, safepoints etc, 4167 // within hotspot. Currently used by JFR's OSThreadSampler 4168 // 4169 // The remaining code is greatly simplified from the more general suspension 4170 // code that used to be used. 4171 // 4172 // The protocol is quite simple: 4173 // - suspend: 4174 // - sends a signal to the target thread 4175 // - polls the suspend state of the osthread using a yield loop 4176 // - target thread signal handler (SR_handler) sets suspend state 4177 // and blocks in sigsuspend until continued 4178 // - resume: 4179 // - sets target osthread state to continue 4180 // - sends signal to end the sigsuspend loop in the SR_handler 4181 // 4182 // Note that the SR_lock plays no role in this suspend/resume protocol, 4183 // but is checked for NULL in SR_handler as a thread termination indicator. 4184 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs. 4185 // 4186 // Note that resume_clear_context() and suspend_save_context() are needed 4187 // by SR_handler(), so that fetch_frame_from_ucontext() works, 4188 // which in part is used by: 4189 // - Forte Analyzer: AsyncGetCallTrace() 4190 // - StackBanging: get_frame_at_stack_banging_point() 4191 4192 static void resume_clear_context(OSThread *osthread) { 4193 osthread->set_ucontext(NULL); 4194 osthread->set_siginfo(NULL); 4195 } 4196 4197 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 4198 ucontext_t* context) { 4199 osthread->set_ucontext(context); 4200 osthread->set_siginfo(siginfo); 4201 } 4202 4203 // Handler function invoked when a thread's execution is suspended or 4204 // resumed. We have to be careful that only async-safe functions are 4205 // called here (Note: most pthread functions are not async safe and 4206 // should be avoided.) 4207 // 4208 // Note: sigwait() is a more natural fit than sigsuspend() from an 4209 // interface point of view, but sigwait() prevents the signal hander 4210 // from being run. libpthread would get very confused by not having 4211 // its signal handlers run and prevents sigwait()'s use with the 4212 // mutex granting granting signal. 4213 // 4214 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 4215 // 4216 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 4217 // Save and restore errno to avoid confusing native code with EINTR 4218 // after sigsuspend. 4219 int old_errno = errno; 4220 4221 Thread* thread = Thread::current_or_null_safe(); 4222 assert(thread != NULL, "Missing current thread in SR_handler"); 4223 4224 // On some systems we have seen signal delivery get "stuck" until the signal 4225 // mask is changed as part of thread termination. Check that the current thread 4226 // has not already terminated (via SR_lock()) - else the following assertion 4227 // will fail because the thread is no longer a JavaThread as the ~JavaThread 4228 // destructor has completed. 4229 4230 if (thread->SR_lock() == NULL) { 4231 return; 4232 } 4233 4234 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 4235 4236 OSThread* osthread = thread->osthread(); 4237 4238 os::SuspendResume::State current = osthread->sr.state(); 4239 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 4240 suspend_save_context(osthread, siginfo, context); 4241 4242 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 4243 os::SuspendResume::State state = osthread->sr.suspended(); 4244 if (state == os::SuspendResume::SR_SUSPENDED) { 4245 sigset_t suspend_set; // signals for sigsuspend() 4246 sigemptyset(&suspend_set); 4247 // get current set of blocked signals and unblock resume signal 4248 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 4249 sigdelset(&suspend_set, SR_signum); 4250 4251 sr_semaphore.signal(); 4252 // wait here until we are resumed 4253 while (1) { 4254 sigsuspend(&suspend_set); 4255 4256 os::SuspendResume::State result = osthread->sr.running(); 4257 if (result == os::SuspendResume::SR_RUNNING) { 4258 sr_semaphore.signal(); 4259 break; 4260 } 4261 } 4262 4263 } else if (state == os::SuspendResume::SR_RUNNING) { 4264 // request was cancelled, continue 4265 } else { 4266 ShouldNotReachHere(); 4267 } 4268 4269 resume_clear_context(osthread); 4270 } else if (current == os::SuspendResume::SR_RUNNING) { 4271 // request was cancelled, continue 4272 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 4273 // ignore 4274 } else { 4275 // ignore 4276 } 4277 4278 errno = old_errno; 4279 } 4280 4281 static int SR_initialize() { 4282 struct sigaction act; 4283 char *s; 4284 4285 // Get signal number to use for suspend/resume 4286 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4287 int sig = ::strtol(s, 0, 10); 4288 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 4289 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 4290 SR_signum = sig; 4291 } else { 4292 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 4293 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 4294 } 4295 } 4296 4297 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4298 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4299 4300 sigemptyset(&SR_sigset); 4301 sigaddset(&SR_sigset, SR_signum); 4302 4303 // Set up signal handler for suspend/resume 4304 act.sa_flags = SA_RESTART|SA_SIGINFO; 4305 act.sa_handler = (void (*)(int)) SR_handler; 4306 4307 // SR_signum is blocked by default. 4308 // 4528190 - We also need to block pthread restart signal (32 on all 4309 // supported Linux platforms). Note that LinuxThreads need to block 4310 // this signal for all threads to work properly. So we don't have 4311 // to use hard-coded signal number when setting up the mask. 4312 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4313 4314 if (sigaction(SR_signum, &act, 0) == -1) { 4315 return -1; 4316 } 4317 4318 // Save signal flag 4319 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4320 return 0; 4321 } 4322 4323 static int sr_notify(OSThread* osthread) { 4324 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4325 assert_status(status == 0, status, "pthread_kill"); 4326 return status; 4327 } 4328 4329 // "Randomly" selected value for how long we want to spin 4330 // before bailing out on suspending a thread, also how often 4331 // we send a signal to a thread we want to resume 4332 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4333 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4334 4335 // returns true on success and false on error - really an error is fatal 4336 // but this seems the normal response to library errors 4337 static bool do_suspend(OSThread* osthread) { 4338 assert(osthread->sr.is_running(), "thread should be running"); 4339 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4340 4341 // mark as suspended and send signal 4342 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4343 // failed to switch, state wasn't running? 4344 ShouldNotReachHere(); 4345 return false; 4346 } 4347 4348 if (sr_notify(osthread) != 0) { 4349 ShouldNotReachHere(); 4350 } 4351 4352 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4353 while (true) { 4354 if (sr_semaphore.timedwait(2)) { 4355 break; 4356 } else { 4357 // timeout 4358 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4359 if (cancelled == os::SuspendResume::SR_RUNNING) { 4360 return false; 4361 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4362 // make sure that we consume the signal on the semaphore as well 4363 sr_semaphore.wait(); 4364 break; 4365 } else { 4366 ShouldNotReachHere(); 4367 return false; 4368 } 4369 } 4370 } 4371 4372 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4373 return true; 4374 } 4375 4376 static void do_resume(OSThread* osthread) { 4377 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4378 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4379 4380 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4381 // failed to switch to WAKEUP_REQUEST 4382 ShouldNotReachHere(); 4383 return; 4384 } 4385 4386 while (true) { 4387 if (sr_notify(osthread) == 0) { 4388 if (sr_semaphore.timedwait(2)) { 4389 if (osthread->sr.is_running()) { 4390 return; 4391 } 4392 } 4393 } else { 4394 ShouldNotReachHere(); 4395 } 4396 } 4397 4398 guarantee(osthread->sr.is_running(), "Must be running!"); 4399 } 4400 4401 /////////////////////////////////////////////////////////////////////////////////// 4402 // signal handling (except suspend/resume) 4403 4404 // This routine may be used by user applications as a "hook" to catch signals. 4405 // The user-defined signal handler must pass unrecognized signals to this 4406 // routine, and if it returns true (non-zero), then the signal handler must 4407 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4408 // routine will never retun false (zero), but instead will execute a VM panic 4409 // routine kill the process. 4410 // 4411 // If this routine returns false, it is OK to call it again. This allows 4412 // the user-defined signal handler to perform checks either before or after 4413 // the VM performs its own checks. Naturally, the user code would be making 4414 // a serious error if it tried to handle an exception (such as a null check 4415 // or breakpoint) that the VM was generating for its own correct operation. 4416 // 4417 // This routine may recognize any of the following kinds of signals: 4418 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4419 // It should be consulted by handlers for any of those signals. 4420 // 4421 // The caller of this routine must pass in the three arguments supplied 4422 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4423 // field of the structure passed to sigaction(). This routine assumes that 4424 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4425 // 4426 // Note that the VM will print warnings if it detects conflicting signal 4427 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4428 // 4429 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4430 siginfo_t* siginfo, 4431 void* ucontext, 4432 int abort_if_unrecognized); 4433 4434 static void signalHandler(int sig, siginfo_t* info, void* uc) { 4435 assert(info != NULL && uc != NULL, "it must be old kernel"); 4436 int orig_errno = errno; // Preserve errno value over signal handler. 4437 JVM_handle_linux_signal(sig, info, uc, true); 4438 errno = orig_errno; 4439 } 4440 4441 4442 // This boolean allows users to forward their own non-matching signals 4443 // to JVM_handle_linux_signal, harmlessly. 4444 bool os::Linux::signal_handlers_are_installed = false; 4445 4446 // For signal-chaining 4447 bool os::Linux::libjsig_is_loaded = false; 4448 typedef struct sigaction *(*get_signal_t)(int); 4449 get_signal_t os::Linux::get_signal_action = NULL; 4450 4451 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4452 struct sigaction *actp = NULL; 4453 4454 if (libjsig_is_loaded) { 4455 // Retrieve the old signal handler from libjsig 4456 actp = (*get_signal_action)(sig); 4457 } 4458 if (actp == NULL) { 4459 // Retrieve the preinstalled signal handler from jvm 4460 actp = os::Posix::get_preinstalled_handler(sig); 4461 } 4462 4463 return actp; 4464 } 4465 4466 static bool call_chained_handler(struct sigaction *actp, int sig, 4467 siginfo_t *siginfo, void *context) { 4468 // Call the old signal handler 4469 if (actp->sa_handler == SIG_DFL) { 4470 // It's more reasonable to let jvm treat it as an unexpected exception 4471 // instead of taking the default action. 4472 return false; 4473 } else if (actp->sa_handler != SIG_IGN) { 4474 if ((actp->sa_flags & SA_NODEFER) == 0) { 4475 // automaticlly block the signal 4476 sigaddset(&(actp->sa_mask), sig); 4477 } 4478 4479 sa_handler_t hand = NULL; 4480 sa_sigaction_t sa = NULL; 4481 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4482 // retrieve the chained handler 4483 if (siginfo_flag_set) { 4484 sa = actp->sa_sigaction; 4485 } else { 4486 hand = actp->sa_handler; 4487 } 4488 4489 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4490 actp->sa_handler = SIG_DFL; 4491 } 4492 4493 // try to honor the signal mask 4494 sigset_t oset; 4495 sigemptyset(&oset); 4496 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4497 4498 // call into the chained handler 4499 if (siginfo_flag_set) { 4500 (*sa)(sig, siginfo, context); 4501 } else { 4502 (*hand)(sig); 4503 } 4504 4505 // restore the signal mask 4506 pthread_sigmask(SIG_SETMASK, &oset, NULL); 4507 } 4508 // Tell jvm's signal handler the signal is taken care of. 4509 return true; 4510 } 4511 4512 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4513 bool chained = false; 4514 // signal-chaining 4515 if (UseSignalChaining) { 4516 struct sigaction *actp = get_chained_signal_action(sig); 4517 if (actp != NULL) { 4518 chained = call_chained_handler(actp, sig, siginfo, context); 4519 } 4520 } 4521 return chained; 4522 } 4523 4524 // for diagnostic 4525 int sigflags[NSIG]; 4526 4527 int os::Linux::get_our_sigflags(int sig) { 4528 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4529 return sigflags[sig]; 4530 } 4531 4532 void os::Linux::set_our_sigflags(int sig, int flags) { 4533 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4534 if (sig > 0 && sig < NSIG) { 4535 sigflags[sig] = flags; 4536 } 4537 } 4538 4539 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4540 // Check for overwrite. 4541 struct sigaction oldAct; 4542 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4543 4544 void* oldhand = oldAct.sa_sigaction 4545 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4546 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4547 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4548 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4549 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4550 if (AllowUserSignalHandlers || !set_installed) { 4551 // Do not overwrite; user takes responsibility to forward to us. 4552 return; 4553 } else if (UseSignalChaining) { 4554 // save the old handler in jvm 4555 os::Posix::save_preinstalled_handler(sig, oldAct); 4556 // libjsig also interposes the sigaction() call below and saves the 4557 // old sigaction on it own. 4558 } else { 4559 fatal("Encountered unexpected pre-existing sigaction handler " 4560 "%#lx for signal %d.", (long)oldhand, sig); 4561 } 4562 } 4563 4564 struct sigaction sigAct; 4565 sigfillset(&(sigAct.sa_mask)); 4566 sigAct.sa_handler = SIG_DFL; 4567 if (!set_installed) { 4568 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4569 } else { 4570 sigAct.sa_sigaction = signalHandler; 4571 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4572 } 4573 // Save flags, which are set by ours 4574 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4575 sigflags[sig] = sigAct.sa_flags; 4576 4577 int ret = sigaction(sig, &sigAct, &oldAct); 4578 assert(ret == 0, "check"); 4579 4580 void* oldhand2 = oldAct.sa_sigaction 4581 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4582 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4583 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4584 } 4585 4586 // install signal handlers for signals that HotSpot needs to 4587 // handle in order to support Java-level exception handling. 4588 4589 void os::Linux::install_signal_handlers() { 4590 if (!signal_handlers_are_installed) { 4591 signal_handlers_are_installed = true; 4592 4593 // signal-chaining 4594 typedef void (*signal_setting_t)(); 4595 signal_setting_t begin_signal_setting = NULL; 4596 signal_setting_t end_signal_setting = NULL; 4597 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4598 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4599 if (begin_signal_setting != NULL) { 4600 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4601 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4602 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4603 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4604 libjsig_is_loaded = true; 4605 assert(UseSignalChaining, "should enable signal-chaining"); 4606 } 4607 if (libjsig_is_loaded) { 4608 // Tell libjsig jvm is setting signal handlers 4609 (*begin_signal_setting)(); 4610 } 4611 4612 os::Posix::init_sigs(); 4613 set_signal_handler(SIGSEGV, true); 4614 set_signal_handler(SIGPIPE, true); 4615 set_signal_handler(SIGBUS, true); 4616 set_signal_handler(SIGILL, true); 4617 set_signal_handler(SIGFPE, true); 4618 #if defined(PPC64) 4619 set_signal_handler(SIGTRAP, true); 4620 #endif 4621 set_signal_handler(SIGXFSZ, true); 4622 4623 if (libjsig_is_loaded) { 4624 // Tell libjsig jvm finishes setting signal handlers 4625 (*end_signal_setting)(); 4626 } 4627 4628 // We don't activate signal checker if libjsig is in place, we trust ourselves 4629 // and if UserSignalHandler is installed all bets are off. 4630 // Log that signal checking is off only if -verbose:jni is specified. 4631 if (CheckJNICalls) { 4632 if (libjsig_is_loaded) { 4633 if (PrintJNIResolving) { 4634 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4635 } 4636 check_signals = false; 4637 } 4638 if (AllowUserSignalHandlers) { 4639 if (PrintJNIResolving) { 4640 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4641 } 4642 check_signals = false; 4643 } 4644 } 4645 } 4646 } 4647 4648 // This is the fastest way to get thread cpu time on Linux. 4649 // Returns cpu time (user+sys) for any thread, not only for current. 4650 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4651 // It might work on 2.6.10+ with a special kernel/glibc patch. 4652 // For reference, please, see IEEE Std 1003.1-2004: 4653 // http://www.unix.org/single_unix_specification 4654 4655 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4656 struct timespec tp; 4657 int rc = os::Posix::clock_gettime(clockid, &tp); 4658 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4659 4660 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4661 } 4662 4663 void os::Linux::initialize_os_info() { 4664 assert(_os_version == 0, "OS info already initialized"); 4665 4666 struct utsname _uname; 4667 4668 uint32_t major; 4669 uint32_t minor; 4670 uint32_t fix; 4671 4672 int rc; 4673 4674 // Kernel version is unknown if 4675 // verification below fails. 4676 _os_version = 0x01000000; 4677 4678 rc = uname(&_uname); 4679 if (rc != -1) { 4680 4681 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix); 4682 if (rc == 3) { 4683 4684 if (major < 256 && minor < 256 && fix < 256) { 4685 // Kernel version format is as expected, 4686 // set it overriding unknown state. 4687 _os_version = (major << 16) | 4688 (minor << 8 ) | 4689 (fix << 0 ) ; 4690 } 4691 } 4692 } 4693 } 4694 4695 uint32_t os::Linux::os_version() { 4696 assert(_os_version != 0, "not initialized"); 4697 return _os_version & 0x00FFFFFF; 4698 } 4699 4700 bool os::Linux::os_version_is_known() { 4701 assert(_os_version != 0, "not initialized"); 4702 return _os_version & 0x01000000 ? false : true; 4703 } 4704 4705 ///// 4706 // glibc on Linux platform uses non-documented flag 4707 // to indicate, that some special sort of signal 4708 // trampoline is used. 4709 // We will never set this flag, and we should 4710 // ignore this flag in our diagnostic 4711 #ifdef SIGNIFICANT_SIGNAL_MASK 4712 #undef SIGNIFICANT_SIGNAL_MASK 4713 #endif 4714 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4715 4716 static const char* get_signal_handler_name(address handler, 4717 char* buf, int buflen) { 4718 int offset = 0; 4719 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4720 if (found) { 4721 // skip directory names 4722 const char *p1, *p2; 4723 p1 = buf; 4724 size_t len = strlen(os::file_separator()); 4725 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4726 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4727 } else { 4728 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4729 } 4730 return buf; 4731 } 4732 4733 static void print_signal_handler(outputStream* st, int sig, 4734 char* buf, size_t buflen) { 4735 struct sigaction sa; 4736 4737 sigaction(sig, NULL, &sa); 4738 4739 // See comment for SIGNIFICANT_SIGNAL_MASK define 4740 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4741 4742 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4743 4744 address handler = (sa.sa_flags & SA_SIGINFO) 4745 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4746 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4747 4748 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4749 st->print("SIG_DFL"); 4750 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4751 st->print("SIG_IGN"); 4752 } else { 4753 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4754 } 4755 4756 st->print(", sa_mask[0]="); 4757 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4758 4759 address rh = VMError::get_resetted_sighandler(sig); 4760 // May be, handler was resetted by VMError? 4761 if (rh != NULL) { 4762 handler = rh; 4763 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4764 } 4765 4766 st->print(", sa_flags="); 4767 os::Posix::print_sa_flags(st, sa.sa_flags); 4768 4769 // Check: is it our handler? 4770 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4771 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4772 // It is our signal handler 4773 // check for flags, reset system-used one! 4774 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4775 st->print( 4776 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4777 os::Linux::get_our_sigflags(sig)); 4778 } 4779 } 4780 st->cr(); 4781 } 4782 4783 4784 #define DO_SIGNAL_CHECK(sig) \ 4785 do { \ 4786 if (!sigismember(&check_signal_done, sig)) { \ 4787 os::Linux::check_signal_handler(sig); \ 4788 } \ 4789 } while (0) 4790 4791 // This method is a periodic task to check for misbehaving JNI applications 4792 // under CheckJNI, we can add any periodic checks here 4793 4794 void os::run_periodic_checks() { 4795 if (check_signals == false) return; 4796 4797 // SEGV and BUS if overridden could potentially prevent 4798 // generation of hs*.log in the event of a crash, debugging 4799 // such a case can be very challenging, so we absolutely 4800 // check the following for a good measure: 4801 DO_SIGNAL_CHECK(SIGSEGV); 4802 DO_SIGNAL_CHECK(SIGILL); 4803 DO_SIGNAL_CHECK(SIGFPE); 4804 DO_SIGNAL_CHECK(SIGBUS); 4805 DO_SIGNAL_CHECK(SIGPIPE); 4806 DO_SIGNAL_CHECK(SIGXFSZ); 4807 #if defined(PPC64) 4808 DO_SIGNAL_CHECK(SIGTRAP); 4809 #endif 4810 4811 // ReduceSignalUsage allows the user to override these handlers 4812 // see comments at the very top and jvm_md.h 4813 if (!ReduceSignalUsage) { 4814 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4815 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4816 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4817 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4818 } 4819 4820 DO_SIGNAL_CHECK(SR_signum); 4821 } 4822 4823 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4824 4825 static os_sigaction_t os_sigaction = NULL; 4826 4827 void os::Linux::check_signal_handler(int sig) { 4828 char buf[O_BUFLEN]; 4829 address jvmHandler = NULL; 4830 4831 4832 struct sigaction act; 4833 if (os_sigaction == NULL) { 4834 // only trust the default sigaction, in case it has been interposed 4835 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4836 if (os_sigaction == NULL) return; 4837 } 4838 4839 os_sigaction(sig, (struct sigaction*)NULL, &act); 4840 4841 4842 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4843 4844 address thisHandler = (act.sa_flags & SA_SIGINFO) 4845 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4846 : CAST_FROM_FN_PTR(address, act.sa_handler); 4847 4848 4849 switch (sig) { 4850 case SIGSEGV: 4851 case SIGBUS: 4852 case SIGFPE: 4853 case SIGPIPE: 4854 case SIGILL: 4855 case SIGXFSZ: 4856 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4857 break; 4858 4859 case SHUTDOWN1_SIGNAL: 4860 case SHUTDOWN2_SIGNAL: 4861 case SHUTDOWN3_SIGNAL: 4862 case BREAK_SIGNAL: 4863 jvmHandler = (address)user_handler(); 4864 break; 4865 4866 default: 4867 if (sig == SR_signum) { 4868 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4869 } else { 4870 return; 4871 } 4872 break; 4873 } 4874 4875 if (thisHandler != jvmHandler) { 4876 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4877 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4878 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4879 // No need to check this sig any longer 4880 sigaddset(&check_signal_done, sig); 4881 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4882 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4883 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4884 exception_name(sig, buf, O_BUFLEN)); 4885 } 4886 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4887 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4888 tty->print("expected:"); 4889 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 4890 tty->cr(); 4891 tty->print(" found:"); 4892 os::Posix::print_sa_flags(tty, act.sa_flags); 4893 tty->cr(); 4894 // No need to check this sig any longer 4895 sigaddset(&check_signal_done, sig); 4896 } 4897 4898 // Dump all the signal 4899 if (sigismember(&check_signal_done, sig)) { 4900 print_signal_handlers(tty, buf, O_BUFLEN); 4901 } 4902 } 4903 4904 extern void report_error(char* file_name, int line_no, char* title, 4905 char* format, ...); 4906 4907 // this is called _before_ most of the global arguments have been parsed 4908 void os::init(void) { 4909 char dummy; // used to get a guess on initial stack address 4910 4911 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4912 4913 init_random(1234567); 4914 4915 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4916 if (Linux::page_size() == -1) { 4917 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 4918 os::strerror(errno)); 4919 } 4920 init_page_sizes((size_t) Linux::page_size()); 4921 4922 Linux::initialize_system_info(); 4923 4924 Linux::initialize_os_info(); 4925 4926 // _main_thread points to the thread that created/loaded the JVM. 4927 Linux::_main_thread = pthread_self(); 4928 4929 // retrieve entry point for pthread_setname_np 4930 Linux::_pthread_setname_np = 4931 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4932 4933 os::Posix::init(); 4934 4935 initial_time_count = javaTimeNanos(); 4936 4937 // Always warn if no monotonic clock available 4938 if (!os::Posix::supports_monotonic_clock()) { 4939 warning("No monotonic clock was available - timed services may " \ 4940 "be adversely affected if the time-of-day clock changes"); 4941 } 4942 } 4943 4944 // To install functions for atexit system call 4945 extern "C" { 4946 static void perfMemory_exit_helper() { 4947 perfMemory_exit(); 4948 } 4949 } 4950 4951 void os::pd_init_container_support() { 4952 OSContainer::init(); 4953 } 4954 4955 void os::Linux::numa_init() { 4956 4957 // Java can be invoked as 4958 // 1. Without numactl and heap will be allocated/configured on all nodes as 4959 // per the system policy. 4960 // 2. With numactl --interleave: 4961 // Use numa_get_interleave_mask(v2) API to get nodes bitmask. The same 4962 // API for membind case bitmask is reset. 4963 // Interleave is only hint and Kernel can fallback to other nodes if 4964 // no memory is available on the target nodes. 4965 // 3. With numactl --membind: 4966 // Use numa_get_membind(v2) API to get nodes bitmask. The same API for 4967 // interleave case returns bitmask of all nodes. 4968 // numa_all_nodes_ptr holds bitmask of all nodes. 4969 // numa_get_interleave_mask(v2) and numa_get_membind(v2) APIs returns correct 4970 // bitmask when externally configured to run on all or fewer nodes. 4971 4972 if (!Linux::libnuma_init()) { 4973 UseNUMA = false; 4974 } else { 4975 if ((Linux::numa_max_node() < 1) || Linux::is_bound_to_single_node()) { 4976 // If there's only one node (they start from 0) or if the process 4977 // is bound explicitly to a single node using membind, disable NUMA. 4978 UseNUMA = false; 4979 } else { 4980 4981 LogTarget(Info,os) log; 4982 LogStream ls(log); 4983 4984 Linux::set_configured_numa_policy(Linux::identify_numa_policy()); 4985 4986 struct bitmask* bmp = Linux::_numa_membind_bitmask; 4987 const char* numa_mode = "membind"; 4988 4989 if (Linux::is_running_in_interleave_mode()) { 4990 bmp = Linux::_numa_interleave_bitmask; 4991 numa_mode = "interleave"; 4992 } 4993 4994 ls.print("UseNUMA is enabled and invoked in '%s' mode." 4995 " Heap will be configured using NUMA memory nodes:", numa_mode); 4996 4997 for (int node = 0; node <= Linux::numa_max_node(); node++) { 4998 if (Linux::_numa_bitmask_isbitset(bmp, node)) { 4999 ls.print(" %d", node); 5000 } 5001 } 5002 } 5003 } 5004 5005 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 5006 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 5007 // we can make the adaptive lgrp chunk resizing work. If the user specified both 5008 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn 5009 // and disable adaptive resizing. 5010 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 5011 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, " 5012 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 5013 UseAdaptiveSizePolicy = false; 5014 UseAdaptiveNUMAChunkSizing = false; 5015 } 5016 } 5017 5018 if (!UseNUMA && ForceNUMA) { 5019 UseNUMA = true; 5020 } 5021 } 5022 5023 // this is called _after_ the global arguments have been parsed 5024 jint os::init_2(void) { 5025 5026 // This could be set after os::Posix::init() but all platforms 5027 // have to set it the same so we have to mirror Solaris. 5028 DEBUG_ONLY(os::set_mutex_init_done();) 5029 5030 os::Posix::init_2(); 5031 5032 Linux::fast_thread_clock_init(); 5033 5034 // initialize suspend/resume support - must do this before signal_sets_init() 5035 if (SR_initialize() != 0) { 5036 perror("SR_initialize failed"); 5037 return JNI_ERR; 5038 } 5039 5040 Linux::signal_sets_init(); 5041 Linux::install_signal_handlers(); 5042 // Initialize data for jdk.internal.misc.Signal 5043 if (!ReduceSignalUsage) { 5044 jdk_misc_signal_init(); 5045 } 5046 5047 // Check and sets minimum stack sizes against command line options 5048 if (Posix::set_minimum_stack_sizes() == JNI_ERR) { 5049 return JNI_ERR; 5050 } 5051 5052 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher(); 5053 if (!suppress_primordial_thread_resolution) { 5054 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 5055 } 5056 5057 #if defined(IA32) 5058 workaround_expand_exec_shield_cs_limit(); 5059 #endif 5060 5061 Linux::libpthread_init(); 5062 Linux::sched_getcpu_init(); 5063 log_info(os)("HotSpot is running with %s, %s", 5064 Linux::glibc_version(), Linux::libpthread_version()); 5065 5066 if (UseNUMA) { 5067 Linux::numa_init(); 5068 } 5069 5070 if (MaxFDLimit) { 5071 // set the number of file descriptors to max. print out error 5072 // if getrlimit/setrlimit fails but continue regardless. 5073 struct rlimit nbr_files; 5074 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 5075 if (status != 0) { 5076 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno)); 5077 } else { 5078 nbr_files.rlim_cur = nbr_files.rlim_max; 5079 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 5080 if (status != 0) { 5081 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno)); 5082 } 5083 } 5084 } 5085 5086 // Initialize lock used to serialize thread creation (see os::create_thread) 5087 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 5088 5089 // at-exit methods are called in the reverse order of their registration. 5090 // atexit functions are called on return from main or as a result of a 5091 // call to exit(3C). There can be only 32 of these functions registered 5092 // and atexit() does not set errno. 5093 5094 if (PerfAllowAtExitRegistration) { 5095 // only register atexit functions if PerfAllowAtExitRegistration is set. 5096 // atexit functions can be delayed until process exit time, which 5097 // can be problematic for embedded VM situations. Embedded VMs should 5098 // call DestroyJavaVM() to assure that VM resources are released. 5099 5100 // note: perfMemory_exit_helper atexit function may be removed in 5101 // the future if the appropriate cleanup code can be added to the 5102 // VM_Exit VMOperation's doit method. 5103 if (atexit(perfMemory_exit_helper) != 0) { 5104 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 5105 } 5106 } 5107 5108 // initialize thread priority policy 5109 prio_init(); 5110 5111 if (!FLAG_IS_DEFAULT(AllocateHeapAt) || !FLAG_IS_DEFAULT(AllocateOldGenAt)) { 5112 set_coredump_filter(DAX_SHARED_BIT); 5113 } 5114 5115 if (DumpPrivateMappingsInCore) { 5116 set_coredump_filter(FILE_BACKED_PVT_BIT); 5117 } 5118 5119 if (DumpSharedMappingsInCore) { 5120 set_coredump_filter(FILE_BACKED_SHARED_BIT); 5121 } 5122 5123 return JNI_OK; 5124 } 5125 5126 // Mark the polling page as unreadable 5127 void os::make_polling_page_unreadable(void) { 5128 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 5129 fatal("Could not disable polling page"); 5130 } 5131 } 5132 5133 // Mark the polling page as readable 5134 void os::make_polling_page_readable(void) { 5135 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 5136 fatal("Could not enable polling page"); 5137 } 5138 } 5139 5140 // older glibc versions don't have this macro (which expands to 5141 // an optimized bit-counting function) so we have to roll our own 5142 #ifndef CPU_COUNT 5143 5144 static int _cpu_count(const cpu_set_t* cpus) { 5145 int count = 0; 5146 // only look up to the number of configured processors 5147 for (int i = 0; i < os::processor_count(); i++) { 5148 if (CPU_ISSET(i, cpus)) { 5149 count++; 5150 } 5151 } 5152 return count; 5153 } 5154 5155 #define CPU_COUNT(cpus) _cpu_count(cpus) 5156 5157 #endif // CPU_COUNT 5158 5159 // Get the current number of available processors for this process. 5160 // This value can change at any time during a process's lifetime. 5161 // sched_getaffinity gives an accurate answer as it accounts for cpusets. 5162 // If it appears there may be more than 1024 processors then we do a 5163 // dynamic check - see 6515172 for details. 5164 // If anything goes wrong we fallback to returning the number of online 5165 // processors - which can be greater than the number available to the process. 5166 int os::Linux::active_processor_count() { 5167 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 5168 cpu_set_t* cpus_p = &cpus; 5169 int cpus_size = sizeof(cpu_set_t); 5170 5171 int configured_cpus = os::processor_count(); // upper bound on available cpus 5172 int cpu_count = 0; 5173 5174 // old build platforms may not support dynamic cpu sets 5175 #ifdef CPU_ALLOC 5176 5177 // To enable easy testing of the dynamic path on different platforms we 5178 // introduce a diagnostic flag: UseCpuAllocPath 5179 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 5180 // kernel may use a mask bigger than cpu_set_t 5181 log_trace(os)("active_processor_count: using dynamic path %s" 5182 "- configured processors: %d", 5183 UseCpuAllocPath ? "(forced) " : "", 5184 configured_cpus); 5185 cpus_p = CPU_ALLOC(configured_cpus); 5186 if (cpus_p != NULL) { 5187 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 5188 // zero it just to be safe 5189 CPU_ZERO_S(cpus_size, cpus_p); 5190 } 5191 else { 5192 // failed to allocate so fallback to online cpus 5193 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 5194 log_trace(os)("active_processor_count: " 5195 "CPU_ALLOC failed (%s) - using " 5196 "online processor count: %d", 5197 os::strerror(errno), online_cpus); 5198 return online_cpus; 5199 } 5200 } 5201 else { 5202 log_trace(os)("active_processor_count: using static path - configured processors: %d", 5203 configured_cpus); 5204 } 5205 #else // CPU_ALLOC 5206 // these stubs won't be executed 5207 #define CPU_COUNT_S(size, cpus) -1 5208 #define CPU_FREE(cpus) 5209 5210 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 5211 configured_cpus); 5212 #endif // CPU_ALLOC 5213 5214 // pid 0 means the current thread - which we have to assume represents the process 5215 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 5216 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5217 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 5218 } 5219 else { 5220 cpu_count = CPU_COUNT(cpus_p); 5221 } 5222 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 5223 } 5224 else { 5225 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 5226 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 5227 "which may exceed available processors", os::strerror(errno), cpu_count); 5228 } 5229 5230 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5231 CPU_FREE(cpus_p); 5232 } 5233 5234 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check"); 5235 return cpu_count; 5236 } 5237 5238 // Determine the active processor count from one of 5239 // three different sources: 5240 // 5241 // 1. User option -XX:ActiveProcessorCount 5242 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN) 5243 // 3. extracted from cgroup cpu subsystem (shares and quotas) 5244 // 5245 // Option 1, if specified, will always override. 5246 // If the cgroup subsystem is active and configured, we 5247 // will return the min of the cgroup and option 2 results. 5248 // This is required since tools, such as numactl, that 5249 // alter cpu affinity do not update cgroup subsystem 5250 // cpuset configuration files. 5251 int os::active_processor_count() { 5252 // User has overridden the number of active processors 5253 if (ActiveProcessorCount > 0) { 5254 log_trace(os)("active_processor_count: " 5255 "active processor count set by user : %d", 5256 ActiveProcessorCount); 5257 return ActiveProcessorCount; 5258 } 5259 5260 int active_cpus; 5261 if (OSContainer::is_containerized()) { 5262 active_cpus = OSContainer::active_processor_count(); 5263 log_trace(os)("active_processor_count: determined by OSContainer: %d", 5264 active_cpus); 5265 } else { 5266 active_cpus = os::Linux::active_processor_count(); 5267 } 5268 5269 return active_cpus; 5270 } 5271 5272 uint os::processor_id() { 5273 const int id = Linux::sched_getcpu(); 5274 assert(id >= 0 && id < _processor_count, "Invalid processor id"); 5275 return (uint)id; 5276 } 5277 5278 void os::set_native_thread_name(const char *name) { 5279 if (Linux::_pthread_setname_np) { 5280 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 5281 snprintf(buf, sizeof(buf), "%s", name); 5282 buf[sizeof(buf) - 1] = '\0'; 5283 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 5284 // ERANGE should not happen; all other errors should just be ignored. 5285 assert(rc != ERANGE, "pthread_setname_np failed"); 5286 } 5287 } 5288 5289 bool os::distribute_processes(uint length, uint* distribution) { 5290 // Not yet implemented. 5291 return false; 5292 } 5293 5294 bool os::bind_to_processor(uint processor_id) { 5295 // Not yet implemented. 5296 return false; 5297 } 5298 5299 /// 5300 5301 void os::SuspendedThreadTask::internal_do_task() { 5302 if (do_suspend(_thread->osthread())) { 5303 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 5304 do_task(context); 5305 do_resume(_thread->osthread()); 5306 } 5307 } 5308 5309 //////////////////////////////////////////////////////////////////////////////// 5310 // debug support 5311 5312 bool os::find(address addr, outputStream* st) { 5313 Dl_info dlinfo; 5314 memset(&dlinfo, 0, sizeof(dlinfo)); 5315 if (dladdr(addr, &dlinfo) != 0) { 5316 st->print(PTR_FORMAT ": ", p2i(addr)); 5317 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5318 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 5319 p2i(addr) - p2i(dlinfo.dli_saddr)); 5320 } else if (dlinfo.dli_fbase != NULL) { 5321 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 5322 } else { 5323 st->print("<absolute address>"); 5324 } 5325 if (dlinfo.dli_fname != NULL) { 5326 st->print(" in %s", dlinfo.dli_fname); 5327 } 5328 if (dlinfo.dli_fbase != NULL) { 5329 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 5330 } 5331 st->cr(); 5332 5333 if (Verbose) { 5334 // decode some bytes around the PC 5335 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5336 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5337 address lowest = (address) dlinfo.dli_sname; 5338 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5339 if (begin < lowest) begin = lowest; 5340 Dl_info dlinfo2; 5341 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5342 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 5343 end = (address) dlinfo2.dli_saddr; 5344 } 5345 Disassembler::decode(begin, end, st); 5346 } 5347 return true; 5348 } 5349 return false; 5350 } 5351 5352 //////////////////////////////////////////////////////////////////////////////// 5353 // misc 5354 5355 // This does not do anything on Linux. This is basically a hook for being 5356 // able to use structured exception handling (thread-local exception filters) 5357 // on, e.g., Win32. 5358 void 5359 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5360 JavaCallArguments* args, Thread* thread) { 5361 f(value, method, args, thread); 5362 } 5363 5364 void os::print_statistics() { 5365 } 5366 5367 bool os::message_box(const char* title, const char* message) { 5368 int i; 5369 fdStream err(defaultStream::error_fd()); 5370 for (i = 0; i < 78; i++) err.print_raw("="); 5371 err.cr(); 5372 err.print_raw_cr(title); 5373 for (i = 0; i < 78; i++) err.print_raw("-"); 5374 err.cr(); 5375 err.print_raw_cr(message); 5376 for (i = 0; i < 78; i++) err.print_raw("="); 5377 err.cr(); 5378 5379 char buf[16]; 5380 // Prevent process from exiting upon "read error" without consuming all CPU 5381 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5382 5383 return buf[0] == 'y' || buf[0] == 'Y'; 5384 } 5385 5386 // Is a (classpath) directory empty? 5387 bool os::dir_is_empty(const char* path) { 5388 DIR *dir = NULL; 5389 struct dirent *ptr; 5390 5391 dir = opendir(path); 5392 if (dir == NULL) return true; 5393 5394 // Scan the directory 5395 bool result = true; 5396 while (result && (ptr = readdir(dir)) != NULL) { 5397 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5398 result = false; 5399 } 5400 } 5401 closedir(dir); 5402 return result; 5403 } 5404 5405 // This code originates from JDK's sysOpen and open64_w 5406 // from src/solaris/hpi/src/system_md.c 5407 5408 int os::open(const char *path, int oflag, int mode) { 5409 if (strlen(path) > MAX_PATH - 1) { 5410 errno = ENAMETOOLONG; 5411 return -1; 5412 } 5413 5414 // All file descriptors that are opened in the Java process and not 5415 // specifically destined for a subprocess should have the close-on-exec 5416 // flag set. If we don't set it, then careless 3rd party native code 5417 // might fork and exec without closing all appropriate file descriptors 5418 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5419 // turn might: 5420 // 5421 // - cause end-of-file to fail to be detected on some file 5422 // descriptors, resulting in mysterious hangs, or 5423 // 5424 // - might cause an fopen in the subprocess to fail on a system 5425 // suffering from bug 1085341. 5426 // 5427 // (Yes, the default setting of the close-on-exec flag is a Unix 5428 // design flaw) 5429 // 5430 // See: 5431 // 1085341: 32-bit stdio routines should support file descriptors >255 5432 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5433 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5434 // 5435 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5436 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5437 // because it saves a system call and removes a small window where the flag 5438 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5439 // and we fall back to using FD_CLOEXEC (see below). 5440 #ifdef O_CLOEXEC 5441 oflag |= O_CLOEXEC; 5442 #endif 5443 5444 int fd = ::open64(path, oflag, mode); 5445 if (fd == -1) return -1; 5446 5447 //If the open succeeded, the file might still be a directory 5448 { 5449 struct stat64 buf64; 5450 int ret = ::fstat64(fd, &buf64); 5451 int st_mode = buf64.st_mode; 5452 5453 if (ret != -1) { 5454 if ((st_mode & S_IFMT) == S_IFDIR) { 5455 errno = EISDIR; 5456 ::close(fd); 5457 return -1; 5458 } 5459 } else { 5460 ::close(fd); 5461 return -1; 5462 } 5463 } 5464 5465 #ifdef FD_CLOEXEC 5466 // Validate that the use of the O_CLOEXEC flag on open above worked. 5467 // With recent kernels, we will perform this check exactly once. 5468 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5469 if (!O_CLOEXEC_is_known_to_work) { 5470 int flags = ::fcntl(fd, F_GETFD); 5471 if (flags != -1) { 5472 if ((flags & FD_CLOEXEC) != 0) 5473 O_CLOEXEC_is_known_to_work = 1; 5474 else 5475 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5476 } 5477 } 5478 #endif 5479 5480 return fd; 5481 } 5482 5483 5484 // create binary file, rewriting existing file if required 5485 int os::create_binary_file(const char* path, bool rewrite_existing) { 5486 int oflags = O_WRONLY | O_CREAT; 5487 if (!rewrite_existing) { 5488 oflags |= O_EXCL; 5489 } 5490 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5491 } 5492 5493 // return current position of file pointer 5494 jlong os::current_file_offset(int fd) { 5495 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5496 } 5497 5498 // move file pointer to the specified offset 5499 jlong os::seek_to_file_offset(int fd, jlong offset) { 5500 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5501 } 5502 5503 // This code originates from JDK's sysAvailable 5504 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5505 5506 int os::available(int fd, jlong *bytes) { 5507 jlong cur, end; 5508 int mode; 5509 struct stat64 buf64; 5510 5511 if (::fstat64(fd, &buf64) >= 0) { 5512 mode = buf64.st_mode; 5513 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5514 int n; 5515 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5516 *bytes = n; 5517 return 1; 5518 } 5519 } 5520 } 5521 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5522 return 0; 5523 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5524 return 0; 5525 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5526 return 0; 5527 } 5528 *bytes = end - cur; 5529 return 1; 5530 } 5531 5532 // Map a block of memory. 5533 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5534 char *addr, size_t bytes, bool read_only, 5535 bool allow_exec) { 5536 int prot; 5537 int flags = MAP_PRIVATE; 5538 5539 if (read_only) { 5540 prot = PROT_READ; 5541 } else { 5542 prot = PROT_READ | PROT_WRITE; 5543 } 5544 5545 if (allow_exec) { 5546 prot |= PROT_EXEC; 5547 } 5548 5549 if (addr != NULL) { 5550 flags |= MAP_FIXED; 5551 } 5552 5553 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5554 fd, file_offset); 5555 if (mapped_address == MAP_FAILED) { 5556 return NULL; 5557 } 5558 return mapped_address; 5559 } 5560 5561 5562 // Remap a block of memory. 5563 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5564 char *addr, size_t bytes, bool read_only, 5565 bool allow_exec) { 5566 // same as map_memory() on this OS 5567 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5568 allow_exec); 5569 } 5570 5571 5572 // Unmap a block of memory. 5573 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5574 return munmap(addr, bytes) == 0; 5575 } 5576 5577 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5578 5579 static jlong fast_cpu_time(Thread *thread) { 5580 clockid_t clockid; 5581 int rc = os::Linux::pthread_getcpuclockid(thread->osthread()->pthread_id(), 5582 &clockid); 5583 if (rc == 0) { 5584 return os::Linux::fast_thread_cpu_time(clockid); 5585 } else { 5586 // It's possible to encounter a terminated native thread that failed 5587 // to detach itself from the VM - which should result in ESRCH. 5588 assert_status(rc == ESRCH, rc, "pthread_getcpuclockid failed"); 5589 return -1; 5590 } 5591 } 5592 5593 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5594 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5595 // of a thread. 5596 // 5597 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5598 // the fast estimate available on the platform. 5599 5600 jlong os::current_thread_cpu_time() { 5601 if (os::Linux::supports_fast_thread_cpu_time()) { 5602 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5603 } else { 5604 // return user + sys since the cost is the same 5605 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5606 } 5607 } 5608 5609 jlong os::thread_cpu_time(Thread* thread) { 5610 // consistent with what current_thread_cpu_time() returns 5611 if (os::Linux::supports_fast_thread_cpu_time()) { 5612 return fast_cpu_time(thread); 5613 } else { 5614 return slow_thread_cpu_time(thread, true /* user + sys */); 5615 } 5616 } 5617 5618 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5619 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5620 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5621 } else { 5622 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5623 } 5624 } 5625 5626 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5627 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5628 return fast_cpu_time(thread); 5629 } else { 5630 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5631 } 5632 } 5633 5634 // -1 on error. 5635 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5636 pid_t tid = thread->osthread()->thread_id(); 5637 char *s; 5638 char stat[2048]; 5639 int statlen; 5640 char proc_name[64]; 5641 int count; 5642 long sys_time, user_time; 5643 char cdummy; 5644 int idummy; 5645 long ldummy; 5646 FILE *fp; 5647 5648 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5649 fp = fopen(proc_name, "r"); 5650 if (fp == NULL) return -1; 5651 statlen = fread(stat, 1, 2047, fp); 5652 stat[statlen] = '\0'; 5653 fclose(fp); 5654 5655 // Skip pid and the command string. Note that we could be dealing with 5656 // weird command names, e.g. user could decide to rename java launcher 5657 // to "java 1.4.2 :)", then the stat file would look like 5658 // 1234 (java 1.4.2 :)) R ... ... 5659 // We don't really need to know the command string, just find the last 5660 // occurrence of ")" and then start parsing from there. See bug 4726580. 5661 s = strrchr(stat, ')'); 5662 if (s == NULL) return -1; 5663 5664 // Skip blank chars 5665 do { s++; } while (s && isspace(*s)); 5666 5667 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5668 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5669 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5670 &user_time, &sys_time); 5671 if (count != 13) return -1; 5672 if (user_sys_cpu_time) { 5673 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5674 } else { 5675 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5676 } 5677 } 5678 5679 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5680 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5681 info_ptr->may_skip_backward = false; // elapsed time not wall time 5682 info_ptr->may_skip_forward = false; // elapsed time not wall time 5683 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5684 } 5685 5686 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5687 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5688 info_ptr->may_skip_backward = false; // elapsed time not wall time 5689 info_ptr->may_skip_forward = false; // elapsed time not wall time 5690 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5691 } 5692 5693 bool os::is_thread_cpu_time_supported() { 5694 return true; 5695 } 5696 5697 // System loadavg support. Returns -1 if load average cannot be obtained. 5698 // Linux doesn't yet have a (official) notion of processor sets, 5699 // so just return the system wide load average. 5700 int os::loadavg(double loadavg[], int nelem) { 5701 return ::getloadavg(loadavg, nelem); 5702 } 5703 5704 void os::pause() { 5705 char filename[MAX_PATH]; 5706 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5707 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5708 } else { 5709 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5710 } 5711 5712 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5713 if (fd != -1) { 5714 struct stat buf; 5715 ::close(fd); 5716 while (::stat(filename, &buf) == 0) { 5717 (void)::poll(NULL, 0, 100); 5718 } 5719 } else { 5720 jio_fprintf(stderr, 5721 "Could not open pause file '%s', continuing immediately.\n", filename); 5722 } 5723 } 5724 5725 extern char** environ; 5726 5727 // Run the specified command in a separate process. Return its exit value, 5728 // or -1 on failure (e.g. can't fork a new process). 5729 // Unlike system(), this function can be called from signal handler. It 5730 // doesn't block SIGINT et al. 5731 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) { 5732 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5733 5734 pid_t pid ; 5735 5736 if (use_vfork_if_available) { 5737 pid = vfork(); 5738 } else { 5739 pid = fork(); 5740 } 5741 5742 if (pid < 0) { 5743 // fork failed 5744 return -1; 5745 5746 } else if (pid == 0) { 5747 // child process 5748 5749 execve("/bin/sh", (char* const*)argv, environ); 5750 5751 // execve failed 5752 _exit(-1); 5753 5754 } else { 5755 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5756 // care about the actual exit code, for now. 5757 5758 int status; 5759 5760 // Wait for the child process to exit. This returns immediately if 5761 // the child has already exited. */ 5762 while (waitpid(pid, &status, 0) < 0) { 5763 switch (errno) { 5764 case ECHILD: return 0; 5765 case EINTR: break; 5766 default: return -1; 5767 } 5768 } 5769 5770 if (WIFEXITED(status)) { 5771 // The child exited normally; get its exit code. 5772 return WEXITSTATUS(status); 5773 } else if (WIFSIGNALED(status)) { 5774 // The child exited because of a signal 5775 // The best value to return is 0x80 + signal number, 5776 // because that is what all Unix shells do, and because 5777 // it allows callers to distinguish between process exit and 5778 // process death by signal. 5779 return 0x80 + WTERMSIG(status); 5780 } else { 5781 // Unknown exit code; pass it through 5782 return status; 5783 } 5784 } 5785 } 5786 5787 // Get the default path to the core file 5788 // Returns the length of the string 5789 int os::get_core_path(char* buffer, size_t bufferSize) { 5790 /* 5791 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 5792 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 5793 */ 5794 const int core_pattern_len = 129; 5795 char core_pattern[core_pattern_len] = {0}; 5796 5797 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 5798 if (core_pattern_file == -1) { 5799 return -1; 5800 } 5801 5802 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 5803 ::close(core_pattern_file); 5804 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 5805 return -1; 5806 } 5807 if (core_pattern[ret-1] == '\n') { 5808 core_pattern[ret-1] = '\0'; 5809 } else { 5810 core_pattern[ret] = '\0'; 5811 } 5812 5813 // Replace the %p in the core pattern with the process id. NOTE: we do this 5814 // only if the pattern doesn't start with "|", and we support only one %p in 5815 // the pattern. 5816 char *pid_pos = strstr(core_pattern, "%p"); 5817 const char* tail = (pid_pos != NULL) ? (pid_pos + 2) : ""; // skip over the "%p" 5818 int written; 5819 5820 if (core_pattern[0] == '/') { 5821 if (pid_pos != NULL) { 5822 *pid_pos = '\0'; 5823 written = jio_snprintf(buffer, bufferSize, "%s%d%s", core_pattern, 5824 current_process_id(), tail); 5825 } else { 5826 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 5827 } 5828 } else { 5829 char cwd[PATH_MAX]; 5830 5831 const char* p = get_current_directory(cwd, PATH_MAX); 5832 if (p == NULL) { 5833 return -1; 5834 } 5835 5836 if (core_pattern[0] == '|') { 5837 written = jio_snprintf(buffer, bufferSize, 5838 "\"%s\" (or dumping to %s/core.%d)", 5839 &core_pattern[1], p, current_process_id()); 5840 } else if (pid_pos != NULL) { 5841 *pid_pos = '\0'; 5842 written = jio_snprintf(buffer, bufferSize, "%s/%s%d%s", p, core_pattern, 5843 current_process_id(), tail); 5844 } else { 5845 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 5846 } 5847 } 5848 5849 if (written < 0) { 5850 return -1; 5851 } 5852 5853 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 5854 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 5855 5856 if (core_uses_pid_file != -1) { 5857 char core_uses_pid = 0; 5858 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 5859 ::close(core_uses_pid_file); 5860 5861 if (core_uses_pid == '1') { 5862 jio_snprintf(buffer + written, bufferSize - written, 5863 ".%d", current_process_id()); 5864 } 5865 } 5866 } 5867 5868 return strlen(buffer); 5869 } 5870 5871 bool os::start_debugging(char *buf, int buflen) { 5872 int len = (int)strlen(buf); 5873 char *p = &buf[len]; 5874 5875 jio_snprintf(p, buflen-len, 5876 "\n\n" 5877 "Do you want to debug the problem?\n\n" 5878 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 5879 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 5880 "Otherwise, press RETURN to abort...", 5881 os::current_process_id(), os::current_process_id(), 5882 os::current_thread_id(), os::current_thread_id()); 5883 5884 bool yes = os::message_box("Unexpected Error", buf); 5885 5886 if (yes) { 5887 // yes, user asked VM to launch debugger 5888 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d", 5889 os::current_process_id(), os::current_process_id()); 5890 5891 os::fork_and_exec(buf); 5892 yes = false; 5893 } 5894 return yes; 5895 } 5896 5897 5898 // Java/Compiler thread: 5899 // 5900 // Low memory addresses 5901 // P0 +------------------------+ 5902 // | |\ Java thread created by VM does not have glibc 5903 // | glibc guard page | - guard page, attached Java thread usually has 5904 // | |/ 1 glibc guard page. 5905 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 5906 // | |\ 5907 // | HotSpot Guard Pages | - red, yellow and reserved pages 5908 // | |/ 5909 // +------------------------+ JavaThread::stack_reserved_zone_base() 5910 // | |\ 5911 // | Normal Stack | - 5912 // | |/ 5913 // P2 +------------------------+ Thread::stack_base() 5914 // 5915 // Non-Java thread: 5916 // 5917 // Low memory addresses 5918 // P0 +------------------------+ 5919 // | |\ 5920 // | glibc guard page | - usually 1 page 5921 // | |/ 5922 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 5923 // | |\ 5924 // | Normal Stack | - 5925 // | |/ 5926 // P2 +------------------------+ Thread::stack_base() 5927 // 5928 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size 5929 // returned from pthread_attr_getstack(). 5930 // ** Due to NPTL implementation error, linux takes the glibc guard page out 5931 // of the stack size given in pthread_attr. We work around this for 5932 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.) 5933 // 5934 #ifndef ZERO 5935 static void current_stack_region(address * bottom, size_t * size) { 5936 if (os::is_primordial_thread()) { 5937 // primordial thread needs special handling because pthread_getattr_np() 5938 // may return bogus value. 5939 *bottom = os::Linux::initial_thread_stack_bottom(); 5940 *size = os::Linux::initial_thread_stack_size(); 5941 } else { 5942 pthread_attr_t attr; 5943 5944 int rslt = pthread_getattr_np(pthread_self(), &attr); 5945 5946 // JVM needs to know exact stack location, abort if it fails 5947 if (rslt != 0) { 5948 if (rslt == ENOMEM) { 5949 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 5950 } else { 5951 fatal("pthread_getattr_np failed with error = %d", rslt); 5952 } 5953 } 5954 5955 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 5956 fatal("Cannot locate current stack attributes!"); 5957 } 5958 5959 // Work around NPTL stack guard error. 5960 size_t guard_size = 0; 5961 rslt = pthread_attr_getguardsize(&attr, &guard_size); 5962 if (rslt != 0) { 5963 fatal("pthread_attr_getguardsize failed with error = %d", rslt); 5964 } 5965 *bottom += guard_size; 5966 *size -= guard_size; 5967 5968 pthread_attr_destroy(&attr); 5969 5970 } 5971 assert(os::current_stack_pointer() >= *bottom && 5972 os::current_stack_pointer() < *bottom + *size, "just checking"); 5973 } 5974 5975 address os::current_stack_base() { 5976 address bottom; 5977 size_t size; 5978 current_stack_region(&bottom, &size); 5979 return (bottom + size); 5980 } 5981 5982 size_t os::current_stack_size() { 5983 // This stack size includes the usable stack and HotSpot guard pages 5984 // (for the threads that have Hotspot guard pages). 5985 address bottom; 5986 size_t size; 5987 current_stack_region(&bottom, &size); 5988 return size; 5989 } 5990 #endif 5991 5992 static inline struct timespec get_mtime(const char* filename) { 5993 struct stat st; 5994 int ret = os::stat(filename, &st); 5995 assert(ret == 0, "failed to stat() file '%s': %s", filename, os::strerror(errno)); 5996 return st.st_mtim; 5997 } 5998 5999 int os::compare_file_modified_times(const char* file1, const char* file2) { 6000 struct timespec filetime1 = get_mtime(file1); 6001 struct timespec filetime2 = get_mtime(file2); 6002 int diff = filetime1.tv_sec - filetime2.tv_sec; 6003 if (diff == 0) { 6004 return filetime1.tv_nsec - filetime2.tv_nsec; 6005 } 6006 return diff; 6007 } 6008 6009 /////////////// Unit tests /////////////// 6010 6011 #ifndef PRODUCT 6012 6013 class TestReserveMemorySpecial : AllStatic { 6014 public: 6015 static void small_page_write(void* addr, size_t size) { 6016 size_t page_size = os::vm_page_size(); 6017 6018 char* end = (char*)addr + size; 6019 for (char* p = (char*)addr; p < end; p += page_size) { 6020 *p = 1; 6021 } 6022 } 6023 6024 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6025 if (!UseHugeTLBFS) { 6026 return; 6027 } 6028 6029 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6030 6031 if (addr != NULL) { 6032 small_page_write(addr, size); 6033 6034 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6035 } 6036 } 6037 6038 static void test_reserve_memory_special_huge_tlbfs_only() { 6039 if (!UseHugeTLBFS) { 6040 return; 6041 } 6042 6043 size_t lp = os::large_page_size(); 6044 6045 for (size_t size = lp; size <= lp * 10; size += lp) { 6046 test_reserve_memory_special_huge_tlbfs_only(size); 6047 } 6048 } 6049 6050 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6051 size_t lp = os::large_page_size(); 6052 size_t ag = os::vm_allocation_granularity(); 6053 6054 // sizes to test 6055 const size_t sizes[] = { 6056 lp, lp + ag, lp + lp / 2, lp * 2, 6057 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6058 lp * 10, lp * 10 + lp / 2 6059 }; 6060 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6061 6062 // For each size/alignment combination, we test three scenarios: 6063 // 1) with req_addr == NULL 6064 // 2) with a non-null req_addr at which we expect to successfully allocate 6065 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6066 // expect the allocation to either fail or to ignore req_addr 6067 6068 // Pre-allocate two areas; they shall be as large as the largest allocation 6069 // and aligned to the largest alignment we will be testing. 6070 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6071 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6072 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6073 -1, 0); 6074 assert(mapping1 != MAP_FAILED, "should work"); 6075 6076 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6077 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6078 -1, 0); 6079 assert(mapping2 != MAP_FAILED, "should work"); 6080 6081 // Unmap the first mapping, but leave the second mapping intact: the first 6082 // mapping will serve as a value for a "good" req_addr (case 2). The second 6083 // mapping, still intact, as "bad" req_addr (case 3). 6084 ::munmap(mapping1, mapping_size); 6085 6086 // Case 1 6087 for (int i = 0; i < num_sizes; i++) { 6088 const size_t size = sizes[i]; 6089 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6090 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6091 if (p != NULL) { 6092 assert(is_aligned(p, alignment), "must be"); 6093 small_page_write(p, size); 6094 os::Linux::release_memory_special_huge_tlbfs(p, size); 6095 } 6096 } 6097 } 6098 6099 // Case 2 6100 for (int i = 0; i < num_sizes; i++) { 6101 const size_t size = sizes[i]; 6102 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6103 char* const req_addr = align_up(mapping1, alignment); 6104 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6105 if (p != NULL) { 6106 assert(p == req_addr, "must be"); 6107 small_page_write(p, size); 6108 os::Linux::release_memory_special_huge_tlbfs(p, size); 6109 } 6110 } 6111 } 6112 6113 // Case 3 6114 for (int i = 0; i < num_sizes; i++) { 6115 const size_t size = sizes[i]; 6116 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6117 char* const req_addr = align_up(mapping2, alignment); 6118 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6119 // as the area around req_addr contains already existing mappings, the API should always 6120 // return NULL (as per contract, it cannot return another address) 6121 assert(p == NULL, "must be"); 6122 } 6123 } 6124 6125 ::munmap(mapping2, mapping_size); 6126 6127 } 6128 6129 static void test_reserve_memory_special_huge_tlbfs() { 6130 if (!UseHugeTLBFS) { 6131 return; 6132 } 6133 6134 test_reserve_memory_special_huge_tlbfs_only(); 6135 test_reserve_memory_special_huge_tlbfs_mixed(); 6136 } 6137 6138 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6139 if (!UseSHM) { 6140 return; 6141 } 6142 6143 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6144 6145 if (addr != NULL) { 6146 assert(is_aligned(addr, alignment), "Check"); 6147 assert(is_aligned(addr, os::large_page_size()), "Check"); 6148 6149 small_page_write(addr, size); 6150 6151 os::Linux::release_memory_special_shm(addr, size); 6152 } 6153 } 6154 6155 static void test_reserve_memory_special_shm() { 6156 size_t lp = os::large_page_size(); 6157 size_t ag = os::vm_allocation_granularity(); 6158 6159 for (size_t size = ag; size < lp * 3; size += ag) { 6160 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6161 test_reserve_memory_special_shm(size, alignment); 6162 } 6163 } 6164 } 6165 6166 static void test() { 6167 test_reserve_memory_special_huge_tlbfs(); 6168 test_reserve_memory_special_shm(); 6169 } 6170 }; 6171 6172 void TestReserveMemorySpecial_test() { 6173 TestReserveMemorySpecial::test(); 6174 } 6175 6176 #endif