JDK14/Java14源码在线阅读
/*
* Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
// no precompiled headers
#include "jvm.h"
#include "classfile/classLoader.hpp"
#include "classfile/systemDictionary.hpp"
#include "classfile/vmSymbols.hpp"
#include "code/icBuffer.hpp"
#include "code/vtableStubs.hpp"
#include "compiler/compileBroker.hpp"
#include "compiler/disassembler.hpp"
#include "interpreter/interpreter.hpp"
#include "logging/log.hpp"
#include "logging/logStream.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/filemap.hpp"
#include "oops/oop.inline.hpp"
#include "os_linux.inline.hpp"
#include "os_posix.inline.hpp"
#include "os_share_linux.hpp"
#include "osContainer_linux.hpp"
#include "prims/jniFastGetField.hpp"
#include "prims/jvm_misc.hpp"
#include "runtime/arguments.hpp"
#include "runtime/atomic.hpp"
#include "runtime/extendedPC.hpp"
#include "runtime/globals.hpp"
#include "runtime/interfaceSupport.inline.hpp"
#include "runtime/init.hpp"
#include "runtime/java.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/objectMonitor.hpp"
#include "runtime/osThread.hpp"
#include "runtime/perfMemory.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/statSampler.hpp"
#include "runtime/stubRoutines.hpp"
#include "runtime/thread.inline.hpp"
#include "runtime/threadCritical.hpp"
#include "runtime/threadSMR.hpp"
#include "runtime/timer.hpp"
#include "runtime/vm_version.hpp"
#include "semaphore_posix.hpp"
#include "services/attachListener.hpp"
#include "services/memTracker.hpp"
#include "services/runtimeService.hpp"
#include "utilities/align.hpp"
#include "utilities/decoder.hpp"
#include "utilities/defaultStream.hpp"
#include "utilities/events.hpp"
#include "utilities/elfFile.hpp"
#include "utilities/growableArray.hpp"
#include "utilities/macros.hpp"
#include "utilities/vmError.hpp"
// put OS-includes here
# include <sys/types.h>
# include <sys/mman.h>
# include <sys/stat.h>
# include <sys/select.h>
# include <pthread.h>
# include <signal.h>
# include <endian.h>
# include <errno.h>
# include <dlfcn.h>
# include <stdio.h>
# include <unistd.h>
# include <sys/resource.h>
# include <pthread.h>
# include <sys/stat.h>
# include <sys/time.h>
# include <sys/times.h>
# include <sys/utsname.h>
# include <sys/socket.h>
# include <sys/wait.h>
# include <pwd.h>
# include <poll.h>
# include <fcntl.h>
# include <string.h>
# include <syscall.h>
# include <sys/sysinfo.h>
# include <gnu/libc-version.h>
# include <sys/ipc.h>
# include <sys/shm.h>
# include <link.h>
# include <stdint.h>
# include <inttypes.h>
# include <sys/ioctl.h>
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#include <sched.h>
#undef _GNU_SOURCE
#else
#include <sched.h>
#endif
// if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
// getrusage() is prepared to handle the associated failure.
#ifndef RUSAGE_THREAD
#define RUSAGE_THREAD (1) /* only the calling thread */
#endif
#define MAX_PATH (2 * K)
#define MAX_SECS 100000000
// for timer info max values which include all bits
#define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
enum CoredumpFilterBit {
FILE_BACKED_PVT_BIT = 1 << 2,
FILE_BACKED_SHARED_BIT = 1 << 3,
LARGEPAGES_BIT = 1 << 6,
DAX_SHARED_BIT = 1 << 8
};
////////////////////////////////////////////////////////////////////////////////
// global variables
julong os::Linux::_physical_memory = 0;
address os::Linux::_initial_thread_stack_bottom = NULL;
uintptr_t os::Linux::_initial_thread_stack_size = 0;
int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
pthread_t os::Linux::_main_thread;
int os::Linux::_page_size = -1;
bool os::Linux::_supports_fast_thread_cpu_time = false;
const char * os::Linux::_glibc_version = NULL;
const char * os::Linux::_libpthread_version = NULL;
static jlong initial_time_count=0;
static int clock_tics_per_sec = 100;
// If the VM might have been created on the primordial thread, we need to resolve the
// primordial thread stack bounds and check if the current thread might be the
// primordial thread in places. If we know that the primordial thread is never used,
// such as when the VM was created by one of the standard java launchers, we can
// avoid this
static bool suppress_primordial_thread_resolution = false;
// For diagnostics to print a message once. see run_periodic_checks
static sigset_t check_signal_done;
static bool check_signals = true;
// Signal number used to suspend/resume a thread
// do not use any signal number less than SIGSEGV, see 4355769
static int SR_signum = SIGUSR2;
sigset_t SR_sigset;
// utility functions
static int SR_initialize();
julong os::available_memory() {
return Linux::available_memory();
}
julong os::Linux::available_memory() {
// values in struct sysinfo are "unsigned long"
struct sysinfo si;
julong avail_mem;
if (OSContainer::is_containerized()) {
jlong mem_limit, mem_usage;
if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) {
log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
}
if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) {
log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage);
}
if (mem_limit > 0 && mem_usage > 0 ) {
avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0;
log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem);
return avail_mem;
}
}
sysinfo(&si);
avail_mem = (julong)si.freeram * si.mem_unit;
log_trace(os)("available memory: " JULONG_FORMAT, avail_mem);
return avail_mem;
}
julong os::physical_memory() {
jlong phys_mem = 0;
if (OSContainer::is_containerized()) {
jlong mem_limit;
if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) {
log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit);
return mem_limit;
}
log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
}
phys_mem = Linux::physical_memory();
log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem);
return phys_mem;
}
static uint64_t initial_total_ticks = 0;
static uint64_t initial_steal_ticks = 0;
static bool has_initial_tick_info = false;
static void next_line(FILE *f) {
int c;
do {
c = fgetc(f);
} while (c != '\n' && c != EOF);
}
bool os::Linux::get_tick_information(CPUPerfTicks* pticks, int which_logical_cpu) {
FILE* fh;
uint64_t userTicks, niceTicks, systemTicks, idleTicks;
// since at least kernel 2.6 : iowait: time waiting for I/O to complete
// irq: time servicing interrupts; softirq: time servicing softirqs
uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0;
// steal (since kernel 2.6.11): time spent in other OS when running in a virtualized environment
uint64_t stealTicks = 0;
// guest (since kernel 2.6.24): time spent running a virtual CPU for guest OS under the
// control of the Linux kernel
uint64_t guestNiceTicks = 0;
int logical_cpu = -1;
const int required_tickinfo_count = (which_logical_cpu == -1) ? 4 : 5;
int n;
memset(pticks, 0, sizeof(CPUPerfTicks));
if ((fh = fopen("/proc/stat", "r")) == NULL) {
return false;
}
if (which_logical_cpu == -1) {
n = fscanf(fh, "cpu " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
UINT64_FORMAT " " UINT64_FORMAT " ",
&userTicks, &niceTicks, &systemTicks, &idleTicks,
&iowTicks, &irqTicks, &sirqTicks,
&stealTicks, &guestNiceTicks);
} else {
// Move to next line
next_line(fh);
// find the line for requested cpu faster to just iterate linefeeds?
for (int i = 0; i < which_logical_cpu; i++) {
next_line(fh);
}
n = fscanf(fh, "cpu%u " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
UINT64_FORMAT " " UINT64_FORMAT " ",
&logical_cpu, &userTicks, &niceTicks,
&systemTicks, &idleTicks, &iowTicks, &irqTicks, &sirqTicks,
&stealTicks, &guestNiceTicks);
}
fclose(fh);
if (n < required_tickinfo_count || logical_cpu != which_logical_cpu) {
return false;
}
pticks->used = userTicks + niceTicks;
pticks->usedKernel = systemTicks + irqTicks + sirqTicks;
pticks->total = userTicks + niceTicks + systemTicks + idleTicks +
iowTicks + irqTicks + sirqTicks + stealTicks + guestNiceTicks;
if (n > required_tickinfo_count + 3) {
pticks->steal = stealTicks;
pticks->has_steal_ticks = true;
} else {
pticks->steal = 0;
pticks->has_steal_ticks = false;
}
return true;
}
// Return true if user is running as root.
bool os::have_special_privileges() {
static bool init = false;
static bool privileges = false;
if (!init) {
privileges = (getuid() != geteuid()) || (getgid() != getegid());
init = true;
}
return privileges;
}
#ifndef SYS_gettid
// i386: 224, ia64: 1105, amd64: 186, sparc 143
#ifdef __ia64__
#define SYS_gettid 1105
#else
#ifdef __i386__
#define SYS_gettid 224
#else
#ifdef __amd64__
#define SYS_gettid 186
#else
#ifdef __sparc__
#define SYS_gettid 143
#else
#error define gettid for the arch
#endif
#endif
#endif
#endif
#endif
// pid_t gettid()
//
// Returns the kernel thread id of the currently running thread. Kernel
// thread id is used to access /proc.
pid_t os::Linux::gettid() {
int rslt = syscall(SYS_gettid);
assert(rslt != -1, "must be."); // old linuxthreads implementation?
return (pid_t)rslt;
}
// Most versions of linux have a bug where the number of processors are
// determined by looking at the /proc file system. In a chroot environment,
// the system call returns 1.
static bool unsafe_chroot_detected = false;
static const char *unstable_chroot_error = "/proc file system not found.\n"
"Java may be unstable running multithreaded in a chroot "
"environment on Linux when /proc filesystem is not mounted.";
void os::Linux::initialize_system_info() {
set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
if (processor_count() == 1) {
pid_t pid = os::Linux::gettid();
char fname[32];
jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
FILE *fp = fopen(fname, "r");
if (fp == NULL) {
unsafe_chroot_detected = true;
} else {
fclose(fp);
}
}
_physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
assert(processor_count() > 0, "linux error");
}
void os::init_system_properties_values() {
// The next steps are taken in the product version:
//
// Obtain the JAVA_HOME value from the location of libjvm.so.
// This library should be located at:
// <JAVA_HOME>/lib/{client|server}/libjvm.so.
//
// If "/jre/lib/" appears at the right place in the path, then we
// assume libjvm.so is installed in a JDK and we use this path.
//
// Otherwise exit with message: "Could not create the Java virtual machine."
//
// The following extra steps are taken in the debugging version:
//
// If "/jre/lib/" does NOT appear at the right place in the path
// instead of exit check for $JAVA_HOME environment variable.
//
// If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
// then we append a fake suffix "hotspot/libjvm.so" to this path so
// it looks like libjvm.so is installed there
// <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
//
// Otherwise exit.
//
// Important note: if the location of libjvm.so changes this
// code needs to be changed accordingly.
// See ld(1):
// The linker uses the following search paths to locate required
// shared libraries:
// 1: ...
// ...
// 7: The default directories, normally /lib and /usr/lib.
#ifndef OVERRIDE_LIBPATH
#if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390)
#define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
#else
#define DEFAULT_LIBPATH "/lib:/usr/lib"
#endif
#else
#define DEFAULT_LIBPATH OVERRIDE_LIBPATH
#endif
// Base path of extensions installed on the system.
#define SYS_EXT_DIR "/usr/java/packages"
#define EXTENSIONS_DIR "/lib/ext"
// Buffer that fits several sprintfs.
// Note that the space for the colon and the trailing null are provided
// by the nulls included by the sizeof operator.
const size_t bufsize =
MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
(size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
char *buf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
// sysclasspath, java_home, dll_dir
{
char *pslash;
os::jvm_path(buf, bufsize);
// Found the full path to libjvm.so.
// Now cut the path to <java_home>/jre if we can.
pslash = strrchr(buf, '/');
if (pslash != NULL) {
*pslash = '\0'; // Get rid of /libjvm.so.
}
pslash = strrchr(buf, '/');
if (pslash != NULL) {
*pslash = '\0'; // Get rid of /{client|server|hotspot}.
}
Arguments::set_dll_dir(buf);
if (pslash != NULL) {
pslash = strrchr(buf, '/');
if (pslash != NULL) {
*pslash = '\0'; // Get rid of /lib.
}
}
Arguments::set_java_home(buf);
if (!set_boot_path('/', ':')) {
vm_exit_during_initialization("Failed setting boot class path.", NULL);
}
}
// Where to look for native libraries.
//
// Note: Due to a legacy implementation, most of the library path
// is set in the launcher. This was to accomodate linking restrictions
// on legacy Linux implementations (which are no longer supported).
// Eventually, all the library path setting will be done here.
//
// However, to prevent the proliferation of improperly built native
// libraries, the new path component /usr/java/packages is added here.
// Eventually, all the library path setting will be done here.
{
// Get the user setting of LD_LIBRARY_PATH, and prepended it. It
// should always exist (until the legacy problem cited above is
// addressed).
const char *v = ::getenv("LD_LIBRARY_PATH");
const char *v_colon = ":";
if (v == NULL) { v = ""; v_colon = ""; }
// That's +1 for the colon and +1 for the trailing '\0'.
char *ld_library_path = NEW_C_HEAP_ARRAY(char,
strlen(v) + 1 +
sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1,
mtInternal);
sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon);
Arguments::set_library_path(ld_library_path);
FREE_C_HEAP_ARRAY(char, ld_library_path);
}
// Extensions directories.
sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
Arguments::set_ext_dirs(buf);
FREE_C_HEAP_ARRAY(char, buf);
#undef DEFAULT_LIBPATH
#undef SYS_EXT_DIR
#undef EXTENSIONS_DIR
}
////////////////////////////////////////////////////////////////////////////////
// breakpoint support
void os::breakpoint() {
BREAKPOINT;
}
extern "C" void breakpoint() {
// use debugger to set breakpoint here
}
////////////////////////////////////////////////////////////////////////////////
// signal support
debug_only(static bool signal_sets_initialized = false);
static sigset_t unblocked_sigs, vm_sigs;
void os::Linux::signal_sets_init() {
// Should also have an assertion stating we are still single-threaded.
assert(!signal_sets_initialized, "Already initialized");
// Fill in signals that are necessarily unblocked for all threads in
// the VM. Currently, we unblock the following signals:
// SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
// by -Xrs (=ReduceSignalUsage));
// BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
// other threads. The "ReduceSignalUsage" boolean tells us not to alter
// the dispositions or masks wrt these signals.
// Programs embedding the VM that want to use the above signals for their
// own purposes must, at this time, use the "-Xrs" option to prevent
// interference with shutdown hooks and BREAK_SIGNAL thread dumping.
// (See bug 4345157, and other related bugs).
// In reality, though, unblocking these signals is really a nop, since
// these signals are not blocked by default.
sigemptyset(&unblocked_sigs);
sigaddset(&unblocked_sigs, SIGILL);
sigaddset(&unblocked_sigs, SIGSEGV);
sigaddset(&unblocked_sigs, SIGBUS);
sigaddset(&unblocked_sigs, SIGFPE);
#if defined(PPC64)
sigaddset(&unblocked_sigs, SIGTRAP);
#endif
sigaddset(&unblocked_sigs, SR_signum);
if (!ReduceSignalUsage) {
if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
}
if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
}
if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
}
}
// Fill in signals that are blocked by all but the VM thread.
sigemptyset(&vm_sigs);
if (!ReduceSignalUsage) {
sigaddset(&vm_sigs, BREAK_SIGNAL);
}
debug_only(signal_sets_initialized = true);
}
// These are signals that are unblocked while a thread is running Java.
// (For some reason, they get blocked by default.)
sigset_t* os::Linux::unblocked_signals() {
assert(signal_sets_initialized, "Not initialized");
return &unblocked_sigs;
}
// These are the signals that are blocked while a (non-VM) thread is
// running Java. Only the VM thread handles these signals.
sigset_t* os::Linux::vm_signals() {
assert(signal_sets_initialized, "Not initialized");
return &vm_sigs;
}
void os::Linux::hotspot_sigmask(Thread* thread) {
//Save caller's signal mask before setting VM signal mask
sigset_t caller_sigmask;
pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
OSThread* osthread = thread->osthread();
osthread->set_caller_sigmask(caller_sigmask);
pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
if (!ReduceSignalUsage) {
if (thread->is_VM_thread()) {
// Only the VM thread handles BREAK_SIGNAL ...
pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
} else {
// ... all other threads block BREAK_SIGNAL
pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
}
}
}
//////////////////////////////////////////////////////////////////////////////
// detecting pthread library
void os::Linux::libpthread_init() {
// Save glibc and pthread version strings.
#if !defined(_CS_GNU_LIBC_VERSION) || \
!defined(_CS_GNU_LIBPTHREAD_VERSION)
#error "glibc too old (< 2.3.2)"
#endif
size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
assert(n > 0, "cannot retrieve glibc version");
char *str = (char *)malloc(n, mtInternal);
confstr(_CS_GNU_LIBC_VERSION, str, n);
os::Linux::set_glibc_version(str);
n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
assert(n > 0, "cannot retrieve pthread version");
str = (char *)malloc(n, mtInternal);
confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
os::Linux::set_libpthread_version(str);
}
/////////////////////////////////////////////////////////////////////////////
// thread stack expansion
// os::Linux::manually_expand_stack() takes care of expanding the thread
// stack. Note that this is normally not needed: pthread stacks allocate
// thread stack using mmap() without MAP_NORESERVE, so the stack is already
// committed. Therefore it is not necessary to expand the stack manually.
//
// Manually expanding the stack was historically needed on LinuxThreads
// thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
// it is kept to deal with very rare corner cases:
//
// For one, user may run the VM on an own implementation of threads
// whose stacks are - like the old LinuxThreads - implemented using
// mmap(MAP_GROWSDOWN).
//
// Also, this coding may be needed if the VM is running on the primordial
// thread. Normally we avoid running on the primordial thread; however,
// user may still invoke the VM on the primordial thread.
//
// The following historical comment describes the details about running
// on a thread stack allocated with mmap(MAP_GROWSDOWN):
// Force Linux kernel to expand current thread stack. If "bottom" is close
// to the stack guard, caller should block all signals.
//
// MAP_GROWSDOWN:
// A special mmap() flag that is used to implement thread stacks. It tells
// kernel that the memory region should extend downwards when needed. This
// allows early versions of LinuxThreads to only mmap the first few pages
// when creating a new thread. Linux kernel will automatically expand thread
// stack as needed (on page faults).
//
// However, because the memory region of a MAP_GROWSDOWN stack can grow on
// demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
// region, it's hard to tell if the fault is due to a legitimate stack
// access or because of reading/writing non-exist memory (e.g. buffer
// overrun). As a rule, if the fault happens below current stack pointer,
// Linux kernel does not expand stack, instead a SIGSEGV is sent to the
// application (see Linux kernel fault.c).
//
// This Linux feature can cause SIGSEGV when VM bangs thread stack for
// stack overflow detection.
//
// Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
// not use MAP_GROWSDOWN.
//
// To get around the problem and allow stack banging on Linux, we need to
// manually expand thread stack after receiving the SIGSEGV.
//
// There are two ways to expand thread stack to address "bottom", we used
// both of them in JVM before 1.5:
// 1. adjust stack pointer first so that it is below "bottom", and then
// touch "bottom"
// 2. mmap() the page in question
//
// Now alternate signal stack is gone, it's harder to use 2. For instance,
// if current sp is already near the lower end of page 101, and we need to
// call mmap() to map page 100, it is possible that part of the mmap() frame
// will be placed in page 100. When page 100 is mapped, it is zero-filled.
// That will destroy the mmap() frame and cause VM to crash.
//
// The following code works by adjusting sp first, then accessing the "bottom"
// page to force a page fault. Linux kernel will then automatically expand the
// stack mapping.
//
// _expand_stack_to() assumes its frame size is less than page size, which
// should always be true if the function is not inlined.
static void NOINLINE _expand_stack_to(address bottom) {
address sp;
size_t size;
volatile char *p;
// Adjust bottom to point to the largest address within the same page, it
// gives us a one-page buffer if alloca() allocates slightly more memory.
bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size());
bottom += os::Linux::page_size() - 1;
// sp might be slightly above current stack pointer; if that's the case, we
// will alloca() a little more space than necessary, which is OK. Don't use
// os::current_stack_pointer(), as its result can be slightly below current
// stack pointer, causing us to not alloca enough to reach "bottom".
sp = (address)&sp;
if (sp > bottom) {
size = sp - bottom;
p = (volatile char *)alloca(size);
assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
p[0] = '\0';
}
}
void os::Linux::expand_stack_to(address bottom) {
_expand_stack_to(bottom);
}
bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
assert(t!=NULL, "just checking");
assert(t->osthread()->expanding_stack(), "expand should be set");
assert(t->stack_base() != NULL, "stack_base was not initialized");
if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) {
sigset_t mask_all, old_sigset;
sigfillset(&mask_all);
pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
_expand_stack_to(addr);
pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
return true;
}
return false;
}
//////////////////////////////////////////////////////////////////////////////
// create new thread
// Thread start routine for all newly created threads
static void *thread_native_entry(Thread *thread) {
thread->record_stack_base_and_size();
// Try to randomize the cache line index of hot stack frames.
// This helps when threads of the same stack traces evict each other's
// cache lines. The threads can be either from the same JVM instance, or
// from different JVM instances. The benefit is especially true for
// processors with hyperthreading technology.
static int counter = 0;
int pid = os::current_process_id();
alloca(((pid ^ counter++) & 7) * 128);
thread->initialize_thread_current();
OSThread* osthread = thread->osthread();
Monitor* sync = osthread->startThread_lock();
osthread->set_thread_id(os::current_thread_id());
log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
os::current_thread_id(), (uintx) pthread_self());
if (UseNUMA) {
int lgrp_id = os::numa_get_group_id();
if (lgrp_id != -1) {
thread->set_lgrp_id(lgrp_id);
}
}
// initialize signal mask for this thread
os::Linux::hotspot_sigmask(thread);
// initialize floating point control register
os::Linux::init_thread_fpu_state();
// handshaking with parent thread
{
MutexLocker ml(sync, Mutex::_no_safepoint_check_flag);
// notify parent thread
osthread->set_state(INITIALIZED);
sync->notify_all();
// wait until os::start_thread()
while (osthread->get_state() == INITIALIZED) {
sync->wait_without_safepoint_check();
}
}
assert(osthread->pthread_id() != 0, "pthread_id was not set as expected");
// call one more level start routine
thread->call_run();
// Note: at this point the thread object may already have deleted itself.
// Prevent dereferencing it from here on out.
thread = NULL;
log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
os::current_thread_id(), (uintx) pthread_self());
return 0;
}
// On Linux, glibc places static TLS blocks (for __thread variables) on
// the thread stack. This decreases the stack size actually available
// to threads.
//
// For large static TLS sizes, this may cause threads to malfunction due
// to insufficient stack space. This is a well-known issue in glibc:
// http://sourceware.org/bugzilla/show_bug.cgi?id=11787.
//
// As a workaround, we call a private but assumed-stable glibc function,
// __pthread_get_minstack() to obtain the minstack size and derive the
// static TLS size from it. We then increase the user requested stack
// size by this TLS size.
//
// Due to compatibility concerns, this size adjustment is opt-in and
// controlled via AdjustStackSizeForTLS.
typedef size_t (*GetMinStack)(const pthread_attr_t *attr);
GetMinStack _get_minstack_func = NULL;
static void get_minstack_init() {
_get_minstack_func =
(GetMinStack)dlsym(RTLD_DEFAULT, "__pthread_get_minstack");
log_info(os, thread)("Lookup of __pthread_get_minstack %s",
_get_minstack_func == NULL ? "failed" : "succeeded");
}
// Returns the size of the static TLS area glibc puts on thread stacks.
// The value is cached on first use, which occurs when the first thread
// is created during VM initialization.
static size_t get_static_tls_area_size(const pthread_attr_t *attr) {
size_t tls_size = 0;
if (_get_minstack_func != NULL) {
// Obtain the pthread minstack size by calling __pthread_get_minstack.
size_t minstack_size = _get_minstack_func(attr);
// Remove non-TLS area size included in minstack size returned
// by __pthread_get_minstack() to get the static TLS size.
// In glibc before 2.27, minstack size includes guard_size.
// In glibc 2.27 and later, guard_size is automatically added
// to the stack size by pthread_create and is no longer included
// in minstack size. In both cases, the guard_size is taken into
// account, so there is no need to adjust the result for that.
//
// Although __pthread_get_minstack() is a private glibc function,
// it is expected to have a stable behavior across future glibc
// versions while glibc still allocates the static TLS blocks off
// the stack. Following is glibc 2.28 __pthread_get_minstack():
//
// size_t
// __pthread_get_minstack (const pthread_attr_t *attr)
// {
// return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN;
// }
//
//
// The following 'minstack_size > os::vm_page_size() + PTHREAD_STACK_MIN'
// if check is done for precaution.
if (minstack_size > (size_t)os::vm_page_size() + PTHREAD_STACK_MIN) {
tls_size = minstack_size - os::vm_page_size() - PTHREAD_STACK_MIN;
}
}
log_info(os, thread)("Stack size adjustment for TLS is " SIZE_FORMAT,
tls_size);
return tls_size;
}
bool os::create_thread(Thread* thread, ThreadType thr_type,
size_t req_stack_size) {
assert(thread->osthread() == NULL, "caller responsible");
// Allocate the OSThread object
OSThread* osthread = new OSThread(NULL, NULL);
if (osthread == NULL) {
return false;
}
// set the correct thread state
osthread->set_thread_type(thr_type);
// Initial state is ALLOCATED but not INITIALIZED
osthread->set_state(ALLOCATED);
thread->set_osthread(osthread);
// init thread attributes
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
// Calculate stack size if it's not specified by caller.
size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
// In glibc versions prior to 2.7 the guard size mechanism
// is not implemented properly. The posix standard requires adding
// the size of the guard pages to the stack size, instead Linux
// takes the space out of 'stacksize'. Thus we adapt the requested
// stack_size by the size of the guard pages to mimick proper
// behaviour. However, be careful not to end up with a size
// of zero due to overflow. Don't add the guard page in that case.
size_t guard_size = os::Linux::default_guard_size(thr_type);
// Configure glibc guard page. Must happen before calling
// get_static_tls_area_size(), which uses the guard_size.
pthread_attr_setguardsize(&attr, guard_size);
size_t stack_adjust_size = 0;
if (AdjustStackSizeForTLS) {
// Adjust the stack_size for on-stack TLS - see get_static_tls_area_size().
stack_adjust_size += get_static_tls_area_size(&attr);
} else {
stack_adjust_size += guard_size;
}
stack_adjust_size = align_up(stack_adjust_size, os::vm_page_size());
if (stack_size <= SIZE_MAX - stack_adjust_size) {
stack_size += stack_adjust_size;
}
assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned");
int status = pthread_attr_setstacksize(&attr, stack_size);
assert_status(status == 0, status, "pthread_attr_setstacksize");
ThreadState state;
{
pthread_t tid;
int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
char buf[64];
if (ret == 0) {
log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
(uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
} else {
log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.",
os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
// Log some OS information which might explain why creating the thread failed.
log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads());
LogStream st(Log(os, thread)::info());
os::Posix::print_rlimit_info(&st);
os::print_memory_info(&st);
os::Linux::print_proc_sys_info(&st);
os::Linux::print_container_info(&st);
}
pthread_attr_destroy(&attr);
if (ret != 0) {
// Need to clean up stuff we've allocated so far
thread->set_osthread(NULL);
delete osthread;
return false;
}
// Store pthread info into the OSThread
osthread->set_pthread_id(tid);
// Wait until child thread is either initialized or aborted
{
Monitor* sync_with_child = osthread->startThread_lock();
MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
while ((state = osthread->get_state()) == ALLOCATED) {
sync_with_child->wait_without_safepoint_check();
}
}
}
// Aborted due to thread limit being reached
if (state == ZOMBIE) {
thread->set_osthread(NULL);
delete osthread;
return false;
}
// The thread is returned suspended (in state INITIALIZED),
// and is started higher up in the call chain
assert(state == INITIALIZED, "race condition");
return true;
}
/////////////////////////////////////////////////////////////////////////////
// attach existing thread
// bootstrap the main thread
bool os::create_main_thread(JavaThread* thread) {
assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
return create_attached_thread(thread);
}
bool os::create_attached_thread(JavaThread* thread) {
#ifdef ASSERT
thread->verify_not_published();
#endif
// Allocate the OSThread object
OSThread* osthread = new OSThread(NULL, NULL);
if (osthread == NULL) {
return false;
}
// Store pthread info into the OSThread
osthread->set_thread_id(os::Linux::gettid());
osthread->set_pthread_id(::pthread_self());
// initialize floating point control register
os::Linux::init_thread_fpu_state();
// Initial thread state is RUNNABLE
osthread->set_state(RUNNABLE);
thread->set_osthread(osthread);
if (UseNUMA) {
int lgrp_id = os::numa_get_group_id();
if (lgrp_id != -1) {
thread->set_lgrp_id(lgrp_id);
}
}
if (os::is_primordial_thread()) {
// If current thread is primordial thread, its stack is mapped on demand,
// see notes about MAP_GROWSDOWN. Here we try to force kernel to map
// the entire stack region to avoid SEGV in stack banging.
// It is also useful to get around the heap-stack-gap problem on SuSE
// kernel (see 4821821 for details). We first expand stack to the top
// of yellow zone, then enable stack yellow zone (order is significant,
// enabling yellow zone first will crash JVM on SuSE Linux), so there
// is no gap between the last two virtual memory regions.
JavaThread *jt = (JavaThread *)thread;
address addr = jt->stack_reserved_zone_base();
assert(addr != NULL, "initialization problem?");
assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
osthread->set_expanding_stack();
os::Linux::manually_expand_stack(jt, addr);
osthread->clear_expanding_stack();
}
// initialize signal mask for this thread
// and save the caller's signal mask
os::Linux::hotspot_sigmask(thread);
log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
os::current_thread_id(), (uintx) pthread_self());
return true;
}
void os::pd_start_thread(Thread* thread) {
OSThread * osthread = thread->osthread();
assert(osthread->get_state() != INITIALIZED, "just checking");
Monitor* sync_with_child = osthread->startThread_lock();
MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
sync_with_child->notify();
}
// Free Linux resources related to the OSThread
void os::free_thread(OSThread* osthread) {
assert(osthread != NULL, "osthread not set");
// We are told to free resources of the argument thread,
// but we can only really operate on the current thread.
assert(Thread::current()->osthread() == osthread,
"os::free_thread but not current thread");
#ifdef ASSERT
sigset_t current;
sigemptyset(¤t);
pthread_sigmask(SIG_SETMASK, NULL, ¤t);
assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!");
#endif
// Restore caller's signal mask
sigset_t sigmask = osthread->caller_sigmask();
pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
delete osthread;
}
//////////////////////////////////////////////////////////////////////////////
// primordial thread
// Check if current thread is the primordial thread, similar to Solaris thr_main.
bool os::is_primordial_thread(void) {
if (suppress_primordial_thread_resolution) {
return false;
}
char dummy;
// If called before init complete, thread stack bottom will be null.
// Can be called if fatal error occurs before initialization.
if (os::Linux::initial_thread_stack_bottom() == NULL) return false;
assert(os::Linux::initial_thread_stack_bottom() != NULL &&
os::Linux::initial_thread_stack_size() != 0,
"os::init did not locate primordial thread's stack region");
if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() &&
(address)&dummy < os::Linux::initial_thread_stack_bottom() +
os::Linux::initial_thread_stack_size()) {
return true;
} else {
return false;
}
}
// Find the virtual memory area that contains addr
static bool find_vma(address addr, address* vma_low, address* vma_high) {
FILE *fp = fopen("/proc/self/maps", "r");
if (fp) {
address low, high;
while (!feof(fp)) {
if (fscanf(fp, "%p-%p", &low, &high) == 2) {
if (low <= addr && addr < high) {
if (vma_low) *vma_low = low;
if (vma_high) *vma_high = high;
fclose(fp);
return true;
}
}
for (;;) {
int ch = fgetc(fp);
if (ch == EOF || ch == (int)'\n') break;
}
}
fclose(fp);
}
return false;
}
// Locate primordial thread stack. This special handling of primordial thread stack
// is needed because pthread_getattr_np() on most (all?) Linux distros returns
// bogus value for the primordial process thread. While the launcher has created
// the VM in a new thread since JDK 6, we still have to allow for the use of the
// JNI invocation API from a primordial thread.
void os::Linux::capture_initial_stack(size_t max_size) {
// max_size is either 0 (which means accept OS default for thread stacks) or
// a user-specified value known to be at least the minimum needed. If we
// are actually on the primordial thread we can make it appear that we have a
// smaller max_size stack by inserting the guard pages at that location. But we
// cannot do anything to emulate a larger stack than what has been provided by
// the OS or threading library. In fact if we try to use a stack greater than
// what is set by rlimit then we will crash the hosting process.
// Maximum stack size is the easy part, get it from RLIMIT_STACK.
// If this is "unlimited" then it will be a huge value.
struct rlimit rlim;
getrlimit(RLIMIT_STACK, &rlim);
size_t stack_size = rlim.rlim_cur;
// 6308388: a bug in ld.so will relocate its own .data section to the
// lower end of primordial stack; reduce ulimit -s value a little bit
// so we won't install guard page on ld.so's data section.
// But ensure we don't underflow the stack size - allow 1 page spare
if (stack_size >= (size_t)(3 * page_size())) {
stack_size -= 2 * page_size();
}
// Try to figure out where the stack base (top) is. This is harder.
//
// When an application is started, glibc saves the initial stack pointer in
// a global variable "__libc_stack_end", which is then used by system
// libraries. __libc_stack_end should be pretty close to stack top. The
// variable is available since the very early days. However, because it is
// a private interface, it could disappear in the future.
//
// Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
// to __libc_stack_end, it is very close to stack top, but isn't the real
// stack top. Note that /proc may not exist if VM is running as a chroot
// program, so reading /proc/<pid>/stat could fail. Also the contents of
// /proc/<pid>/stat could change in the future (though unlikely).
//
// We try __libc_stack_end first. If that doesn't work, look for
// /proc/<pid>/stat. If neither of them works, we use current stack pointer
// as a hint, which should work well in most cases.
uintptr_t stack_start;
// try __libc_stack_end first
uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
if (p && *p) {
stack_start = *p;
} else {
// see if we can get the start_stack field from /proc/self/stat
FILE *fp;
int pid;
char state;
int ppid;
int pgrp;
int session;
int nr;
int tpgrp;
unsigned long flags;
unsigned long minflt;
unsigned long cminflt;
unsigned long majflt;
unsigned long cmajflt;
unsigned long utime;
unsigned long stime;
long cutime;
long cstime;
long prio;
long nice;
long junk;
long it_real;
uintptr_t start;
uintptr_t vsize;
intptr_t rss;
uintptr_t rsslim;
uintptr_t scodes;
uintptr_t ecode;
int i;
// Figure what the primordial thread stack base is. Code is inspired
// by email from Hans Boehm. /proc/self/stat begins with current pid,
// followed by command name surrounded by parentheses, state, etc.
char stat[2048];
int statlen;
fp = fopen("/proc/self/stat", "r");
if (fp) {
statlen = fread(stat, 1, 2047, fp);
stat[statlen] = '\0';
fclose(fp);
// Skip pid and the command string. Note that we could be dealing with
// weird command names, e.g. user could decide to rename java launcher
// to "java 1.4.2 :)", then the stat file would look like
// 1234 (java 1.4.2 :)) R ... ...
// We don't really need to know the command string, just find the last
// occurrence of ")" and then start parsing from there. See bug 4726580.
char * s = strrchr(stat, ')');
i = 0;
if (s) {
// Skip blank chars
do { s++; } while (s && isspace(*s));
#define _UFM UINTX_FORMAT
#define _DFM INTX_FORMAT
// 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
// 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
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,
&state, // 3 %c
&ppid, // 4 %d
&pgrp, // 5 %d
&session, // 6 %d
&nr, // 7 %d
&tpgrp, // 8 %d
&flags, // 9 %lu
&minflt, // 10 %lu
&cminflt, // 11 %lu
&majflt, // 12 %lu
&cmajflt, // 13 %lu
&utime, // 14 %lu
&stime, // 15 %lu
&cutime, // 16 %ld
&cstime, // 17 %ld
&prio, // 18 %ld
&nice, // 19 %ld
&junk, // 20 %ld
&it_real, // 21 %ld
&start, // 22 UINTX_FORMAT
&vsize, // 23 UINTX_FORMAT
&rss, // 24 INTX_FORMAT
&rsslim, // 25 UINTX_FORMAT
&scodes, // 26 UINTX_FORMAT
&ecode, // 27 UINTX_FORMAT
&stack_start); // 28 UINTX_FORMAT
}
#undef _UFM
#undef _DFM
if (i != 28 - 2) {
assert(false, "Bad conversion from /proc/self/stat");
// product mode - assume we are the primordial thread, good luck in the
// embedded case.
warning("Can't detect primordial thread stack location - bad conversion");
stack_start = (uintptr_t) &rlim;
}
} else {
// For some reason we can't open /proc/self/stat (for example, running on
// FreeBSD with a Linux emulator, or inside chroot), this should work for
// most cases, so don't abort:
warning("Can't detect primordial thread stack location - no /proc/self/stat");
stack_start = (uintptr_t) &rlim;
}
}
// Now we have a pointer (stack_start) very close to the stack top, the
// next thing to do is to figure out the exact location of stack top. We
// can find out the virtual memory area that contains stack_start by
// reading /proc/self/maps, it should be the last vma in /proc/self/maps,
// and its upper limit is the real stack top. (again, this would fail if
// running inside chroot, because /proc may not exist.)
uintptr_t stack_top;
address low, high;
if (find_vma((address)stack_start, &low, &high)) {
// success, "high" is the true stack top. (ignore "low", because initial
// thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
stack_top = (uintptr_t)high;
} else {
// failed, likely because /proc/self/maps does not exist
warning("Can't detect primordial thread stack location - find_vma failed");
// best effort: stack_start is normally within a few pages below the real
// stack top, use it as stack top, and reduce stack size so we won't put
// guard page outside stack.
stack_top = stack_start;
stack_size -= 16 * page_size();
}
// stack_top could be partially down the page so align it
stack_top = align_up(stack_top, page_size());
// Allowed stack value is minimum of max_size and what we derived from rlimit
if (max_size > 0) {
_initial_thread_stack_size = MIN2(max_size, stack_size);
} else {
// Accept the rlimit max, but if stack is unlimited then it will be huge, so
// clamp it at 8MB as we do on Solaris
_initial_thread_stack_size = MIN2(stack_size, 8*M);
}
_initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size());
_initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
if (log_is_enabled(Info, os, thread)) {
// See if we seem to be on primordial process thread
bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) &&
uintptr_t(&rlim) < stack_top;
log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: "
SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT,
primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K,
stack_top, intptr_t(_initial_thread_stack_bottom));
}
}
////////////////////////////////////////////////////////////////////////////////
// time support
#ifndef SUPPORTS_CLOCK_MONOTONIC
#error "Build platform doesn't support clock_gettime and related functionality"
#endif
// Time since start-up in seconds to a fine granularity.
// Used by VMSelfDestructTimer and the MemProfiler.
double os::elapsedTime() {
return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
}
jlong os::elapsed_counter() {
return javaTimeNanos() - initial_time_count;
}
jlong os::elapsed_frequency() {
return NANOSECS_PER_SEC; // nanosecond resolution
}
bool os::supports_vtime() { return true; }
double os::elapsedVTime() {
struct rusage usage;
int retval = getrusage(RUSAGE_THREAD, &usage);
if (retval == 0) {
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);
} else {
// better than nothing, but not much
return elapsedTime();
}
}
jlong os::javaTimeMillis() {
timeval time;
int status = gettimeofday(&time, NULL);
assert(status != -1, "linux error");
return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
}
void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
timeval time;
int status = gettimeofday(&time, NULL);
assert(status != -1, "linux error");
seconds = jlong(time.tv_sec);
nanos = jlong(time.tv_usec) * 1000;
}
void os::Linux::fast_thread_clock_init() {
if (!UseLinuxPosixThreadCPUClocks) {
return;
}
clockid_t clockid;
struct timespec tp;
int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
(int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
// Switch to using fast clocks for thread cpu time if
// the clock_getres() returns 0 error code.
// Note, that some kernels may support the current thread
// clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
// returned by the pthread_getcpuclockid().
// If the fast Posix clocks are supported then the clock_getres()
// must return at least tp.tv_sec == 0 which means a resolution
// better than 1 sec. This is extra check for reliability.
if (pthread_getcpuclockid_func &&
pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
os::Posix::clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
_supports_fast_thread_cpu_time = true;
_pthread_getcpuclockid = pthread_getcpuclockid_func;
}
}
jlong os::javaTimeNanos() {
if (os::supports_monotonic_clock()) {
struct timespec tp;
int status = os::Posix::clock_gettime(CLOCK_MONOTONIC, &tp);
assert(status == 0, "gettime error");
jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
return result;
} else {
timeval time;
int status = gettimeofday(&time, NULL);
assert(status != -1, "linux error");
jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
return 1000 * usecs;
}
}
void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
if (os::supports_monotonic_clock()) {
info_ptr->max_value = ALL_64_BITS;
// CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
info_ptr->may_skip_backward = false; // not subject to resetting or drifting
info_ptr->may_skip_forward = false; // not subject to resetting or drifting
} else {
// gettimeofday - based on time in seconds since the Epoch thus does not wrap
info_ptr->max_value = ALL_64_BITS;
// gettimeofday is a real time clock so it skips
info_ptr->may_skip_backward = true;
info_ptr->may_skip_forward = true;
}
info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
}
// Return the real, user, and system times in seconds from an
// arbitrary fixed point in the past.
bool os::getTimesSecs(double* process_real_time,
double* process_user_time,
double* process_system_time) {
struct tms ticks;
clock_t real_ticks = times(&ticks);
if (real_ticks == (clock_t) (-1)) {
return false;
} else {
double ticks_per_second = (double) clock_tics_per_sec;
*process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
*process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
*process_real_time = ((double) real_ticks) / ticks_per_second;
return true;
}
}
char * os::local_time_string(char *buf, size_t buflen) {
struct tm t;
time_t long_time;
time(&long_time);
localtime_r(&long_time, &t);
jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
t.tm_hour, t.tm_min, t.tm_sec);
return buf;
}
struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
return localtime_r(clock, res);
}
////////////////////////////////////////////////////////////////////////////////
// runtime exit support
// Note: os::shutdown() might be called very early during initialization, or
// called from signal handler. Before adding something to os::shutdown(), make
// sure it is async-safe and can handle partially initialized VM.
void os::shutdown() {
// allow PerfMemory to attempt cleanup of any persistent resources
perfMemory_exit();
// needs to remove object in file system
AttachListener::abort();
// flush buffered output, finish log files
ostream_abort();
// Check for abort hook
abort_hook_t abort_hook = Arguments::abort_hook();
if (abort_hook != NULL) {
abort_hook();
}
}
// Note: os::abort() might be called very early during initialization, or
// called from signal handler. Before adding something to os::abort(), make
// sure it is async-safe and can handle partially initialized VM.
void os::abort(bool dump_core, void* siginfo, const void* context) {
os::shutdown();
if (dump_core) {
if (DumpPrivateMappingsInCore) {
ClassLoader::close_jrt_image();
}
#ifndef PRODUCT
fdStream out(defaultStream::output_fd());
out.print_raw("Current thread is ");
char buf[16];
jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
out.print_raw_cr(buf);
out.print_raw_cr("Dumping core ...");
#endif
::abort(); // dump core
}
::exit(1);
}
// Die immediately, no exit hook, no abort hook, no cleanup.
// Dump a core file, if possible, for debugging.
void os::die() {
if (TestUnresponsiveErrorHandler && !CreateCoredumpOnCrash) {
// For TimeoutInErrorHandlingTest.java, we just kill the VM
// and don't take the time to generate a core file.
os::signal_raise(SIGKILL);
} else {
::abort();
}
}
// thread_id is kernel thread id (similar to Solaris LWP id)
intx os::current_thread_id() { return os::Linux::gettid(); }
int os::current_process_id() {
return ::getpid();
}
// DLL functions
const char* os::dll_file_extension() { return ".so"; }
// This must be hard coded because it's the system's temporary
// directory not the java application's temp directory, ala java.io.tmpdir.
const char* os::get_temp_directory() { return "/tmp"; }
static bool file_exists(const char* filename) {
struct stat statbuf;
if (filename == NULL || strlen(filename) == 0) {
return false;
}
return os::stat(filename, &statbuf) == 0;
}
// check if addr is inside libjvm.so
bool os::address_is_in_vm(address addr) {
static address libjvm_base_addr;
Dl_info dlinfo;
if (libjvm_base_addr == NULL) {
if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
libjvm_base_addr = (address)dlinfo.dli_fbase;
}
assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
}
if (dladdr((void *)addr, &dlinfo) != 0) {
if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
}
return false;
}
bool os::dll_address_to_function_name(address addr, char *buf,
int buflen, int *offset,
bool demangle) {
// buf is not optional, but offset is optional
assert(buf != NULL, "sanity check");
Dl_info dlinfo;
if (dladdr((void*)addr, &dlinfo) != 0) {
// see if we have a matching symbol
if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
}
if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
return true;
}
// no matching symbol so try for just file info
if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
buf, buflen, offset, dlinfo.dli_fname, demangle)) {
return true;
}
}
}
buf[0] = '\0';
if (offset != NULL) *offset = -1;
return false;
}
struct _address_to_library_name {
address addr; // input : memory address
size_t buflen; // size of fname
char* fname; // output: library name
address base; // library base addr
};
static int address_to_library_name_callback(struct dl_phdr_info *info,
size_t size, void *data) {
int i;
bool found = false;
address libbase = NULL;
struct _address_to_library_name * d = (struct _address_to_library_name *)data;
// iterate through all loadable segments
for (i = 0; i < info->dlpi_phnum; i++) {
address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
if (info->dlpi_phdr[i].p_type == PT_LOAD) {
// base address of a library is the lowest address of its loaded
// segments.
if (libbase == NULL || libbase > segbase) {
libbase = segbase;
}
// see if 'addr' is within current segment
if (segbase <= d->addr &&
d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
found = true;
}
}
}
// dlpi_name is NULL or empty if the ELF file is executable, return 0
// so dll_address_to_library_name() can fall through to use dladdr() which
// can figure out executable name from argv[0].
if (found && info->dlpi_name && info->dlpi_name[0]) {
d->base = libbase;
if (d->fname) {
jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
}
return 1;
}
return 0;
}
bool os::dll_address_to_library_name(address addr, char* buf,
int buflen, int* offset) {
// buf is not optional, but offset is optional
assert(buf != NULL, "sanity check");
Dl_info dlinfo;
struct _address_to_library_name data;
// There is a bug in old glibc dladdr() implementation that it could resolve
// to wrong library name if the .so file has a base address != NULL. Here
// we iterate through the program headers of all loaded libraries to find
// out which library 'addr' really belongs to. This workaround can be
// removed once the minimum requirement for glibc is moved to 2.3.x.
data.addr = addr;
data.fname = buf;
data.buflen = buflen;
data.base = NULL;
int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
if (rslt) {
// buf already contains library name
if (offset) *offset = addr - data.base;
return true;
}
if (dladdr((void*)addr, &dlinfo) != 0) {
if (dlinfo.dli_fname != NULL) {
jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
}
if (dlinfo.dli_fbase != NULL && offset != NULL) {
*offset = addr - (address)dlinfo.dli_fbase;
}
return true;
}
buf[0] = '\0';
if (offset) *offset = -1;
return false;
}
// Loads .dll/.so and
// in case of error it checks if .dll/.so was built for the
// same architecture as Hotspot is running on
// Remember the stack's state. The Linux dynamic linker will change
// the stack to 'executable' at most once, so we must safepoint only once.
bool os::Linux::_stack_is_executable = false;
// VM operation that loads a library. This is necessary if stack protection
// of the Java stacks can be lost during loading the library. If we
// do not stop the Java threads, they can stack overflow before the stacks
// are protected again.
class VM_LinuxDllLoad: public VM_Operation {
private:
const char *_filename;
char *_ebuf;
int _ebuflen;
void *_lib;
public:
VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
_filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
VMOp_Type type() const { return VMOp_LinuxDllLoad; }
void doit() {
_lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
os::Linux::_stack_is_executable = true;
}
void* loaded_library() { return _lib; }
};
void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
void * result = NULL;
bool load_attempted = false;
log_info(os)("attempting shared library load of %s", filename);
// Check whether the library to load might change execution rights
// of the stack. If they are changed, the protection of the stack
// guard pages will be lost. We need a safepoint to fix this.
//
// See Linux man page execstack(8) for more info.
if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
if (!ElfFile::specifies_noexecstack(filename)) {
if (!is_init_completed()) {
os::Linux::_stack_is_executable = true;
// This is OK - No Java threads have been created yet, and hence no
// stack guard pages to fix.
//
// Dynamic loader will make all stacks executable after
// this function returns, and will not do that again.
assert(Threads::number_of_threads() == 0, "no Java threads should exist yet.");
} else {
warning("You have loaded library %s which might have disabled stack guard. "
"The VM will try to fix the stack guard now.\n"
"It's highly recommended that you fix the library with "
"'execstack -c <libfile>', or link it with '-z noexecstack'.",
filename);
assert(Thread::current()->is_Java_thread(), "must be Java thread");
JavaThread *jt = JavaThread::current();
if (jt->thread_state() != _thread_in_native) {
// This happens when a compiler thread tries to load a hsdis-<arch>.so file
// that requires ExecStack. Cannot enter safe point. Let's give up.
warning("Unable to fix stack guard. Giving up.");
} else {
if (!LoadExecStackDllInVMThread) {
// This is for the case where the DLL has an static
// constructor function that executes JNI code. We cannot
// load such DLLs in the VMThread.
result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
}
ThreadInVMfromNative tiv(jt);
debug_only(VMNativeEntryWrapper vew;)
VM_LinuxDllLoad op(filename, ebuf, ebuflen);
VMThread::execute(&op);
if (LoadExecStackDllInVMThread) {
result = op.loaded_library();
}
load_attempted = true;
}
}
}
}
if (!load_attempted) {
result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
}
if (result != NULL) {
// Successful loading
return result;
}
Elf32_Ehdr elf_head;
int diag_msg_max_length=ebuflen-strlen(ebuf);
char* diag_msg_buf=ebuf+strlen(ebuf);
if (diag_msg_max_length==0) {
// No more space in ebuf for additional diagnostics message
return NULL;
}
int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
if (file_descriptor < 0) {
// Can't open library, report dlerror() message
return NULL;
}
bool failed_to_read_elf_head=
(sizeof(elf_head)!=
(::read(file_descriptor, &elf_head,sizeof(elf_head))));
::close(file_descriptor);
if (failed_to_read_elf_head) {
// file i/o error - report dlerror() msg
return NULL;
}
if (elf_head.e_ident[EI_DATA] != LITTLE_ENDIAN_ONLY(ELFDATA2LSB) BIG_ENDIAN_ONLY(ELFDATA2MSB)) {
// handle invalid/out of range endianness values
if (elf_head.e_ident[EI_DATA] == 0 || elf_head.e_ident[EI_DATA] > 2) {
return NULL;
}
#if defined(VM_LITTLE_ENDIAN)
// VM is LE, shared object BE
elf_head.e_machine = be16toh(elf_head.e_machine);
#else
// VM is BE, shared object LE
elf_head.e_machine = le16toh(elf_head.e_machine);
#endif
}
typedef struct {
Elf32_Half code; // Actual value as defined in elf.h
Elf32_Half compat_class; // Compatibility of archs at VM's sense
unsigned char elf_class; // 32 or 64 bit
unsigned char endianness; // MSB or LSB
char* name; // String representation
} arch_t;
#ifndef EM_486
#define EM_486 6 /* Intel 80486 */
#endif
#ifndef EM_AARCH64
#define EM_AARCH64 183 /* ARM AARCH64 */
#endif
static const arch_t arch_array[]={
{EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
{EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
{EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
{EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
{EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
{EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
{EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
{EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
#if defined(VM_LITTLE_ENDIAN)
{EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"},
{EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"},
#else
{EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
{EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"},
#endif
{EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
// we only support 64 bit z architecture
{EM_S390, EM_S390, ELFCLASS64, ELFDATA2MSB, (char*)"IBM System/390"},
{EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
{EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
{EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
{EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
{EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
{EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
};
#if (defined IA32)
static Elf32_Half running_arch_code=EM_386;
#elif (defined AMD64) || (defined X32)
static Elf32_Half running_arch_code=EM_X86_64;
#elif (defined IA64)
static Elf32_Half running_arch_code=EM_IA_64;
#elif (defined __sparc) && (defined _LP64)
static Elf32_Half running_arch_code=EM_SPARCV9;
#elif (defined __sparc) && (!defined _LP64)
static Elf32_Half running_arch_code=EM_SPARC;
#elif (defined __powerpc64__)
static Elf32_Half running_arch_code=EM_PPC64;
#elif (defined __powerpc__)
static Elf32_Half running_arch_code=EM_PPC;
#elif (defined AARCH64)
static Elf32_Half running_arch_code=EM_AARCH64;
#elif (defined ARM)
static Elf32_Half running_arch_code=EM_ARM;
#elif (defined S390)
static Elf32_Half running_arch_code=EM_S390;
#elif (defined ALPHA)
static Elf32_Half running_arch_code=EM_ALPHA;
#elif (defined MIPSEL)
static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
#elif (defined PARISC)
static Elf32_Half running_arch_code=EM_PARISC;
#elif (defined MIPS)
static Elf32_Half running_arch_code=EM_MIPS;
#elif (defined M68K)
static Elf32_Half running_arch_code=EM_68K;
#elif (defined SH)
static Elf32_Half running_arch_code=EM_SH;
#else
#error Method os::dll_load requires that one of following is defined:\
AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, SH, __sparc
#endif
// Identify compatibility class for VM's architecture and library's architecture
// Obtain string descriptions for architectures
arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
int running_arch_index=-1;
for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
if (running_arch_code == arch_array[i].code) {
running_arch_index = i;
}
if (lib_arch.code == arch_array[i].code) {
lib_arch.compat_class = arch_array[i].compat_class;
lib_arch.name = arch_array[i].name;
}
}
assert(running_arch_index != -1,
"Didn't find running architecture code (running_arch_code) in arch_array");
if (running_arch_index == -1) {
// Even though running architecture detection failed
// we may still continue with reporting dlerror() message
return NULL;
}
if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
if (lib_arch.name != NULL) {
::snprintf(diag_msg_buf, diag_msg_max_length-1,
" (Possible cause: can't load %s .so on a %s platform)",
lib_arch.name, arch_array[running_arch_index].name);
} else {
::snprintf(diag_msg_buf, diag_msg_max_length-1,
" (Possible cause: can't load this .so (machine code=0x%x) on a %s platform)",
lib_arch.code, arch_array[running_arch_index].name);
}
return NULL;
}
if (lib_arch.endianness != arch_array[running_arch_index].endianness) {
::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: endianness mismatch)");
return NULL;
}
// ELF file class/capacity : 0 - invalid, 1 - 32bit, 2 - 64bit
if (lib_arch.elf_class > 2 || lib_arch.elf_class < 1) {
::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: invalid ELF file class)");
return NULL;
}
if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
::snprintf(diag_msg_buf, diag_msg_max_length-1,
" (Possible cause: architecture word width mismatch, can't load %d-bit .so on a %d-bit platform)",
(int) lib_arch.elf_class * 32, arch_array[running_arch_index].elf_class * 32);
return NULL;
}
return NULL;
}
void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
int ebuflen) {
void * result = ::dlopen(filename, RTLD_LAZY);
if (result == NULL) {
const char* error_report = ::dlerror();
if (error_report == NULL) {
error_report = "dlerror returned no error description";
}
if (ebuf != NULL && ebuflen > 0) {
::strncpy(ebuf, error_report, ebuflen-1);
ebuf[ebuflen-1]='\0';
}
Events::log(NULL, "Loading shared library %s failed, %s", filename, error_report);
log_info(os)("shared library load of %s failed, %s", filename, error_report);
} else {
Events::log(NULL, "Loaded shared library %s", filename);
log_info(os)("shared library load of %s was successful", filename);
}
return result;
}
void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
int ebuflen) {
void * result = NULL;
if (LoadExecStackDllInVMThread) {
result = dlopen_helper(filename, ebuf, ebuflen);
}
// Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
// library that requires an executable stack, or which does not have this
// stack attribute set, dlopen changes the stack attribute to executable. The
// read protection of the guard pages gets lost.
//
// Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
// may have been queued at the same time.
if (!_stack_is_executable) {
for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
jt->stack_guards_enabled()) { // No pending stack overflow exceptions
if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
warning("Attempt to reguard stack yellow zone failed.");
}
}
}
}
return result;
}
void* os::dll_lookup(void* handle, const char* name) {
void* res = dlsym(handle, name);
return res;
}
void* os::get_default_process_handle() {
return (void*)::dlopen(NULL, RTLD_LAZY);
}
static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) {
int fd = ::open(filename, O_RDONLY);
if (fd == -1) {
return false;
}
if (hdr != NULL) {
st->print_cr("%s", hdr);
}
char buf[33];
int bytes;
buf[32] = '\0';
while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
st->print_raw(buf, bytes);
}
::close(fd);
return true;
}
void os::print_dll_info(outputStream *st) {
st->print_cr("Dynamic libraries:");
char fname[32];
pid_t pid = os::Linux::gettid();
jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
if (!_print_ascii_file(fname, st)) {
st->print("Can not get library information for pid = %d\n", pid);
}
}
int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
FILE *procmapsFile = NULL;
// Open the procfs maps file for the current process
if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
// Allocate PATH_MAX for file name plus a reasonable size for other fields.
char line[PATH_MAX + 100];
// Read line by line from 'file'
while (fgets(line, sizeof(line), procmapsFile) != NULL) {
u8 base, top, offset, inode;
char permissions[5];
char device[6];
char name[sizeof(line)];
// Parse fields from line
int matches = sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s",
&base, &top, permissions, &offset, device, &inode, name);
// the last entry 'name' is empty for some entries, so we might have 6 matches instead of 7 for some lines
if (matches < 6) continue;
if (matches == 6) name[0] = '\0';
// Filter by device id '00:00' so that we only get file system mapped files.
if (strcmp(device, "00:00") != 0) {
// Call callback with the fields of interest
if(callback(name, (address)base, (address)top, param)) {
// Oops abort, callback aborted
fclose(procmapsFile);
return 1;
}
}
}
fclose(procmapsFile);
}
return 0;
}
void os::print_os_info_brief(outputStream* st) {
os::Linux::print_distro_info(st);
os::Posix::print_uname_info(st);
os::Linux::print_libversion_info(st);
}
void os::print_os_info(outputStream* st) {
st->print("OS:");
os::Linux::print_distro_info(st);
os::Posix::print_uname_info(st);
os::Linux::print_uptime_info(st);
// Print warning if unsafe chroot environment detected
if (unsafe_chroot_detected) {
st->print("WARNING!! ");
st->print_cr("%s", unstable_chroot_error);
}
os::Linux::print_libversion_info(st);
os::Posix::print_rlimit_info(st);
os::Posix::print_load_average(st);
os::Linux::print_full_memory_info(st);
os::Linux::print_proc_sys_info(st);
os::Linux::print_ld_preload_file(st);
os::Linux::print_container_info(st);
VM_Version::print_platform_virtualization_info(st);
os::Linux::print_steal_info(st);
}
// Try to identify popular distros.
// Most Linux distributions have a /etc/XXX-release file, which contains
// the OS version string. Newer Linux distributions have a /etc/lsb-release
// file that also contains the OS version string. Some have more than one
// /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
// /etc/redhat-release.), so the order is important.
// Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
// their own specific XXX-release file as well as a redhat-release file.
// Because of this the XXX-release file needs to be searched for before the
// redhat-release file.
// Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
// search for redhat-release / SuSE-release needs to be before lsb-release.
// Since the lsb-release file is the new standard it needs to be searched
// before the older style release files.
// Searching system-release (Red Hat) and os-release (other Linuxes) are a
// next to last resort. The os-release file is a new standard that contains
// distribution information and the system-release file seems to be an old
// standard that has been replaced by the lsb-release and os-release files.
// Searching for the debian_version file is the last resort. It contains
// an informative string like "6.0.6" or "wheezy/sid". Because of this
// "Debian " is printed before the contents of the debian_version file.
const char* distro_files[] = {
"/etc/oracle-release",
"/etc/mandriva-release",
"/etc/mandrake-release",
"/etc/sun-release",
"/etc/redhat-release",
"/etc/SuSE-release",
"/etc/lsb-release",
"/etc/turbolinux-release",
"/etc/gentoo-release",
"/etc/ltib-release",
"/etc/angstrom-version",
"/etc/system-release",
"/etc/os-release",
NULL };
void os::Linux::print_distro_info(outputStream* st) {
for (int i = 0;; i++) {
const char* file = distro_files[i];
if (file == NULL) {
break; // done
}
// If file prints, we found it.
if (_print_ascii_file(file, st)) {
return;
}
}
if (file_exists("/etc/debian_version")) {
st->print("Debian ");
_print_ascii_file("/etc/debian_version", st);
} else {
st->print("Linux");
}
st->cr();
}
static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
char buf[256];
while (fgets(buf, sizeof(buf), fp)) {
// Edit out extra stuff in expected format
if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
char* ptr = strstr(buf, "\""); // the name is in quotes
if (ptr != NULL) {
ptr++; // go beyond first quote
char* nl = strchr(ptr, '\"');
if (nl != NULL) *nl = '\0';
strncpy(distro, ptr, length);
} else {
ptr = strstr(buf, "=");
ptr++; // go beyond equals then
char* nl = strchr(ptr, '\n');
if (nl != NULL) *nl = '\0';
strncpy(distro, ptr, length);
}
return;
} else if (get_first_line) {
char* nl = strchr(buf, '\n');
if (nl != NULL) *nl = '\0';
strncpy(distro, buf, length);
return;
}
}
// print last line and close
char* nl = strchr(buf, '\n');
if (nl != NULL) *nl = '\0';
strncpy(distro, buf, length);
}
static void parse_os_info(char* distro, size_t length, const char* file) {
FILE* fp = fopen(file, "r");
if (fp != NULL) {
// if suse format, print out first line
bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
parse_os_info_helper(fp, distro, length, get_first_line);
fclose(fp);
}
}
void os::get_summary_os_info(char* buf, size_t buflen) {
for (int i = 0;; i++) {
const char* file = distro_files[i];
if (file == NULL) {
break; // ran out of distro_files
}
if (file_exists(file)) {
parse_os_info(buf, buflen, file);
return;
}
}
// special case for debian
if (file_exists("/etc/debian_version")) {
strncpy(buf, "Debian ", buflen);
if (buflen > 7) {
parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
}
} else {
strncpy(buf, "Linux", buflen);
}
}
void os::Linux::print_libversion_info(outputStream* st) {
// libc, pthread
st->print("libc:");
st->print("%s ", os::Linux::glibc_version());
st->print("%s ", os::Linux::libpthread_version());
st->cr();
}
void os::Linux::print_proc_sys_info(outputStream* st) {
st->cr();
st->print_cr("/proc/sys/kernel/threads-max (system-wide limit on the number of threads):");
_print_ascii_file("/proc/sys/kernel/threads-max", st);
st->cr();
st->cr();
st->print_cr("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have):");
_print_ascii_file("/proc/sys/vm/max_map_count", st);
st->cr();
st->cr();
st->print_cr("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers):");
_print_ascii_file("/proc/sys/kernel/pid_max", st);
st->cr();
st->cr();
}
void os::Linux::print_full_memory_info(outputStream* st) {
st->print("\n/proc/meminfo:\n");
_print_ascii_file("/proc/meminfo", st);
st->cr();
}
void os::Linux::print_ld_preload_file(outputStream* st) {
_print_ascii_file("/etc/ld.so.preload", st, "\n/etc/ld.so.preload:");
st->cr();
}
void os::Linux::print_uptime_info(outputStream* st) {
struct sysinfo sinfo;
int ret = sysinfo(&sinfo);
if (ret == 0) {
os::print_dhm(st, "OS uptime:", (long) sinfo.uptime);
}
}
void os::Linux::print_container_info(outputStream* st) {
if (!OSContainer::is_containerized()) {
return;
}
st->print("container (cgroup) information:\n");
const char *p_ct = OSContainer::container_type();
st->print("container_type: %s\n", p_ct != NULL ? p_ct : "not supported");
char *p = OSContainer::cpu_cpuset_cpus();
st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "not supported");
free(p);
p = OSContainer::cpu_cpuset_memory_nodes();
st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "not supported");
free(p);
int i = OSContainer::active_processor_count();
st->print("active_processor_count: ");
if (i > 0) {
st->print("%d\n", i);
} else {
st->print("not supported\n");
}
i = OSContainer::cpu_quota();
st->print("cpu_quota: ");
if (i > 0) {
st->print("%d\n", i);
} else {
st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no quota");
}
i = OSContainer::cpu_period();
st->print("cpu_period: ");
if (i > 0) {
st->print("%d\n", i);
} else {
st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no period");
}
i = OSContainer::cpu_shares();
st->print("cpu_shares: ");
if (i > 0) {
st->print("%d\n", i);
} else {
st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no shares");
}
jlong j = OSContainer::memory_limit_in_bytes();
st->print("memory_limit_in_bytes: ");
if (j > 0) {
st->print(JLONG_FORMAT "\n", j);
} else {
st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
}
j = OSContainer::memory_and_swap_limit_in_bytes();
st->print("memory_and_swap_limit_in_bytes: ");
if (j > 0) {
st->print(JLONG_FORMAT "\n", j);
} else {
st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
}
j = OSContainer::memory_soft_limit_in_bytes();
st->print("memory_soft_limit_in_bytes: ");
if (j > 0) {
st->print(JLONG_FORMAT "\n", j);
} else {
st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
}
j = OSContainer::OSContainer::memory_usage_in_bytes();
st->print("memory_usage_in_bytes: ");
if (j > 0) {
st->print(JLONG_FORMAT "\n", j);
} else {
st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
}
j = OSContainer::OSContainer::memory_max_usage_in_bytes();
st->print("memory_max_usage_in_bytes: ");
if (j > 0) {
st->print(JLONG_FORMAT "\n", j);
} else {
st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
}
st->cr();
}
void os::Linux::print_steal_info(outputStream* st) {
if (has_initial_tick_info) {
CPUPerfTicks pticks;
bool res = os::Linux::get_tick_information(&pticks, -1);
if (res && pticks.has_steal_ticks) {
uint64_t steal_ticks_difference = pticks.steal - initial_steal_ticks;
uint64_t total_ticks_difference = pticks.total - initial_total_ticks;
double steal_ticks_perc = 0.0;
if (total_ticks_difference != 0) {
steal_ticks_perc = (double) steal_ticks_difference / total_ticks_difference;
}
st->print_cr("Steal ticks since vm start: " UINT64_FORMAT, steal_ticks_difference);
st->print_cr("Steal ticks percentage since vm start:%7.3f", steal_ticks_perc);
}
}
}
void os::print_memory_info(outputStream* st) {
st->print("Memory:");
st->print(" %dk page", os::vm_page_size()>>10);
// values in struct sysinfo are "unsigned long"
struct sysinfo si;
sysinfo(&si);
st->print(", physical " UINT64_FORMAT "k",
os::physical_memory() >> 10);
st->print("(" UINT64_FORMAT "k free)",
os::available_memory() >> 10);
st->print(", swap " UINT64_FORMAT "k",
((jlong)si.totalswap * si.mem_unit) >> 10);
st->print("(" UINT64_FORMAT "k free)",
((jlong)si.freeswap * si.mem_unit) >> 10);
st->cr();
}
// Print the first "model name" line and the first "flags" line
// that we find and nothing more. We assume "model name" comes
// before "flags" so if we find a second "model name", then the
// "flags" field is considered missing.
static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
#if defined(IA32) || defined(AMD64)
// Other platforms have less repetitive cpuinfo files
FILE *fp = fopen("/proc/cpuinfo", "r");
if (fp) {
while (!feof(fp)) {
if (fgets(buf, buflen, fp)) {
// Assume model name comes before flags
bool model_name_printed = false;
if (strstr(buf, "model name") != NULL) {
if (!model_name_printed) {
st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
st->print_raw(buf);
model_name_printed = true;
} else {
// model name printed but not flags? Odd, just return
fclose(fp);
return true;
}
}
// print the flags line too
if (strstr(buf, "flags") != NULL) {
st->print_raw(buf);
fclose(fp);
return true;
}
}
}
fclose(fp);
}
#endif // x86 platforms
return false;
}
void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
// Only print the model name if the platform provides this as a summary
if (!print_model_name_and_flags(st, buf, buflen)) {
st->print("\n/proc/cpuinfo:\n");
if (!_print_ascii_file("/proc/cpuinfo", st)) {
st->print_cr(" <Not Available>");
}
}
}
#if defined(AMD64) || defined(IA32) || defined(X32)
const char* search_string = "model name";
#elif defined(M68K)
const char* search_string = "CPU";
#elif defined(PPC64)
const char* search_string = "cpu";
#elif defined(S390)
const char* search_string = "machine =";
#elif defined(SPARC)
const char* search_string = "cpu";
#else
const char* search_string = "Processor";
#endif
// Parses the cpuinfo file for string representing the model name.
void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
FILE* fp = fopen("/proc/cpuinfo", "r");
if (fp != NULL) {
while (!feof(fp)) {
char buf[256];
if (fgets(buf, sizeof(buf), fp)) {
char* start = strstr(buf, search_string);
if (start != NULL) {
char *ptr = start + strlen(search_string);
char *end = buf + strlen(buf);
while (ptr != end) {
// skip whitespace and colon for the rest of the name.
if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
break;
}
ptr++;
}
if (ptr != end) {
// reasonable string, get rid of newline and keep the rest
char* nl = strchr(buf, '\n');
if (nl != NULL) *nl = '\0';
strncpy(cpuinfo, ptr, length);
fclose(fp);
return;
}
}
}
}
fclose(fp);
}
// cpuinfo not found or parsing failed, just print generic string. The entire
// /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
#if defined(AARCH64)
strncpy(cpuinfo, "AArch64", length);
#elif defined(AMD64)
strncpy(cpuinfo, "x86_64", length);
#elif defined(ARM) // Order wrt. AARCH64 is relevant!
strncpy(cpuinfo, "ARM", length);
#elif defined(IA32)
strncpy(cpuinfo, "x86_32", length);
#elif defined(IA64)
strncpy(cpuinfo, "IA64", length);
#elif defined(PPC)
strncpy(cpuinfo, "PPC64", length);
#elif defined(S390)
strncpy(cpuinfo, "S390", length);
#elif defined(SPARC)
strncpy(cpuinfo, "sparcv9", length);
#elif defined(ZERO_LIBARCH)
strncpy(cpuinfo, ZERO_LIBARCH, length);
#else
strncpy(cpuinfo, "unknown", length);
#endif
}
static void print_signal_handler(outputStream* st, int sig,
char* buf, size_t buflen);
void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
st->print_cr("Signal Handlers:");
print_signal_handler(st, SIGSEGV, buf, buflen);
print_signal_handler(st, SIGBUS , buf, buflen);
print_signal_handler(st, SIGFPE , buf, buflen);
print_signal_handler(st, SIGPIPE, buf, buflen);
print_signal_handler(st, SIGXFSZ, buf, buflen);
print_signal_handler(st, SIGILL , buf, buflen);
print_signal_handler(st, SR_signum, buf, buflen);
print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
#if defined(PPC64)
print_signal_handler(st, SIGTRAP, buf, buflen);
#endif
}
static char saved_jvm_path[MAXPATHLEN] = {0};
// Find the full path to the current module, libjvm.so
void os::jvm_path(char *buf, jint buflen) {
// Error checking.
if (buflen < MAXPATHLEN) {
assert(false, "must use a large-enough buffer");
buf[0] = '\0';
return;
}
// Lazy resolve the path to current module.
if (saved_jvm_path[0] != 0) {
strcpy(buf, saved_jvm_path);
return;
}
char dli_fname[MAXPATHLEN];
bool ret = dll_address_to_library_name(
CAST_FROM_FN_PTR(address, os::jvm_path),
dli_fname, sizeof(dli_fname), NULL);
assert(ret, "cannot locate libjvm");
char *rp = NULL;
if (ret && dli_fname[0] != '\0') {
rp = os::Posix::realpath(dli_fname, buf, buflen);
}
if (rp == NULL) {
return;
}
if (Arguments::sun_java_launcher_is_altjvm()) {
// Support for the java launcher's '-XXaltjvm=<path>' option. Typical
// value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
// If "/jre/lib/" appears at the right place in the string, then
// assume we are installed in a JDK and we're done. Otherwise, check
// for a JAVA_HOME environment variable and fix up the path so it
// looks like libjvm.so is installed there (append a fake suffix
// hotspot/libjvm.so).
const char *p = buf + strlen(buf) - 1;
for (int count = 0; p > buf && count < 5; ++count) {
for (--p; p > buf && *p != '/'; --p)
/* empty */ ;
}
if (strncmp(p, "/jre/lib/", 9) != 0) {
// Look for JAVA_HOME in the environment.
char* java_home_var = ::getenv("JAVA_HOME");
if (java_home_var != NULL && java_home_var[0] != 0) {
char* jrelib_p;
int len;
// Check the current module name "libjvm.so".
p = strrchr(buf, '/');
if (p == NULL) {
return;
}
assert(strstr(p, "/libjvm") == p, "invalid library name");
rp = os::Posix::realpath(java_home_var, buf, buflen);
if (rp == NULL) {
return;
}
// determine if this is a legacy image or modules image
// modules image doesn't have "jre" subdirectory
len = strlen(buf);
assert(len < buflen, "Ran out of buffer room");
jrelib_p = buf + len;
snprintf(jrelib_p, buflen-len, "/jre/lib");
if (0 != access(buf, F_OK)) {
snprintf(jrelib_p, buflen-len, "/lib");
}
if (0 == access(buf, F_OK)) {
// Use current module name "libjvm.so"
len = strlen(buf);
snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
} else {
// Go back to path of .so
rp = os::Posix::realpath(dli_fname, buf, buflen);
if (rp == NULL) {
return;
}
}
}
}
}
strncpy(saved_jvm_path, buf, MAXPATHLEN);
saved_jvm_path[MAXPATHLEN - 1] = '\0';
}
void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
// no prefix required, not even "_"
}
void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
// no suffix required
}
////////////////////////////////////////////////////////////////////////////////
// sun.misc.Signal support
static void UserHandler(int sig, void *siginfo, void *context) {
// Ctrl-C is pressed during error reporting, likely because the error
// handler fails to abort. Let VM die immediately.
if (sig == SIGINT && VMError::is_error_reported()) {
os::die();
}
os::signal_notify(sig);
}
void* os::user_handler() {
return CAST_FROM_FN_PTR(void*, UserHandler);
}
extern "C" {
typedef void (*sa_handler_t)(int);
typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
}
void* os::signal(int signal_number, void* handler) {
struct sigaction sigAct, oldSigAct;
sigfillset(&(sigAct.sa_mask));
sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
if (sigaction(signal_number, &sigAct, &oldSigAct)) {
// -1 means registration failed
return (void *)-1;
}
return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
}
void os::signal_raise(int signal_number) {
::raise(signal_number);
}
// The following code is moved from os.cpp for making this
// code platform specific, which it is by its very nature.
// Will be modified when max signal is changed to be dynamic
int os::sigexitnum_pd() {
return NSIG;
}
// a counter for each possible signal value
static volatile jint pending_signals[NSIG+1] = { 0 };
// Linux(POSIX) specific hand shaking semaphore.
static Semaphore* sig_sem = NULL;
static PosixSemaphore sr_semaphore;
static void jdk_misc_signal_init() {
// Initialize signal structures
::memset((void*)pending_signals, 0, sizeof(pending_signals));
// Initialize signal semaphore
sig_sem = new Semaphore();
}
void os::signal_notify(int sig) {
if (sig_sem != NULL) {
Atomic::inc(&pending_signals[sig]);
sig_sem->signal();
} else {
// Signal thread is not created with ReduceSignalUsage and jdk_misc_signal_init
// initialization isn't called.
assert(ReduceSignalUsage, "signal semaphore should be created");
}
}
static int check_pending_signals() {
for (;;) {
for (int i = 0; i < NSIG + 1; i++) {
jint n = pending_signals[i];
if (n > 0 && n == Atomic::cmpxchg(&pending_signals[i], n, n - 1)) {
return i;
}
}
JavaThread *thread = JavaThread::current();
ThreadBlockInVM tbivm(thread);
bool threadIsSuspended;
do {
thread->set_suspend_equivalent();
// cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
sig_sem->wait();
// were we externally suspended while we were waiting?
threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
if (threadIsSuspended) {
// The semaphore has been incremented, but while we were waiting
// another thread suspended us. We don't want to continue running
// while suspended because that would surprise the thread that
// suspended us.
sig_sem->signal();
thread->java_suspend_self();
}
} while (threadIsSuspended);
}
}
int os::signal_wait() {
return check_pending_signals();
}
////////////////////////////////////////////////////////////////////////////////
// Virtual Memory
int os::vm_page_size() {
// Seems redundant as all get out
assert(os::Linux::page_size() != -1, "must call os::init");
return os::Linux::page_size();
}
// Solaris allocates memory by pages.
int os::vm_allocation_granularity() {
assert(os::Linux::page_size() != -1, "must call os::init");
return os::Linux::page_size();
}
// Rationale behind this function:
// current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
// mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
// samples for JITted code. Here we create private executable mapping over the code cache
// and then we can use standard (well, almost, as mapping can change) way to provide
// info for the reporting script by storing timestamp and location of symbol
void linux_wrap_code(char* base, size_t size) {
static volatile jint cnt = 0;
if (!UseOprofile) {
return;
}
char buf[PATH_MAX+1];
int num = Atomic::add(&cnt, 1);
snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
os::get_temp_directory(), os::current_process_id(), num);
unlink(buf);
int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
if (fd != -1) {
off_t rv = ::lseek(fd, size-2, SEEK_SET);
if (rv != (off_t)-1) {
if (::write(fd, "", 1) == 1) {
mmap(base, size,
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
}
}
::close(fd);
unlink(buf);
}
}
static bool recoverable_mmap_error(int err) {
// See if the error is one we can let the caller handle. This
// list of errno values comes from JBS-6843484. I can't find a
// Linux man page that documents this specific set of errno
// values so while this list currently matches Solaris, it may
// change as we gain experience with this failure mode.
switch (err) {
case EBADF:
case EINVAL:
case ENOTSUP:
// let the caller deal with these errors
return true;
default:
// Any remaining errors on this OS can cause our reserved mapping
// to be lost. That can cause confusion where different data
// structures think they have the same memory mapped. The worst
// scenario is if both the VM and a library think they have the
// same memory mapped.
return false;
}
}
static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
int err) {
warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
os::strerror(err), err);
}
static void warn_fail_commit_memory(char* addr, size_t size,
size_t alignment_hint, bool exec,
int err) {
warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
alignment_hint, exec, os::strerror(err), err);
}
// NOTE: Linux kernel does not really reserve the pages for us.
// All it does is to check if there are enough free pages
// left at the time of mmap(). This could be a potential
// problem.
int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
if (res != (uintptr_t) MAP_FAILED) {
if (UseNUMAInterleaving) {
numa_make_global(addr, size);
}
return 0;
}
int err = errno; // save errno from mmap() call above
if (!recoverable_mmap_error(err)) {
warn_fail_commit_memory(addr, size, exec, err);
vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
}
return err;
}
bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
return os::Linux::commit_memory_impl(addr, size, exec) == 0;
}
void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
const char* mesg) {
assert(mesg != NULL, "mesg must be specified");
int err = os::Linux::commit_memory_impl(addr, size, exec);
if (err != 0) {
// the caller wants all commit errors to exit with the specified mesg:
warn_fail_commit_memory(addr, size, exec, err);
vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
}
}
// Define MAP_HUGETLB here so we can build HotSpot on old systems.
#ifndef MAP_HUGETLB
#define MAP_HUGETLB 0x40000
#endif
// Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
#ifndef MADV_HUGEPAGE
#define MADV_HUGEPAGE 14
#endif
int os::Linux::commit_memory_impl(char* addr, size_t size,
size_t alignment_hint, bool exec) {
int err = os::Linux::commit_memory_impl(addr, size, exec);
if (err == 0) {
realign_memory(addr, size, alignment_hint);
}
return err;
}
bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
bool exec) {
return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
}
void os::pd_commit_memory_or_exit(char* addr, size_t size,
size_t alignment_hint, bool exec,
const char* mesg) {
assert(mesg != NULL, "mesg must be specified");
int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
if (err != 0) {
// the caller wants all commit errors to exit with the specified mesg:
warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
}
}
void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
// We don't check the return value: madvise(MADV_HUGEPAGE) may not
// be supported or the memory may already be backed by huge pages.
::madvise(addr, bytes, MADV_HUGEPAGE);
}
}
void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
// This method works by doing an mmap over an existing mmaping and effectively discarding
// the existing pages. However it won't work for SHM-based large pages that cannot be
// uncommitted at all. We don't do anything in this case to avoid creating a segment with
// small pages on top of the SHM segment. This method always works for small pages, so we
// allow that in any case.
if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
commit_memory(addr, bytes, alignment_hint, !ExecMem);
}
}
void os::numa_make_global(char *addr, size_t bytes) {
Linux::numa_interleave_memory(addr, bytes);
}
// Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
// bind policy to MPOL_PREFERRED for the current thread.
#define USE_MPOL_PREFERRED 0
void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
// To make NUMA and large pages more robust when both enabled, we need to ease
// the requirements on where the memory should be allocated. MPOL_BIND is the
// default policy and it will force memory to be allocated on the specified
// node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
// the specified node, but will not force it. Using this policy will prevent
// getting SIGBUS when trying to allocate large pages on NUMA nodes with no
// free large pages.
Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
}
bool os::numa_topology_changed() { return false; }
size_t os::numa_get_groups_num() {
// Return just the number of nodes in which it's possible to allocate memory
// (in numa terminology, configured nodes).
return Linux::numa_num_configured_nodes();
}
int os::numa_get_group_id() {
int cpu_id = Linux::sched_getcpu();
if (cpu_id != -1) {
int lgrp_id = Linux::get_node_by_cpu(cpu_id);
if (lgrp_id != -1) {
return lgrp_id;
}
}
return 0;
}
int os::numa_get_group_id_for_address(const void* address) {
void** pages = const_cast<void**>(&address);
int id = -1;
if (os::Linux::numa_move_pages(0, 1, pages, NULL, &id, 0) == -1) {
return -1;
}
if (id < 0) {
return -1;
}
return id;
}
int os::Linux::get_existing_num_nodes() {
int node;
int highest_node_number = Linux::numa_max_node();
int num_nodes = 0;
// Get the total number of nodes in the system including nodes without memory.
for (node = 0; node <= highest_node_number; node++) {
if (is_node_in_existing_nodes(node)) {
num_nodes++;
}
}
return num_nodes;
}
size_t os::numa_get_leaf_groups(int *ids, size_t size) {
int highest_node_number = Linux::numa_max_node();
size_t i = 0;
// Map all node ids in which it is possible to allocate memory. Also nodes are
// not always consecutively available, i.e. available from 0 to the highest
// node number. If the nodes have been bound explicitly using numactl membind,
// then allocate memory from those nodes only.
for (int node = 0; node <= highest_node_number; node++) {
if (Linux::is_node_in_bound_nodes((unsigned int)node)) {
ids[i++] = node;
}
}
return i;
}
bool os::get_page_info(char *start, page_info* info) {
return false;
}
char *os::scan_pages(char *start, char* end, page_info* page_expected,
page_info* page_found) {
return end;
}
int os::Linux::sched_getcpu_syscall(void) {
unsigned int cpu = 0;
int retval = -1;
#if defined(IA32)
#ifndef SYS_getcpu
#define SYS_getcpu 318
#endif
retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
#elif defined(AMD64)
// Unfortunately we have to bring all these macros here from vsyscall.h
// to be able to compile on old linuxes.
#define __NR_vgetcpu 2
#define VSYSCALL_START (-10UL << 20)
#define VSYSCALL_SIZE 1024
#define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
retval = vgetcpu(&cpu, NULL, NULL);
#endif
return (retval == -1) ? retval : cpu;
}
void os::Linux::sched_getcpu_init() {
// sched_getcpu() should be in libc.
set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
dlsym(RTLD_DEFAULT, "sched_getcpu")));
// If it's not, try a direct syscall.
if (sched_getcpu() == -1) {
set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
(void*)&sched_getcpu_syscall));
}
if (sched_getcpu() == -1) {
vm_exit_during_initialization("getcpu(2) system call not supported by kernel");
}
}
// Something to do with the numa-aware allocator needs these symbols
extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
extern "C" JNIEXPORT void numa_error(char *where) { }
// Handle request to load libnuma symbol version 1.1 (API v1). If it fails
// load symbol from base version instead.
void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
void *f = dlvsym(handle, name, "libnuma_1.1");
if (f == NULL) {
f = dlsym(handle, name);
}
return f;
}
// Handle request to load libnuma symbol version 1.2 (API v2) only.
// Return NULL if the symbol is not defined in this particular version.
void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) {
return dlvsym(handle, name, "libnuma_1.2");
}
bool os::Linux::libnuma_init() {
if (sched_getcpu() != -1) { // Requires sched_getcpu() support
void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
if (handle != NULL) {
set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
libnuma_dlsym(handle, "numa_node_to_cpus")));
set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
libnuma_dlsym(handle, "numa_max_node")));
set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t,
libnuma_dlsym(handle, "numa_num_configured_nodes")));
set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
libnuma_dlsym(handle, "numa_available")));
set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
libnuma_dlsym(handle, "numa_tonode_memory")));
set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
libnuma_dlsym(handle, "numa_interleave_memory")));
set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t,
libnuma_v2_dlsym(handle, "numa_interleave_memory")));
set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
libnuma_dlsym(handle, "numa_set_bind_policy")));
set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t,
libnuma_dlsym(handle, "numa_bitmask_isbitset")));
set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t,
libnuma_dlsym(handle, "numa_distance")));
set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t,
libnuma_v2_dlsym(handle, "numa_get_membind")));
set_numa_get_interleave_mask(CAST_TO_FN_PTR(numa_get_interleave_mask_func_t,
libnuma_v2_dlsym(handle, "numa_get_interleave_mask")));
set_numa_move_pages(CAST_TO_FN_PTR(numa_move_pages_func_t,
libnuma_dlsym(handle, "numa_move_pages")));
if (numa_available() != -1) {
set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr"));
set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr"));
set_numa_interleave_bitmask(_numa_get_interleave_mask());
set_numa_membind_bitmask(_numa_get_membind());
// Create an index -> node mapping, since nodes are not always consecutive
_nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
rebuild_nindex_to_node_map();
// Create a cpu -> node mapping
_cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
rebuild_cpu_to_node_map();
return true;
}
}
}
return false;
}
size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
// Creating guard page is very expensive. Java thread has HotSpot
// guard pages, only enable glibc guard page for non-Java threads.
// (Remember: compiler thread is a Java thread, too!)
return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size());
}
void os::Linux::rebuild_nindex_to_node_map() {
int highest_node_number = Linux::numa_max_node();
nindex_to_node()->clear();
for (int node = 0; node <= highest_node_number; node++) {
if (Linux::is_node_in_existing_nodes(node)) {
nindex_to_node()->append(node);
}
}
}
// rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
// The table is later used in get_node_by_cpu().
void os::Linux::rebuild_cpu_to_node_map() {
const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
// in libnuma (possible values are starting from 16,
// and continuing up with every other power of 2, but less
// than the maximum number of CPUs supported by kernel), and
// is a subject to change (in libnuma version 2 the requirements
// are more reasonable) we'll just hardcode the number they use
// in the library.
const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
size_t cpu_num = processor_count();
size_t cpu_map_size = NCPUS / BitsPerCLong;
size_t cpu_map_valid_size =
MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
cpu_to_node()->clear();
cpu_to_node()->at_grow(cpu_num - 1);
size_t node_num = get_existing_num_nodes();
int distance = 0;
int closest_distance = INT_MAX;
int closest_node = 0;
unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
for (size_t i = 0; i < node_num; i++) {
// Check if node is configured (not a memory-less node). If it is not, find
// the closest configured node. Check also if node is bound, i.e. it's allowed
// to allocate memory from the node. If it's not allowed, map cpus in that node
// to the closest node from which memory allocation is allowed.
if (!is_node_in_configured_nodes(nindex_to_node()->at(i)) ||
!is_node_in_bound_nodes(nindex_to_node()->at(i))) {
closest_distance = INT_MAX;
// Check distance from all remaining nodes in the system. Ignore distance
// from itself, from another non-configured node, and from another non-bound
// node.
for (size_t m = 0; m < node_num; m++) {
if (m != i &&
is_node_in_configured_nodes(nindex_to_node()->at(m)) &&
is_node_in_bound_nodes(nindex_to_node()->at(m))) {
distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m));
// If a closest node is found, update. There is always at least one
// configured and bound node in the system so there is always at least
// one node close.
if (distance != 0 && distance < closest_distance) {
closest_distance = distance;
closest_node = nindex_to_node()->at(m);
}
}
}
} else {
// Current node is already a configured node.
closest_node = nindex_to_node()->at(i);
}
// Get cpus from the original node and map them to the closest node. If node
// is a configured node (not a memory-less node), then original node and
// closest node are the same.
if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
for (size_t j = 0; j < cpu_map_valid_size; j++) {
if (cpu_map[j] != 0) {
for (size_t k = 0; k < BitsPerCLong; k++) {
if (cpu_map[j] & (1UL << k)) {
cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node);
}
}
}
}
}
}
FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
}
int os::Linux::get_node_by_cpu(int cpu_id) {
if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
return cpu_to_node()->at(cpu_id);
}
return -1;
}
GrowableArray<int>* os::Linux::_cpu_to_node;
GrowableArray<int>* os::Linux::_nindex_to_node;
os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes;
os::Linux::numa_available_func_t os::Linux::_numa_available;
os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2;
os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset;
os::Linux::numa_distance_func_t os::Linux::_numa_distance;
os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind;
os::Linux::numa_get_interleave_mask_func_t os::Linux::_numa_get_interleave_mask;
os::Linux::numa_move_pages_func_t os::Linux::_numa_move_pages;
os::Linux::NumaAllocationPolicy os::Linux::_current_numa_policy;
unsigned long* os::Linux::_numa_all_nodes;
struct bitmask* os::Linux::_numa_all_nodes_ptr;
struct bitmask* os::Linux::_numa_nodes_ptr;
struct bitmask* os::Linux::_numa_interleave_bitmask;
struct bitmask* os::Linux::_numa_membind_bitmask;
bool os::pd_uncommit_memory(char* addr, size_t size) {
uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
return res != (uintptr_t) MAP_FAILED;
}
static address get_stack_commited_bottom(address bottom, size_t size) {
address nbot = bottom;
address ntop = bottom + size;
size_t page_sz = os::vm_page_size();
unsigned pages = size / page_sz;
unsigned char vec[1];
unsigned imin = 1, imax = pages + 1, imid;
int mincore_return_value = 0;
assert(imin <= imax, "Unexpected page size");
while (imin < imax) {
imid = (imax + imin) / 2;
nbot = ntop - (imid * page_sz);
// Use a trick with mincore to check whether the page is mapped or not.
// mincore sets vec to 1 if page resides in memory and to 0 if page
// is swapped output but if page we are asking for is unmapped
// it returns -1,ENOMEM
mincore_return_value = mincore(nbot, page_sz, vec);
if (mincore_return_value == -1) {
// Page is not mapped go up
// to find first mapped page
if (errno != EAGAIN) {
assert(errno == ENOMEM, "Unexpected mincore errno");
imax = imid;
}
} else {
// Page is mapped go down
// to find first not mapped page
imin = imid + 1;
}
}
nbot = nbot + page_sz;
// Adjust stack bottom one page up if last checked page is not mapped
if (mincore_return_value == -1) {
nbot = nbot + page_sz;
}
return nbot;
}
bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
int mincore_return_value;
const size_t stripe = 1024; // query this many pages each time
unsigned char vec[stripe + 1];
// set a guard
vec[stripe] = 'X';
const size_t page_sz = os::vm_page_size();
size_t pages = size / page_sz;
assert(is_aligned(start, page_sz), "Start address must be page aligned");
assert(is_aligned(size, page_sz), "Size must be page aligned");
committed_start = NULL;
int loops = (pages + stripe - 1) / stripe;
int committed_pages = 0;
address loop_base = start;
bool found_range = false;
for (int index = 0; index < loops && !found_range; index ++) {
assert(pages > 0, "Nothing to do");
int pages_to_query = (pages >= stripe) ? stripe : pages;
pages -= pages_to_query;
// Get stable read
while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN);
// During shutdown, some memory goes away without properly notifying NMT,
// E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object.
// Bailout and return as not committed for now.
if (mincore_return_value == -1 && errno == ENOMEM) {
return false;
}
assert(vec[stripe] == 'X', "overflow guard");
assert(mincore_return_value == 0, "Range must be valid");
// Process this stripe
for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) {
if ((vec[vecIdx] & 0x01) == 0) { // not committed
// End of current contiguous region
if (committed_start != NULL) {
found_range = true;
break;
}
} else { // committed
// Start of region
if (committed_start == NULL) {
committed_start = loop_base + page_sz * vecIdx;
}
committed_pages ++;
}
}
loop_base += pages_to_query * page_sz;
}
if (committed_start != NULL) {
assert(committed_pages > 0, "Must have committed region");
assert(committed_pages <= int(size / page_sz), "Can not commit more than it has");
assert(committed_start >= start && committed_start < start + size, "Out of range");
committed_size = page_sz * committed_pages;
return true;
} else {
assert(committed_pages == 0, "Should not have committed region");
return false;
}
}
// Linux uses a growable mapping for the stack, and if the mapping for
// the stack guard pages is not removed when we detach a thread the
// stack cannot grow beyond the pages where the stack guard was
// mapped. If at some point later in the process the stack expands to
// that point, the Linux kernel cannot expand the stack any further
// because the guard pages are in the way, and a segfault occurs.
//
// However, it's essential not to split the stack region by unmapping
// a region (leaving a hole) that's already part of the stack mapping,
// so if the stack mapping has already grown beyond the guard pages at
// the time we create them, we have to truncate the stack mapping.
// So, we need to know the extent of the stack mapping when
// create_stack_guard_pages() is called.
// We only need this for stacks that are growable: at the time of
// writing thread stacks don't use growable mappings (i.e. those
// creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
// only applies to the main thread.
// If the (growable) stack mapping already extends beyond the point
// where we're going to put our guard pages, truncate the mapping at
// that point by munmap()ping it. This ensures that when we later
// munmap() the guard pages we don't leave a hole in the stack
// mapping. This only affects the main/primordial thread
bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
if (os::is_primordial_thread()) {
// As we manually grow stack up to bottom inside create_attached_thread(),
// it's likely that os::Linux::initial_thread_stack_bottom is mapped and
// we don't need to do anything special.
// Check it first, before calling heavy function.
uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
unsigned char vec[1];
if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
// Fallback to slow path on all errors, including EAGAIN
stack_extent = (uintptr_t) get_stack_commited_bottom(
os::Linux::initial_thread_stack_bottom(),
(size_t)addr - stack_extent);
}
if (stack_extent < (uintptr_t)addr) {
::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
}
}
return os::commit_memory(addr, size, !ExecMem);
}
// If this is a growable mapping, remove the guard pages entirely by
// munmap()ping them. If not, just call uncommit_memory(). This only
// affects the main/primordial thread, but guard against future OS changes.
// It's safe to always unmap guard pages for primordial thread because we
// always place it right after end of the mapped region.
bool os::remove_stack_guard_pages(char* addr, size_t size) {
uintptr_t stack_extent, stack_base;
if (os::is_primordial_thread()) {
return ::munmap(addr, size) == 0;
}
return os::uncommit_memory(addr, size);
}
// If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
// at 'requested_addr'. If there are existing memory mappings at the same
// location, however, they will be overwritten. If 'fixed' is false,
// 'requested_addr' is only treated as a hint, the return value may or
// may not start from the requested address. Unlike Linux mmap(), this
// function returns NULL to indicate failure.
static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
char * addr;
int flags;
flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
if (fixed) {
assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
flags |= MAP_FIXED;
}
// Map reserved/uncommitted pages PROT_NONE so we fail early if we
// touch an uncommitted page. Otherwise, the read/write might
// succeed if we have enough swap space to back the physical page.
addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
flags, -1, 0);
return addr == MAP_FAILED ? NULL : addr;
}
// Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
// (req_addr != NULL) or with a given alignment.
// - bytes shall be a multiple of alignment.
// - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
// - alignment sets the alignment at which memory shall be allocated.
// It must be a multiple of allocation granularity.
// Returns address of memory or NULL. If req_addr was not NULL, will only return
// req_addr or NULL.
static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
size_t extra_size = bytes;
if (req_addr == NULL && alignment > 0) {
extra_size += alignment;
}
char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
-1, 0);
if (start == MAP_FAILED) {
start = NULL;
} else {
if (req_addr != NULL) {
if (start != req_addr) {
::munmap(start, extra_size);
start = NULL;
}
} else {
char* const start_aligned = align_up(start, alignment);
char* const end_aligned = start_aligned + bytes;
char* const end = start + extra_size;
if (start_aligned > start) {
::munmap(start, start_aligned - start);
}
if (end_aligned < end) {
::munmap(end_aligned, end - end_aligned);
}
start = start_aligned;
}
}
return start;
}
static int anon_munmap(char * addr, size_t size) {
return ::munmap(addr, size) == 0;
}
char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
size_t alignment_hint) {
return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
}
bool os::pd_release_memory(char* addr, size_t size) {
return anon_munmap(addr, size);
}
static bool linux_mprotect(char* addr, size_t size, int prot) {
// Linux wants the mprotect address argument to be page aligned.
char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size());
// According to SUSv3, mprotect() should only be used with mappings
// established by mmap(), and mmap() always maps whole pages. Unaligned
// 'addr' likely indicates problem in the VM (e.g. trying to change
// protection of malloc'ed or statically allocated memory). Check the
// caller if you hit this assert.
assert(addr == bottom, "sanity check");
size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with protection modes %x", p2i(bottom), p2i(bottom+size), prot);
return ::mprotect(bottom, size, prot) == 0;
}
// Set protections specified
bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
bool is_committed) {
unsigned int p = 0;
switch (prot) {
case MEM_PROT_NONE: p = PROT_NONE; break;
case MEM_PROT_READ: p = PROT_READ; break;
case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
default:
ShouldNotReachHere();
}
// is_committed is unused.
return linux_mprotect(addr, bytes, p);
}
bool os::guard_memory(char* addr, size_t size) {
return linux_mprotect(addr, size, PROT_NONE);
}
bool os::unguard_memory(char* addr, size_t size) {
return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
}
bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
size_t page_size) {
bool result = false;
void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE,
-1, 0);
if (p != MAP_FAILED) {
void *aligned_p = align_up(p, page_size);
result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
munmap(p, page_size * 2);
}
if (warn && !result) {
warning("TransparentHugePages is not supported by the operating system.");
}
return result;
}
bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
bool result = false;
void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
-1, 0);
if (p != MAP_FAILED) {
// We don't know if this really is a huge page or not.
FILE *fp = fopen("/proc/self/maps", "r");
if (fp) {
while (!feof(fp)) {
char chars[257];
long x = 0;
if (fgets(chars, sizeof(chars), fp)) {
if (sscanf(chars, "%lx-%*x", &x) == 1
&& x == (long)p) {
if (strstr (chars, "hugepage")) {
result = true;
break;
}
}
}
}
fclose(fp);
}
munmap(p, page_size);
}
if (warn && !result) {
warning("HugeTLBFS is not supported by the operating system.");
}
return result;
}
// From the coredump_filter documentation:
//
// - (bit 0) anonymous private memory
// - (bit 1) anonymous shared memory
// - (bit 2) file-backed private memory
// - (bit 3) file-backed shared memory
// - (bit 4) ELF header pages in file-backed private memory areas (it is
// effective only if the bit 2 is cleared)
// - (bit 5) hugetlb private memory
// - (bit 6) hugetlb shared memory
// - (bit 7) dax private memory
// - (bit 8) dax shared memory
//
static void set_coredump_filter(CoredumpFilterBit bit) {
FILE *f;
long cdm;
if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
return;
}
if (fscanf(f, "%lx", &cdm) != 1) {
fclose(f);
return;
}
long saved_cdm = cdm;
rewind(f);
cdm |= bit;
if (cdm != saved_cdm) {
fprintf(f, "%#lx", cdm);
}
fclose(f);
}
// Large page support
static size_t _large_page_size = 0;
size_t os::Linux::find_large_page_size() {
size_t large_page_size = 0;
// large_page_size on Linux is used to round up heap size. x86 uses either
// 2M or 4M page, depending on whether PAE (Physical Address Extensions)
// mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
// page as large as 256M.
//
// Here we try to figure out page size by parsing /proc/meminfo and looking
// for a line with the following format:
// Hugepagesize: 2048 kB
//
// If we can't determine the value (e.g. /proc is not mounted, or the text
// format has been changed), we'll use the largest page size supported by
// the processor.
#ifndef ZERO
large_page_size =
AARCH64_ONLY(2 * M)
AMD64_ONLY(2 * M)
ARM32_ONLY(2 * M)
IA32_ONLY(4 * M)
IA64_ONLY(256 * M)
PPC_ONLY(4 * M)
S390_ONLY(1 * M)
SPARC_ONLY(4 * M);
#endif // ZERO
FILE *fp = fopen("/proc/meminfo", "r");
if (fp) {
while (!feof(fp)) {
int x = 0;
char buf[16];
if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
large_page_size = x * K;
break;
}
} else {
// skip to next line
for (;;) {
int ch = fgetc(fp);
if (ch == EOF || ch == (int)'\n') break;
}
}
}
fclose(fp);
}
if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
proper_unit_for_byte_size(large_page_size));
}
return large_page_size;
}
size_t os::Linux::setup_large_page_size() {
_large_page_size = Linux::find_large_page_size();
const size_t default_page_size = (size_t)Linux::page_size();
if (_large_page_size > default_page_size) {
_page_sizes[0] = _large_page_size;
_page_sizes[1] = default_page_size;
_page_sizes[2] = 0;
}
return _large_page_size;
}
bool os::Linux::setup_large_page_type(size_t page_size) {
if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
FLAG_IS_DEFAULT(UseSHM) &&
FLAG_IS_DEFAULT(UseTransparentHugePages)) {
// The type of large pages has not been specified by the user.
// Try UseHugeTLBFS and then UseSHM.
UseHugeTLBFS = UseSHM = true;
// Don't try UseTransparentHugePages since there are known
// performance issues with it turned on. This might change in the future.
UseTransparentHugePages = false;
}
if (UseTransparentHugePages) {
bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
UseHugeTLBFS = false;
UseSHM = false;
return true;
}
UseTransparentHugePages = false;
}
if (UseHugeTLBFS) {
bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
UseSHM = false;
return true;
}
UseHugeTLBFS = false;
}
return UseSHM;
}
void os::large_page_init() {
if (!UseLargePages &&
!UseTransparentHugePages &&
!UseHugeTLBFS &&
!UseSHM) {
// Not using large pages.
return;
}
if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
// The user explicitly turned off large pages.
// Ignore the rest of the large pages flags.
UseTransparentHugePages = false;
UseHugeTLBFS = false;
UseSHM = false;
return;
}
size_t large_page_size = Linux::setup_large_page_size();
UseLargePages = Linux::setup_large_page_type(large_page_size);
set_coredump_filter(LARGEPAGES_BIT);
}
#ifndef SHM_HUGETLB
#define SHM_HUGETLB 04000
#endif
#define shm_warning_format(format, ...) \
do { \
if (UseLargePages && \
(!FLAG_IS_DEFAULT(UseLargePages) || \
!FLAG_IS_DEFAULT(UseSHM) || \
!FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
warning(format, __VA_ARGS__); \
} \
} while (0)
#define shm_warning(str) shm_warning_format("%s", str)
#define shm_warning_with_errno(str) \
do { \
int err = errno; \
shm_warning_format(str " (error = %d)", err); \
} while (0)
static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
assert(is_aligned(bytes, alignment), "Must be divisible by the alignment");
if (!is_aligned(alignment, SHMLBA)) {
assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
return NULL;
}
// To ensure that we get 'alignment' aligned memory from shmat,
// we pre-reserve aligned virtual memory and then attach to that.
char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
if (pre_reserved_addr == NULL) {
// Couldn't pre-reserve aligned memory.
shm_warning("Failed to pre-reserve aligned memory for shmat.");
return NULL;
}
// SHM_REMAP is needed to allow shmat to map over an existing mapping.
char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
if ((intptr_t)addr == -1) {
int err = errno;
shm_warning_with_errno("Failed to attach shared memory.");
assert(err != EACCES, "Unexpected error");
assert(err != EIDRM, "Unexpected error");
assert(err != EINVAL, "Unexpected error");
// Since we don't know if the kernel unmapped the pre-reserved memory area
// we can't unmap it, since that would potentially unmap memory that was
// mapped from other threads.
return NULL;
}
return addr;
}
static char* shmat_at_address(int shmid, char* req_addr) {
if (!is_aligned(req_addr, SHMLBA)) {
assert(false, "Requested address needs to be SHMLBA aligned");
return NULL;
}
char* addr = (char*)shmat(shmid, req_addr, 0);
if ((intptr_t)addr == -1) {
shm_warning_with_errno("Failed to attach shared memory.");
return NULL;
}
return addr;
}
static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
// If a req_addr has been provided, we assume that the caller has already aligned the address.
if (req_addr != NULL) {
assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment");
return shmat_at_address(shmid, req_addr);
}
// Since shmid has been setup with SHM_HUGETLB, shmat will automatically
// return large page size aligned memory addresses when req_addr == NULL.
// However, if the alignment is larger than the large page size, we have
// to manually ensure that the memory returned is 'alignment' aligned.
if (alignment > os::large_page_size()) {
assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
return shmat_with_alignment(shmid, bytes, alignment);
} else {
return shmat_at_address(shmid, NULL);
}
}
char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
char* req_addr, bool exec) {
// "exec" is passed in but not used. Creating the shared image for
// the code cache doesn't have an SHM_X executable permission to check.
assert(UseLargePages && UseSHM, "only for SHM large pages");
assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
assert(is_aligned(req_addr, alignment), "Unaligned address");
if (!is_aligned(bytes, os::large_page_size())) {
return NULL; // Fallback to small pages.
}
// Create a large shared memory region to attach to based on size.
// Currently, size is the total size of the heap.
int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
if (shmid == -1) {
// Possible reasons for shmget failure:
// 1. shmmax is too small for Java heap.
// > check shmmax value: cat /proc/sys/kernel/shmmax
// > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
// 2. not enough large page memory.
// > check available large pages: cat /proc/meminfo
// > increase amount of large pages:
// echo new_value > /proc/sys/vm/nr_hugepages
// Note 1: different Linux may use different name for this property,
// e.g. on Redhat AS-3 it is "hugetlb_pool".
// Note 2: it's possible there's enough physical memory available but
// they are so fragmented after a long run that they can't
// coalesce into large pages. Try to reserve large pages when
// the system is still "fresh".
shm_warning_with_errno("Failed to reserve shared memory.");
return NULL;
}
// Attach to the region.
char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
// Remove shmid. If shmat() is successful, the actual shared memory segment
// will be deleted when it's detached by shmdt() or when the process
// terminates. If shmat() is not successful this will remove the shared
// segment immediately.
shmctl(shmid, IPC_RMID, NULL);
return addr;
}
static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
int error) {
assert(error == ENOMEM, "Only expect to fail if no memory is available");
bool warn_on_failure = UseLargePages &&
(!FLAG_IS_DEFAULT(UseLargePages) ||
!FLAG_IS_DEFAULT(UseHugeTLBFS) ||
!FLAG_IS_DEFAULT(LargePageSizeInBytes));
if (warn_on_failure) {
char msg[128];
jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
warning("%s", msg);
}
}
char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
char* req_addr,
bool exec) {
assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
assert(is_aligned(bytes, os::large_page_size()), "Unaligned size");
assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
char* addr = (char*)::mmap(req_addr, bytes, prot,
MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
-1, 0);
if (addr == MAP_FAILED) {
warn_on_large_pages_failure(req_addr, bytes, errno);
return NULL;
}
assert(is_aligned(addr, os::large_page_size()), "Must be");
return addr;
}
// Reserve memory using mmap(MAP_HUGETLB).
// - bytes shall be a multiple of alignment.
// - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
// - alignment sets the alignment at which memory shall be allocated.
// It must be a multiple of allocation granularity.
// Returns address of memory or NULL. If req_addr was not NULL, will only return
// req_addr or NULL.
char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
size_t alignment,
char* req_addr,
bool exec) {
size_t large_page_size = os::large_page_size();
assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
assert(is_aligned(req_addr, alignment), "Must be");
assert(is_aligned(bytes, alignment), "Must be");
// First reserve - but not commit - the address range in small pages.
char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
if (start == NULL) {
return NULL;
}
assert(is_aligned(start, alignment), "Must be");
char* end = start + bytes;
// Find the regions of the allocated chunk that can be promoted to large pages.
char* lp_start = align_up(start, large_page_size);
char* lp_end = align_down(end, large_page_size);
size_t lp_bytes = lp_end - lp_start;
assert(is_aligned(lp_bytes, large_page_size), "Must be");
if (lp_bytes == 0) {
// The mapped region doesn't even span the start and the end of a large page.
// Fall back to allocate a non-special area.
::munmap(start, end - start);
return NULL;
}
int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
void* result;
// Commit small-paged leading area.
if (start != lp_start) {
result = ::mmap(start, lp_start - start, prot,
MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
-1, 0);
if (result == MAP_FAILED) {
::munmap(lp_start, end - lp_start);
return NULL;
}
}
// Commit large-paged area.
result = ::mmap(lp_start, lp_bytes, prot,
MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
-1, 0);
if (result == MAP_FAILED) {
warn_on_large_pages_failure(lp_start, lp_bytes, errno);
// If the mmap above fails, the large pages region will be unmapped and we
// have regions before and after with small pages. Release these regions.
//
// | mapped | unmapped | mapped |
// ^ ^ ^ ^
// start lp_start lp_end end
//
::munmap(start, lp_start - start);
::munmap(lp_end, end - lp_end);
return NULL;
}
// Commit small-paged trailing area.
if (lp_end != end) {
result = ::mmap(lp_end, end - lp_end, prot,
MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
-1, 0);
if (result == MAP_FAILED) {
::munmap(start, lp_end - start);
return NULL;
}
}
return start;
}
char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
size_t alignment,
char* req_addr,
bool exec) {
assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
assert(is_aligned(req_addr, alignment), "Must be");
assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be");
assert(is_power_of_2(os::large_page_size()), "Must be");
assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
} else {
return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
}
}
char* os::reserve_memory_special(size_t bytes, size_t alignment,
char* req_addr, bool exec) {
assert(UseLargePages, "only for large pages");
char* addr;
if (UseSHM) {
addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
} else {
assert(UseHugeTLBFS, "must be");
addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
}
if (addr != NULL) {
if (UseNUMAInterleaving) {
numa_make_global(addr, bytes);
}
// The memory is committed
MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
}
return addr;
}
bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
// detaching the SHM segment will also delete it, see reserve_memory_special_shm()
return shmdt(base) == 0;
}
bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
return pd_release_memory(base, bytes);
}
bool os::release_memory_special(char* base, size_t bytes) {
bool res;
if (MemTracker::tracking_level() > NMT_minimal) {
Tracker tkr(Tracker::release);
res = os::Linux::release_memory_special_impl(base, bytes);
if (res) {
tkr.record((address)base, bytes);
}
} else {
res = os::Linux::release_memory_special_impl(base, bytes);
}
return res;
}
bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
assert(UseLargePages, "only for large pages");
bool res;
if (UseSHM) {
res = os::Linux::release_memory_special_shm(base, bytes);
} else {
assert(UseHugeTLBFS, "must be");
res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
}
return res;
}
size_t os::large_page_size() {
return _large_page_size;
}
// With SysV SHM the entire memory region must be allocated as shared
// memory.
// HugeTLBFS allows application to commit large page memory on demand.
// However, when committing memory with HugeTLBFS fails, the region
// that was supposed to be committed will lose the old reservation
// and allow other threads to steal that memory region. Because of this
// behavior we can't commit HugeTLBFS memory.
bool os::can_commit_large_page_memory() {
return UseTransparentHugePages;
}
bool os::can_execute_large_page_memory() {
return UseTransparentHugePages || UseHugeTLBFS;
}
char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) {
assert(file_desc >= 0, "file_desc is not valid");
char* result = pd_attempt_reserve_memory_at(bytes, requested_addr);
if (result != NULL) {
if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) {
vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
}
}
return result;
}
// Reserve memory at an arbitrary address, only if that area is
// available (and not reserved for something else).
char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
// Assert only that the size is a multiple of the page size, since
// that's all that mmap requires, and since that's all we really know
// about at this low abstraction level. If we need higher alignment,
// we can either pass an alignment to this method or verify alignment
// in one of the methods further up the call chain. See bug 5044738.
assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
// Repeatedly allocate blocks until the block is allocated at the
// right spot.
// Linux mmap allows caller to pass an address as hint; give it a try first,
// if kernel honors the hint then we can return immediately.
char * addr = anon_mmap(requested_addr, bytes, false);
if (addr == requested_addr) {
return requested_addr;
}
if (addr != NULL) {
// mmap() is successful but it fails to reserve at the requested address
anon_munmap(addr, bytes);
}
return NULL;
}
// Sleep forever; naked call to OS-specific sleep; use with CAUTION
void os::infinite_sleep() {
while (true) { // sleep forever ...
::sleep(100); // ... 100 seconds at a time
}
}
// Used to convert frequent JVM_Yield() to nops
bool os::dont_yield() {
return DontYieldALot;
}
// Linux CFS scheduler (since 2.6.23) does not guarantee sched_yield(2) will
// actually give up the CPU. Since skip buddy (v2.6.28):
//
// * Sets the yielding task as skip buddy for current CPU's run queue.
// * Picks next from run queue, if empty, picks a skip buddy (can be the yielding task).
// * Clears skip buddies for this run queue (yielding task no longer a skip buddy).
//
// An alternative is calling os::naked_short_nanosleep with a small number to avoid
// getting re-scheduled immediately.
//
void os::naked_yield() {
sched_yield();
}
////////////////////////////////////////////////////////////////////////////////
// thread priority support
// Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
// only supports dynamic priority, static priority must be zero. For real-time
// applications, Linux supports SCHED_RR which allows static priority (1-99).
// However, for large multi-threaded applications, SCHED_RR is not only slower
// than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
// of 5 runs - Sep 2005).
//
// The following code actually changes the niceness of kernel-thread/LWP. It
// has an assumption that setpriority() only modifies one kernel-thread/LWP,
// not the entire user process, and user level threads are 1:1 mapped to kernel
// threads. It has always been the case, but could change in the future. For
// this reason, the code should not be used as default (ThreadPriorityPolicy=0).
// It is only used when ThreadPriorityPolicy=1 and may require system level permission
// (e.g., root privilege or CAP_SYS_NICE capability).
int os::java_to_os_priority[CriticalPriority + 1] = {
19, // 0 Entry should never be used
4, // 1 MinPriority
3, // 2
2, // 3
1, // 4
0, // 5 NormPriority
-1, // 6
-2, // 7
-3, // 8
-4, // 9 NearMaxPriority
-5, // 10 MaxPriority
-5 // 11 CriticalPriority
};
static int prio_init() {
if (ThreadPriorityPolicy == 1) {
if (geteuid() != 0) {
if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \
"e.g., being the root user. If the necessary permission is not " \
"possessed, changes to priority will be silently ignored.");
}
}
}
if (UseCriticalJavaThreadPriority) {
os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
}
return 0;
}
OSReturn os::set_native_priority(Thread* thread, int newpri) {
if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
return (ret == 0) ? OS_OK : OS_ERR;
}
OSReturn os::get_native_priority(const Thread* const thread,
int *priority_ptr) {
if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
*priority_ptr = java_to_os_priority[NormPriority];
return OS_OK;
}
errno = 0;
*priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
}
////////////////////////////////////////////////////////////////////////////////
// suspend/resume support
// The low-level signal-based suspend/resume support is a remnant from the
// old VM-suspension that used to be for java-suspension, safepoints etc,
// within hotspot. Currently used by JFR's OSThreadSampler
//
// The remaining code is greatly simplified from the more general suspension
// code that used to be used.
//
// The protocol is quite simple:
// - suspend:
// - sends a signal to the target thread
// - polls the suspend state of the osthread using a yield loop
// - target thread signal handler (SR_handler) sets suspend state
// and blocks in sigsuspend until continued
// - resume:
// - sets target osthread state to continue
// - sends signal to end the sigsuspend loop in the SR_handler
//
// Note that the SR_lock plays no role in this suspend/resume protocol,
// but is checked for NULL in SR_handler as a thread termination indicator.
// The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
//
// Note that resume_clear_context() and suspend_save_context() are needed
// by SR_handler(), so that fetch_frame_from_ucontext() works,
// which in part is used by:
// - Forte Analyzer: AsyncGetCallTrace()
// - StackBanging: get_frame_at_stack_banging_point()
static void resume_clear_context(OSThread *osthread) {
osthread->set_ucontext(NULL);
osthread->set_siginfo(NULL);
}
static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
ucontext_t* context) {
osthread->set_ucontext(context);
osthread->set_siginfo(siginfo);
}
// Handler function invoked when a thread's execution is suspended or
// resumed. We have to be careful that only async-safe functions are
// called here (Note: most pthread functions are not async safe and
// should be avoided.)
//
// Note: sigwait() is a more natural fit than sigsuspend() from an
// interface point of view, but sigwait() prevents the signal hander
// from being run. libpthread would get very confused by not having
// its signal handlers run and prevents sigwait()'s use with the
// mutex granting granting signal.
//
// Currently only ever called on the VMThread and JavaThreads (PC sampling)
//
static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
// Save and restore errno to avoid confusing native code with EINTR
// after sigsuspend.
int old_errno = errno;
Thread* thread = Thread::current_or_null_safe();
assert(thread != NULL, "Missing current thread in SR_handler");
// On some systems we have seen signal delivery get "stuck" until the signal
// mask is changed as part of thread termination. Check that the current thread
// has not already terminated (via SR_lock()) - else the following assertion
// will fail because the thread is no longer a JavaThread as the ~JavaThread
// destructor has completed.
if (thread->SR_lock() == NULL) {
return;
}
assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
OSThread* osthread = thread->osthread();
os::SuspendResume::State current = osthread->sr.state();
if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
suspend_save_context(osthread, siginfo, context);
// attempt to switch the state, we assume we had a SUSPEND_REQUEST
os::SuspendResume::State state = osthread->sr.suspended();
if (state == os::SuspendResume::SR_SUSPENDED) {
sigset_t suspend_set; // signals for sigsuspend()
sigemptyset(&suspend_set);
// get current set of blocked signals and unblock resume signal
pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
sigdelset(&suspend_set, SR_signum);
sr_semaphore.signal();
// wait here until we are resumed
while (1) {
sigsuspend(&suspend_set);
os::SuspendResume::State result = osthread->sr.running();
if (result == os::SuspendResume::SR_RUNNING) {
sr_semaphore.signal();
break;
}
}
} else if (state == os::SuspendResume::SR_RUNNING) {
// request was cancelled, continue
} else {
ShouldNotReachHere();
}
resume_clear_context(osthread);
} else if (current == os::SuspendResume::SR_RUNNING) {
// request was cancelled, continue
} else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
// ignore
} else {
// ignore
}
errno = old_errno;
}
static int SR_initialize() {
struct sigaction act;
char *s;
// Get signal number to use for suspend/resume
if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
int sig = ::strtol(s, 0, 10);
if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
sig < NSIG) { // Must be legal signal and fit into sigflags[].
SR_signum = sig;
} else {
warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
}
}
assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
"SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
sigemptyset(&SR_sigset);
sigaddset(&SR_sigset, SR_signum);
// Set up signal handler for suspend/resume
act.sa_flags = SA_RESTART|SA_SIGINFO;
act.sa_handler = (void (*)(int)) SR_handler;
// SR_signum is blocked by default.
// 4528190 - We also need to block pthread restart signal (32 on all
// supported Linux platforms). Note that LinuxThreads need to block
// this signal for all threads to work properly. So we don't have
// to use hard-coded signal number when setting up the mask.
pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
if (sigaction(SR_signum, &act, 0) == -1) {
return -1;
}
// Save signal flag
os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
return 0;
}
static int sr_notify(OSThread* osthread) {
int status = pthread_kill(osthread->pthread_id(), SR_signum);
assert_status(status == 0, status, "pthread_kill");
return status;
}
// "Randomly" selected value for how long we want to spin
// before bailing out on suspending a thread, also how often
// we send a signal to a thread we want to resume
static const int RANDOMLY_LARGE_INTEGER = 1000000;
static const int RANDOMLY_LARGE_INTEGER2 = 100;
// returns true on success and false on error - really an error is fatal
// but this seems the normal response to library errors
static bool do_suspend(OSThread* osthread) {
assert(osthread->sr.is_running(), "thread should be running");
assert(!sr_semaphore.trywait(), "semaphore has invalid state");
// mark as suspended and send signal
if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
// failed to switch, state wasn't running?
ShouldNotReachHere();
return false;
}
if (sr_notify(osthread) != 0) {
ShouldNotReachHere();
}
// managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
while (true) {
if (sr_semaphore.timedwait(2)) {
break;
} else {
// timeout
os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
if (cancelled == os::SuspendResume::SR_RUNNING) {
return false;
} else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
// make sure that we consume the signal on the semaphore as well
sr_semaphore.wait();
break;
} else {
ShouldNotReachHere();
return false;
}
}
}
guarantee(osthread->sr.is_suspended(), "Must be suspended");
return true;
}
static void do_resume(OSThread* osthread) {
assert(osthread->sr.is_suspended(), "thread should be suspended");
assert(!sr_semaphore.trywait(), "invalid semaphore state");
if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
// failed to switch to WAKEUP_REQUEST
ShouldNotReachHere();
return;
}
while (true) {
if (sr_notify(osthread) == 0) {
if (sr_semaphore.timedwait(2)) {
if (osthread->sr.is_running()) {
return;
}
}
} else {
ShouldNotReachHere();
}
}
guarantee(osthread->sr.is_running(), "Must be running!");
}
///////////////////////////////////////////////////////////////////////////////////
// signal handling (except suspend/resume)
// This routine may be used by user applications as a "hook" to catch signals.
// The user-defined signal handler must pass unrecognized signals to this
// routine, and if it returns true (non-zero), then the signal handler must
// return immediately. If the flag "abort_if_unrecognized" is true, then this
// routine will never retun false (zero), but instead will execute a VM panic
// routine kill the process.
//
// If this routine returns false, it is OK to call it again. This allows
// the user-defined signal handler to perform checks either before or after
// the VM performs its own checks. Naturally, the user code would be making
// a serious error if it tried to handle an exception (such as a null check
// or breakpoint) that the VM was generating for its own correct operation.
//
// This routine may recognize any of the following kinds of signals:
// SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
// It should be consulted by handlers for any of those signals.
//
// The caller of this routine must pass in the three arguments supplied
// to the function referred to in the "sa_sigaction" (not the "sa_handler")
// field of the structure passed to sigaction(). This routine assumes that
// the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
//
// Note that the VM will print warnings if it detects conflicting signal
// handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
//
extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
siginfo_t* siginfo,
void* ucontext,
int abort_if_unrecognized);
static void signalHandler(int sig, siginfo_t* info, void* uc) {
assert(info != NULL && uc != NULL, "it must be old kernel");
int orig_errno = errno; // Preserve errno value over signal handler.
JVM_handle_linux_signal(sig, info, uc, true);
errno = orig_errno;
}
// This boolean allows users to forward their own non-matching signals
// to JVM_handle_linux_signal, harmlessly.
bool os::Linux::signal_handlers_are_installed = false;
// For signal-chaining
bool os::Linux::libjsig_is_loaded = false;
typedef struct sigaction *(*get_signal_t)(int);
get_signal_t os::Linux::get_signal_action = NULL;
struct sigaction* os::Linux::get_chained_signal_action(int sig) {
struct sigaction *actp = NULL;
if (libjsig_is_loaded) {
// Retrieve the old signal handler from libjsig
actp = (*get_signal_action)(sig);
}
if (actp == NULL) {
// Retrieve the preinstalled signal handler from jvm
actp = os::Posix::get_preinstalled_handler(sig);
}
return actp;
}
static bool call_chained_handler(struct sigaction *actp, int sig,
siginfo_t *siginfo, void *context) {
// Call the old signal handler
if (actp->sa_handler == SIG_DFL) {
// It's more reasonable to let jvm treat it as an unexpected exception
// instead of taking the default action.
return false;
} else if (actp->sa_handler != SIG_IGN) {
if ((actp->sa_flags & SA_NODEFER) == 0) {
// automaticlly block the signal
sigaddset(&(actp->sa_mask), sig);
}
sa_handler_t hand = NULL;
sa_sigaction_t sa = NULL;
bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
// retrieve the chained handler
if (siginfo_flag_set) {
sa = actp->sa_sigaction;
} else {
hand = actp->sa_handler;
}
if ((actp->sa_flags & SA_RESETHAND) != 0) {
actp->sa_handler = SIG_DFL;
}
// try to honor the signal mask
sigset_t oset;
sigemptyset(&oset);
pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
// call into the chained handler
if (siginfo_flag_set) {
(*sa)(sig, siginfo, context);
} else {
(*hand)(sig);
}
// restore the signal mask
pthread_sigmask(SIG_SETMASK, &oset, NULL);
}
// Tell jvm's signal handler the signal is taken care of.
return true;
}
bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
bool chained = false;
// signal-chaining
if (UseSignalChaining) {
struct sigaction *actp = get_chained_signal_action(sig);
if (actp != NULL) {
chained = call_chained_handler(actp, sig, siginfo, context);
}
}
return chained;
}
// for diagnostic
int sigflags[NSIG];
int os::Linux::get_our_sigflags(int sig) {
assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
return sigflags[sig];
}
void os::Linux::set_our_sigflags(int sig, int flags) {
assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
if (sig > 0 && sig < NSIG) {
sigflags[sig] = flags;
}
}
void os::Linux::set_signal_handler(int sig, bool set_installed) {
// Check for overwrite.
struct sigaction oldAct;
sigaction(sig, (struct sigaction*)NULL, &oldAct);
void* oldhand = oldAct.sa_sigaction
? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
: CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
if (AllowUserSignalHandlers || !set_installed) {
// Do not overwrite; user takes responsibility to forward to us.
return;
} else if (UseSignalChaining) {
// save the old handler in jvm
os::Posix::save_preinstalled_handler(sig, oldAct);
// libjsig also interposes the sigaction() call below and saves the
// old sigaction on it own.
} else {
fatal("Encountered unexpected pre-existing sigaction handler "
"%#lx for signal %d.", (long)oldhand, sig);
}
}
struct sigaction sigAct;
sigfillset(&(sigAct.sa_mask));
sigAct.sa_handler = SIG_DFL;
if (!set_installed) {
sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
} else {
sigAct.sa_sigaction = signalHandler;
sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
}
// Save flags, which are set by ours
assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
sigflags[sig] = sigAct.sa_flags;
int ret = sigaction(sig, &sigAct, &oldAct);
assert(ret == 0, "check");
void* oldhand2 = oldAct.sa_sigaction
? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
: CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
assert(oldhand2 == oldhand, "no concurrent signal handler installation");
}
// install signal handlers for signals that HotSpot needs to
// handle in order to support Java-level exception handling.
void os::Linux::install_signal_handlers() {
if (!signal_handlers_are_installed) {
signal_handlers_are_installed = true;
// signal-chaining
typedef void (*signal_setting_t)();
signal_setting_t begin_signal_setting = NULL;
signal_setting_t end_signal_setting = NULL;
begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
if (begin_signal_setting != NULL) {
end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
get_signal_action = CAST_TO_FN_PTR(get_signal_t,
dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
libjsig_is_loaded = true;
assert(UseSignalChaining, "should enable signal-chaining");
}
if (libjsig_is_loaded) {
// Tell libjsig jvm is setting signal handlers
(*begin_signal_setting)();
}
set_signal_handler(SIGSEGV, true);
set_signal_handler(SIGPIPE, true);
set_signal_handler(SIGBUS, true);
set_signal_handler(SIGILL, true);
set_signal_handler(SIGFPE, true);
#if defined(PPC64)
set_signal_handler(SIGTRAP, true);
#endif
set_signal_handler(SIGXFSZ, true);
if (libjsig_is_loaded) {
// Tell libjsig jvm finishes setting signal handlers
(*end_signal_setting)();
}
// We don't activate signal checker if libjsig is in place, we trust ourselves
// and if UserSignalHandler is installed all bets are off.
// Log that signal checking is off only if -verbose:jni is specified.
if (CheckJNICalls) {
if (libjsig_is_loaded) {
log_debug(jni, resolve)("Info: libjsig is activated, all active signal checking is disabled");
check_signals = false;
}
if (AllowUserSignalHandlers) {
log_debug(jni, resolve)("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
check_signals = false;
}
}
}
}
// This is the fastest way to get thread cpu time on Linux.
// Returns cpu time (user+sys) for any thread, not only for current.
// POSIX compliant clocks are implemented in the kernels 2.6.16+.
// It might work on 2.6.10+ with a special kernel/glibc patch.
// For reference, please, see IEEE Std 1003.1-2004:
// http://www.unix.org/single_unix_specification
jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
struct timespec tp;
int rc = os::Posix::clock_gettime(clockid, &tp);
assert(rc == 0, "clock_gettime is expected to return 0 code");
return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
}
/////
// glibc on Linux platform uses non-documented flag
// to indicate, that some special sort of signal
// trampoline is used.
// We will never set this flag, and we should
// ignore this flag in our diagnostic
#ifdef SIGNIFICANT_SIGNAL_MASK
#undef SIGNIFICANT_SIGNAL_MASK
#endif
#define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
static const char* get_signal_handler_name(address handler,
char* buf, int buflen) {
int offset = 0;
bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
if (found) {
// skip directory names
const char *p1, *p2;
p1 = buf;
size_t len = strlen(os::file_separator());
while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
} else {
jio_snprintf(buf, buflen, PTR_FORMAT, handler);
}
return buf;
}
static void print_signal_handler(outputStream* st, int sig,
char* buf, size_t buflen) {
struct sigaction sa;
sigaction(sig, NULL, &sa);
// See comment for SIGNIFICANT_SIGNAL_MASK define
sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
st->print("%s: ", os::exception_name(sig, buf, buflen));
address handler = (sa.sa_flags & SA_SIGINFO)
? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
: CAST_FROM_FN_PTR(address, sa.sa_handler);
if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
st->print("SIG_DFL");
} else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
st->print("SIG_IGN");
} else {
st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
}
st->print(", sa_mask[0]=");
os::Posix::print_signal_set_short(st, &sa.sa_mask);
address rh = VMError::get_resetted_sighandler(sig);
// May be, handler was resetted by VMError?
if (rh != NULL) {
handler = rh;
sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
}
st->print(", sa_flags=");
os::Posix::print_sa_flags(st, sa.sa_flags);
// Check: is it our handler?
if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
// It is our signal handler
// check for flags, reset system-used one!
if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
st->print(
", flags was changed from " PTR32_FORMAT ", consider using jsig library",
os::Linux::get_our_sigflags(sig));
}
}
st->cr();
}
#define DO_SIGNAL_CHECK(sig) \
do { \
if (!sigismember(&check_signal_done, sig)) { \
os::Linux::check_signal_handler(sig); \
} \
} while (0)
// This method is a periodic task to check for misbehaving JNI applications
// under CheckJNI, we can add any periodic checks here
void os::run_periodic_checks() {
if (check_signals == false) return;
// SEGV and BUS if overridden could potentially prevent
// generation of hs*.log in the event of a crash, debugging
// such a case can be very challenging, so we absolutely
// check the following for a good measure:
DO_SIGNAL_CHECK(SIGSEGV);
DO_SIGNAL_CHECK(SIGILL);
DO_SIGNAL_CHECK(SIGFPE);
DO_SIGNAL_CHECK(SIGBUS);
DO_SIGNAL_CHECK(SIGPIPE);
DO_SIGNAL_CHECK(SIGXFSZ);
#if defined(PPC64)
DO_SIGNAL_CHECK(SIGTRAP);
#endif
// ReduceSignalUsage allows the user to override these handlers
// see comments at the very top and jvm_md.h
if (!ReduceSignalUsage) {
DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
DO_SIGNAL_CHECK(BREAK_SIGNAL);
}
DO_SIGNAL_CHECK(SR_signum);
}
typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
static os_sigaction_t os_sigaction = NULL;
void os::Linux::check_signal_handler(int sig) {
char buf[O_BUFLEN];
address jvmHandler = NULL;
struct sigaction act;
if (os_sigaction == NULL) {
// only trust the default sigaction, in case it has been interposed
os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
if (os_sigaction == NULL) return;
}
os_sigaction(sig, (struct sigaction*)NULL, &act);
act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
address thisHandler = (act.sa_flags & SA_SIGINFO)
? CAST_FROM_FN_PTR(address, act.sa_sigaction)
: CAST_FROM_FN_PTR(address, act.sa_handler);
switch (sig) {
case SIGSEGV:
case SIGBUS:
case SIGFPE:
case SIGPIPE:
case SIGILL:
case SIGXFSZ:
jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
break;
case SHUTDOWN1_SIGNAL:
case SHUTDOWN2_SIGNAL:
case SHUTDOWN3_SIGNAL:
case BREAK_SIGNAL:
jvmHandler = (address)user_handler();
break;
default:
if (sig == SR_signum) {
jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
} else {
return;
}
break;
}
if (thisHandler != jvmHandler) {
tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
// No need to check this sig any longer
sigaddset(&check_signal_done, sig);
// Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
exception_name(sig, buf, O_BUFLEN));
}
} else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
tty->print("expected:");
os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
tty->cr();
tty->print(" found:");
os::Posix::print_sa_flags(tty, act.sa_flags);
tty->cr();
// No need to check this sig any longer
sigaddset(&check_signal_done, sig);
}
// Dump all the signal
if (sigismember(&check_signal_done, sig)) {
print_signal_handlers(tty, buf, O_BUFLEN);
}
}
extern void report_error(char* file_name, int line_no, char* title,
char* format, ...);
// this is called _before_ most of the global arguments have been parsed
void os::init(void) {
char dummy; // used to get a guess on initial stack address
clock_tics_per_sec = sysconf(_SC_CLK_TCK);
init_random(1234567);
Linux::set_page_size(sysconf(_SC_PAGESIZE));
if (Linux::page_size() == -1) {
fatal("os_linux.cpp: os::init: sysconf failed (%s)",
os::strerror(errno));
}
init_page_sizes((size_t) Linux::page_size());
Linux::initialize_system_info();
os::Linux::CPUPerfTicks pticks;
bool res = os::Linux::get_tick_information(&pticks, -1);
if (res && pticks.has_steal_ticks) {
has_initial_tick_info = true;
initial_total_ticks = pticks.total;
initial_steal_ticks = pticks.steal;
}
// _main_thread points to the thread that created/loaded the JVM.
Linux::_main_thread = pthread_self();
// retrieve entry point for pthread_setname_np
Linux::_pthread_setname_np =
(int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
os::Posix::init();
initial_time_count = javaTimeNanos();
// Always warn if no monotonic clock available
if (!os::Posix::supports_monotonic_clock()) {
warning("No monotonic clock was available - timed services may " \
"be adversely affected if the time-of-day clock changes");
}
}
// To install functions for atexit system call
extern "C" {
static void perfMemory_exit_helper() {
perfMemory_exit();
}
}
void os::pd_init_container_support() {
OSContainer::init();
}
void os::Linux::numa_init() {
// Java can be invoked as
// 1. Without numactl and heap will be allocated/configured on all nodes as
// per the system policy.
// 2. With numactl --interleave:
// Use numa_get_interleave_mask(v2) API to get nodes bitmask. The same
// API for membind case bitmask is reset.
// Interleave is only hint and Kernel can fallback to other nodes if
// no memory is available on the target nodes.
// 3. With numactl --membind:
// Use numa_get_membind(v2) API to get nodes bitmask. The same API for
// interleave case returns bitmask of all nodes.
// numa_all_nodes_ptr holds bitmask of all nodes.
// numa_get_interleave_mask(v2) and numa_get_membind(v2) APIs returns correct
// bitmask when externally configured to run on all or fewer nodes.
if (!Linux::libnuma_init()) {
UseNUMA = false;
} else {
if ((Linux::numa_max_node() < 1) || Linux::is_bound_to_single_node()) {
// If there's only one node (they start from 0) or if the process
// is bound explicitly to a single node using membind, disable NUMA.
UseNUMA = false;
} else {
LogTarget(Info,os) log;
LogStream ls(log);
Linux::set_configured_numa_policy(Linux::identify_numa_policy());
struct bitmask* bmp = Linux::_numa_membind_bitmask;
const char* numa_mode = "membind";
if (Linux::is_running_in_interleave_mode()) {
bmp = Linux::_numa_interleave_bitmask;
numa_mode = "interleave";
}
ls.print("UseNUMA is enabled and invoked in '%s' mode."
" Heap will be configured using NUMA memory nodes:", numa_mode);
for (int node = 0; node <= Linux::numa_max_node(); node++) {
if (Linux::_numa_bitmask_isbitset(bmp, node)) {
ls.print(" %d", node);
}
}
}
}
if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
// With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
// we can make the adaptive lgrp chunk resizing work. If the user specified both
// UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn
// and disable adaptive resizing.
if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, "
"disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
UseAdaptiveSizePolicy = false;
UseAdaptiveNUMAChunkSizing = false;
}
}
if (!UseNUMA && ForceNUMA) {
UseNUMA = true;
}
}
// this is called _after_ the global arguments have been parsed
jint os::init_2(void) {
// This could be set after os::Posix::init() but all platforms
// have to set it the same so we have to mirror Solaris.
DEBUG_ONLY(os::set_mutex_init_done();)
os::Posix::init_2();
Linux::fast_thread_clock_init();
// initialize suspend/resume support - must do this before signal_sets_init()
if (SR_initialize() != 0) {
perror("SR_initialize failed");
return JNI_ERR;
}
Linux::signal_sets_init();
Linux::install_signal_handlers();
// Initialize data for jdk.internal.misc.Signal
if (!ReduceSignalUsage) {
jdk_misc_signal_init();
}
if (AdjustStackSizeForTLS) {
get_minstack_init();
}
// Check and sets minimum stack sizes against command line options
if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
return JNI_ERR;
}
#if defined(IA32)
// Need to ensure we've determined the process's initial stack to
// perform the workaround
Linux::capture_initial_stack(JavaThread::stack_size_at_create());
workaround_expand_exec_shield_cs_limit();
#else
suppress_primordial_thread_resolution = Arguments::created_by_java_launcher();
if (!suppress_primordial_thread_resolution) {
Linux::capture_initial_stack(JavaThread::stack_size_at_create());
}
#endif
Linux::libpthread_init();
Linux::sched_getcpu_init();
log_info(os)("HotSpot is running with %s, %s",
Linux::glibc_version(), Linux::libpthread_version());
if (UseNUMA) {
Linux::numa_init();
}
if (MaxFDLimit) {
// set the number of file descriptors to max. print out error
// if getrlimit/setrlimit fails but continue regardless.
struct rlimit nbr_files;
int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
if (status != 0) {
log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
} else {
nbr_files.rlim_cur = nbr_files.rlim_max;
status = setrlimit(RLIMIT_NOFILE, &nbr_files);
if (status != 0) {
log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
}
}
}
// at-exit methods are called in the reverse order of their registration.
// atexit functions are called on return from main or as a result of a
// call to exit(3C). There can be only 32 of these functions registered
// and atexit() does not set errno.
if (PerfAllowAtExitRegistration) {
// only register atexit functions if PerfAllowAtExitRegistration is set.
// atexit functions can be delayed until process exit time, which
// can be problematic for embedded VM situations. Embedded VMs should
// call DestroyJavaVM() to assure that VM resources are released.
// note: perfMemory_exit_helper atexit function may be removed in
// the future if the appropriate cleanup code can be added to the
// VM_Exit VMOperation's doit method.
if (atexit(perfMemory_exit_helper) != 0) {
warning("os::init_2 atexit(perfMemory_exit_helper) failed");
}
}
// initialize thread priority policy
prio_init();
if (!FLAG_IS_DEFAULT(AllocateHeapAt) || !FLAG_IS_DEFAULT(AllocateOldGenAt)) {
set_coredump_filter(DAX_SHARED_BIT);
}
if (DumpPrivateMappingsInCore) {
set_coredump_filter(FILE_BACKED_PVT_BIT);
}
if (DumpSharedMappingsInCore) {
set_coredump_filter(FILE_BACKED_SHARED_BIT);
}
return JNI_OK;
}
// Mark the polling page as unreadable
void os::make_polling_page_unreadable(void) {
if (!guard_memory((char*)_polling_page, Linux::page_size())) {
fatal("Could not disable polling page");
}
}
// Mark the polling page as readable
void os::make_polling_page_readable(void) {
if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
fatal("Could not enable polling page");
}
}
// older glibc versions don't have this macro (which expands to
// an optimized bit-counting function) so we have to roll our own
#ifndef CPU_COUNT
static int _cpu_count(const cpu_set_t* cpus) {
int count = 0;
// only look up to the number of configured processors
for (int i = 0; i < os::processor_count(); i++) {
if (CPU_ISSET(i, cpus)) {
count++;
}
}
return count;
}
#define CPU_COUNT(cpus) _cpu_count(cpus)
#endif // CPU_COUNT
// Get the current number of available processors for this process.
// This value can change at any time during a process's lifetime.
// sched_getaffinity gives an accurate answer as it accounts for cpusets.
// If it appears there may be more than 1024 processors then we do a
// dynamic check - see 6515172 for details.
// If anything goes wrong we fallback to returning the number of online
// processors - which can be greater than the number available to the process.
int os::Linux::active_processor_count() {
cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
cpu_set_t* cpus_p = &cpus;
int cpus_size = sizeof(cpu_set_t);
int configured_cpus = os::processor_count(); // upper bound on available cpus
int cpu_count = 0;
// old build platforms may not support dynamic cpu sets
#ifdef CPU_ALLOC
// To enable easy testing of the dynamic path on different platforms we
// introduce a diagnostic flag: UseCpuAllocPath
if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
// kernel may use a mask bigger than cpu_set_t
log_trace(os)("active_processor_count: using dynamic path %s"
"- configured processors: %d",
UseCpuAllocPath ? "(forced) " : "",
configured_cpus);
cpus_p = CPU_ALLOC(configured_cpus);
if (cpus_p != NULL) {
cpus_size = CPU_ALLOC_SIZE(configured_cpus);
// zero it just to be safe
CPU_ZERO_S(cpus_size, cpus_p);
}
else {
// failed to allocate so fallback to online cpus
int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
log_trace(os)("active_processor_count: "
"CPU_ALLOC failed (%s) - using "
"online processor count: %d",
os::strerror(errno), online_cpus);
return online_cpus;
}
}
else {
log_trace(os)("active_processor_count: using static path - configured processors: %d",
configured_cpus);
}
#else // CPU_ALLOC
// these stubs won't be executed
#define CPU_COUNT_S(size, cpus) -1
#define CPU_FREE(cpus)
log_trace(os)("active_processor_count: only static path available - configured processors: %d",
configured_cpus);
#endif // CPU_ALLOC
// pid 0 means the current thread - which we have to assume represents the process
if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
}
else {
cpu_count = CPU_COUNT(cpus_p);
}
log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
}
else {
cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
warning("sched_getaffinity failed (%s)- using online processor count (%d) "
"which may exceed available processors", os::strerror(errno), cpu_count);
}
if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
CPU_FREE(cpus_p);
}
assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check");
return cpu_count;
}
// Determine the active processor count from one of
// three different sources:
//
// 1. User option -XX:ActiveProcessorCount
// 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN)
// 3. extracted from cgroup cpu subsystem (shares and quotas)
//
// Option 1, if specified, will always override.
// If the cgroup subsystem is active and configured, we
// will return the min of the cgroup and option 2 results.
// This is required since tools, such as numactl, that
// alter cpu affinity do not update cgroup subsystem
// cpuset configuration files.
int os::active_processor_count() {
// User has overridden the number of active processors
if (ActiveProcessorCount > 0) {
log_trace(os)("active_processor_count: "
"active processor count set by user : %d",
ActiveProcessorCount);
return ActiveProcessorCount;
}
int active_cpus;
if (OSContainer::is_containerized()) {
active_cpus = OSContainer::active_processor_count();
log_trace(os)("active_processor_count: determined by OSContainer: %d",
active_cpus);
} else {
active_cpus = os::Linux::active_processor_count();
}
return active_cpus;
}
uint os::processor_id() {
const int id = Linux::sched_getcpu();
assert(id >= 0 && id < _processor_count, "Invalid processor id");
return (uint)id;
}
void os::set_native_thread_name(const char *name) {
if (Linux::_pthread_setname_np) {
char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
snprintf(buf, sizeof(buf), "%s", name);
buf[sizeof(buf) - 1] = '\0';
const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
// ERANGE should not happen; all other errors should just be ignored.
assert(rc != ERANGE, "pthread_setname_np failed");
}
}
bool os::bind_to_processor(uint processor_id) {
// Not yet implemented.
return false;
}
///
void os::SuspendedThreadTask::internal_do_task() {
if (do_suspend(_thread->osthread())) {
SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
do_task(context);
do_resume(_thread->osthread());
}
}
////////////////////////////////////////////////////////////////////////////////
// debug support
bool os::find(address addr, outputStream* st) {
Dl_info dlinfo;
memset(&dlinfo, 0, sizeof(dlinfo));
if (dladdr(addr, &dlinfo) != 0) {
st->print(PTR_FORMAT ": ", p2i(addr));
if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
p2i(addr) - p2i(dlinfo.dli_saddr));
} else if (dlinfo.dli_fbase != NULL) {
st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
} else {
st->print("<absolute address>");
}
if (dlinfo.dli_fname != NULL) {
st->print(" in %s", dlinfo.dli_fname);
}
if (dlinfo.dli_fbase != NULL) {
st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
}
st->cr();
if (Verbose) {
// decode some bytes around the PC
address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
address lowest = (address) dlinfo.dli_sname;
if (!lowest) lowest = (address) dlinfo.dli_fbase;
if (begin < lowest) begin = lowest;
Dl_info dlinfo2;
if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
&& end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
end = (address) dlinfo2.dli_saddr;
}
Disassembler::decode(begin, end, st);
}
return true;
}
return false;
}
////////////////////////////////////////////////////////////////////////////////
// misc
// This does not do anything on Linux. This is basically a hook for being
// able to use structured exception handling (thread-local exception filters)
// on, e.g., Win32.
void
os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
JavaCallArguments* args, Thread* thread) {
f(value, method, args, thread);
}
void os::print_statistics() {
}
bool os::message_box(const char* title, const char* message) {
int i;
fdStream err(defaultStream::error_fd());
for (i = 0; i < 78; i++) err.print_raw("=");
err.cr();
err.print_raw_cr(title);
for (i = 0; i < 78; i++) err.print_raw("-");
err.cr();
err.print_raw_cr(message);
for (i = 0; i < 78; i++) err.print_raw("=");
err.cr();
char buf[16];
// Prevent process from exiting upon "read error" without consuming all CPU
while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
return buf[0] == 'y' || buf[0] == 'Y';
}
// Is a (classpath) directory empty?
bool os::dir_is_empty(const char* path) {
DIR *dir = NULL;
struct dirent *ptr;
dir = opendir(path);
if (dir == NULL) return true;
// Scan the directory
bool result = true;
while (result && (ptr = readdir(dir)) != NULL) {
if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
result = false;
}
}
closedir(dir);
return result;
}
// This code originates from JDK's sysOpen and open64_w
// from src/solaris/hpi/src/system_md.c
int os::open(const char *path, int oflag, int mode) {
if (strlen(path) > MAX_PATH - 1) {
errno = ENAMETOOLONG;
return -1;
}
// All file descriptors that are opened in the Java process and not
// specifically destined for a subprocess should have the close-on-exec
// flag set. If we don't set it, then careless 3rd party native code
// might fork and exec without closing all appropriate file descriptors
// (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
// turn might:
//
// - cause end-of-file to fail to be detected on some file
// descriptors, resulting in mysterious hangs, or
//
// - might cause an fopen in the subprocess to fail on a system
// suffering from bug 1085341.
//
// (Yes, the default setting of the close-on-exec flag is a Unix
// design flaw)
//
// See:
// 1085341: 32-bit stdio routines should support file descriptors >255
// 4843136: (process) pipe file descriptor from Runtime.exec not being closed
// 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
//
// Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
// O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
// because it saves a system call and removes a small window where the flag
// is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
// and we fall back to using FD_CLOEXEC (see below).
#ifdef O_CLOEXEC
oflag |= O_CLOEXEC;
#endif
int fd = ::open64(path, oflag, mode);
if (fd == -1) return -1;
//If the open succeeded, the file might still be a directory
{
struct stat64 buf64;
int ret = ::fstat64(fd, &buf64);
int st_mode = buf64.st_mode;
if (ret != -1) {
if ((st_mode & S_IFMT) == S_IFDIR) {
errno = EISDIR;
::close(fd);
return -1;
}
} else {
::close(fd);
return -1;
}
}
#ifdef FD_CLOEXEC
// Validate that the use of the O_CLOEXEC flag on open above worked.
// With recent kernels, we will perform this check exactly once.
static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
if (!O_CLOEXEC_is_known_to_work) {
int flags = ::fcntl(fd, F_GETFD);
if (flags != -1) {
if ((flags & FD_CLOEXEC) != 0)
O_CLOEXEC_is_known_to_work = 1;
else
::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
}
}
#endif
return fd;
}
// create binary file, rewriting existing file if required
int os::create_binary_file(const char* path, bool rewrite_existing) {
int oflags = O_WRONLY | O_CREAT;
if (!rewrite_existing) {
oflags |= O_EXCL;
}
/**代码未完, 请加载全部代码(NowJava.com).**/
关注时代Java
关注时代Java