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pthread_support.c
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pthread_support.c
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/*
* Copyright (c) 1994 by Xerox Corporation. All rights reserved.
* Copyright (c) 1996 by Silicon Graphics. All rights reserved.
* Copyright (c) 1998 by Fergus Henderson. All rights reserved.
* Copyright (c) 2000-2005 by Hewlett-Packard Company. All rights reserved.
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*/
#include "private/pthread_support.h"
/*
* Support code originally for LinuxThreads, the clone()-based kernel
* thread package for Linux which is included in libc6.
*
* This code no doubt makes some assumptions beyond what is
* guaranteed by the pthread standard, though it now does
* very little of that. It now also supports NPTL, and many
* other Posix thread implementations. We are trying to merge
* all flavors of pthread support code into this file.
*/
/*
* Linux_threads.c now also includes some code to support HPUX and
* OSF1 (Compaq Tru64 Unix, really). The OSF1 support is based on Eric Benson's
* patch.
*
* Eric also suggested an alternate basis for a lock implementation in
* his code:
* + #elif defined(OSF1)
* + unsigned long GC_allocate_lock = 0;
* + msemaphore GC_allocate_semaphore;
* + # define GC_TRY_LOCK() \
* + ((msem_lock(&GC_allocate_semaphore, MSEM_IF_NOWAIT) == 0) \
* + ? (GC_allocate_lock = 1) \
* + : 0)
* + # define GC_LOCK_TAKEN GC_allocate_lock
*/
#if defined(GC_PTHREADS) && !defined(GC_WIN32_THREADS)
# include <stdlib.h>
# include <pthread.h>
# include <sched.h>
# include <time.h>
# include <errno.h>
# include <unistd.h>
# if !defined(GC_RTEMS_PTHREADS)
# include <sys/mman.h>
# endif
# include <sys/time.h>
# include <sys/types.h>
# include <sys/stat.h>
# include <fcntl.h>
# include <signal.h>
# include "gc_inline.h"
#if defined(GC_DARWIN_THREADS)
# include "private/darwin_semaphore.h"
#else
# include <semaphore.h>
#endif /* !GC_DARWIN_THREADS */
#if defined(GC_DARWIN_THREADS) || defined(GC_FREEBSD_THREADS)
# include <sys/sysctl.h>
#endif /* GC_DARWIN_THREADS */
#if defined(GC_NETBSD_THREADS) || defined(GC_OPENBSD_THREADS)
# include <sys/param.h>
# include <sys/sysctl.h>
#endif /* GC_NETBSD_THREADS */
/* Allocator lock definitions. */
#if !defined(USE_SPIN_LOCK)
GC_INNER pthread_mutex_t GC_allocate_ml = PTHREAD_MUTEX_INITIALIZER;
#endif
#ifdef GC_ASSERTIONS
GC_INNER unsigned long GC_lock_holder = NO_THREAD;
/* Used only for assertions. */
#endif
#if defined(GC_DGUX386_THREADS)
# include <sys/dg_sys_info.h>
# include <sys/_int_psem.h>
/* sem_t is an uint in DG/UX */
typedef unsigned int sem_t;
#endif /* GC_DGUX386_THREADS */
/* Undefine macros used to redirect pthread primitives. */
# undef pthread_create
# ifndef GC_NO_PTHREAD_SIGMASK
# undef pthread_sigmask
# endif
# ifndef GC_NO_PTHREAD_CANCEL
# undef pthread_cancel
# endif
# ifdef GC_PTHREAD_EXIT_ATTRIBUTE
# undef pthread_exit
# endif
# undef pthread_join
# undef pthread_detach
# if defined(GC_OSF1_THREADS) && defined(_PTHREAD_USE_MANGLED_NAMES_) \
&& !defined(_PTHREAD_USE_PTDNAM_)
/* Restore the original mangled names on Tru64 UNIX. */
# define pthread_create __pthread_create
# define pthread_join __pthread_join
# define pthread_detach __pthread_detach
# ifndef GC_NO_PTHREAD_CANCEL
# define pthread_cancel __pthread_cancel
# endif
# ifdef GC_PTHREAD_EXIT_ATTRIBUTE
# define pthread_exit __pthread_exit
# endif
# endif
#ifdef GC_USE_LD_WRAP
# define WRAP_FUNC(f) __wrap_##f
# define REAL_FUNC(f) __real_##f
int REAL_FUNC(pthread_create)(pthread_t *,
GC_PTHREAD_CREATE_CONST pthread_attr_t *,
void *(*start_routine)(void *), void *);
int REAL_FUNC(pthread_join)(pthread_t, void **);
int REAL_FUNC(pthread_detach)(pthread_t);
# ifndef GC_NO_PTHREAD_SIGMASK
int REAL_FUNC(pthread_sigmask)(int, const sigset_t *, sigset_t *);
# endif
# ifndef GC_NO_PTHREAD_CANCEL
int REAL_FUNC(pthread_cancel)(pthread_t);
# endif
# ifdef GC_PTHREAD_EXIT_ATTRIBUTE
void REAL_FUNC(pthread_exit)(void *) GC_PTHREAD_EXIT_ATTRIBUTE;
# endif
#else
# ifdef GC_USE_DLOPEN_WRAP
# include <dlfcn.h>
# define WRAP_FUNC(f) f
# define REAL_FUNC(f) GC_real_##f
/* We define both GC_f and plain f to be the wrapped function. */
/* In that way plain calls work, as do calls from files that */
/* included gc.h, which redefined f to GC_f. */
/* FIXME: Needs work for DARWIN and True64 (OSF1) */
typedef int (* GC_pthread_create_t)(pthread_t *,
GC_PTHREAD_CREATE_CONST pthread_attr_t *,
void * (*)(void *), void *);
static GC_pthread_create_t REAL_FUNC(pthread_create);
# ifndef GC_NO_PTHREAD_SIGMASK
typedef int (* GC_pthread_sigmask_t)(int, const sigset_t *,
sigset_t *);
static GC_pthread_sigmask_t REAL_FUNC(pthread_sigmask);
# endif
typedef int (* GC_pthread_join_t)(pthread_t, void **);
static GC_pthread_join_t REAL_FUNC(pthread_join);
typedef int (* GC_pthread_detach_t)(pthread_t);
static GC_pthread_detach_t REAL_FUNC(pthread_detach);
# ifndef GC_NO_PTHREAD_CANCEL
typedef int (* GC_pthread_cancel_t)(pthread_t);
static GC_pthread_cancel_t REAL_FUNC(pthread_cancel);
# endif
# ifdef GC_PTHREAD_EXIT_ATTRIBUTE
typedef void (* GC_pthread_exit_t)(void *) GC_PTHREAD_EXIT_ATTRIBUTE;
static GC_pthread_exit_t REAL_FUNC(pthread_exit);
# endif
# else
# define WRAP_FUNC(f) GC_##f
# if !defined(GC_DGUX386_THREADS)
# define REAL_FUNC(f) f
# else /* GC_DGUX386_THREADS */
# define REAL_FUNC(f) __d10_##f
# endif /* GC_DGUX386_THREADS */
# endif
#endif
#if defined(GC_USE_LD_WRAP) || defined(GC_USE_DLOPEN_WRAP)
/* Define GC_ functions as aliases for the plain ones, which will */
/* be intercepted. This allows files which include gc.h, and hence */
/* generate references to the GC_ symbols, to see the right symbols. */
GC_API int GC_pthread_create(pthread_t * t,
GC_PTHREAD_CREATE_CONST pthread_attr_t *a,
void * (* fn)(void *), void * arg)
{
return pthread_create(t, a, fn, arg);
}
# ifndef GC_NO_PTHREAD_SIGMASK
GC_API int GC_pthread_sigmask(int how, const sigset_t *mask,
sigset_t *old)
{
return pthread_sigmask(how, mask, old);
}
# endif /* !GC_NO_PTHREAD_SIGMASK */
GC_API int GC_pthread_join(pthread_t t, void **res)
{
return pthread_join(t, res);
}
GC_API int GC_pthread_detach(pthread_t t)
{
return pthread_detach(t);
}
# ifndef GC_NO_PTHREAD_CANCEL
GC_API int GC_pthread_cancel(pthread_t t)
{
return pthread_cancel(t);
}
# endif /* !GC_NO_PTHREAD_CANCEL */
# ifdef GC_PTHREAD_EXIT_ATTRIBUTE
GC_API GC_PTHREAD_EXIT_ATTRIBUTE void GC_pthread_exit(void *retval)
{
pthread_exit(retval);
}
# endif /* GC_PTHREAD_EXIT_ATTRIBUTE */
#endif /* Linker-based interception. */
#ifdef GC_USE_DLOPEN_WRAP
STATIC GC_bool GC_syms_initialized = FALSE;
STATIC void GC_init_real_syms(void)
{
void *dl_handle;
if (GC_syms_initialized) return;
# ifdef RTLD_NEXT
dl_handle = RTLD_NEXT;
# else
dl_handle = dlopen("libpthread.so.0", RTLD_LAZY);
if (NULL == dl_handle) {
dl_handle = dlopen("libpthread.so", RTLD_LAZY); /* without ".0" */
}
if (NULL == dl_handle) ABORT("Couldn't open libpthread");
# endif
REAL_FUNC(pthread_create) = (GC_pthread_create_t)
dlsym(dl_handle, "pthread_create");
# ifdef RTLD_NEXT
if (REAL_FUNC(pthread_create) == 0)
ABORT("pthread_create not found"
" (probably -lgc is specified after -lpthread)");
# endif
# ifndef GC_NO_PTHREAD_SIGMASK
REAL_FUNC(pthread_sigmask) = (GC_pthread_sigmask_t)
dlsym(dl_handle, "pthread_sigmask");
# endif
REAL_FUNC(pthread_join) = (GC_pthread_join_t)
dlsym(dl_handle, "pthread_join");
REAL_FUNC(pthread_detach) = (GC_pthread_detach_t)
dlsym(dl_handle, "pthread_detach");
# ifndef GC_NO_PTHREAD_CANCEL
REAL_FUNC(pthread_cancel) = (GC_pthread_cancel_t)
dlsym(dl_handle, "pthread_cancel");
# endif
# ifdef GC_PTHREAD_EXIT_ATTRIBUTE
REAL_FUNC(pthread_exit) = (GC_pthread_exit_t)
dlsym(dl_handle, "pthread_exit");
# endif
GC_syms_initialized = TRUE;
}
# define INIT_REAL_SYMS() if (EXPECT(GC_syms_initialized, TRUE)) {} \
else GC_init_real_syms()
#else
# define INIT_REAL_SYMS() (void)0
#endif
static GC_bool parallel_initialized = FALSE;
#ifndef GC_ALWAYS_MULTITHREADED
GC_INNER GC_bool GC_need_to_lock = FALSE;
#endif
STATIC int GC_nprocs = 1;
/* Number of processors. We may not have */
/* access to all of them, but this is as good */
/* a guess as any ... */
#ifdef THREAD_LOCAL_ALLOC
/* We must explicitly mark ptrfree and gcj free lists, since the free */
/* list links wouldn't otherwise be found. We also set them in the */
/* normal free lists, since that involves touching less memory than */
/* if we scanned them normally. */
GC_INNER void GC_mark_thread_local_free_lists(void)
{
int i;
GC_thread p;
for (i = 0; i < THREAD_TABLE_SZ; ++i) {
for (p = GC_threads[i]; 0 != p; p = p -> next) {
if (!(p -> flags & FINISHED))
GC_mark_thread_local_fls_for(&(p->tlfs));
}
}
}
# if defined(GC_ASSERTIONS)
void GC_check_tls_for(GC_tlfs p);
# if defined(USE_CUSTOM_SPECIFIC)
void GC_check_tsd_marks(tsd *key);
# endif
/* Check that all thread-local free-lists are completely marked. */
/* Also check that thread-specific-data structures are marked. */
void GC_check_tls(void)
{
int i;
GC_thread p;
for (i = 0; i < THREAD_TABLE_SZ; ++i) {
for (p = GC_threads[i]; 0 != p; p = p -> next) {
if (!(p -> flags & FINISHED))
GC_check_tls_for(&(p->tlfs));
}
}
# if defined(USE_CUSTOM_SPECIFIC)
if (GC_thread_key != 0)
GC_check_tsd_marks(GC_thread_key);
# endif
}
# endif /* GC_ASSERTIONS */
#endif /* THREAD_LOCAL_ALLOC */
#ifdef PARALLEL_MARK
# ifndef MAX_MARKERS
# define MAX_MARKERS 16
# endif
static ptr_t marker_sp[MAX_MARKERS - 1] = {0};
#ifdef IA64
static ptr_t marker_bsp[MAX_MARKERS - 1] = {0};
#endif
#if defined(GC_DARWIN_THREADS) && !defined(GC_NO_THREADS_DISCOVERY)
static mach_port_t marker_mach_threads[MAX_MARKERS - 1] = {0};
/* Used only by GC_suspend_thread_list(). */
GC_INNER GC_bool GC_is_mach_marker(thread_act_t thread)
{
int i;
for (i = 0; i < GC_markers_m1; i++) {
if (marker_mach_threads[i] == thread)
return TRUE;
}
return FALSE;
}
#endif /* GC_DARWIN_THREADS */
STATIC void * GC_mark_thread(void * id)
{
word my_mark_no = 0;
IF_CANCEL(int cancel_state;)
if ((word)id == (word)-1) return 0; /* to make compiler happy */
DISABLE_CANCEL(cancel_state);
/* Mark threads are not cancellable; they */
/* should be invisible to client. */
marker_sp[(word)id] = GC_approx_sp();
# ifdef IA64
marker_bsp[(word)id] = GC_save_regs_in_stack();
# endif
# if defined(GC_DARWIN_THREADS) && !defined(GC_NO_THREADS_DISCOVERY)
marker_mach_threads[(word)id] = mach_thread_self();
# endif
for (;; ++my_mark_no) {
/* GC_mark_no is passed only to allow GC_help_marker to terminate */
/* promptly. This is important if it were called from the signal */
/* handler or from the GC lock acquisition code. Under Linux, it's */
/* not safe to call it from a signal handler, since it uses mutexes */
/* and condition variables. Since it is called only here, the */
/* argument is unnecessary. */
if (my_mark_no < GC_mark_no || my_mark_no > GC_mark_no + 2) {
/* resynchronize if we get far off, e.g. because GC_mark_no */
/* wrapped. */
my_mark_no = GC_mark_no;
}
# ifdef DEBUG_THREADS
GC_log_printf("Starting mark helper for mark number %lu\n",
(unsigned long)my_mark_no);
# endif
GC_help_marker(my_mark_no);
}
}
STATIC pthread_t GC_mark_threads[MAX_MARKERS];
#ifdef CAN_HANDLE_FORK
static int available_markers_m1 = 0;
# define start_mark_threads GC_start_mark_threads
GC_API void GC_CALL
#else
# define available_markers_m1 GC_markers_m1
static void
#endif
start_mark_threads(void)
{
int i;
pthread_attr_t attr;
GC_ASSERT(I_DONT_HOLD_LOCK());
# ifdef CAN_HANDLE_FORK
if (available_markers_m1 <= 0 || GC_parallel) return;
/* Skip if parallel markers disabled or already started. */
# endif
INIT_REAL_SYMS(); /* for pthread_create */
if (0 != pthread_attr_init(&attr)) ABORT("pthread_attr_init failed");
if (0 != pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED))
ABORT("pthread_attr_setdetachstate failed");
# if defined(HPUX) || defined(GC_DGUX386_THREADS)
/* Default stack size is usually too small: fix it. */
/* Otherwise marker threads or GC may run out of */
/* space. */
# define MIN_STACK_SIZE (8*HBLKSIZE*sizeof(word))
{
size_t old_size;
if (pthread_attr_getstacksize(&attr, &old_size) != 0)
ABORT("pthread_attr_getstacksize failed");
if (old_size < MIN_STACK_SIZE) {
if (pthread_attr_setstacksize(&attr, MIN_STACK_SIZE) != 0)
ABORT("pthread_attr_setstacksize failed");
}
}
# endif /* HPUX || GC_DGUX386_THREADS */
for (i = 0; i < available_markers_m1; ++i) {
if (0 != REAL_FUNC(pthread_create)(GC_mark_threads + i, &attr,
GC_mark_thread, (void *)(word)i)) {
WARN("Marker thread creation failed, errno = %" WARN_PRIdPTR "\n",
errno);
/* Don't try to create other marker threads. */
break;
}
}
GC_markers_m1 = i;
pthread_attr_destroy(&attr);
GC_COND_LOG_PRINTF("Started %d mark helper threads\n", GC_markers_m1);
}
#endif /* PARALLEL_MARK */
GC_INNER GC_bool GC_thr_initialized = FALSE;
GC_INNER volatile GC_thread GC_threads[THREAD_TABLE_SZ] = {0};
void GC_push_thread_structures(void)
{
GC_ASSERT(I_HOLD_LOCK());
GC_push_all((ptr_t)(GC_threads), (ptr_t)(GC_threads)+sizeof(GC_threads));
# if defined(THREAD_LOCAL_ALLOC)
GC_push_all((ptr_t)(&GC_thread_key),
(ptr_t)(&GC_thread_key) + sizeof(GC_thread_key));
# endif
}
#ifdef DEBUG_THREADS
STATIC int GC_count_threads(void)
{
int i;
int count = 0;
GC_ASSERT(I_HOLD_LOCK());
for (i = 0; i < THREAD_TABLE_SZ; ++i) {
GC_thread th = GC_threads[i];
while (th) {
if (!(th->flags & FINISHED))
++count;
th = th->next;
}
}
return count;
}
#endif /* DEBUG_THREADS */
/* It may not be safe to allocate when we register the first thread. */
static struct GC_Thread_Rep first_thread;
/* Add a thread to GC_threads. We assume it wasn't already there. */
/* Caller holds allocation lock. */
STATIC GC_thread GC_new_thread(pthread_t id)
{
int hv = NUMERIC_THREAD_ID(id) % THREAD_TABLE_SZ;
GC_thread result;
static GC_bool first_thread_used = FALSE;
# ifdef DEBUG_THREADS
GC_log_printf("Creating thread %p\n", (void *)id);
# endif
GC_ASSERT(I_HOLD_LOCK());
if (!EXPECT(first_thread_used, TRUE)) {
result = &first_thread;
first_thread_used = TRUE;
} else {
result = (struct GC_Thread_Rep *)
GC_INTERNAL_MALLOC(sizeof(struct GC_Thread_Rep), NORMAL);
if (result == 0) return(0);
}
result -> id = id;
# ifdef PLATFORM_ANDROID
result -> kernel_id = gettid();
# endif
result -> next = GC_threads[hv];
GC_threads[hv] = result;
# ifdef NACL
GC_nacl_gc_thread_self = result;
GC_nacl_initialize_gc_thread();
# endif
GC_ASSERT(result -> flags == 0 && result -> thread_blocked == 0);
return(result);
}
/* Delete a thread from GC_threads. We assume it is there. */
/* (The code intentionally traps if it wasn't.) */
/* It is safe to delete the main thread. */
STATIC void GC_delete_thread(pthread_t id)
{
int hv = NUMERIC_THREAD_ID(id) % THREAD_TABLE_SZ;
register GC_thread p = GC_threads[hv];
register GC_thread prev = 0;
# ifdef DEBUG_THREADS
GC_log_printf("Deleting thread %p, n_threads = %d\n",
(void *)id, GC_count_threads());
# endif
# ifdef NACL
GC_nacl_shutdown_gc_thread();
GC_nacl_gc_thread_self = NULL;
# endif
GC_ASSERT(I_HOLD_LOCK());
while (!THREAD_EQUAL(p -> id, id)) {
prev = p;
p = p -> next;
}
if (prev == 0) {
GC_threads[hv] = p -> next;
} else {
prev -> next = p -> next;
}
if (p != &first_thread) {
# ifdef GC_DARWIN_THREADS
mach_port_deallocate(mach_task_self(), p->stop_info.mach_thread);
# endif
GC_INTERNAL_FREE(p);
}
}
/* If a thread has been joined, but we have not yet */
/* been notified, then there may be more than one thread */
/* in the table with the same pthread id. */
/* This is OK, but we need a way to delete a specific one. */
STATIC void GC_delete_gc_thread(GC_thread t)
{
pthread_t id = t -> id;
int hv = NUMERIC_THREAD_ID(id) % THREAD_TABLE_SZ;
register GC_thread p = GC_threads[hv];
register GC_thread prev = 0;
GC_ASSERT(I_HOLD_LOCK());
while (p != t) {
prev = p;
p = p -> next;
}
if (prev == 0) {
GC_threads[hv] = p -> next;
} else {
prev -> next = p -> next;
}
# ifdef GC_DARWIN_THREADS
mach_port_deallocate(mach_task_self(), p->stop_info.mach_thread);
# endif
GC_INTERNAL_FREE(p);
# ifdef DEBUG_THREADS
GC_log_printf("Deleted thread %p, n_threads = %d\n",
(void *)id, GC_count_threads());
# endif
}
/* Return a GC_thread corresponding to a given pthread_t. */
/* Returns 0 if it's not there. */
/* Caller holds allocation lock or otherwise inhibits */
/* updates. */
/* If there is more than one thread with the given id we */
/* return the most recent one. */
GC_INNER GC_thread GC_lookup_thread(pthread_t id)
{
int hv = NUMERIC_THREAD_ID(id) % THREAD_TABLE_SZ;
register GC_thread p = GC_threads[hv];
while (p != 0 && !THREAD_EQUAL(p -> id, id)) p = p -> next;
return(p);
}
/* Called by GC_finalize() (in case of an allocation failure observed). */
GC_INNER void GC_reset_finalizer_nested(void)
{
GC_thread me = GC_lookup_thread(pthread_self());
me->finalizer_nested = 0;
}
/* Checks and updates the thread-local level of finalizers recursion. */
/* Returns NULL if GC_invoke_finalizers() should not be called by the */
/* collector (to minimize the risk of a deep finalizers recursion), */
/* otherwise returns a pointer to the thread-local finalizer_nested. */
/* Called by GC_notify_or_invoke_finalizers() only (the lock is held). */
GC_INNER unsigned char *GC_check_finalizer_nested(void)
{
GC_thread me = GC_lookup_thread(pthread_self());
unsigned nesting_level = me->finalizer_nested;
if (nesting_level) {
/* We are inside another GC_invoke_finalizers(). */
/* Skip some implicitly-called GC_invoke_finalizers() */
/* depending on the nesting (recursion) level. */
if (++me->finalizer_skipped < (1U << nesting_level)) return NULL;
me->finalizer_skipped = 0;
}
me->finalizer_nested = (unsigned char)(nesting_level + 1);
return &me->finalizer_nested;
}
#if defined(GC_ASSERTIONS) && defined(THREAD_LOCAL_ALLOC)
/* This is called from thread-local GC_malloc(). */
GC_bool GC_is_thread_tsd_valid(void *tsd)
{
GC_thread me;
DCL_LOCK_STATE;
LOCK();
me = GC_lookup_thread(pthread_self());
UNLOCK();
return (word)tsd >= (word)(&me->tlfs)
&& (word)tsd < (word)(&me->tlfs) + sizeof(me->tlfs);
}
#endif /* GC_ASSERTIONS && THREAD_LOCAL_ALLOC */
GC_API int GC_CALL GC_thread_is_registered(void)
{
pthread_t self = pthread_self();
GC_thread me;
DCL_LOCK_STATE;
LOCK();
me = GC_lookup_thread(self);
UNLOCK();
return me != NULL;
}
#ifdef CAN_HANDLE_FORK
/* Remove all entries from the GC_threads table, except the */
/* one for the current thread. We need to do this in the child */
/* process after a fork(), since only the current thread */
/* survives in the child. */
STATIC void GC_remove_all_threads_but_me(void)
{
pthread_t self = pthread_self();
int hv;
GC_thread p, next, me;
for (hv = 0; hv < THREAD_TABLE_SZ; ++hv) {
me = 0;
for (p = GC_threads[hv]; 0 != p; p = next) {
next = p -> next;
if (THREAD_EQUAL(p -> id, self)) {
me = p;
p -> next = 0;
# ifdef GC_DARWIN_THREADS
/* Update thread Id after fork (it is OK to call */
/* GC_destroy_thread_local and GC_free_internal */
/* before update). */
me -> stop_info.mach_thread = mach_thread_self();
# elif defined(PLATFORM_ANDROID)
me -> kernel_id = gettid();
# endif
# if defined(THREAD_LOCAL_ALLOC) && !defined(USE_CUSTOM_SPECIFIC)
/* Some TLS implementations might be not fork-friendly, so */
/* we re-assign thread-local pointer to 'tlfs' for safety */
/* instead of the assertion check (again, it is OK to call */
/* GC_destroy_thread_local and GC_free_internal before). */
if (GC_setspecific(GC_thread_key, &me->tlfs) != 0)
ABORT("GC_setspecific failed (in child)");
# endif
} else {
# ifdef THREAD_LOCAL_ALLOC
if (!(p -> flags & FINISHED)) {
GC_destroy_thread_local(&(p->tlfs));
GC_remove_specific(GC_thread_key);
}
# endif
if (p != &first_thread) GC_INTERNAL_FREE(p);
}
}
GC_threads[hv] = me;
}
}
#endif /* CAN_HANDLE_FORK */
#ifdef USE_PROC_FOR_LIBRARIES
GC_INNER GC_bool GC_segment_is_thread_stack(ptr_t lo, ptr_t hi)
{
int i;
GC_thread p;
GC_ASSERT(I_HOLD_LOCK());
# ifdef PARALLEL_MARK
for (i = 0; i < GC_markers_m1; ++i) {
if ((word)marker_sp[i] > (word)lo && (word)marker_sp[i] < (word)hi)
return TRUE;
# ifdef IA64
if ((word)marker_bsp[i] > (word)lo
&& (word)marker_bsp[i] < (word)hi)
return TRUE;
# endif
}
# endif
for (i = 0; i < THREAD_TABLE_SZ; i++) {
for (p = GC_threads[i]; p != 0; p = p -> next) {
if (0 != p -> stack_end) {
# ifdef STACK_GROWS_UP
if ((word)p->stack_end >= (word)lo
&& (word)p->stack_end < (word)hi)
return TRUE;
# else /* STACK_GROWS_DOWN */
if ((word)p->stack_end > (word)lo
&& (word)p->stack_end <= (word)hi)
return TRUE;
# endif
}
}
}
return FALSE;
}
#endif /* USE_PROC_FOR_LIBRARIES */
#ifdef IA64
/* Find the largest stack_base smaller than bound. May be used */
/* to find the boundary between a register stack and adjacent */
/* immediately preceding memory stack. */
GC_INNER ptr_t GC_greatest_stack_base_below(ptr_t bound)
{
int i;
GC_thread p;
ptr_t result = 0;
GC_ASSERT(I_HOLD_LOCK());
# ifdef PARALLEL_MARK
for (i = 0; i < GC_markers_m1; ++i) {
if ((word)marker_sp[i] > (word)result
&& (word)marker_sp[i] < (word)bound)
result = marker_sp[i];
}
# endif
for (i = 0; i < THREAD_TABLE_SZ; i++) {
for (p = GC_threads[i]; p != 0; p = p -> next) {
if ((word)p->stack_end > (word)result
&& (word)p->stack_end < (word)bound) {
result = p -> stack_end;
}
}
}
return result;
}
#endif /* IA64 */
#ifndef STAT_READ
/* Also defined in os_dep.c. */
# define STAT_BUF_SIZE 4096
# define STAT_READ read
/* If read is wrapped, this may need to be redefined to call */
/* the real one. */
#endif
#ifdef GC_HPUX_THREADS
# define GC_get_nprocs() pthread_num_processors_np()
#elif defined(GC_OSF1_THREADS) || defined(GC_AIX_THREADS) \
|| defined(GC_SOLARIS_THREADS) || defined(GC_GNU_THREADS) \
|| defined(PLATFORM_ANDROID) || defined(NACL)
GC_INLINE int GC_get_nprocs(void)
{
int nprocs = (int)sysconf(_SC_NPROCESSORS_ONLN);
return nprocs > 0 ? nprocs : 1; /* ignore error silently */
}
#elif defined(GC_IRIX_THREADS)
GC_INLINE int GC_get_nprocs(void)
{
int nprocs = (int)sysconf(_SC_NPROC_ONLN);
return nprocs > 0 ? nprocs : 1; /* ignore error silently */
}
#elif defined(GC_LINUX_THREADS) /* && !PLATFORM_ANDROID && !NACL */
/* Return the number of processors. */
STATIC int GC_get_nprocs(void)
{
/* Should be "return sysconf(_SC_NPROCESSORS_ONLN);" but that */
/* appears to be buggy in many cases. */
/* We look for lines "cpu<n>" in /proc/stat. */
char stat_buf[STAT_BUF_SIZE];
int f;
int result, i, len;
f = open("/proc/stat", O_RDONLY);
if (f < 0) {
WARN("Couldn't read /proc/stat\n", 0);
return 1; /* assume an uniprocessor */
}
len = STAT_READ(f, stat_buf, STAT_BUF_SIZE);
close(f);
result = 1;
/* Some old kernels only have a single "cpu nnnn ..." */
/* entry in /proc/stat. We identify those as */
/* uniprocessors. */
for (i = 0; i < len - 100; ++i) {
if (stat_buf[i] == '\n' && stat_buf[i+1] == 'c'
&& stat_buf[i+2] == 'p' && stat_buf[i+3] == 'u') {
int cpu_no = atoi(&stat_buf[i + 4]);
if (cpu_no >= result)
result = cpu_no + 1;
}
}
return result;
}
#elif defined(GC_DGUX386_THREADS)
/* Return the number of processors, or i <= 0 if it can't be determined. */
STATIC int GC_get_nprocs(void)
{
int numCpus;
struct dg_sys_info_pm_info pm_sysinfo;
int status = 0;
status = dg_sys_info((long int *) &pm_sysinfo,
DG_SYS_INFO_PM_INFO_TYPE, DG_SYS_INFO_PM_CURRENT_VERSION);
if (status < 0)
/* set -1 for error */
numCpus = -1;
else
/* Active CPUs */
numCpus = pm_sysinfo.idle_vp_count;
return(numCpus);
}
#elif defined(GC_DARWIN_THREADS) || defined(GC_FREEBSD_THREADS) \
|| defined(GC_NETBSD_THREADS) || defined(GC_OPENBSD_THREADS)
STATIC int GC_get_nprocs(void)
{
int mib[] = {CTL_HW,HW_NCPU};
int res;
size_t len = sizeof(res);
sysctl(mib, sizeof(mib)/sizeof(int), &res, &len, NULL, 0);
return res;
}
#else
/* E.g., GC_RTEMS_PTHREADS */
# define GC_get_nprocs() 1 /* not implemented */
#endif /* !GC_LINUX_THREADS && !GC_DARWIN_THREADS && ... */
#if defined(ARM32) && defined(GC_LINUX_THREADS) && !defined(NACL)
/* Some buggy Linux/arm kernels show only non-sleeping CPUs in */
/* /proc/stat (and /proc/cpuinfo), so another data system source is */
/* tried first. Result <= 0 on error. */
STATIC int GC_get_nprocs_present(void)
{
char stat_buf[16];
int f;
int len;
f = open("/sys/devices/system/cpu/present", O_RDONLY);
if (f < 0)
return -1; /* cannot open the file */
len = STAT_READ(f, stat_buf, sizeof(stat_buf));
close(f);
/* Recognized file format: "0\n" or "0-<max_cpu_id>\n" */
/* The file might probably contain a comma-separated list */
/* but we do not need to handle it (just silently ignore). */
if (len < 2 || stat_buf[0] != '0' || stat_buf[len - 1] != '\n') {
return 0; /* read error or unrecognized content */
} else if (len == 2) {
return 1; /* an uniprocessor */
} else if (stat_buf[1] != '-') {
return 0; /* unrecognized content */
}
stat_buf[len - 1] = '\0'; /* terminate the string */
return atoi(&stat_buf[2]) + 1; /* skip "0-" and parse max_cpu_num */
}
#endif /* ARM32 && GC_LINUX_THREADS && !NACL */
/* We hold the GC lock. Wait until an in-progress GC has finished. */
/* Repeatedly RELEASES GC LOCK in order to wait. */
/* If wait_for_all is true, then we exit with the GC lock held and no */
/* collection in progress; otherwise we just wait for the current GC */
/* to finish. */
STATIC void GC_wait_for_gc_completion(GC_bool wait_for_all)
{
DCL_LOCK_STATE;
GC_ASSERT(I_HOLD_LOCK());
ASSERT_CANCEL_DISABLED();
if (GC_incremental && GC_collection_in_progress()) {
word old_gc_no = GC_gc_no;
/* Make sure that no part of our stack is still on the mark stack, */
/* since it's about to be unmapped. */
while (GC_incremental && GC_collection_in_progress()
&& (wait_for_all || old_gc_no == GC_gc_no)) {
ENTER_GC();
GC_in_thread_creation = TRUE;
GC_collect_a_little_inner(1);
GC_in_thread_creation = FALSE;
EXIT_GC();
UNLOCK();
sched_yield();
LOCK();
}
}
}
#ifdef CAN_HANDLE_FORK
/* Procedures called before and after a fork. The goal here is to make */
/* it safe to call GC_malloc() in a forked child. It's unclear that is */
/* attainable, since the single UNIX spec seems to imply that one */
/* should only call async-signal-safe functions, and we probably can't */
/* quite guarantee that. But we give it our best shot. (That same */
/* spec also implies that it's not safe to call the system malloc */
/* between fork() and exec(). Thus we're doing no worse than it.) */
IF_CANCEL(static int fork_cancel_state;)
/* protected by allocation lock. */
/* Called before a fork() */
static void fork_prepare_proc(void)
{
/* Acquire all relevant locks, so that after releasing the locks */
/* the child will see a consistent state in which monitor */
/* invariants hold. Unfortunately, we can't acquire libc locks */
/* we might need, and there seems to be no guarantee that libc */
/* must install a suitable fork handler. */
/* Wait for an ongoing GC to finish, since we can't finish it in */
/* the (one remaining thread in) the child. */
LOCK();
DISABLE_CANCEL(fork_cancel_state);
/* Following waits may include cancellation points. */
# if defined(PARALLEL_MARK)
if (GC_parallel)
GC_wait_for_reclaim();
# endif
GC_wait_for_gc_completion(TRUE);
# if defined(PARALLEL_MARK)
if (GC_parallel)
GC_acquire_mark_lock();
# endif
}
/* Called in parent after a fork() (even if the latter failed). */
static void fork_parent_proc(void)
{
# if defined(PARALLEL_MARK)
if (GC_parallel)
GC_release_mark_lock();
# endif
RESTORE_CANCEL(fork_cancel_state);
UNLOCK();
}
/* Called in child after a fork() */
static void fork_child_proc(void)
{
/* Clean up the thread table, so that just our thread is left. */
# if defined(PARALLEL_MARK)
if (GC_parallel)
GC_release_mark_lock();
# endif
GC_remove_all_threads_but_me();
# ifdef PARALLEL_MARK
/* Turn off parallel marking in the child, since we are probably */
/* just going to exec, and we would have to restart mark threads. */
GC_parallel = FALSE;
# endif /* PARALLEL_MARK */
RESTORE_CANCEL(fork_cancel_state);
UNLOCK();
}