+++ /dev/null
-/*
- * 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) 2000-2001 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.
- */
-/*
- * Support code for LinuxThreads, the clone()-based kernel
- * thread package for Linux which is included in libc6.
- *
- * This code relies on implementation details of LinuxThreads,
- * (i.e. properties not guaranteed by the Pthread standard),
- * though this version now does less of that than the other Pthreads
- * support code.
- *
- * Note that there is a lot of code duplication between linux_threads.c
- * and thread support for some of the other Posix platforms; any changes
- * made here may need to be reflected there too.
- */
-/*
- * Linux_threads.c now also includes some code to support HPUX and
- * OSF1 (Compaq Tru64 Unix, really). The OSF1 support is not yet
- * functional. The OSF1 code is based on Eric Benson's
- * patch, though that was originally against hpux_irix_threads. The code
- * here is completely untested. With 0.0000001% probability, it might
- * actually work.
- *
- * 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
- */
-
-/* #define DEBUG_THREADS 1 */
-
-/* ANSI C requires that a compilation unit contains something */
-
-# include "gc.h"
-
-# if defined(GC_PTHREADS) && !defined(GC_SOLARIS_THREADS) \
- && !defined(GC_IRIX_THREADS)
-
-# include "private/gc_priv.h"
-
-# if defined(GC_HPUX_THREADS) && !defined(USE_PTHREAD_SPECIFIC) \
- && !defined(USE_HPUX_TLS)
-# define USE_HPUX_TLS
-# endif
-
-# ifdef THREAD_LOCAL_ALLOC
-# if !defined(USE_PTHREAD_SPECIFIC) && !defined(USE_HPUX_TLS)
-# include "private/specific.h"
-# endif
-# if defined(USE_PTHREAD_SPECIFIC)
-# define GC_getspecific pthread_getspecific
-# define GC_setspecific pthread_setspecific
-# define GC_key_create pthread_key_create
- typedef pthread_key_t GC_key_t;
-# endif
-# if defined(USE_HPUX_TLS)
-# define GC_getspecific(x) (x)
-# define GC_setspecific(key, v) ((key) = (v), 0)
-# define GC_key_create(key, d) 0
- typedef void * GC_key_t;
-# endif
-# endif
-# include <stdlib.h>
-# include <pthread.h>
-# include <sched.h>
-# include <time.h>
-# include <errno.h>
-# include <unistd.h>
-# include <sys/mman.h>
-# include <sys/time.h>
-# include <semaphore.h>
-# include <signal.h>
-# include <sys/types.h>
-# include <sys/stat.h>
-# include <fcntl.h>
-
-#ifndef __GNUC__
-# define __inline__
-#endif
-
-#ifdef GC_USE_LD_WRAP
-# define WRAP_FUNC(f) __wrap_##f
-# define REAL_FUNC(f) __real_##f
-#else
-# define WRAP_FUNC(f) GC_##f
-# define REAL_FUNC(f) f
-# undef pthread_create
-# undef pthread_sigmask
-# undef pthread_join
-# undef pthread_detach
-#endif
-
-
-void GC_thr_init();
-
-#if 0
-void GC_print_sig_mask()
-{
- sigset_t blocked;
- int i;
-
- if (pthread_sigmask(SIG_BLOCK, NULL, &blocked) != 0)
- ABORT("pthread_sigmask");
- GC_printf0("Blocked: ");
- for (i = 1; i <= MAXSIG; i++) {
- if (sigismember(&blocked, i)) { GC_printf1("%ld ",(long) i); }
- }
- GC_printf0("\n");
-}
-#endif
-
-
-/* We use the allocation lock to protect thread-related data structures. */
-
-/* The set of all known threads. We intercept thread creation and */
-/* joins. */
-/* Protected by allocation/GC lock. */
-/* Some of this should be declared volatile, but that's inconsistent */
-/* with some library routine declarations. */
-typedef struct GC_Thread_Rep {
- struct GC_Thread_Rep * next; /* More recently allocated threads */
- /* with a given pthread id come */
- /* first. (All but the first are */
- /* guaranteed to be dead, but we may */
- /* not yet have registered the join.) */
- pthread_t id;
- short flags;
-# define FINISHED 1 /* Thread has exited. */
-# define DETACHED 2 /* Thread is intended to be detached. */
-# define MAIN_THREAD 4 /* True for the original thread only. */
- short thread_blocked; /* Protected by GC lock. */
- /* Treated as a boolean value. If set, */
- /* thread will acquire GC lock before */
- /* doing any pointer manipulations, and */
- /* has set its sp value. Thus it does */
- /* not need to be sent a signal to stop */
- /* it. */
- ptr_t stack_end; /* Cold end of the stack. */
- ptr_t stack_ptr; /* Valid only when stopped. */
-# ifdef IA64
- ptr_t backing_store_end;
- ptr_t backing_store_ptr;
-# endif
- int signal;
- void * status; /* The value returned from the thread. */
- /* Used only to avoid premature */
- /* reclamation of any data it might */
- /* reference. */
-# ifdef THREAD_LOCAL_ALLOC
-# if CPP_WORDSZ == 64 && defined(ALIGN_DOUBLE)
-# define GRANULARITY 16
-# define NFREELISTS 49
-# else
-# define GRANULARITY 8
-# define NFREELISTS 65
-# endif
- /* The ith free list corresponds to size i*GRANULARITY */
-# define INDEX_FROM_BYTES(n) ((ADD_SLOP(n) + GRANULARITY - 1)/GRANULARITY)
-# define BYTES_FROM_INDEX(i) ((i) * GRANULARITY - EXTRA_BYTES)
-# define SMALL_ENOUGH(bytes) (ADD_SLOP(bytes) <= \
- (NFREELISTS-1)*GRANULARITY)
- ptr_t ptrfree_freelists[NFREELISTS];
- ptr_t normal_freelists[NFREELISTS];
-# ifdef GC_GCJ_SUPPORT
- ptr_t gcj_freelists[NFREELISTS];
-# endif
- /* Free lists contain either a pointer or a small count */
- /* reflecting the number of granules allocated at that */
- /* size. */
- /* 0 ==> thread-local allocation in use, free list */
- /* empty. */
- /* > 0, <= DIRECT_GRANULES ==> Using global allocation, */
- /* too few objects of this size have been */
- /* allocated by this thread. */
- /* >= HBLKSIZE => pointer to nonempty free list. */
- /* > DIRECT_GRANULES, < HBLKSIZE ==> transition to */
- /* local alloc, equivalent to 0. */
-# define DIRECT_GRANULES (HBLKSIZE/GRANULARITY)
- /* Don't use local free lists for up to this much */
- /* allocation. */
-# endif
-} * GC_thread;
-
-GC_thread GC_lookup_thread(pthread_t id);
-
-static GC_bool parallel_initialized = FALSE;
-
-void GC_init_parallel();
-
-# if defined(THREAD_LOCAL_ALLOC) && !defined(DBG_HDRS_ALL)
-
-/* We don't really support thread-local allocation with DBG_HDRS_ALL */
-
-#ifdef USE_HPUX_TLS
- __thread
-#endif
-GC_key_t GC_thread_key;
-
-static GC_bool keys_initialized;
-
-/* Recover the contents of the freelist array fl into the global one gfl.*/
-/* Note that the indexing scheme differs, in that gfl has finer size */
-/* resolution, even if not all entries are used. */
-/* We hold the allocator lock. */
-static void return_freelists(ptr_t *fl, ptr_t *gfl)
-{
- int i;
- ptr_t q, *qptr;
- size_t nwords;
-
- for (i = 1; i < NFREELISTS; ++i) {
- nwords = i * (GRANULARITY/sizeof(word));
- qptr = fl + i;
- q = *qptr;
- if ((word)q >= HBLKSIZE) {
- if (gfl[nwords] == 0) {
- gfl[nwords] = q;
- } else {
- /* Concatenate: */
- for (; (word)q >= HBLKSIZE; qptr = &(obj_link(q)), q = *qptr);
- GC_ASSERT(0 == q);
- *qptr = gfl[nwords];
- gfl[nwords] = fl[i];
- }
- }
- /* Clear fl[i], since the thread structure may hang around. */
- /* Do it in a way that is likely to trap if we access it. */
- fl[i] = (ptr_t)HBLKSIZE;
- }
-}
-
-/* We statically allocate a single "size 0" object. It is linked to */
-/* itself, and is thus repeatedly reused for all size 0 allocation */
-/* requests. (Size 0 gcj allocation requests are incorrect, and */
-/* we arrange for those to fault asap.) */
-static ptr_t size_zero_object = (ptr_t)(&size_zero_object);
-
-/* Each thread structure must be initialized. */
-/* This call must be made from the new thread. */
-/* Caller holds allocation lock. */
-void GC_init_thread_local(GC_thread p)
-{
- int i;
-
- if (!keys_initialized) {
- if (0 != GC_key_create(&GC_thread_key, 0)) {
- ABORT("Failed to create key for local allocator");
- }
- keys_initialized = TRUE;
- }
- if (0 != GC_setspecific(GC_thread_key, p)) {
- ABORT("Failed to set thread specific allocation pointers");
- }
- for (i = 1; i < NFREELISTS; ++i) {
- p -> ptrfree_freelists[i] = (ptr_t)1;
- p -> normal_freelists[i] = (ptr_t)1;
-# ifdef GC_GCJ_SUPPORT
- p -> gcj_freelists[i] = (ptr_t)1;
-# endif
- }
- /* Set up the size 0 free lists. */
- p -> ptrfree_freelists[0] = (ptr_t)(&size_zero_object);
- p -> normal_freelists[0] = (ptr_t)(&size_zero_object);
-# ifdef GC_GCJ_SUPPORT
- p -> gcj_freelists[0] = (ptr_t)(-1);
-# endif
-}
-
-#ifdef GC_GCJ_SUPPORT
- extern ptr_t * GC_gcjobjfreelist;
-#endif
-
-/* We hold the allocator lock. */
-void GC_destroy_thread_local(GC_thread p)
-{
- /* We currently only do this from the thread itself. */
- GC_ASSERT(GC_getspecific(GC_thread_key) == (void *)p);
- return_freelists(p -> ptrfree_freelists, GC_aobjfreelist);
- return_freelists(p -> normal_freelists, GC_objfreelist);
-# ifdef GC_GCJ_SUPPORT
- return_freelists(p -> gcj_freelists, GC_gcjobjfreelist);
-# endif
-}
-
-extern GC_PTR GC_generic_malloc_many();
-
-GC_PTR GC_local_malloc(size_t bytes)
-{
- if (EXPECT(!SMALL_ENOUGH(bytes),0)) {
- return(GC_malloc(bytes));
- } else {
- int index = INDEX_FROM_BYTES(bytes);
- ptr_t * my_fl;
- ptr_t my_entry;
- GC_key_t k = GC_thread_key;
- void * tsd;
-
-# if defined(REDIRECT_MALLOC) && !defined(USE_PTHREAD_SPECIFIC) \
- || !defined(__GNUC__)
- if (EXPECT(0 == k, 0)) {
- /* This can happen if we get called when the world is */
- /* being initialized. Whether we can actually complete */
- /* the initialization then is unclear. */
- GC_init_parallel();
- k = GC_thread_key;
- }
-# endif
- tsd = GC_getspecific(GC_thread_key);
-# ifdef GC_ASSERTIONS
- LOCK();
- GC_ASSERT(tsd == (void *)GC_lookup_thread(pthread_self()));
- UNLOCK();
-# endif
- my_fl = ((GC_thread)tsd) -> normal_freelists + index;
- my_entry = *my_fl;
- if (EXPECT((word)my_entry >= HBLKSIZE, 1)) {
- ptr_t next = obj_link(my_entry);
- GC_PTR result = (GC_PTR)my_entry;
- *my_fl = next;
- obj_link(my_entry) = 0;
- PREFETCH_FOR_WRITE(next);
- return result;
- } else if ((word)my_entry - 1 < DIRECT_GRANULES) {
- *my_fl = my_entry + index + 1;
- return GC_malloc(bytes);
- } else {
- GC_generic_malloc_many(BYTES_FROM_INDEX(index), NORMAL, my_fl);
- if (*my_fl == 0) return GC_oom_fn(bytes);
- return GC_local_malloc(bytes);
- }
- }
-}
-
-GC_PTR GC_local_malloc_atomic(size_t bytes)
-{
- if (EXPECT(!SMALL_ENOUGH(bytes), 0)) {
- return(GC_malloc_atomic(bytes));
- } else {
- int index = INDEX_FROM_BYTES(bytes);
- ptr_t * my_fl = ((GC_thread)GC_getspecific(GC_thread_key))
- -> ptrfree_freelists + index;
- ptr_t my_entry = *my_fl;
- if (EXPECT((word)my_entry >= HBLKSIZE, 1)) {
- GC_PTR result = (GC_PTR)my_entry;
- *my_fl = obj_link(my_entry);
- return result;
- } else if ((word)my_entry - 1 < DIRECT_GRANULES) {
- *my_fl = my_entry + index + 1;
- return GC_malloc_atomic(bytes);
- } else {
- GC_generic_malloc_many(BYTES_FROM_INDEX(index), PTRFREE, my_fl);
- /* *my_fl is updated while the collector is excluded; */
- /* the free list is always visible to the collector as */
- /* such. */
- if (*my_fl == 0) return GC_oom_fn(bytes);
- return GC_local_malloc_atomic(bytes);
- }
- }
-}
-
-#ifdef GC_GCJ_SUPPORT
-
-#include "include/gc_gcj.h"
-
-#ifdef GC_ASSERTIONS
- extern GC_bool GC_gcj_malloc_initialized;
-#endif
-
-extern int GC_gcj_kind;
-
-GC_PTR GC_local_gcj_malloc(size_t bytes,
- void * ptr_to_struct_containing_descr)
-{
- GC_ASSERT(GC_gcj_malloc_initialized);
- if (EXPECT(!SMALL_ENOUGH(bytes), 0)) {
- return GC_gcj_malloc(bytes, ptr_to_struct_containing_descr);
- } else {
- int index = INDEX_FROM_BYTES(bytes);
- ptr_t * my_fl = ((GC_thread)GC_getspecific(GC_thread_key))
- -> gcj_freelists + index;
- ptr_t my_entry = *my_fl;
- if (EXPECT((word)my_entry >= HBLKSIZE, 1)) {
- GC_PTR result = (GC_PTR)my_entry;
- GC_ASSERT(!GC_incremental);
- /* We assert that any concurrent marker will stop us. */
- /* Thus it is impossible for a mark procedure to see the */
- /* allocation of the next object, but to see this object */
- /* still containing a free list pointer. Otherwise the */
- /* marker might find a random "mark descriptor". */
- *(volatile ptr_t *)my_fl = obj_link(my_entry);
- /* We must update the freelist before we store the pointer. */
- /* Otherwise a GC at this point would see a corrupted */
- /* free list. */
- /* A memory barrier is probably never needed, since the */
- /* action of stopping this thread will cause prior writes */
- /* to complete. */
- GC_ASSERT(((void * volatile *)result)[1] == 0);
- *(void * volatile *)result = ptr_to_struct_containing_descr;
- return result;
- } else if ((word)my_entry - 1 < DIRECT_GRANULES) {
- *my_fl = my_entry + index + 1;
- return GC_gcj_malloc(bytes, ptr_to_struct_containing_descr);
- } else {
- GC_generic_malloc_many(BYTES_FROM_INDEX(index), GC_gcj_kind, my_fl);
- if (*my_fl == 0) return GC_oom_fn(bytes);
- return GC_local_gcj_malloc(bytes, ptr_to_struct_containing_descr);
- }
- }
-}
-
-#endif /* GC_GCJ_SUPPORT */
-
-# else /* !THREAD_LOCAL_ALLOC && !DBG_HDRS_ALL */
-
-# define GC_destroy_thread_local(t)
-
-# endif /* !THREAD_LOCAL_ALLOC */
-
-/*
- * We use signals to stop threads during GC.
- *
- * Suspended threads wait in signal handler for SIG_THR_RESTART.
- * That's more portable than semaphores or condition variables.
- * (We do use sem_post from a signal handler, but that should be portable.)
- *
- * The thread suspension signal SIG_SUSPEND is now defined in gc_priv.h.
- * Note that we can't just stop a thread; we need it to save its stack
- * pointer(s) and acknowledge.
- */
-
-#ifndef SIG_THR_RESTART
-# if defined(GC_HPUX_THREADS) || defined(GC_OSF1_THREADS)
-# define SIG_THR_RESTART _SIGRTMIN + 5
-# else
-# define SIG_THR_RESTART SIGXCPU
-# endif
-#endif
-
-sem_t GC_suspend_ack_sem;
-
-#if 0
-/*
-To make sure that we're using LinuxThreads and not some other thread
-package, we generate a dummy reference to `pthread_kill_other_threads_np'
-(was `__pthread_initial_thread_bos' but that disappeared),
-which is a symbol defined in LinuxThreads, but (hopefully) not in other
-thread packages.
-
-We no longer do this, since this code is now portable enough that it might
-actually work for something else.
-*/
-void (*dummy_var_to_force_linux_threads)() = pthread_kill_other_threads_np;
-#endif /* 0 */
-
-#if defined(SPARC) || defined(IA64)
- extern word GC_save_regs_in_stack();
-#endif
-
-long 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 PARALLEL_MARK
-
-# ifndef MAX_MARKERS
-# define MAX_MARKERS 16
-# endif
-
-static ptr_t marker_sp[MAX_MARKERS] = {0};
-
-void * GC_mark_thread(void * id)
-{
- word my_mark_no = 0;
-
- marker_sp[(word)id] = GC_approx_sp();
- 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_printf1("Starting mark helper for mark number %ld\n", my_mark_no);
-# endif
- GC_help_marker(my_mark_no);
- }
-}
-
-extern long GC_markers; /* Number of mark threads we would */
- /* like to have. Includes the */
- /* initiating thread. */
-
-pthread_t GC_mark_threads[MAX_MARKERS];
-
-#define PTHREAD_CREATE REAL_FUNC(pthread_create)
-
-static void start_mark_threads()
-{
- unsigned i;
- pthread_attr_t attr;
-
- if (GC_markers > MAX_MARKERS) {
- WARN("Limiting number of mark threads\n", 0);
- GC_markers = MAX_MARKERS;
- }
- 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");
-
-# ifdef HPUX
- /* 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;
- int code;
-
- if (pthread_attr_getstacksize(&attr, &old_size) != 0)
- ABORT("pthread_attr_getstacksize failed\n");
- if (old_size < MIN_STACK_SIZE) {
- if (pthread_attr_setstacksize(&attr, MIN_STACK_SIZE) != 0)
- ABORT("pthread_attr_setstacksize failed\n");
- }
- }
-# endif /* HPUX */
-# ifdef CONDPRINT
- if (GC_print_stats) {
- GC_printf1("Starting %ld marker threads\n", GC_markers - 1);
- }
-# endif
- for (i = 0; i < GC_markers - 1; ++i) {
- if (0 != PTHREAD_CREATE(GC_mark_threads + i, &attr,
- GC_mark_thread, (void *)(word)i)) {
- WARN("Marker thread creation failed, errno = %ld.\n", errno);
- }
- }
-}
-
-#else /* !PARALLEL_MARK */
-
-static __inline__ void start_mark_threads()
-{
-}
-
-#endif /* !PARALLEL_MARK */
-
-void GC_suspend_handler(int sig)
-{
- int dummy;
- pthread_t my_thread = pthread_self();
- GC_thread me;
- sigset_t all_sigs;
- sigset_t old_sigs;
- int i;
- sigset_t mask;
-# ifdef PARALLEL_MARK
- word my_mark_no = GC_mark_no;
- /* Marker can't proceed until we acknowledge. Thus this is */
- /* guaranteed to be the mark_no correspending to our */
- /* suspension, i.e. the marker can't have incremented it yet. */
-# endif
-
- if (sig != SIG_SUSPEND) ABORT("Bad signal in suspend_handler");
-
-#if DEBUG_THREADS
- GC_printf1("Suspending 0x%x\n", my_thread);
-#endif
-
- me = GC_lookup_thread(my_thread);
- /* The lookup here is safe, since I'm doing this on behalf */
- /* of a thread which holds the allocation lock in order */
- /* to stop the world. Thus concurrent modification of the */
- /* data structure is impossible. */
-# ifdef SPARC
- me -> stack_ptr = (ptr_t)GC_save_regs_in_stack();
-# else
- me -> stack_ptr = (ptr_t)(&dummy);
-# endif
-# ifdef IA64
- me -> backing_store_ptr = (ptr_t)GC_save_regs_in_stack();
-# endif
-
- /* Tell the thread that wants to stop the world that this */
- /* thread has been stopped. Note that sem_post() is */
- /* the only async-signal-safe primitive in LinuxThreads. */
- sem_post(&GC_suspend_ack_sem);
-
- /* Wait until that thread tells us to restart by sending */
- /* this thread a SIG_THR_RESTART signal. */
- /* SIG_THR_RESTART should be masked at this point. Thus there */
- /* is no race. */
- if (sigfillset(&mask) != 0) ABORT("sigfillset() failed");
- if (sigdelset(&mask, SIG_THR_RESTART) != 0) ABORT("sigdelset() failed");
-# ifdef NO_SIGNALS
- if (sigdelset(&mask, SIGINT) != 0) ABORT("sigdelset() failed");
- if (sigdelset(&mask, SIGQUIT) != 0) ABORT("sigdelset() failed");
- if (sigdelset(&mask, SIGTERM) != 0) ABORT("sigdelset() failed");
- if (sigdelset(&mask, SIGABRT) != 0) ABORT("sigdelset() failed");
-# endif
- do {
- me->signal = 0;
- sigsuspend(&mask); /* Wait for signal */
- } while (me->signal != SIG_THR_RESTART);
-
-#if DEBUG_THREADS
- GC_printf1("Continuing 0x%x\n", my_thread);
-#endif
-}
-
-void GC_restart_handler(int sig)
-{
- GC_thread me;
-
- if (sig != SIG_THR_RESTART) ABORT("Bad signal in suspend_handler");
-
- /* Let the GC_suspend_handler() know that we got a SIG_THR_RESTART. */
- /* The lookup here is safe, since I'm doing this on behalf */
- /* of a thread which holds the allocation lock in order */
- /* to stop the world. Thus concurrent modification of the */
- /* data structure is impossible. */
- me = GC_lookup_thread(pthread_self());
- me->signal = SIG_THR_RESTART;
-
- /*
- ** Note: even if we didn't do anything useful here,
- ** it would still be necessary to have a signal handler,
- ** rather than ignoring the signals, otherwise
- ** the signals will not be delivered at all, and
- ** will thus not interrupt the sigsuspend() above.
- */
-
-#if DEBUG_THREADS
- GC_printf1("In GC_restart_handler for 0x%x\n", pthread_self());
-#endif
-}
-
-/* Defining INSTALL_LOOPING_SEGV_HANDLER causes SIGSEGV and SIGBUS to */
-/* result in an infinite loop in a signal handler. This can be very */
-/* useful for debugging, since (as of RH7) gdb still seems to have */
-/* serious problems with threads. */
-#ifdef INSTALL_LOOPING_SEGV_HANDLER
-void GC_looping_handler(int sig)
-{
- GC_printf3("Signal %ld in thread %lx, pid %ld\n",
- sig, pthread_self(), getpid());
- for (;;);
-}
-#endif
-
-GC_bool GC_thr_initialized = FALSE;
-
-# define THREAD_TABLE_SZ 128 /* Must be power of 2 */
-volatile GC_thread GC_threads[THREAD_TABLE_SZ];
-
-void GC_push_thread_structures GC_PROTO((void))
-{
- GC_push_all((ptr_t)(GC_threads), (ptr_t)(GC_threads)+sizeof(GC_threads));
-}
-
-#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. */
-void GC_mark_thread_local_free_lists(void)
-{
- int i, j;
- GC_thread p;
- ptr_t q;
-
- for (i = 0; i < THREAD_TABLE_SZ; ++i) {
- for (p = GC_threads[i]; 0 != p; p = p -> next) {
- for (j = 1; j < NFREELISTS; ++j) {
- q = p -> ptrfree_freelists[j];
- if ((word)q > HBLKSIZE) GC_set_fl_marks(q);
- q = p -> normal_freelists[j];
- if ((word)q > HBLKSIZE) GC_set_fl_marks(q);
-# ifdef GC_GCJ_SUPPORT
- q = p -> gcj_freelists[j];
- if ((word)q > HBLKSIZE) GC_set_fl_marks(q);
-# endif /* GC_GCJ_SUPPORT */
- }
- }
- }
-}
-#endif /* THREAD_LOCAL_ALLOC */
-
-/* Add a thread to GC_threads. We assume it wasn't already there. */
-/* Caller holds allocation lock. */
-GC_thread GC_new_thread(pthread_t id)
-{
- int hv = ((word)id) % THREAD_TABLE_SZ;
- GC_thread result;
- static struct GC_Thread_Rep first_thread;
- static GC_bool first_thread_used = FALSE;
-
- if (!first_thread_used) {
- 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;
- result -> next = GC_threads[hv];
- GC_threads[hv] = result;
- 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.) */
-/* Caller holds allocation lock. */
-void GC_delete_thread(pthread_t id)
-{
- int hv = ((word)id) % THREAD_TABLE_SZ;
- register GC_thread p = GC_threads[hv];
- register GC_thread prev = 0;
-
- while (!pthread_equal(p -> id, id)) {
- prev = p;
- p = p -> next;
- }
- if (prev == 0) {
- GC_threads[hv] = p -> next;
- } else {
- prev -> next = p -> next;
- }
- 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. */
-void GC_delete_gc_thread(pthread_t id, GC_thread gc_id)
-{
- int hv = ((word)id) % THREAD_TABLE_SZ;
- register GC_thread p = GC_threads[hv];
- register GC_thread prev = 0;
-
- while (p != gc_id) {
- prev = p;
- p = p -> next;
- }
- if (prev == 0) {
- GC_threads[hv] = p -> next;
- } else {
- prev -> next = p -> next;
- }
- GC_INTERNAL_FREE(p);
-}
-
-/* Return a GC_thread corresponding to a given thread_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_thread GC_lookup_thread(pthread_t id)
-{
- int hv = ((word)id) % THREAD_TABLE_SZ;
- register GC_thread p = GC_threads[hv];
-
- while (p != 0 && !pthread_equal(p -> id, id)) p = p -> next;
- return(p);
-}
-
-/* There seems to be a very rare thread stopping problem. To help us */
-/* debug that, we save the ids of the stopping thread. */
-pthread_t GC_stopping_thread;
-int GC_stopping_pid;
-
-/* Caller holds allocation lock. */
-void GC_stop_world()
-{
- pthread_t my_thread = pthread_self();
- register int i;
- register GC_thread p;
- register int n_live_threads = 0;
- register int result;
-
- GC_stopping_thread = my_thread; /* debugging only. */
- GC_stopping_pid = getpid(); /* debugging only. */
- /* Make sure all free list construction has stopped before we start. */
- /* No new construction can start, since free list construction is */
- /* required to acquire and release the GC lock before it starts, */
- /* and we have the lock. */
-# ifdef PARALLEL_MARK
- GC_acquire_mark_lock();
- GC_ASSERT(GC_fl_builder_count == 0);
- /* We should have previously waited for it to become zero. */
-# endif /* PARALLEL_MARK */
- for (i = 0; i < THREAD_TABLE_SZ; i++) {
- for (p = GC_threads[i]; p != 0; p = p -> next) {
- if (p -> id != my_thread) {
- if (p -> flags & FINISHED) continue;
- if (p -> thread_blocked) /* Will wait */ continue;
- n_live_threads++;
- #if DEBUG_THREADS
- GC_printf1("Sending suspend signal to 0x%x\n", p -> id);
- #endif
- result = pthread_kill(p -> id, SIG_SUSPEND);
- switch(result) {
- case ESRCH:
- /* Not really there anymore. Possible? */
- n_live_threads--;
- break;
- case 0:
- break;
- default:
- ABORT("pthread_kill failed");
- }
- }
- }
- }
- for (i = 0; i < n_live_threads; i++) {
- if (0 != sem_wait(&GC_suspend_ack_sem))
- ABORT("sem_wait in handler failed");
- }
-# ifdef PARALLEL_MARK
- GC_release_mark_lock();
-# endif
- #if DEBUG_THREADS
- GC_printf1("World stopped 0x%x\n", pthread_self());
- #endif
- GC_stopping_thread = 0; /* debugging only */
-}
-
-/* Caller holds allocation lock, and has held it continuously since */
-/* the world stopped. */
-void GC_start_world()
-{
- pthread_t my_thread = pthread_self();
- register int i;
- register GC_thread p;
- register int n_live_threads = 0;
- register int result;
-
-# if DEBUG_THREADS
- GC_printf0("World starting\n");
-# endif
-
- for (i = 0; i < THREAD_TABLE_SZ; i++) {
- for (p = GC_threads[i]; p != 0; p = p -> next) {
- if (p -> id != my_thread) {
- if (p -> flags & FINISHED) continue;
- if (p -> thread_blocked) continue;
- n_live_threads++;
- #if DEBUG_THREADS
- GC_printf1("Sending restart signal to 0x%x\n", p -> id);
- #endif
- result = pthread_kill(p -> id, SIG_THR_RESTART);
- switch(result) {
- case ESRCH:
- /* Not really there anymore. Possible? */
- n_live_threads--;
- break;
- case 0:
- break;
- default:
- ABORT("pthread_kill failed");
- }
- }
- }
- }
- #if DEBUG_THREADS
- GC_printf0("World started\n");
- #endif
- GC_stopping_thread = 0; /* debugging only */
-}
-
-# ifdef IA64
-# define IF_IA64(x) x
-# else
-# define IF_IA64(x)
-# endif
-/* We hold allocation lock. Should do exactly the right thing if the */
-/* world is stopped. Should not fail if it isn't. */
-void GC_push_all_stacks()
-{
- int i;
- GC_thread p;
- ptr_t sp = GC_approx_sp();
- ptr_t lo, hi;
- /* On IA64, we also need to scan the register backing store. */
- IF_IA64(ptr_t bs_lo; ptr_t bs_hi;)
- pthread_t me = pthread_self();
-
- if (!GC_thr_initialized) GC_thr_init();
- #if DEBUG_THREADS
- GC_printf1("Pushing stacks from thread 0x%lx\n", (unsigned long) me);
- #endif
- for (i = 0; i < THREAD_TABLE_SZ; i++) {
- for (p = GC_threads[i]; p != 0; p = p -> next) {
- if (p -> flags & FINISHED) continue;
- if (pthread_equal(p -> id, me)) {
-# ifdef SPARC
- lo = (ptr_t)GC_save_regs_in_stack();
-# else
- lo = GC_approx_sp();
-# endif
- IF_IA64(bs_hi = (ptr_t)GC_save_regs_in_stack();)
- } else {
- lo = p -> stack_ptr;
- IF_IA64(bs_hi = p -> backing_store_ptr;)
- }
- if ((p -> flags & MAIN_THREAD) == 0) {
- hi = p -> stack_end;
- IF_IA64(bs_lo = p -> backing_store_end);
- } else {
- /* The original stack. */
- hi = GC_stackbottom;
- IF_IA64(bs_lo = BACKING_STORE_BASE;)
- }
- #if DEBUG_THREADS
- GC_printf3("Stack for thread 0x%lx = [%lx,%lx)\n",
- (unsigned long) p -> id,
- (unsigned long) lo, (unsigned long) hi);
- #endif
- if (0 == lo) ABORT("GC_push_all_stacks: sp not set!\n");
-# ifdef STACK_GROWS_UP
- /* We got them backwards! */
- GC_push_all_stack(hi, lo);
-# else
- GC_push_all_stack(lo, hi);
-# endif
-# ifdef IA64
- if (pthread_equal(p -> id, me)) {
- GC_push_all_eager(bs_lo, bs_hi);
- } else {
- GC_push_all_stack(bs_lo, bs_hi);
- }
-# endif
- }
- }
-}
-
-#ifdef USE_PROC_FOR_LIBRARIES
-int GC_segment_is_thread_stack(ptr_t lo, ptr_t hi)
-{
- int i;
- GC_thread p;
-
-# ifdef PARALLEL_MARK
- for (i = 0; i < GC_markers; ++i) {
- if (marker_sp[i] > lo & marker_sp[i] < hi) return 1;
- }
-# 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 (p -> stack_end >= lo && p -> stack_end < hi) return 1;
-# else /* STACK_GROWS_DOWN */
- if (p -> stack_end > lo && p -> stack_end <= hi) return 1;
-# endif
- }
- }
- }
- return 0;
-}
-#endif /* USE_PROC_FOR_LIBRARIES */
-
-#ifdef GC_LINUX_THREADS
-/* Return the number of processors, or i<= 0 if it can't be determined. */
-int GC_get_nprocs()
-{
- /* 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. */
-# define STAT_BUF_SIZE 4096
-# if defined(GC_USE_LD_WRAP)
-# define STAT_READ __real_read
-# else
-# define STAT_READ read
-# endif
- char stat_buf[STAT_BUF_SIZE];
- int f;
- char c;
- word result = 1;
- /* Some old kernels only have a single "cpu nnnn ..." */
- /* entry in /proc/stat. We identify those as */
- /* uniprocessors. */
- size_t i, len = 0;
-
- f = open("/proc/stat", O_RDONLY);
- if (f < 0 || (len = STAT_READ(f, stat_buf, STAT_BUF_SIZE)) < 100) {
- WARN("Couldn't read /proc/stat\n", 0);
- return -1;
- }
- close(f);
- 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;
-}
-#endif /* GC_LINUX_THREADS */
-
-/* We hold the allocation lock. */
-void GC_thr_init()
-{
- int dummy;
- GC_thread t;
- struct sigaction act;
-
- if (GC_thr_initialized) return;
- GC_thr_initialized = TRUE;
-
- if (sem_init(&GC_suspend_ack_sem, 0, 0) != 0)
- ABORT("sem_init failed");
-
- act.sa_flags = SA_RESTART;
- if (sigfillset(&act.sa_mask) != 0) {
- ABORT("sigfillset() failed");
- }
-# ifdef NO_SIGNALS
- if (sigdelset(&act.sa_mask, SIGINT) != 0
- || sigdelset(&act.sa_mask, SIGQUIT != 0)
- || sigdelset(&act.sa_mask, SIGABRT != 0)
- || sigdelset(&act.sa_mask, SIGTERM != 0)) {
- ABORT("sigdelset() failed");
- }
-# endif
-
- /* SIG_THR_RESTART is unmasked by the handler when necessary. */
- act.sa_handler = GC_suspend_handler;
- if (sigaction(SIG_SUSPEND, &act, NULL) != 0) {
- ABORT("Cannot set SIG_SUSPEND handler");
- }
-
- act.sa_handler = GC_restart_handler;
- if (sigaction(SIG_THR_RESTART, &act, NULL) != 0) {
- ABORT("Cannot set SIG_THR_RESTART handler");
- }
-# ifdef INSTALL_LOOPING_SEGV_HANDLER
- act.sa_handler = GC_looping_handler;
- if (sigaction(SIGSEGV, &act, NULL) != 0
- || sigaction(SIGBUS, &act, NULL) != 0) {
- ABORT("Cannot set SIGSEGV or SIGBUS looping handler");
- }
-# endif /* INSTALL_LOOPING_SEGV_HANDLER */
-
- /* Add the initial thread, so we can stop it. */
- t = GC_new_thread(pthread_self());
- t -> stack_ptr = (ptr_t)(&dummy);
- t -> flags = DETACHED | MAIN_THREAD;
-
- /* Set GC_nprocs. */
- {
- char * nprocs_string = GETENV("GC_NPROCS");
- GC_nprocs = -1;
- if (nprocs_string != NULL) GC_nprocs = atoi(nprocs_string);
- }
- if (GC_nprocs <= 0) {
-# if defined(GC_HPUX_THREADS)
- GC_nprocs = pthread_num_processors_np();
-# endif
-# if defined(GC_OSF1_THREADS) || defined(GC_FREEBSD_THREADS)
- GC_nprocs = 1;
-# endif
-# if defined(GC_LINUX_THREADS)
- GC_nprocs = GC_get_nprocs();
-# endif
- }
- if (GC_nprocs <= 0) {
- WARN("GC_get_nprocs() returned %ld\n", GC_nprocs);
- GC_nprocs = 2;
-# ifdef PARALLEL_MARK
- GC_markers = 1;
-# endif
- } else {
-# ifdef PARALLEL_MARK
- GC_markers = GC_nprocs;
-# endif
- }
-# ifdef PARALLEL_MARK
-# ifdef CONDPRINT
- if (GC_print_stats) {
- GC_printf2("Number of processors = %ld, "
- "number of marker threads = %ld\n", GC_nprocs, GC_markers);
- }
-# endif
- if (GC_markers == 1) {
- GC_parallel = FALSE;
-# ifdef CONDPRINT
- if (GC_print_stats) {
- GC_printf0("Single marker thread, turning off parallel marking\n");
- }
-# endif
- } else {
- GC_parallel = TRUE;
- }
-# endif
-}
-
-
-/* Perform all initializations, including those that */
-/* may require allocation. */
-/* Called as constructor without allocation lock. */
-/* Must be called before a second thread is created. */
-/* Called without allocation lock. */
-void GC_init_parallel()
-{
- if (parallel_initialized) return;
- parallel_initialized = TRUE;
- /* GC_init() calls us back, so set flag first. */
- if (!GC_is_initialized) GC_init();
- /* If we are using a parallel marker, start the helper threads. */
-# ifdef PARALLEL_MARK
- if (GC_parallel) start_mark_threads();
-# endif
- /* Initialize thread local free lists if used. */
-# if defined(THREAD_LOCAL_ALLOC) && !defined(DBG_HDRS_ALL)
- LOCK();
- GC_init_thread_local(GC_lookup_thread(pthread_self()));
- UNLOCK();
-# endif
-}
-
-
-int WRAP_FUNC(pthread_sigmask)(int how, const sigset_t *set, sigset_t *oset)
-{
- sigset_t fudged_set;
-
- if (set != NULL && (how == SIG_BLOCK || how == SIG_SETMASK)) {
- fudged_set = *set;
- sigdelset(&fudged_set, SIG_SUSPEND);
- set = &fudged_set;
- }
- return(REAL_FUNC(pthread_sigmask)(how, set, oset));
-}
-
-/* Wrappers for functions that are likely to block for an appreciable */
-/* length of time. Must be called in pairs, if at all. */
-/* Nothing much beyond the system call itself should be executed */
-/* between these. */
-
-void GC_start_blocking(void) {
-# define SP_SLOP 128
- GC_thread me;
- LOCK();
- me = GC_lookup_thread(pthread_self());
- GC_ASSERT(!(me -> thread_blocked));
-# ifdef SPARC
- me -> stack_ptr = (ptr_t)GC_save_regs_in_stack();
-# else
- me -> stack_ptr = (ptr_t)GC_approx_sp();
-# endif
-# ifdef IA64
- me -> backing_store_ptr = (ptr_t)GC_save_regs_in_stack() + SP_SLOP;
-# endif
- /* Add some slop to the stack pointer, since the wrapped call may */
- /* end up pushing more callee-save registers. */
-# ifdef STACK_GROWS_UP
- me -> stack_ptr += SP_SLOP;
-# else
- me -> stack_ptr -= SP_SLOP;
-# endif
- me -> thread_blocked = TRUE;
- UNLOCK();
-}
-
-GC_end_blocking(void) {
- GC_thread me;
- LOCK(); /* This will block if the world is stopped. */
- me = GC_lookup_thread(pthread_self());
- GC_ASSERT(me -> thread_blocked);
- me -> thread_blocked = FALSE;
- UNLOCK();
-}
-
-/* A wrapper for the standard C sleep function */
-int WRAP_FUNC(sleep) (unsigned int seconds)
-{
- int result;
-
- GC_start_blocking();
- result = REAL_FUNC(sleep)(seconds);
- GC_end_blocking();
- return result;
-}
-
-struct start_info {
- void *(*start_routine)(void *);
- void *arg;
- word flags;
- sem_t registered; /* 1 ==> in our thread table, but */
- /* parent hasn't yet noticed. */
-};
-
-/* Called at thread exit. */
-/* Never called for main thread. That's OK, since it */
-/* results in at most a tiny one-time leak. And */
-/* linuxthreads doesn't reclaim the main threads */
-/* resources or id anyway. */
-void GC_thread_exit_proc(void *arg)
-{
- GC_thread me;
-
- LOCK();
- me = GC_lookup_thread(pthread_self());
- GC_destroy_thread_local(me);
- if (me -> flags & DETACHED) {
- GC_delete_thread(pthread_self());
- } else {
- me -> flags |= FINISHED;
- }
-# if defined(THREAD_LOCAL_ALLOC) && !defined(USE_PTHREAD_SPECIFIC) \
- && !defined(USE_HPUX_TLS) && !defined(DBG_HDRS_ALL)
- GC_remove_specific(GC_thread_key);
-# endif
- if (GC_incremental && GC_collection_in_progress()) {
- int 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()
- && old_gc_no == GC_gc_no) {
- ENTER_GC();
- GC_collect_a_little_inner(1);
- EXIT_GC();
- UNLOCK();
- sched_yield();
- LOCK();
- }
- }
- UNLOCK();
-}
-
-int WRAP_FUNC(pthread_join)(pthread_t thread, void **retval)
-{
- int result;
- GC_thread thread_gc_id;
-
- LOCK();
- thread_gc_id = GC_lookup_thread(thread);
- /* This is guaranteed to be the intended one, since the thread id */
- /* cant have been recycled by pthreads. */
- UNLOCK();
- result = REAL_FUNC(pthread_join)(thread, retval);
-# if defined (GC_FREEBSD_THREADS)
- /* On FreeBSD, the wrapped pthread_join() sometimes returns (what
- appears to be) a spurious EINTR which caused the test and real code
- to gratuitously fail. Having looked at system pthread library source
- code, I see how this return code may be generated. In one path of
- code, pthread_join() just returns the errno setting of the thread
- being joined. This does not match the POSIX specification or the
- local man pages thus I have taken the liberty to catch this one
- spurious return value properly conditionalized on GC_FREEBSD_THREADS. */
- if (result == EINTR) result = 0;
-# endif
- if (result == 0) {
- LOCK();
- /* Here the pthread thread id may have been recycled. */
- GC_delete_gc_thread(thread, thread_gc_id);
- UNLOCK();
- }
- return result;
-}
-
-int
-WRAP_FUNC(pthread_detach)(pthread_t thread)
-{
- int result;
- GC_thread thread_gc_id;
-
- LOCK();
- thread_gc_id = GC_lookup_thread(thread);
- UNLOCK();
- result = REAL_FUNC(pthread_detach)(thread);
- if (result == 0) {
- LOCK();
- thread_gc_id -> flags |= DETACHED;
- /* Here the pthread thread id may have been recycled. */
- if (thread_gc_id -> flags & FINISHED) {
- GC_delete_gc_thread(thread, thread_gc_id);
- }
- UNLOCK();
- }
- return result;
-}
-
-void * GC_start_routine(void * arg)
-{
- int dummy;
- struct start_info * si = arg;
- void * result;
- GC_thread me;
- pthread_t my_pthread;
- void *(*start)(void *);
- void *start_arg;
-
- my_pthread = pthread_self();
-# ifdef DEBUG_THREADS
- GC_printf1("Starting thread 0x%lx\n", my_pthread);
- GC_printf1("pid = %ld\n", (long) getpid());
- GC_printf1("sp = 0x%lx\n", (long) &arg);
-# endif
- LOCK();
- me = GC_new_thread(my_pthread);
- me -> flags = si -> flags;
- me -> stack_ptr = 0;
- /* me -> stack_end = GC_linux_stack_base(); -- currently (11/99) */
- /* doesn't work because the stack base in /proc/self/stat is the */
- /* one for the main thread. There is a strong argument that that's */
- /* a kernel bug, but a pervasive one. */
-# ifdef STACK_GROWS_DOWN
- me -> stack_end = (ptr_t)(((word)(&dummy) + (GC_page_size - 1))
- & ~(GC_page_size - 1));
- me -> stack_ptr = me -> stack_end - 0x10;
- /* Needs to be plausible, since an asynchronous stack mark */
- /* should not crash. */
-# else
- me -> stack_end = (ptr_t)((word)(&dummy) & ~(GC_page_size - 1));
- me -> stack_ptr = me -> stack_end + 0x10;
-# endif
- /* This is dubious, since we may be more than a page into the stack, */
- /* and hence skip some of it, though it's not clear that matters. */
-# ifdef IA64
- me -> backing_store_end = (ptr_t)
- (GC_save_regs_in_stack() & ~(GC_page_size - 1));
- /* This is also < 100% convincing. We should also read this */
- /* from /proc, but the hook to do so isn't there yet. */
-# endif /* IA64 */
- UNLOCK();
- start = si -> start_routine;
-# ifdef DEBUG_THREADS
- GC_printf1("start_routine = 0x%lx\n", start);
-# endif
- start_arg = si -> arg;
- sem_post(&(si -> registered)); /* Last action on si. */
- /* OK to deallocate. */
- pthread_cleanup_push(GC_thread_exit_proc, 0);
-# if defined(THREAD_LOCAL_ALLOC) && !defined(DBG_HDRS_ALL)
- LOCK();
- GC_init_thread_local(me);
- UNLOCK();
-# endif
- result = (*start)(start_arg);
-#if DEBUG_THREADS
- GC_printf1("Finishing thread 0x%x\n", pthread_self());
-#endif
- me -> status = result;
- me -> flags |= FINISHED;
- pthread_cleanup_pop(1);
- /* Cleanup acquires lock, ensuring that we can't exit */
- /* while a collection that thinks we're alive is trying to stop */
- /* us. */
- return(result);
-}
-
-int
-WRAP_FUNC(pthread_create)(pthread_t *new_thread,
- const pthread_attr_t *attr,
- void *(*start_routine)(void *), void *arg)
-{
- int result;
- GC_thread t;
- pthread_t my_new_thread;
- int detachstate;
- word my_flags = 0;
- struct start_info * si;
- /* This is otherwise saved only in an area mmapped by the thread */
- /* library, which isn't visible to the collector. */
-
- LOCK();
- si = (struct start_info *)GC_INTERNAL_MALLOC(sizeof(struct start_info), NORMAL);
- UNLOCK();
- if (!parallel_initialized) GC_init_parallel();
- if (0 == si) return(ENOMEM);
- sem_init(&(si -> registered), 0, 0);
- si -> start_routine = start_routine;
- si -> arg = arg;
- LOCK();
- if (!GC_thr_initialized) GC_thr_init();
- if (NULL == attr) {
- detachstate = PTHREAD_CREATE_JOINABLE;
- } else {
- pthread_attr_getdetachstate(attr, &detachstate);
- }
- if (PTHREAD_CREATE_DETACHED == detachstate) my_flags |= DETACHED;
- si -> flags = my_flags;
- UNLOCK();
-# ifdef DEBUG_THREADS
- GC_printf1("About to start new thread from thread 0x%X\n",
- pthread_self());
-# endif
- result = REAL_FUNC(pthread_create)(new_thread, attr, GC_start_routine, si);
-# ifdef DEBUG_THREADS
- GC_printf1("Started thread 0x%X\n", *new_thread);
-# endif
- /* Wait until child has been added to the thread table. */
- /* This also ensures that we hold onto si until the child is done */
- /* with it. Thus it doesn't matter whether it is otherwise */
- /* visible to the collector. */
- while (0 != sem_wait(&(si -> registered))) {
- if (EINTR != errno) ABORT("sem_wait failed");
- }
- sem_destroy(&(si -> registered));
- LOCK();
- GC_INTERNAL_FREE(si);
- UNLOCK();
- return(result);
-}
-
-#ifdef GENERIC_COMPARE_AND_SWAP
- pthread_mutex_t GC_compare_and_swap_lock = PTHREAD_MUTEX_INITIALIZER;
-
- GC_bool GC_compare_and_exchange(volatile GC_word *addr,
- GC_word old, GC_word new_val)
- {
- GC_bool result;
- pthread_mutex_lock(&GC_compare_and_swap_lock);
- if (*addr == old) {
- *addr = new_val;
- result = TRUE;
- } else {
- result = FALSE;
- }
- pthread_mutex_unlock(&GC_compare_and_swap_lock);
- return result;
- }
-
- GC_word GC_atomic_add(volatile GC_word *addr, GC_word how_much)
- {
- GC_word old;
- pthread_mutex_lock(&GC_compare_and_swap_lock);
- old = *addr;
- *addr = old + how_much;
- pthread_mutex_unlock(&GC_compare_and_swap_lock);
- return old;
- }
-
-#endif /* GENERIC_COMPARE_AND_SWAP */
-/* Spend a few cycles in a way that can't introduce contention with */
-/* othre threads. */
-void GC_pause()
-{
- int i;
- volatile word dummy = 0;
-
- for (i = 0; i < 10; ++i) {
-# ifdef __GNUC__
- __asm__ __volatile__ (" " : : : "memory");
-# else
- /* Something that's unlikely to be optimized away. */
- GC_noop(++dummy);
-# endif
- }
-}
-
-#define SPIN_MAX 1024 /* Maximum number of calls to GC_pause before */
- /* give up. */
-
-VOLATILE GC_bool GC_collecting = 0;
- /* A hint that we're in the collector and */
- /* holding the allocation lock for an */
- /* extended period. */
-
-#if !defined(USE_SPIN_LOCK) || defined(PARALLEL_MARK)
-/* If we don't want to use the below spinlock implementation, either */
-/* because we don't have a GC_test_and_set implementation, or because */
-/* we don't want to risk sleeping, we can still try spinning on */
-/* pthread_mutex_trylock for a while. This appears to be very */
-/* beneficial in many cases. */
-/* I suspect that under high contention this is nearly always better */
-/* than the spin lock. But it's a bit slower on a uniprocessor. */
-/* Hence we still default to the spin lock. */
-/* This is also used to acquire the mark lock for the parallel */
-/* marker. */
-
-/* Here we use a strict exponential backoff scheme. I don't know */
-/* whether that's better or worse than the above. We eventually */
-/* yield by calling pthread_mutex_lock(); it never makes sense to */
-/* explicitly sleep. */
-
-void GC_generic_lock(pthread_mutex_t * lock)
-{
- unsigned pause_length = 1;
- unsigned i;
-
- if (0 == pthread_mutex_trylock(lock)) return;
- for (; pause_length <= SPIN_MAX; pause_length <<= 1) {
- for (i = 0; i < pause_length; ++i) {
- GC_pause();
- }
- switch(pthread_mutex_trylock(lock)) {
- case 0:
- return;
- case EBUSY:
- break;
- default:
- ABORT("Unexpected error from pthread_mutex_trylock");
- }
- }
- pthread_mutex_lock(lock);
-}
-
-#endif /* !USE_SPIN_LOCK || PARALLEL_MARK */
-
-#if defined(USE_SPIN_LOCK)
-
-/* Reasonably fast spin locks. Basically the same implementation */
-/* as STL alloc.h. This isn't really the right way to do this. */
-/* but until the POSIX scheduling mess gets straightened out ... */
-
-volatile unsigned int GC_allocate_lock = 0;
-
-
-void GC_lock()
-{
-# define low_spin_max 30 /* spin cycles if we suspect uniprocessor */
-# define high_spin_max SPIN_MAX /* spin cycles for multiprocessor */
- static unsigned spin_max = low_spin_max;
- unsigned my_spin_max;
- static unsigned last_spins = 0;
- unsigned my_last_spins;
- int i;
-
- if (!GC_test_and_set(&GC_allocate_lock)) {
- return;
- }
- my_spin_max = spin_max;
- my_last_spins = last_spins;
- for (i = 0; i < my_spin_max; i++) {
- if (GC_collecting || GC_nprocs == 1) goto yield;
- if (i < my_last_spins/2 || GC_allocate_lock) {
- GC_pause();
- continue;
- }
- if (!GC_test_and_set(&GC_allocate_lock)) {
- /*
- * got it!
- * Spinning worked. Thus we're probably not being scheduled
- * against the other process with which we were contending.
- * Thus it makes sense to spin longer the next time.
- */
- last_spins = i;
- spin_max = high_spin_max;
- return;
- }
- }
- /* We are probably being scheduled against the other process. Sleep. */
- spin_max = low_spin_max;
-yield:
- for (i = 0;; ++i) {
- if (!GC_test_and_set(&GC_allocate_lock)) {
- return;
- }
-# define SLEEP_THRESHOLD 12
- /* nanosleep(<= 2ms) just spins under Linux. We */
- /* want to be careful to avoid that behavior. */
- if (i < SLEEP_THRESHOLD) {
- sched_yield();
- } else {
- struct timespec ts;
-
- if (i > 24) i = 24;
- /* Don't wait for more than about 15msecs, even */
- /* under extreme contention. */
- ts.tv_sec = 0;
- ts.tv_nsec = 1 << i;
- nanosleep(&ts, 0);
- }
- }
-}
-
-#else /* !USE_SPINLOCK */
-
-void GC_lock()
-{
- if (1 == GC_nprocs || GC_collecting) {
- pthread_mutex_lock(&GC_allocate_ml);
- } else {
- GC_generic_lock(&GC_allocate_ml);
- }
-}
-
-#endif /* !USE_SPINLOCK */
-
-#if defined(PARALLEL_MARK) || defined(THREAD_LOCAL_ALLOC)
-
-#ifdef GC_ASSERTIONS
- pthread_t GC_mark_lock_holder = NO_THREAD;
-#endif
-
-#if 0
- /* Ugly workaround for a linux threads bug in the final versions */
- /* of glibc2.1. Pthread_mutex_trylock sets the mutex owner */
- /* field even when it fails to acquire the mutex. This causes */
- /* pthread_cond_wait to die. Remove for glibc2.2. */
- /* According to the man page, we should use */
- /* PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP, but that isn't actually */
- /* defined. */
- static pthread_mutex_t mark_mutex =
- {0, 0, 0, PTHREAD_MUTEX_ERRORCHECK_NP, {0, 0}};
-#else
- static pthread_mutex_t mark_mutex = PTHREAD_MUTEX_INITIALIZER;
-#endif
-
-static pthread_cond_t builder_cv = PTHREAD_COND_INITIALIZER;
-
-void GC_acquire_mark_lock()
-{
-/*
- if (pthread_mutex_lock(&mark_mutex) != 0) {
- ABORT("pthread_mutex_lock failed");
- }
-*/
- GC_generic_lock(&mark_mutex);
-# ifdef GC_ASSERTIONS
- GC_mark_lock_holder = pthread_self();
-# endif
-}
-
-void GC_release_mark_lock()
-{
- GC_ASSERT(GC_mark_lock_holder == pthread_self());
-# ifdef GC_ASSERTIONS
- GC_mark_lock_holder = NO_THREAD;
-# endif
- if (pthread_mutex_unlock(&mark_mutex) != 0) {
- ABORT("pthread_mutex_unlock failed");
- }
-}
-
-/* Collector must wait for a freelist builders for 2 reasons: */
-/* 1) Mark bits may still be getting examined without lock. */
-/* 2) Partial free lists referenced only by locals may not be scanned */
-/* correctly, e.g. if they contain "pointer-free" objects, since the */
-/* free-list link may be ignored. */
-void GC_wait_builder()
-{
- GC_ASSERT(GC_mark_lock_holder == pthread_self());
-# ifdef GC_ASSERTIONS
- GC_mark_lock_holder = NO_THREAD;
-# endif
- if (pthread_cond_wait(&builder_cv, &mark_mutex) != 0) {
- ABORT("pthread_cond_wait failed");
- }
- GC_ASSERT(GC_mark_lock_holder == NO_THREAD);
-# ifdef GC_ASSERTIONS
- GC_mark_lock_holder = pthread_self();
-# endif
-}
-
-void GC_wait_for_reclaim()
-{
- GC_acquire_mark_lock();
- while (GC_fl_builder_count > 0) {
- GC_wait_builder();
- }
- GC_release_mark_lock();
-}
-
-void GC_notify_all_builder()
-{
- GC_ASSERT(GC_mark_lock_holder == pthread_self());
- if (pthread_cond_broadcast(&builder_cv) != 0) {
- ABORT("pthread_cond_broadcast failed");
- }
-}
-
-#endif /* PARALLEL_MARK || THREAD_LOCAL_ALLOC */
-
-#ifdef PARALLEL_MARK
-
-static pthread_cond_t mark_cv = PTHREAD_COND_INITIALIZER;
-
-void GC_wait_marker()
-{
- GC_ASSERT(GC_mark_lock_holder == pthread_self());
-# ifdef GC_ASSERTIONS
- GC_mark_lock_holder = NO_THREAD;
-# endif
- if (pthread_cond_wait(&mark_cv, &mark_mutex) != 0) {
- ABORT("pthread_cond_wait failed");
- }
- GC_ASSERT(GC_mark_lock_holder == NO_THREAD);
-# ifdef GC_ASSERTIONS
- GC_mark_lock_holder = pthread_self();
-# endif
-}
-
-void GC_notify_all_marker()
-{
- if (pthread_cond_broadcast(&mark_cv) != 0) {
- ABORT("pthread_cond_broadcast failed");
- }
-}
-
-#endif /* PARALLEL_MARK */
-
-# endif /* GC_LINUX_THREADS and friends */
-
projects / msp430-gcc.git / blobdiff