diff options
Diffstat (limited to 'gc/linux_threads.c')
| -rw-r--r-- | gc/linux_threads.c | 1896 |
1 files changed, 0 insertions, 1896 deletions
diff --git a/gc/linux_threads.c b/gc/linux_threads.c deleted file mode 100644 index 98a0e90..0000000 --- a/gc/linux_threads.c +++ /dev/null @@ -1,1896 +0,0 @@ -/* - * 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. - */ - /* DG/UX ix86 support <takis@xfree86.org> */ -/* - * 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) && !defined(GC_WIN32_THREADS) - -# include "private/gc_priv.h" - -# if defined(GC_HPUX_THREADS) && !defined(USE_PTHREAD_SPECIFIC) \ - && !defined(USE_HPUX_TLS) -# define USE_HPUX_TLS -# endif - -# if defined(GC_DGUX386_THREADS) && !defined(USE_PTHREAD_SPECIFIC) -# define USE_PTHREAD_SPECIFIC -# endif - -# if defined(GC_DGUX386_THREADS) && !defined(_POSIX4A_DRAFT10_SOURCE) -# define _POSIX4A_DRAFT10_SOURCE 1 -# endif - -# if defined(GC_DGUX386_THREADS) && !defined(_USING_POSIX4A_DRAFT10) -# define _USING_POSIX4A_DRAFT10 1 -# 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> - -#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 */ - -#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 -# if !defined(GC_DGUX386_THREADS) -# define REAL_FUNC(f) f -# else /* GC_DGUX386_THREADS */ -# define REAL_FUNC(f) __d10_##f -# endif /* GC_DGUX386_THREADS */ -# 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 or from */ - /* the fork handler for a child process. */ -# ifndef HANDLE_FORK - GC_ASSERT(GC_getspecific(GC_thread_key) == (void *)p); -# endif - 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) - 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) { - if (!GC_incremental) *my_fl = my_entry + index + 1; - /* In the incremental case, we always have to take this */ - /* path. Thus we leave the counter alone. */ - 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"); - -# 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; - 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 || GC_DGUX386_THREADS */ -# 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 */ - -static struct GC_Thread_Rep first_thread; - -/* 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 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); -} - -#ifdef 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. */ -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 (p -> id == self) { - me = p; - p -> next = 0; - } else { -# ifdef THREAD_LOCAL_ALLOC - if (!(p -> flags & FINISHED)) { - GC_destroy_thread_local(p); - } -# endif /* THREAD_LOCAL_ALLOC */ - if (p != &first_thread) GC_INTERNAL_FREE(p); - } - } - GC_threads[hv] = me; - } -} -#endif /* HANDLE_FORK */ - -/* 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 -} - -# 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; - } - 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; - } - } - close(f); - return result; -} -#endif /* GC_LINUX_THREADS */ - -/* 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. */ -void GC_wait_for_gc_completion(GC_bool wait_for_all) -{ - 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() - && (wait_for_all || old_gc_no == GC_gc_no)) { - ENTER_GC(); - GC_collect_a_little_inner(1); - EXIT_GC(); - UNLOCK(); - sched_yield(); - LOCK(); - } - } -} - -#ifdef 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. */ - -/* Called before a fork() */ -void GC_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(); -# if defined(PARALLEL_MARK) || defined(THREAD_LOCAL_ALLOC) - GC_wait_for_reclaim(); -# endif - GC_wait_for_gc_completion(TRUE); -# if defined(PARALLEL_MARK) || defined(THREAD_LOCAL_ALLOC) - GC_acquire_mark_lock(); -# endif -} - -/* Called in parent after a fork() */ -void GC_fork_parent_proc(void) -{ -# if defined(PARALLEL_MARK) || defined(THREAD_LOCAL_ALLOC) - GC_release_mark_lock(); -# endif - UNLOCK(); -} - -/* Called in child after a fork() */ -void GC_fork_child_proc(void) -{ - /* Clean up the thread table, so that just our thread is left. */ -# if defined(PARALLEL_MARK) || defined(THREAD_LOCAL_ALLOC) - 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_markers = 1; - GC_parallel = FALSE; -# endif /* PARALLEL_MARK */ - UNLOCK(); -} -#endif /* HANDLE_FORK */ - -#if defined(GC_DGUX386_THREADS) -/* Return the number of processors, or i<= 0 if it can't be determined. */ -int GC_get_nprocs() -{ - /* <takis@XFree86.Org> */ - 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; - -# ifdef DEBUG_THREADS - GC_printf1("Number of active CPUs in this system: %d\n", numCpus); -# endif - return(numCpus); -} -#endif /* GC_DGUX386_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 HANDLE_FORK - /* Prepare for a possible fork. */ - pthread_atfork(GC_fork_prepare_proc, GC_fork_parent_proc, - GC_fork_child_proc); -# endif /* HANDLE_FORK */ - /* 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) || defined(GC_DGUX386_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 - { - char * markers_string = GETENV("GC_MARKERS"); - if (markers_string != NULL) { - GC_markers = atoi(markers_string); - } else { - 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; - /* Disable true incremental collection, but generational is OK. */ - GC_time_limit = GC_TIME_UNLIMITED; - } -# endif -} - - -/* Perform all initializations, including those that */ -/* may require allocation. */ -/* Called 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(); -} - -#if defined(GC_DGUX386_THREADS) -#define __d10_sleep sleep -#endif /* GC_DGUX386_THREADS */ - -/* 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 - GC_wait_for_gc_completion(FALSE); - 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. */ - - /* We resist the temptation to muck with the stack size here, */ - /* even if the default is unreasonably small. That's the client's */ - /* responsibility. */ - - 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 */ - |