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Diffstat (limited to '')
| -rw-r--r-- | gc/irix_threads.c | 730 |
1 files changed, 0 insertions, 730 deletions
diff --git a/gc/irix_threads.c b/gc/irix_threads.c deleted file mode 100644 index 48173e4..0000000 --- a/gc/irix_threads.c +++ /dev/null @@ -1,730 +0,0 @@ -/* - * Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. - * Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved. - * Copyright (c) 1999 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 Irix (>=6.2) Pthreads. This relies on properties - * not guaranteed by the Pthread standard. It may or may not be portable - * to other implementations. - * - * This now also includes an initial attempt at thread support for - * HP/UX 11. - * - * Note that there is a lot of code duplication between linux_threads.c - * and irix_threads.c; any changes made here may need to be reflected - * there too. - */ - -# if defined(GC_IRIX_THREADS) - -# include "private/gc_priv.h" -# include <pthread.h> -# include <semaphore.h> -# include <time.h> -# include <errno.h> -# include <unistd.h> -# include <sys/mman.h> -# include <sys/time.h> - -#undef pthread_create -#undef pthread_sigmask -#undef pthread_join -#undef pthread_detach - -#ifdef HANDLE_FORK - --> Not yet supported. Try porting the code from linux_threads.c. -#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. We never actually create detached threads. We allocate all */ -/* new thread stacks ourselves. These allow us to maintain this */ -/* data structure. */ -/* Protected by GC_thr_lock. */ -/* Some of this should be declared volatile, but that's incosnsistent */ -/* 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; - word stop; -# define NOT_STOPPED 0 -# define PLEASE_STOP 1 -# define STOPPED 2 - word flags; -# define FINISHED 1 /* Thread has exited. */ -# define DETACHED 2 /* Thread is intended to be detached. */ -# define CLIENT_OWNS_STACK 4 - /* Stack was supplied by client. */ - ptr_t stack; - ptr_t stack_ptr; /* Valid only when stopped. */ - /* But must be within stack region at */ - /* all times. */ - size_t stack_size; /* 0 for original thread. */ - void * status; /* Used only to avoid premature */ - /* reclamation of any data it might */ - /* reference. */ -} * GC_thread; - -GC_thread GC_lookup_thread(pthread_t id); - -/* - * The only way to suspend threads given the pthread interface is to send - * signals. Unfortunately, this means we have to reserve - * a signal, and intercept client calls to change the signal mask. - * We use SIG_SUSPEND, defined in gc_priv.h. - */ - -pthread_mutex_t GC_suspend_lock = PTHREAD_MUTEX_INITIALIZER; - /* Number of threads stopped so far */ -pthread_cond_t GC_suspend_ack_cv = PTHREAD_COND_INITIALIZER; -pthread_cond_t GC_continue_cv = PTHREAD_COND_INITIALIZER; - -void GC_suspend_handler(int sig) -{ - int dummy; - GC_thread me; - sigset_t all_sigs; - sigset_t old_sigs; - int i; - - if (sig != SIG_SUSPEND) ABORT("Bad signal in suspend_handler"); - me = GC_lookup_thread(pthread_self()); - /* 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. */ - if (PLEASE_STOP != me -> stop) { - /* Misdirected signal. */ - pthread_mutex_unlock(&GC_suspend_lock); - return; - } - pthread_mutex_lock(&GC_suspend_lock); - me -> stack_ptr = (ptr_t)(&dummy); - me -> stop = STOPPED; - pthread_cond_signal(&GC_suspend_ack_cv); - pthread_cond_wait(&GC_continue_cv, &GC_suspend_lock); - pthread_mutex_unlock(&GC_suspend_lock); - /* GC_printf1("Continuing 0x%x\n", pthread_self()); */ -} - - -GC_bool GC_thr_initialized = FALSE; - -size_t GC_min_stack_sz; - -# define N_FREE_LISTS 25 -ptr_t GC_stack_free_lists[N_FREE_LISTS] = { 0 }; - /* GC_stack_free_lists[i] is free list for stacks of */ - /* size GC_min_stack_sz*2**i. */ - /* Free lists are linked through first word. */ - -/* Return a stack of size at least *stack_size. *stack_size is */ -/* replaced by the actual stack size. */ -/* Caller holds allocation lock. */ -ptr_t GC_stack_alloc(size_t * stack_size) -{ - register size_t requested_sz = *stack_size; - register size_t search_sz = GC_min_stack_sz; - register int index = 0; /* = log2(search_sz/GC_min_stack_sz) */ - register ptr_t result; - - while (search_sz < requested_sz) { - search_sz *= 2; - index++; - } - if ((result = GC_stack_free_lists[index]) == 0 - && (result = GC_stack_free_lists[index+1]) != 0) { - /* Try next size up. */ - search_sz *= 2; index++; - } - if (result != 0) { - GC_stack_free_lists[index] = *(ptr_t *)result; - } else { - result = (ptr_t) GC_scratch_alloc(search_sz + 2*GC_page_size); - result = (ptr_t)(((word)result + GC_page_size) & ~(GC_page_size - 1)); - /* Protect hottest page to detect overflow. */ -# ifdef STACK_GROWS_UP - /* mprotect(result + search_sz, GC_page_size, PROT_NONE); */ -# else - /* mprotect(result, GC_page_size, PROT_NONE); */ - result += GC_page_size; -# endif - } - *stack_size = search_sz; - return(result); -} - -/* Caller holds allocation lock. */ -void GC_stack_free(ptr_t stack, size_t size) -{ - register int index = 0; - register size_t search_sz = GC_min_stack_sz; - - while (search_sz < size) { - search_sz *= 2; - index++; - } - if (search_sz != size) ABORT("Bad stack size"); - *(ptr_t *)stack = GC_stack_free_lists[index]; - GC_stack_free_lists[index] = stack; -} - - - -# 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)); -} - -/* 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; - /* Dont acquire allocation lock, since we may already hold it. */ - } 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; - /* result -> flags = 0; */ - /* result -> stop = 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; - } -} - -/* 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; - } -} - -/* 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); -} - - -/* Caller holds allocation lock. */ -void GC_stop_world() -{ - pthread_t my_thread = pthread_self(); - register int i; - register GC_thread p; - register int result; - struct timespec timeout; - - 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) { - p -> stop = STOPPED; - continue; - } - p -> stop = PLEASE_STOP; - result = pthread_kill(p -> id, SIG_SUSPEND); - /* GC_printf1("Sent signal to 0x%x\n", p -> id); */ - switch(result) { - case ESRCH: - /* Not really there anymore. Possible? */ - p -> stop = STOPPED; - break; - case 0: - break; - default: - ABORT("pthread_kill failed"); - } - } - } - } - pthread_mutex_lock(&GC_suspend_lock); - for (i = 0; i < THREAD_TABLE_SZ; i++) { - for (p = GC_threads[i]; p != 0; p = p -> next) { - while (p -> id != my_thread && p -> stop != STOPPED) { - clock_gettime(CLOCK_REALTIME, &timeout); - timeout.tv_nsec += 50000000; /* 50 msecs */ - if (timeout.tv_nsec >= 1000000000) { - timeout.tv_nsec -= 1000000000; - ++timeout.tv_sec; - } - result = pthread_cond_timedwait(&GC_suspend_ack_cv, - &GC_suspend_lock, - &timeout); - if (result == ETIMEDOUT) { - /* Signal was lost or misdirected. Try again. */ - /* Duplicate signals should be benign. */ - result = pthread_kill(p -> id, SIG_SUSPEND); - } - } - } - } - pthread_mutex_unlock(&GC_suspend_lock); - /* GC_printf1("World stopped 0x%x\n", pthread_self()); */ -} - -/* Caller holds allocation lock. */ -void GC_start_world() -{ - GC_thread p; - unsigned i; - - /* GC_printf0("World starting\n"); */ - for (i = 0; i < THREAD_TABLE_SZ; i++) { - for (p = GC_threads[i]; p != 0; p = p -> next) { - p -> stop = NOT_STOPPED; - } - } - pthread_mutex_lock(&GC_suspend_lock); - /* All other threads are at pthread_cond_wait in signal handler. */ - /* Otherwise we couldn't have acquired the lock. */ - pthread_mutex_unlock(&GC_suspend_lock); - pthread_cond_broadcast(&GC_continue_cv); -} - -# ifdef MMAP_STACKS ---> not really supported yet. -int GC_is_thread_stack(ptr_t addr) -{ - register int i; - register GC_thread p; - - for (i = 0; i < THREAD_TABLE_SZ; i++) { - for (p = GC_threads[i]; p != 0; p = p -> next) { - if (p -> stack_size != 0) { - if (p -> stack <= addr && - addr < p -> stack + p -> stack_size) - return 1; - } - } - } - return 0; -} -# 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() -{ - register int i; - register GC_thread p; - register ptr_t sp = GC_approx_sp(); - register ptr_t hot, cold; - pthread_t me = pthread_self(); - - if (!GC_thr_initialized) GC_thr_init(); - /* GC_printf1("Pushing stacks from thread 0x%x\n", me); */ - 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)) { - hot = GC_approx_sp(); - } else { - hot = p -> stack_ptr; - } - if (p -> stack_size != 0) { -# ifdef STACK_GROWS_UP - cold = p -> stack; -# else - cold = p -> stack + p -> stack_size; -# endif - } else { - /* The original stack. */ - cold = GC_stackbottom; - } -# ifdef STACK_GROWS_UP - GC_push_all_stack(cold, hot); -# else - GC_push_all_stack(hot, cold); -# endif - } - } -} - - -/* We hold the allocation lock. */ -void GC_thr_init() -{ - GC_thread t; - struct sigaction act; - - if (GC_thr_initialized) return; - GC_thr_initialized = TRUE; - GC_min_stack_sz = HBLKSIZE; - (void) sigaction(SIG_SUSPEND, 0, &act); - if (act.sa_handler != SIG_DFL) - ABORT("Previously installed SIG_SUSPEND handler"); - /* Install handler. */ - act.sa_handler = GC_suspend_handler; - act.sa_flags = SA_RESTART; - (void) sigemptyset(&act.sa_mask); - if (0 != sigaction(SIG_SUSPEND, &act, 0)) - ABORT("Failed to install SIG_SUSPEND handler"); - /* Add the initial thread, so we can stop it. */ - t = GC_new_thread(pthread_self()); - t -> stack_size = 0; - t -> stack_ptr = (ptr_t)(&t); - t -> flags = DETACHED; -} - -int GC_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(pthread_sigmask(how, set, oset)); -} - -struct start_info { - void *(*start_routine)(void *); - void *arg; - word flags; - ptr_t stack; - size_t stack_size; - sem_t registered; /* 1 ==> in our thread table, but */ - /* parent hasn't yet noticed. */ -}; - -void GC_thread_exit_proc(void *arg) -{ - GC_thread me; - - LOCK(); - me = GC_lookup_thread(pthread_self()); - if (me -> flags & DETACHED) { - GC_delete_thread(pthread_self()); - } else { - me -> flags |= FINISHED; - } - UNLOCK(); -} - -int GC_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 = pthread_join(thread, retval); - /* Some versions of the Irix pthreads library can erroneously */ - /* return EINTR when the call succeeds. */ - if (EINTR == result) result = 0; - 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 GC_pthread_detach(pthread_t thread) -{ - int result; - GC_thread thread_gc_id; - - LOCK(); - thread_gc_id = GC_lookup_thread(thread); - UNLOCK(); - result = 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) -{ - struct start_info * si = arg; - void * result; - GC_thread me; - pthread_t my_pthread; - void *(*start)(void *); - void *start_arg; - - my_pthread = pthread_self(); - /* If a GC occurs before the thread is registered, that GC will */ - /* ignore this thread. That's fine, since it will block trying to */ - /* acquire the allocation lock, and won't yet hold interesting */ - /* pointers. */ - LOCK(); - /* We register the thread here instead of in the parent, so that */ - /* we don't need to hold the allocation lock during pthread_create. */ - /* Holding the allocation lock there would make REDIRECT_MALLOC */ - /* impossible. It probably still doesn't work, but we're a little */ - /* closer ... */ - /* This unfortunately means that we have to be careful the parent */ - /* doesn't try to do a pthread_join before we're registered. */ - me = GC_new_thread(my_pthread); - me -> flags = si -> flags; - me -> stack = si -> stack; - me -> stack_size = si -> stack_size; - me -> stack_ptr = (ptr_t)si -> stack + si -> stack_size - sizeof(word); - UNLOCK(); - start = si -> start_routine; - start_arg = si -> arg; - sem_post(&(si -> registered)); - pthread_cleanup_push(GC_thread_exit_proc, 0); - result = (*start)(start_arg); - me -> status = result; - me -> flags |= FINISHED; - pthread_cleanup_pop(1); - /* This involves acquiring the lock, ensuring that we can't exit */ - /* while a collection that thinks we're alive is trying to stop */ - /* us. */ - return(result); -} - -# define copy_attr(pa_ptr, source) *(pa_ptr) = *(source) - -int -GC_pthread_create(pthread_t *new_thread, - const pthread_attr_t *attr, - void *(*start_routine)(void *), void *arg) -{ - int result; - GC_thread t; - void * stack; - size_t stacksize; - pthread_attr_t new_attr; - int detachstate; - word my_flags = 0; - struct start_info * si = GC_malloc(sizeof(struct start_info)); - /* This is otherwise saved only in an area mmapped by the thread */ - /* library, which isn't visible to the collector. */ - - if (0 == si) return(ENOMEM); - if (0 != sem_init(&(si -> registered), 0, 0)) { - ABORT("sem_init failed"); - } - si -> start_routine = start_routine; - si -> arg = arg; - LOCK(); - if (!GC_is_initialized) GC_init(); - if (NULL == attr) { - stack = 0; - (void) pthread_attr_init(&new_attr); - } else { - copy_attr(&new_attr, attr); - pthread_attr_getstackaddr(&new_attr, &stack); - } - pthread_attr_getstacksize(&new_attr, &stacksize); - pthread_attr_getdetachstate(&new_attr, &detachstate); - if (stacksize < GC_min_stack_sz) ABORT("Stack too small"); - if (0 == stack) { - stack = (void *)GC_stack_alloc(&stacksize); - if (0 == stack) { - UNLOCK(); - return(ENOMEM); - } - pthread_attr_setstackaddr(&new_attr, stack); - } else { - my_flags |= CLIENT_OWNS_STACK; - } - if (PTHREAD_CREATE_DETACHED == detachstate) my_flags |= DETACHED; - si -> flags = my_flags; - si -> stack = stack; - si -> stack_size = stacksize; - result = pthread_create(new_thread, &new_attr, GC_start_routine, si); - if (0 == new_thread && !(my_flags & CLIENT_OWNS_STACK)) { - GC_stack_free(stack, stacksize); - } - UNLOCK(); - /* 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 (errno != EINTR) { - GC_printf1("Sem_wait: errno = %ld\n", (unsigned long) errno); - ABORT("sem_wait failed"); - } - } - sem_destroy(&(si -> registered)); - pthread_attr_destroy(&new_attr); /* Probably unnecessary under Irix */ - return(result); -} - -VOLATILE GC_bool GC_collecting = 0; - /* A hint that we're in the collector and */ - /* holding the allocation lock for an */ - /* extended period. */ - -/* Reasonably fast spin locks. Basically the same implementation */ -/* as STL alloc.h. */ - -#define SLEEP_THRESHOLD 3 - -unsigned long GC_allocate_lock = 0; -# define GC_TRY_LOCK() !GC_test_and_set(&GC_allocate_lock) -# define GC_LOCK_TAKEN GC_allocate_lock - -void GC_lock() -{ -# define low_spin_max 30 /* spin cycles if we suspect uniprocessor */ -# define high_spin_max 1000 /* spin cycles for multiprocessor */ - static unsigned spin_max = low_spin_max; - unsigned my_spin_max; - static unsigned last_spins = 0; - unsigned my_last_spins; - volatile unsigned junk; -# define PAUSE junk *= junk; junk *= junk; junk *= junk; junk *= junk - int i; - - if (GC_TRY_LOCK()) { - return; - } - junk = 0; - my_spin_max = spin_max; - my_last_spins = last_spins; - for (i = 0; i < my_spin_max; i++) { - if (GC_collecting) goto yield; - if (i < my_last_spins/2 || GC_LOCK_TAKEN) { - PAUSE; - continue; - } - if (GC_TRY_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_TRY_LOCK()) { - return; - } - if (i < SLEEP_THRESHOLD) { - sched_yield(); - } else { - struct timespec ts; - - if (i > 26) i = 26; - /* Don't wait for more than about 60msecs, even */ - /* under extreme contention. */ - ts.tv_sec = 0; - ts.tv_nsec = 1 << i; - nanosleep(&ts, 0); - } - } -} - -# else - -#ifndef LINT - int GC_no_Irix_threads; -#endif - -# endif /* GC_IRIX_THREADS */ - |