pthread_mutex_t all_threads_lock = PTHREAD_MUTEX_INITIALIZER;
-/* When trying to get all_threads_lock one should make sure that
- * SIG_STOP_FOR_GC is not blocked. Else there would be a possible
- * deadlock: gc locks it, other thread blocks signals, gc sends stop
- * request to other thread and waits, other thread blocks on lock. */
-void check_sig_stop_for_gc_can_arrive_or_lose()
-{
- /* Get the current sigmask, by blocking the empty set. */
- sigset_t empty,current;
- sigemptyset(&empty);
- thread_sigmask(SIG_BLOCK, &empty, ¤t);
- if (sigismember(¤t,SIG_STOP_FOR_GC))
- lose("SIG_STOP_FOR_GC cannot arrive: it is blocked\n");
- if (SymbolValue(GC_INHIBIT,arch_os_get_current_thread()) != NIL)
- lose("SIG_STOP_FOR_GC cannot arrive: gc is inhibited\n");
- if (arch_pseudo_atomic_atomic(NULL))
- lose("SIG_STOP_FOR_GC cannot arrive: in pseudo atomic\n");
-}
-
-#define GET_ALL_THREADS_LOCK(name) \
- { \
- sigset_t _newset,_oldset; \
- sigemptyset(&_newset); \
- sigaddset_deferrable(&_newset); \
- thread_sigmask(SIG_BLOCK, &_newset, &_oldset); \
- check_sig_stop_for_gc_can_arrive_or_lose(); \
- FSHOW_SIGNAL((stderr,"/%s:waiting on lock=%ld, thread=%lu\n",name, \
- all_threads_lock,arch_os_get_current_thread()->os_thread)); \
- pthread_mutex_lock(&all_threads_lock); \
- FSHOW_SIGNAL((stderr,"/%s:got lock, thread=%lu\n", \
- name,arch_os_get_current_thread()->os_thread));
-
-#define RELEASE_ALL_THREADS_LOCK(name) \
- FSHOW_SIGNAL((stderr,"/%s:released lock\n",name)); \
- pthread_mutex_unlock(&all_threads_lock); \
- thread_sigmask(SIG_SETMASK,&_oldset,0); \
- }
-
#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
extern lispobj call_into_lisp_first_time(lispobj fun, lispobj *args, int nargs);
#endif
link_thread(th);
th->os_thread=thread_self();
protect_control_stack_guard_page(1);
- th->state = STATE_RUNNING;
#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
return call_into_lisp_first_time(function,args,0);
th->os_thread=thread_self();
protect_control_stack_guard_page(1);
- /* This thread is in STATE_STARTING so the GC is not sending it
- * SIG_STOP_FOR_GC => no danger of deadlocking even with
- * SIG_STOP_FOR_GC blocked. The lock is acquired in order not to
- * enter running state with the gc running. */
+ /* Since GC can only know about this thread from the all_threads
+ * list and we're just adding this thread to it there is no danger
+ * of deadlocking even with SIG_STOP_FOR_GC blocked (which it is
+ * not). */
pthread_mutex_lock(&all_threads_lock);
- th->state = STATE_RUNNING;
+ link_thread(th);
pthread_mutex_unlock(&all_threads_lock);
- /* Now that we entered STATE_RUNNING let the gc suspend this
- * thread. */
- {
- sigset_t sigset;
- sigemptyset(&sigset);
- sigaddset(&sigset, SIG_STOP_FOR_GC);
- thread_sigmask(SIG_UNBLOCK, &sigset, 0);
- }
result = funcall0(function);
th->state=STATE_DEAD;
union per_thread_data *per_thread;
struct thread *th=0; /* subdue gcc */
void *spaces=0;
+ int i;
/* may as well allocate all the spaces at once: it saves us from
* having to decide what to do if only some of the allocations
BINDING_STACK_SIZE+
ALIEN_STACK_SIZE);
- if(all_threads) {
- memcpy(per_thread,arch_os_get_current_thread(),
- dynamic_values_bytes);
- } else {
#ifdef LISP_FEATURE_SB_THREAD
- int i;
- for(i=0;i<(dynamic_values_bytes/sizeof(lispobj));i++)
- per_thread->dynamic_values[i]=NO_TLS_VALUE_MARKER_WIDETAG;
+ for(i = 0; i < (dynamic_values_bytes / sizeof(lispobj)); i++)
+ per_thread->dynamic_values[i] = NO_TLS_VALUE_MARKER_WIDETAG;
+ if (all_threads == 0) {
if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG) {
SetSymbolValue
(FREE_TLS_INDEX,
STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted);
#endif
#undef STATIC_TLS_INIT
-#endif
}
+#endif
th=&per_thread->thread;
th->control_stack_start = spaces;
th->binding_stack_pointer=th->binding_stack_start;
th->this=th;
th->os_thread=0;
- th->state=STATE_STARTING;
+ th->state=STATE_RUNNING;
#ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
th->alien_stack_pointer=((void *)th->alien_stack_start
+ ALIEN_STACK_SIZE-N_WORD_BYTES);
sigset_t newset,oldset;
boolean r=1;
sigemptyset(&newset);
- sigaddset_blockable(&newset);
+ /* Blocking deferrable signals is enough, no need to block
+ * SIG_STOP_FOR_GC because the child process is not linked onto
+ * all_threads until it's ready. */
+ sigaddset_deferrable(&newset);
thread_sigmask(SIG_BLOCK, &newset, &oldset);
if((pthread_attr_init(&attr)) ||
if(linux_no_threads_p) return 0;
- /* The new thread must be linked immediately onto all_threads for
- * gc. */
- GET_ALL_THREADS_LOCK("create_thread")
- /* If it is too slow most of the allocation/initialization can
- * be done without the lock. */
+ /* Assuming that a fresh thread struct has no lisp objects in it,
+ * linking it to all_threads can be left to the thread itself
+ * without fear of gc lossage. initial_function violates this
+ * assumption and must stay pinned until the child starts up. */
th = create_thread_struct(initial_function);
- if (th)
- link_thread(th);
- RELEASE_ALL_THREADS_LOCK("create_thread")
if(th==0) return 0;
if (create_os_thread(th,&kid_tid)) {
return kid_tid;
} else {
- GET_ALL_THREADS_LOCK("create_thread")
- unlink_thread(th);
- RELEASE_ALL_THREADS_LOCK("create_thread")
free_thread_struct(th);
return 0;
}
th->os_thread));
/* stop all other threads by sending them SIG_STOP_FOR_GC */
for(p=all_threads; p; p=p->next) {
+ gc_assert(p->os_thread != 0);
if((p!=th) && ((p->state==STATE_RUNNING))) {
FSHOW_SIGNAL((stderr,"/gc_stop_the_world: suspending %lu\n",
p->os_thread));
/* wait for the running threads to stop or finish */
for(p=all_threads;p;) {
if((p!=th) && (p->state==STATE_RUNNING)) {
- gc_assert(p->os_thread!=0);
sched_yield();
} else {
p=p->next;
* restarting */
FSHOW_SIGNAL((stderr,"/gc_start_the_world:begin\n"));
for(p=all_threads;p;p=p->next) {
- if((p!=th) && (p->state!=STATE_STARTING) && (p->state!=STATE_DEAD)) {
- gc_assert(p->os_thread!=0);
+ gc_assert(p->os_thread!=0);
+ if((p!=th) && (p->state!=STATE_DEAD)) {
if(p->state!=STATE_SUSPENDED) {
lose("gc_start_the_world: wrong thread state is %d\n",
fixnum_value(p->state));
projects / sbcl.git / commitdiff