int dynamic_values_bytes=4096*sizeof(lispobj); /* same for all threads */
struct thread *all_threads;
volatile lispobj all_threads_lock;
-volatile lispobj thread_start_lock;
extern struct interrupt_data * global_interrupt_data;
extern int linux_no_threads_p;
+/* 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 is blocked\n");
+ if (SymbolValue(INTERRUPTS_ENABLED,arch_os_get_current_thread()) == NIL)
+ lose("interrupts disabled\n");
+ if (arch_pseudo_atomic_atomic(NULL))
+ lose("n pseudo atomic\n");
+}
+
+#ifdef QSHOW_SIGNALS
+#define FSHOW_SIGNAL FSHOW
+#else
+#define FSHOW_SIGNAL(args)
+#endif
+
+#define GET_ALL_THREADS_LOCK(name) \
+ { \
+ sigset_t _newset,_oldset; \
+ sigemptyset(&_newset); \
+ sigaddset_blockable(&_newset); \
+ sigdelset(&_newset,SIG_STOP_FOR_GC); \
+ thread_sigmask(SIG_BLOCK, &_newset, &_oldset); \
+ check_sig_stop_for_gc_can_arrive_or_lose(); \
+ FSHOW_SIGNAL((stderr,"/%s:waiting on lock=%ld, thread=%ld\n",name, \
+ all_threads_lock,arch_os_get_current_thread()->os_thread)); \
+ get_spinlock(&all_threads_lock,(long)arch_os_get_current_thread()); \
+ FSHOW_SIGNAL((stderr,"/%s:got lock, thread=%ld\n", \
+ name,arch_os_get_current_thread()->os_thread));
+
+#define RELEASE_ALL_THREADS_LOCK(name) \
+ FSHOW_SIGNAL((stderr,"/%s:released lock\n",name)); \
+ release_spinlock(&all_threads_lock); \
+ thread_sigmask(SIG_SETMASK,&_oldset,0); \
+ }
+
int
initial_thread_trampoline(struct thread *th)
{
}
#ifdef LISP_FEATURE_SB_THREAD
-void mark_thread_dead(struct thread *th) {
- funcall1(SymbolFunction(HANDLE_THREAD_EXIT),alloc_number(th->os_thread));
- /* I hope it's safe for a thread to detach itself inside a
- * cancellation cleanup */
- pthread_detach(th->os_thread);
- th->state=STATE_DEAD;
- /* FIXME: if gc hits here it will rip the stack from under us */
-}
/* this is the first thing that runs in the child (which is why the
* silly calling convention). Basically it calls the user's requested
int
new_thread_trampoline(struct thread *th)
{
- lispobj function,ret;
+ lispobj function;
function = th->unbound_marker;
th->unbound_marker = UNBOUND_MARKER_WIDETAG;
- pthread_cleanup_push((void (*) (void *))mark_thread_dead,th);
- if(arch_os_thread_init(th)==0) return 1;
+ if(arch_os_thread_init(th)==0) return 1;
/* wait here until our thread is linked into all_threads: see below */
while(th->os_thread<1) sched_yield();
th->state=STATE_RUNNING;
- ret = funcall0(function);
- /* execute cleanup */
- pthread_cleanup_pop(1);
- return ret;
+ return funcall0(function);
}
#endif /* LISP_FEATURE_SB_THREAD */
/* this is called from any other thread to create the new one, and
- * initialize all parts of it that can be initialized from another
- * thread
+ * initialize all parts of it that can be initialized from another
+ * thread
*/
struct thread * create_thread_struct(lispobj initial_function) {
int i;
for(i=0;i<(dynamic_values_bytes/sizeof(lispobj));i++)
per_thread->dynamic_values[i]=UNBOUND_MARKER_WIDETAG;
- if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG)
+ if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG)
SetSymbolValue
(FREE_TLS_INDEX,
make_fixnum(MAX_INTERRUPTS+
#define STATIC_TLS_INIT(sym,field) \
((struct symbol *)(sym-OTHER_POINTER_LOWTAG))->tls_index= \
make_fixnum(THREAD_SLOT_OFFSET_WORDS(field))
-
+
STATIC_TLS_INIT(BINDING_STACK_START,binding_stack_start);
STATIC_TLS_INIT(BINDING_STACK_POINTER,binding_stack_pointer);
STATIC_TLS_INIT(CONTROL_STACK_START,control_stack_start);
#ifndef LISP_FEATURE_SB_THREAD
/* the tls-points-into-struct-thread trick is only good for threaded
* sbcl, because unithread sbcl doesn't have tls. So, we copy the
- * appropriate values from struct thread here, and make sure that
+ * appropriate values from struct thread here, and make sure that
* we use the appropriate SymbolValue macros to access any of the
* variable quantities from the C runtime. It's not quite OAOOM,
* it just feels like it */
current_binding_stack_pointer=th->binding_stack_pointer;
current_control_stack_pointer=th->control_stack_start;
#endif
-#endif
+#endif
bind_variable(CURRENT_CATCH_BLOCK,make_fixnum(0),th);
- bind_variable(CURRENT_UNWIND_PROTECT_BLOCK,make_fixnum(0),th);
+ bind_variable(CURRENT_UNWIND_PROTECT_BLOCK,make_fixnum(0),th);
bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,make_fixnum(0),th);
bind_variable(INTERRUPT_PENDING, NIL,th);
bind_variable(INTERRUPTS_ENABLED,T,th);
th->interrupt_data = (struct interrupt_data *)
os_validate(0,(sizeof (struct interrupt_data)));
- if(all_threads)
+ if(all_threads)
memcpy(th->interrupt_data,
arch_os_get_current_thread()->interrupt_data,
sizeof (struct interrupt_data));
- else
+ else
memcpy(th->interrupt_data,global_interrupt_data,
sizeof (struct interrupt_data));
void link_thread(struct thread *th,os_thread_t kid_tid)
{
- sigset_t newset,oldset;
- sigemptyset(&newset);
- sigaddset_blockable(&newset);
- thread_sigmask(SIG_BLOCK, &newset, &oldset);
-
- get_spinlock(&all_threads_lock,kid_tid);
if (all_threads) all_threads->prev=th;
th->next=all_threads;
th->prev=0;
* all_threads_lock to ensure that we don't have >1 thread with
* os_thread=0 on the list at once
*/
- protect_control_stack_guard_page(th->os_thread,1);
+ protect_control_stack_guard_page(th,1);
/* child will not start until this is set */
th->os_thread=kid_tid;
- release_spinlock(&all_threads_lock);
-
- thread_sigmask(SIG_SETMASK,&oldset,0);
}
void create_initial_thread(lispobj initial_function) {
}
#ifdef LISP_FEATURE_SB_THREAD
-os_thread_t create_thread(lispobj initial_function) {
+
+boolean create_os_thread(struct thread *th,os_thread_t *kid_tid)
+{
+ /* The new thread inherits the restrictive signal mask set here,
+ * and enables signals again when it is set up properly. */
+ pthread_attr_t attr;
+ sigset_t newset,oldset;
+ boolean r=1;
+ sigemptyset(&newset);
+ sigaddset_blockable(&newset);
+ thread_sigmask(SIG_BLOCK, &newset, &oldset);
+
+ if((pthread_attr_init(&attr)) ||
+ (pthread_attr_setstack(&attr,th->control_stack_start,
+ THREAD_CONTROL_STACK_SIZE-16)) ||
+ (pthread_create
+ (kid_tid,&attr,(void *(*)(void *))new_thread_trampoline,th)))
+ r=0;
+ thread_sigmask(SIG_SETMASK,&oldset,0);
+ return r;
+}
+
+struct thread *create_thread(lispobj initial_function) {
struct thread *th;
os_thread_t kid_tid=0;
- pthread_attr_t attr;
+ boolean success;
if(linux_no_threads_p) return 0;
+
th=create_thread_struct(initial_function);
if(th==0) return 0;
-#ifdef QSHOW_SIGNALS
- SHOW("create_thread:waiting on lock");
-#endif
- get_spinlock(&thread_start_lock,arch_os_get_current_thread()->os_thread);
-#ifdef QSHOW_SIGNALS
- SHOW("create_thread:got lock");
-#endif
- /* The new thread inherits the restrictive signal mask set here,
- * and enables signals again when it is set up properly. */
- {
- sigset_t newset,oldset;
- sigemptyset(&newset);
- sigaddset_blockable(&newset);
- thread_sigmask(SIG_BLOCK, &newset, &oldset);
- if((pthread_attr_init(&attr)) ||
- (pthread_attr_setstack(&attr,th->control_stack_start,
- THREAD_CONTROL_STACK_SIZE-16)) ||
- (pthread_create
- (&kid_tid,&attr,(void *(*)(void *))new_thread_trampoline,th)))
- kid_tid=0;
- thread_sigmask(SIG_SETMASK,&oldset,0);
- }
- if(kid_tid>0) {
+
+ /* we must not be interrupted here after a successful
+ * create_os_thread, because the kid will be waiting for its
+ * thread struct to be linked */
+ GET_ALL_THREADS_LOCK("create_thread")
+
+ success=create_os_thread(th,&kid_tid);
+ if (success)
link_thread(th,kid_tid);
- /* it's started and initialized, it's safe to gc */
- release_spinlock(&thread_start_lock);
-#ifdef QSHOW_SIGNALS
- SHOW("create_thread:released lock");
-#endif
- /* by now the kid might have already exited */
- return kid_tid;
- } else {
- release_spinlock(&thread_start_lock);
-#ifdef QSHOW_SIGNALS
- SHOW("create_thread:released lock(failure)");
-#endif
+ else
os_invalidate((os_vm_address_t) th->control_stack_start,
((sizeof (lispobj))
* (th->control_stack_end-th->control_stack_start)) +
BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
32*SIGSTKSZ);
- return 0;
- }
-}
-#endif
-struct thread *find_thread_by_os_thread(os_thread_t tid)
-{
- struct thread *th;
- for_each_thread(th)
- if(th->os_thread==tid) return th;
- return 0;
+ RELEASE_ALL_THREADS_LOCK("create_thread")
+
+ if (success)
+ return th;
+ else
+ return 0;
}
+#endif
#if defined LISP_FEATURE_SB_THREAD
/* This is not needed unless #+SB-THREAD, as there's a trivial null
* unithread definition. */
-void reap_dead_threads()
+/* called from lisp from the thread object finalizer */
+void reap_dead_thread(struct thread *th)
{
- struct thread *th,*next,*prev=0;
- th=all_threads;
- while(th) {
- next=th->next;
- if(th->state==STATE_DEAD) {
+ if(th->state!=STATE_DEAD)
+ lose("thread %lx is not joinable, state=%d\n",th,th->state);
#ifdef LISP_FEATURE_GENCGC
- gc_alloc_update_page_tables(0, &th->alloc_region);
-#endif
- get_spinlock(&all_threads_lock,th->os_thread);
- if(prev) prev->next=next;
- else all_threads=next;
- release_spinlock(&all_threads_lock);
- if(th->tls_cookie>=0) arch_os_thread_cleanup(th);
- os_invalidate((os_vm_address_t) th->control_stack_start,
- ((sizeof (lispobj))
- * (th->control_stack_end-th->control_stack_start)) +
- BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
- 32*SIGSTKSZ);
- } else
- prev=th;
- th=next;
+ {
+ sigset_t newset,oldset;
+ sigemptyset(&newset);
+ sigaddset_blockable(&newset);
+ thread_sigmask(SIG_BLOCK, &newset, &oldset);
+ gc_alloc_update_page_tables(0, &th->alloc_region);
+ release_spinlock(&all_threads_lock);
+ thread_sigmask(SIG_SETMASK,&oldset,0);
}
+#endif
+ GET_ALL_THREADS_LOCK("reap_dead_thread")
+ FSHOW((stderr,"/reap_dead_thread: reaping %ld\n",th->os_thread));
+ if(th->prev)
+ th->prev->next=th->next;
+ else all_threads=th->next;
+ if(th->next)
+ th->next->prev=th->prev;
+ RELEASE_ALL_THREADS_LOCK("reap_dead_thread")
+ if(th->tls_cookie>=0) arch_os_thread_cleanup(th);
+ gc_assert(pthread_join(th->os_thread,NULL)==0);
+ os_invalidate((os_vm_address_t) th->control_stack_start,
+ ((sizeof (lispobj))
+ * (th->control_stack_end-th->control_stack_start)) +
+ BINDING_STACK_SIZE+ALIEN_STACK_SIZE+dynamic_values_bytes+
+ 32*SIGSTKSZ);
}
-int interrupt_thread(os_thread_t tid, lispobj function)
+int interrupt_thread(struct thread *th, lispobj function)
{
- struct thread *th;
- for_each_thread(th)
- if((th->os_thread==tid) && (th->state != STATE_DEAD)) {
- /* In clone_threads, if A and B both interrupt C at approximately
- * the same time, it does not matter: the second signal will be
- * masked until the handler has returned from the first one.
- * In pthreads though, we can't put the knowledge of what function
- * to call into the siginfo, so we have to store it in the
- * destination thread, and do it in such a way that A won't
- * clobber B's interrupt. Hence this stupid linked list.
- *
- * This does depend on SIG_INTERRUPT_THREAD being queued
- * (as POSIX RT signals are): we need to keep
- * interrupt_fun data for exactly as many signals as are
- * going to be received by the destination thread.
- */
- struct cons *c;
- int kill_status;
- /* mask the signals in case this thread is being interrupted */
- sigset_t newset,oldset;
- sigemptyset(&newset);
- sigaddset_blockable(&newset);
- thread_sigmask(SIG_BLOCK, &newset, &oldset);
-
- get_spinlock(&th->interrupt_fun_lock,
- (int)arch_os_get_current_thread());
- kill_status=thread_kill(th->os_thread,SIG_INTERRUPT_THREAD);
- if(kill_status==0) {
- c=alloc_cons(function,th->interrupt_fun);
- th->interrupt_fun=c;
- }
- release_spinlock(&th->interrupt_fun_lock);
- thread_sigmask(SIG_SETMASK,&oldset,0);
- return (kill_status ? -1 : 0);
- }
+ /* A thread may also become dead after this test. */
+ if ((th->state != STATE_DEAD)) {
+ /* In clone_threads, if A and B both interrupt C at
+ * approximately the same time, it does not matter: the
+ * second signal will be masked until the handler has
+ * returned from the first one. In pthreads though, we
+ * can't put the knowledge of what function to call into
+ * the siginfo, so we have to store it in the destination
+ * thread, and do it in such a way that A won't clobber
+ * B's interrupt. Hence this stupid linked list.
+ *
+ * This does depend on SIG_INTERRUPT_THREAD being queued
+ * (as POSIX RT signals are): we need to keep
+ * interrupt_fun data for exactly as many signals as are
+ * going to be received by the destination thread.
+ */
+ struct cons *c=alloc_cons(function,NIL);
+ int kill_status;
+ /* interrupt_thread_handler locks this spinlock with
+ * interrupts blocked and it does so for the sake of
+ * arrange_return_to_lisp_function, so we must also block
+ * them. */
+ sigset_t newset,oldset;
+ sigemptyset(&newset);
+ sigaddset_blockable(&newset);
+ thread_sigmask(SIG_BLOCK, &newset, &oldset);
+ get_spinlock(&th->interrupt_fun_lock,
+ (long)arch_os_get_current_thread());
+ kill_status=thread_kill(th->os_thread,SIG_INTERRUPT_THREAD);
+ if(kill_status==0) {
+ ((struct cons *)native_pointer(c))->cdr=th->interrupt_fun;
+ th->interrupt_fun=c;
+ }
+ release_spinlock(&th->interrupt_fun_lock);
+ thread_sigmask(SIG_SETMASK,&oldset,0);
+ return (kill_status ? -1 : 0);
+ }
errno=EPERM; return -1;
}
-/* stopping the world is a two-stage process. From this thread we signal
+/* stopping the world is a two-stage process. From this thread we signal
* all the others with SIG_STOP_FOR_GC. The handler for this signal does
- * the usual pseudo-atomic checks (we don't want to stop a thread while
+ * the usual pseudo-atomic checks (we don't want to stop a thread while
* it's in the middle of allocation) then waits for another SIG_STOP_FOR_GC.
*/
+/* To avoid deadlocks when gc stops the world all clients of each
+ * mutex must enable or disable SIG_STOP_FOR_GC for the duration of
+ * holding the lock, but they must agree on which. */
void gc_stop_the_world()
{
struct thread *p,*th=arch_os_get_current_thread();
-#ifdef QSHOW_SIGNALS
- SHOW("gc_stop_the_world:begin");
-#endif
+ FSHOW_SIGNAL((stderr,"/gc_stop_the_world:waiting on lock, thread=%ld\n",
+ th->os_thread));
/* keep threads from starting while the world is stopped. */
- get_spinlock(&thread_start_lock,th->os_thread);
-#ifdef QSHOW_SIGNALS
- SHOW("gc_stop_the_world:locked");
-#endif
+ get_spinlock(&all_threads_lock,(long)th);
+ FSHOW_SIGNAL((stderr,"/gc_stop_the_world:got lock, thread=%ld\n",
+ th->os_thread));
/* stop all other threads by sending them SIG_STOP_FOR_GC */
for(p=all_threads; p; p=p->next) {
while(p->state==STATE_STARTING) sched_yield();
- if((p!=th) && (p->os_thread!=0) && (p->state==STATE_RUNNING)) {
- p->state=STATE_STOPPING;
+ if((p!=th) && (p->state==STATE_RUNNING)) {
+ FSHOW_SIGNAL((stderr,"/gc_stop_the_world:sending sig_stop to %ld\n",
+ p->os_thread));
if(thread_kill(p->os_thread,SIG_STOP_FOR_GC)==-1) {
- /* FIXME: we can't kill the thread; assume because it died
- * already */
+ /* we can't kill the thread; assume because it died
+ * since we last checked */
p->state=STATE_DEAD;
+ FSHOW_SIGNAL((stderr,"/gc_stop_the_world:assuming %ld dead\n",
+ p->os_thread));
}
}
}
-#ifdef QSHOW_SIGNALS
- SHOW("gc_stop_the_world:signals sent");
-#endif
- /* wait for the running threads to stop */
+ FSHOW_SIGNAL((stderr,"/gc_stop_the_world:signals sent\n"));
+ /* wait for the running threads to stop or finish */
for(p=all_threads;p;) {
- if((p==th) || (p->os_thread==0) || (p->state==STATE_STARTING) ||
- (p->state==STATE_DEAD) || (p->state==STATE_STOPPED)) {
+ gc_assert(p->os_thread!=0);
+ gc_assert(p->state!=STATE_STARTING);
+ if((p==th) || (p->state==STATE_SUSPENDED) ||
+ (p->state==STATE_DEAD)) {
p=p->next;
}
}
-#ifdef QSHOW_SIGNALS
- SHOW("gc_stop_the_world:end");
-#endif
+ FSHOW_SIGNAL((stderr,"/gc_stop_the_world:end\n"));
}
void gc_start_the_world()
/* if a resumed thread creates a new thread before we're done with
* this loop, the new thread will get consed on the front of
* all_threads, but it won't have been stopped so won't need
- * restarting; there can be threads just starting from before
- * gc_stop_the_world, though */
-#ifdef QSHOW_SIGNALS
- SHOW("gc_start_the_world:begin");
-#endif
+ * restarting */
+ FSHOW_SIGNAL((stderr,"/gc_start_the_world:begin\n"));
for(p=all_threads;p;p=p->next) {
- if((p!=th) && (p->os_thread!=0) && (p->state!=STATE_STARTING) &&
- (p->state!=STATE_DEAD)) {
- if(p->state!=STATE_STOPPED) {
+ 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 %ld\n",
fixnum_value(p->state));
}
* risk signal accumulation and lose any meaning of
* thread->state */
for(p=all_threads;p;) {
- gc_assert(p->state!=STATE_STOPPING);
- if((p==th) || (p->os_thread==0) || (p->state!=STATE_STOPPED)) {
+ if((p==th) || (p->state!=STATE_SUSPENDED)) {
p=p->next;
}
}
- release_spinlock(&thread_start_lock);
-#ifdef QSHOW_SIGNALS
- SHOW("gc_start_the_world:end");
-#endif
+ release_spinlock(&all_threads_lock);
+ FSHOW_SIGNAL((stderr,"/gc_start_the_world:end\n"));
}
#endif
projects / sbcl.git / blobdiff