X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fruntime%2Fthread.c;h=bcc470ca9a48a01d21c99b590ceef58631b4e2eb;hb=0d4c7a1323106c6e60511bef929048edcb040205;hp=821e4a2202c1ef597b4bcc8476cd21ae93a0d4a2;hpb=b27fb452f72190637b03a6ef2e1333091da42a98;p=sbcl.git diff --git a/src/runtime/thread.c b/src/runtime/thread.c index 821e4a2..bcc470c 100644 --- a/src/runtime/thread.c +++ b/src/runtime/thread.c @@ -1,16 +1,38 @@ +/* + * This software is part of the SBCL system. See the README file for + * more information. + * + * This software is derived from the CMU CL system, which was + * written at Carnegie Mellon University and released into the + * public domain. The software is in the public domain and is + * provided with absolutely no warranty. See the COPYING and CREDITS + * files for more information. + */ + +#include "sbcl.h" + #include #include #include +#ifndef LISP_FEATURE_WIN32 #include +#endif #include #include #include #include +#ifndef LISP_FEATURE_WIN32 #include +#endif + +#ifdef LISP_FEATURE_MACH_EXCEPTION_HANDLER +#include +#include +#include +#endif -#include "sbcl.h" #include "runtime.h" -#include "validate.h" /* for CONTROL_STACK_SIZE etc */ +#include "validate.h" /* for BINDING_STACK_SIZE etc */ #include "alloc.h" #include "thread.h" #include "arch.h" @@ -23,22 +45,55 @@ #include "interr.h" /* for lose() */ #include "gc-internal.h" +#ifdef LISP_FEATURE_WIN32 +/* + * Win32 doesn't have SIGSTKSZ, and we're not switching stacks anyway, + * so define it arbitrarily + */ +#define SIGSTKSZ 1024 +#endif + +#if defined(LISP_FEATURE_DARWIN) && defined(LISP_FEATURE_SB_THREAD) +#define DELAY_THREAD_POST_MORTEM 5 +#define LOCK_CREATE_THREAD +#endif + +#ifdef LISP_FEATURE_FREEBSD +#define CREATE_CLEANUP_THREAD +#define LOCK_CREATE_THREAD +#endif + #define ALIEN_STACK_SIZE (1*1024*1024) /* 1Mb size chosen at random */ -struct freeable_stack { +#ifdef LISP_FEATURE_SB_THREAD +struct thread_post_mortem { +#ifdef DELAY_THREAD_POST_MORTEM + struct thread_post_mortem *next; +#endif os_thread_t os_thread; - os_vm_address_t stack; + pthread_attr_t *os_attr; + os_vm_address_t os_address; }; -static struct freeable_stack * volatile freeable_stack = 0; +#ifdef DELAY_THREAD_POST_MORTEM +static int pending_thread_post_mortem_count = 0; +pthread_mutex_t thread_post_mortem_lock = PTHREAD_MUTEX_INITIALIZER; +#endif +static struct thread_post_mortem * volatile pending_thread_post_mortem = 0; +#endif -int dynamic_values_bytes=4096*sizeof(lispobj); /* same for all threads */ -struct thread * volatile all_threads; +int dynamic_values_bytes=TLS_SIZE*sizeof(lispobj); /* same for all threads */ +struct thread *all_threads; extern struct interrupt_data * global_interrupt_data; -extern int linux_no_threads_p; #ifdef LISP_FEATURE_SB_THREAD pthread_mutex_t all_threads_lock = PTHREAD_MUTEX_INITIALIZER; +#ifdef LOCK_CREATE_THREAD +static pthread_mutex_t create_thread_lock = PTHREAD_MUTEX_INITIALIZER; +#endif +#ifdef LISP_FEATURE_GCC_TLS +__thread struct thread *current_thread; +#endif #endif #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64) @@ -79,7 +134,9 @@ initial_thread_trampoline(struct thread *th) if(arch_os_thread_init(th)==0) return 1; link_thread(th); th->os_thread=thread_self(); +#ifndef LISP_FEATURE_WIN32 protect_control_stack_guard_page(1); +#endif #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64) return call_into_lisp_first_time(function,args,0); @@ -88,35 +145,104 @@ initial_thread_trampoline(struct thread *th) #endif } -#define THREAD_STRUCT_SIZE (THREAD_CONTROL_STACK_SIZE + BINDING_STACK_SIZE + \ - ALIEN_STACK_SIZE + dynamic_values_bytes + \ - 32 * SIGSTKSZ) +#ifdef LISP_FEATURE_SB_THREAD +#define THREAD_STATE_LOCK_SIZE \ + (sizeof(pthread_mutex_t))+(sizeof(pthread_cond_t)) +#else +#define THREAD_STATE_LOCK_SIZE 0 +#endif + +#define THREAD_STRUCT_SIZE (thread_control_stack_size + BINDING_STACK_SIZE + \ + ALIEN_STACK_SIZE + \ + THREAD_STATE_LOCK_SIZE + \ + dynamic_values_bytes + \ + 32 * SIGSTKSZ + \ + THREAD_ALIGNMENT_BYTES) #ifdef LISP_FEATURE_SB_THREAD +/* THREAD POST MORTEM CLEANUP + * + * Memory allocated for the thread stacks cannot be reclaimed while + * the thread is still alive, so we need a mechanism for post mortem + * cleanups. FIXME: We actually have three, for historical reasons as + * the saying goes. Do we really need three? Nikodemus guesses that + * not anymore, now that we properly call pthread_attr_destroy before + * freeing the stack. */ + +static struct thread_post_mortem * +plan_thread_post_mortem(struct thread *corpse) +{ + if (corpse) { + struct thread_post_mortem *post_mortem = malloc(sizeof(struct thread_post_mortem)); + gc_assert(post_mortem); + post_mortem->os_thread = corpse->os_thread; + post_mortem->os_attr = corpse->os_attr; + post_mortem->os_address = corpse->os_address; +#ifdef DELAY_THREAD_POST_MORTEM + post_mortem->next = NULL; +#endif + return post_mortem; + } else { + /* FIXME: When does this happen? */ + return NULL; + } +} static void -free_thread_stack_later(struct thread *thread_to_be_cleaned_up) +perform_thread_post_mortem(struct thread_post_mortem *post_mortem) { - struct freeable_stack *new_freeable_stack = 0; - if (thread_to_be_cleaned_up) { - new_freeable_stack = (struct freeable_stack *) - os_validate(0, sizeof(struct freeable_stack)); - new_freeable_stack->os_thread = thread_to_be_cleaned_up->os_thread; - new_freeable_stack->stack = (os_vm_address_t) - thread_to_be_cleaned_up->control_stack_start; +#ifdef CREATE_POST_MORTEM_THREAD + pthread_detach(pthread_self()); +#endif + if (post_mortem) { + gc_assert(!pthread_join(post_mortem->os_thread, NULL)); + gc_assert(!pthread_attr_destroy(post_mortem->os_attr)); + free(post_mortem->os_attr); + os_invalidate(post_mortem->os_address, THREAD_STRUCT_SIZE); + free(post_mortem); } - new_freeable_stack = (struct freeable_stack *) - swap_lispobjs((lispobj *)(void *)&freeable_stack, - (lispobj)new_freeable_stack); - if (new_freeable_stack) { - FSHOW((stderr,"/reaping %lu\n", new_freeable_stack->os_thread)); - /* Under NPTL pthread_join really waits until the thread - * exists and the stack can be safely freed. This is sadly not - * mandated by the pthread spec. */ - gc_assert(pthread_join(new_freeable_stack->os_thread, NULL) == 0); - os_invalidate(new_freeable_stack->stack, THREAD_STRUCT_SIZE); - os_invalidate((os_vm_address_t) new_freeable_stack, - sizeof(struct freeable_stack)); +} + +static void +schedule_thread_post_mortem(struct thread *corpse) +{ + struct thread_post_mortem *post_mortem = NULL; + if (corpse) { + post_mortem = plan_thread_post_mortem(corpse); + +#ifdef DELAY_THREAD_POST_MORTEM + pthread_mutex_lock(&thread_post_mortem_lock); + /* First stick the new post mortem to the end of the queue. */ + if (pending_thread_post_mortem) { + struct thread_post_mortem *next = pending_thread_post_mortem; + while (next->next) { + next = next->next; + } + next->next = post_mortem; + } else { + pending_thread_post_mortem = post_mortem; + } + /* Then, if there are enough things in the queue, clean up one + * from the head -- or increment the count, and null out the + * post_mortem we have. */ + if (pending_thread_post_mortem_count > DELAY_THREAD_POST_MORTEM) { + post_mortem = pending_thread_post_mortem; + pending_thread_post_mortem = post_mortem->next; + } else { + pending_thread_post_mortem_count++; + post_mortem = NULL; + } + pthread_mutex_unlock(&thread_post_mortem_lock); + /* Finally run, the cleanup, if any. */ + perform_thread_post_mortem(post_mortem); +#elif defined(CREATE_POST_MORTEM_THREAD) + gc_assert(!pthread_create(&thread, NULL, perform_thread_post_mortem, post_mortem)); +#else + post_mortem = (struct thread_post_mortem *) + swap_lispobjs((lispobj *)(void *)&pending_thread_post_mortem, + (lispobj)post_mortem); + perform_thread_post_mortem(post_mortem); +#endif } } @@ -129,8 +255,11 @@ int new_thread_trampoline(struct thread *th) { lispobj function; - int result; + int result, lock_ret; + FSHOW((stderr,"/creating thread %lu\n", thread_self())); + check_deferrables_blocked_or_lose(); + check_gc_signals_unblocked_or_lose(); function = th->no_tls_value_marker; th->no_tls_value_marker = NO_TLS_VALUE_MARKER_WIDETAG; if(arch_os_thread_init(th)==0) { @@ -141,27 +270,50 @@ new_thread_trampoline(struct thread *th) th->os_thread=thread_self(); protect_control_stack_guard_page(1); /* 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); + * 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). */ + lock_ret = pthread_mutex_lock(&all_threads_lock); + gc_assert(lock_ret == 0); link_thread(th); - pthread_mutex_unlock(&all_threads_lock); + lock_ret = pthread_mutex_unlock(&all_threads_lock); + gc_assert(lock_ret == 0); result = funcall0(function); - th->state=STATE_DEAD; + + /* Block GC */ + block_blockable_signals(); + set_thread_state(th, STATE_DEAD); /* SIG_STOP_FOR_GC is blocked and GC might be waiting for this * thread, but since we are already dead it won't wait long. */ - pthread_mutex_lock(&all_threads_lock); - gc_alloc_update_page_tables(0, &th->alloc_region); + lock_ret = pthread_mutex_lock(&all_threads_lock); + gc_assert(lock_ret == 0); + + gc_alloc_update_page_tables(BOXED_PAGE_FLAG, &th->alloc_region); unlink_thread(th); pthread_mutex_unlock(&all_threads_lock); + gc_assert(lock_ret == 0); if(th->tls_cookie>=0) arch_os_thread_cleanup(th); + pthread_mutex_destroy(th->state_lock); + pthread_cond_destroy(th->state_cond); + os_invalidate((os_vm_address_t)th->interrupt_data, (sizeof (struct interrupt_data))); - free_thread_stack_later(th); + +#ifdef LISP_FEATURE_MACH_EXCEPTION_HANDLER + FSHOW((stderr, "Deallocating mach port %x\n", THREAD_STRUCT_TO_EXCEPTION_PORT(th))); + mach_port_move_member(mach_task_self(), + THREAD_STRUCT_TO_EXCEPTION_PORT(th), + MACH_PORT_NULL); + mach_port_deallocate(mach_task_self(), + THREAD_STRUCT_TO_EXCEPTION_PORT(th)); + mach_port_destroy(mach_task_self(), + THREAD_STRUCT_TO_EXCEPTION_PORT(th)); +#endif + + schedule_thread_post_mortem(th); FSHOW((stderr,"/exiting thread %lu\n", thread_self())); return result; } @@ -174,7 +326,7 @@ free_thread_struct(struct thread *th) if (th->interrupt_data) os_invalidate((os_vm_address_t) th->interrupt_data, (sizeof (struct interrupt_data))); - os_invalidate((os_vm_address_t) th->control_stack_start, + os_invalidate((os_vm_address_t) th->os_address, THREAD_STRUCT_SIZE); } @@ -188,21 +340,33 @@ create_thread_struct(lispobj initial_function) { union per_thread_data *per_thread; struct thread *th=0; /* subdue gcc */ void *spaces=0; + void *aligned_spaces=0; #ifdef LISP_FEATURE_SB_THREAD - int i; + unsigned int i; #endif - /* may as well allocate all the spaces at once: it saves us from + /* 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 - * succeed */ + * succeed. SPACES must be appropriately aligned, since the GC + * expects the control stack to start at a page boundary -- and + * the OS may have even more rigorous requirements. We can't rely + * on the alignment passed from os_validate, since that might + * assume the current (e.g. 4k) pagesize, while we calculate with + * the biggest (e.g. 64k) pagesize allowed by the ABI. */ spaces=os_validate(0, THREAD_STRUCT_SIZE); if(!spaces) - return NULL; + return NULL; + /* Aligning up is safe as THREAD_STRUCT_SIZE has + * THREAD_ALIGNMENT_BYTES padding. */ + aligned_spaces = (void *)((((unsigned long)(char *)spaces) + + THREAD_ALIGNMENT_BYTES-1) + &~(unsigned long)(THREAD_ALIGNMENT_BYTES-1)); per_thread=(union per_thread_data *) - (spaces+ - THREAD_CONTROL_STACK_SIZE+ + (aligned_spaces+ + thread_control_stack_size+ BINDING_STACK_SIZE+ - ALIEN_STACK_SIZE); + ALIEN_STACK_SIZE + + THREAD_STATE_LOCK_SIZE); #ifdef LISP_FEATURE_SB_THREAD for(i = 0; i < (dynamic_values_bytes / sizeof(lispobj)); i++) @@ -227,23 +391,32 @@ create_thread_struct(lispobj initial_function) { STATIC_TLS_INIT(CONTROL_STACK_END,control_stack_end); STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer); #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64) - STATIC_TLS_INIT(PSEUDO_ATOMIC_ATOMIC,pseudo_atomic_atomic); - STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted); + STATIC_TLS_INIT(PSEUDO_ATOMIC_BITS,pseudo_atomic_bits); #endif #undef STATIC_TLS_INIT } #endif th=&per_thread->thread; - th->control_stack_start = spaces; + th->os_address = spaces; + th->control_stack_start = aligned_spaces; th->binding_stack_start= - (lispobj*)((void*)th->control_stack_start+THREAD_CONTROL_STACK_SIZE); + (lispobj*)((void*)th->control_stack_start+thread_control_stack_size); th->control_stack_end = th->binding_stack_start; th->alien_stack_start= (lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE); th->binding_stack_pointer=th->binding_stack_start; th->this=th; th->os_thread=0; +#ifdef LISP_FEATURE_SB_THREAD + th->os_attr=malloc(sizeof(pthread_attr_t)); + th->state_lock=(pthread_mutex_t *)((void *)th->alien_stack_start + + ALIEN_STACK_SIZE); + pthread_mutex_init(th->state_lock, NULL); + th->state_cond=(pthread_cond_t *)((void *)th->state_lock + + (sizeof(pthread_mutex_t))); + pthread_cond_init(th->state_cond, NULL); +#endif th->state=STATE_RUNNING; #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD th->alien_stack_pointer=((void *)th->alien_stack_start @@ -252,8 +425,7 @@ create_thread_struct(lispobj initial_function) { th->alien_stack_pointer=((void *)th->alien_stack_start); #endif #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64) - th->pseudo_atomic_interrupted=0; - th->pseudo_atomic_atomic=0; + th->pseudo_atomic_bits=0; #endif #ifdef LISP_FEATURE_GENCGC gc_set_region_empty(&th->alloc_region); @@ -272,8 +444,7 @@ create_thread_struct(lispobj initial_function) { #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64) SetSymbolValue(BINDING_STACK_POINTER,(lispobj)th->binding_stack_pointer,th); SetSymbolValue(ALIEN_STACK,(lispobj)th->alien_stack_pointer,th); - SetSymbolValue(PSEUDO_ATOMIC_ATOMIC,(lispobj)th->pseudo_atomic_atomic,th); - SetSymbolValue(PSEUDO_ATOMIC_INTERRUPTED,th->pseudo_atomic_interrupted,th); + SetSymbolValue(PSEUDO_ATOMIC_BITS,(lispobj)th->pseudo_atomic_bits,th); #else current_binding_stack_pointer=th->binding_stack_pointer; current_control_stack_pointer=th->control_stack_start; @@ -284,7 +455,9 @@ create_thread_struct(lispobj initial_function) { bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,make_fixnum(0),th); bind_variable(INTERRUPT_PENDING, NIL,th); bind_variable(INTERRUPTS_ENABLED,T,th); + bind_variable(ALLOW_WITH_INTERRUPTS,T,th); bind_variable(GC_PENDING,NIL,th); + bind_variable(ALLOC_SIGNAL,NIL,th); #ifdef LISP_FEATURE_SB_THREAD bind_variable(STOP_FOR_GC_PENDING,NIL,th); #endif @@ -296,13 +469,25 @@ create_thread_struct(lispobj initial_function) { return 0; } th->interrupt_data->pending_handler = 0; + th->interrupt_data->gc_blocked_deferrables = 0; th->no_tls_value_marker=initial_function; + + th->stepping = NIL; return th; } +#ifdef LISP_FEATURE_MACH_EXCEPTION_HANDLER +mach_port_t setup_mach_exception_handling_thread(); +kern_return_t mach_thread_init(mach_port_t thread_exception_port); + +#endif + void create_initial_thread(lispobj initial_function) { struct thread *th=create_thread_struct(initial_function); if(th) { +#ifdef LISP_FEATURE_MACH_EXCEPTION_HANDLER + setup_mach_exception_handling_thread(); +#endif initial_thread_trampoline(th); /* no return */ } else lose("can't create initial thread\n"); } @@ -318,79 +503,64 @@ 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; + sigset_t oldset; boolean r=1; - sigemptyset(&newset); + int retcode = 0, initcode; + + FSHOW_SIGNAL((stderr,"/create_os_thread: creating new thread\n")); + /* 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)) || - (pthread_attr_setstack(&attr,th->control_stack_start, - THREAD_CONTROL_STACK_SIZE-16)) || - (pthread_create - (kid_tid,&attr,(void *(*)(void *))new_thread_trampoline,th))) + thread_sigmask(SIG_BLOCK, &deferrable_sigset, &oldset); + +#ifdef LOCK_CREATE_THREAD + retcode = pthread_mutex_lock(&create_thread_lock); + gc_assert(retcode == 0); + FSHOW_SIGNAL((stderr,"/create_os_thread: got lock\n")); +#endif + + if((initcode = pthread_attr_init(th->os_attr)) || + /* call_into_lisp_first_time switches the stack for the initial thread. For the + * others, we use this. */ + (pthread_attr_setstack(th->os_attr,th->control_stack_start,thread_control_stack_size)) || + (retcode = pthread_create + (kid_tid,th->os_attr,(void *(*)(void *))new_thread_trampoline,th))) { + FSHOW_SIGNAL((stderr, "init = %d\n", initcode)); + FSHOW_SIGNAL((stderr, printf("pthread_create returned %d, errno %d\n", retcode, errno))); + if(retcode < 0) { + perror("create_os_thread"); + } r=0; + } + +#ifdef LOCK_CREATE_THREAD + retcode = pthread_mutex_unlock(&create_thread_lock); + gc_assert(retcode == 0); + FSHOW_SIGNAL((stderr,"/create_os_thread: released lock\n")); +#endif thread_sigmask(SIG_SETMASK,&oldset,0); return r; } os_thread_t create_thread(lispobj initial_function) { - struct thread *th; - os_thread_t kid_tid; - - if(linux_no_threads_p) return 0; + struct thread *th, *thread = arch_os_get_current_thread(); + os_thread_t kid_tid = 0; + /* Must defend against async unwinds. */ + if (SymbolValue(INTERRUPTS_ENABLED, thread) != NIL) + lose("create_thread is not safe when interrupts are enabled.\n"); + /* 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==0) return 0; - - if (create_os_thread(th,&kid_tid)) { - return kid_tid; - } else { + if (th && !create_os_thread(th,&kid_tid)) { free_thread_struct(th); - return 0; - } -} - -/* Send the signo to os_thread, retry if the rt signal queue is - * full. */ -static int kill_thread_safely(os_thread_t os_thread, int signo) -{ - int r; - /* The man page does not mention EAGAIN as a valid return value - * for either pthread_kill or kill. But that's theory, this is - * practice. By waiting here we assume that the delivery of this - * signal is not necessary for the delivery of the signals in the - * queue. In other words, we _assume_ there are no deadlocks. */ - while ((r=pthread_kill(os_thread,signo))==EAGAIN) { - /* wait a bit then try again in the hope of the rt signal - * queue not being full */ - FSHOW_SIGNAL((stderr,"/rt signal queue full\n")); - /* FIXME: some kind of backoff (random, exponential) would be - * nice. */ - sleep(1); - } - return r; -} - -int signal_interrupt_thread(os_thread_t os_thread) -{ - int status = kill_thread_safely(os_thread, SIG_INTERRUPT_THREAD); - if (status == 0) { - return 0; - } else if (status == ESRCH) { - return -1; - } else { - lose("cannot send SIG_INTERRUPT_THREAD to thread=%lu: %d, %s\n", - os_thread, status, strerror(status)); + kid_tid = 0; } + return kid_tid; } /* stopping the world is a two-stage process. From this thread we signal @@ -405,23 +575,35 @@ int signal_interrupt_thread(os_thread_t os_thread) void gc_stop_the_world() { struct thread *p,*th=arch_os_get_current_thread(); - int status; - FSHOW_SIGNAL((stderr,"/gc_stop_the_world:waiting on lock, thread=%lu\n", - th->os_thread)); + int status, lock_ret; +#ifdef LOCK_CREATE_THREAD + /* KLUDGE: Stopping the thread during pthread_create() causes deadlock + * on FreeBSD. */ + FSHOW_SIGNAL((stderr,"/gc_stop_the_world:waiting on create_thread_lock\n")); + lock_ret = pthread_mutex_lock(&create_thread_lock); + gc_assert(lock_ret == 0); + FSHOW_SIGNAL((stderr,"/gc_stop_the_world:got create_thread_lock\n")); +#endif + FSHOW_SIGNAL((stderr,"/gc_stop_the_world:waiting on lock\n")); /* keep threads from starting while the world is stopped. */ - pthread_mutex_lock(&all_threads_lock); \ - FSHOW_SIGNAL((stderr,"/gc_stop_the_world:got lock, thread=%lu\n", - th->os_thread)); + lock_ret = pthread_mutex_lock(&all_threads_lock); \ + gc_assert(lock_ret == 0); + + FSHOW_SIGNAL((stderr,"/gc_stop_the_world:got lock\n")); /* 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", + FSHOW_SIGNAL((stderr,"/gc_stop_the_world: thread=%lu, state=%x\n", + p->os_thread, thread_state(p))); + if((p!=th) && ((thread_state(p)==STATE_RUNNING))) { + FSHOW_SIGNAL((stderr,"/gc_stop_the_world: suspending thread %lu\n", p->os_thread)); - status=kill_thread_safely(p->os_thread,SIG_STOP_FOR_GC); + /* We already hold all_thread_lock, P can become DEAD but + * cannot exit, ergo it's safe to use pthread_kill. */ + status=pthread_kill(p->os_thread,SIG_STOP_FOR_GC); if (status==ESRCH) { /* This thread has exited. */ - gc_assert(p->state==STATE_DEAD); + gc_assert(thread_state(p)==STATE_DEAD); } else if (status) { lose("cannot send suspend thread=%lu: %d, %s\n", p->os_thread,status,strerror(status)); @@ -429,12 +611,15 @@ void gc_stop_the_world() } } 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->state==STATE_RUNNING)) { - sched_yield(); - } else { - p=p->next; + for(p=all_threads;p;p=p->next) { + if (p!=th) { + FSHOW_SIGNAL + ((stderr, + "/gc_stop_the_world: waiting for thread=%lu: state=%x\n", + p->os_thread, thread_state(p))); + wait_for_thread_state_change(p, STATE_RUNNING); + if (p->state == STATE_RUNNING) + lose("/gc_stop_the_world: unexpected state"); } } FSHOW_SIGNAL((stderr,"/gc_stop_the_world:end\n")); @@ -443,7 +628,7 @@ void gc_stop_the_world() void gc_start_the_world() { struct thread *p,*th=arch_os_get_current_thread(); - int status; + int lock_ret; /* 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 @@ -451,26 +636,91 @@ void gc_start_the_world() FSHOW_SIGNAL((stderr,"/gc_start_the_world:begin\n")); for(p=all_threads;p;p=p->next) { 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)); - } - FSHOW_SIGNAL((stderr, "/gc_start_the_world: resuming %lu\n", - p->os_thread)); - p->state=STATE_RUNNING; - status=kill_thread_safely(p->os_thread,SIG_STOP_FOR_GC); - if (status) { - lose("cannot resume thread=%lu: %d, %s\n", - p->os_thread,status,strerror(status)); + if (p!=th) { + lispobj state = thread_state(p); + if (state != STATE_DEAD) { + if(state != STATE_SUSPENDED) { + lose("gc_start_the_world: wrong thread state is %d\n", + fixnum_value(state)); + } + FSHOW_SIGNAL((stderr, "/gc_start_the_world: resuming %lu\n", + p->os_thread)); + set_thread_state(p, STATE_RUNNING); } } } - /* If we waited here until all threads leave STATE_SUSPENDED, then - * SIG_STOP_FOR_GC wouldn't need to be a rt signal. That has some - * performance implications, but does away with the 'rt signal - * queue full' problem. */ - pthread_mutex_unlock(&all_threads_lock); \ + + lock_ret = pthread_mutex_unlock(&all_threads_lock); + gc_assert(lock_ret == 0); +#ifdef LOCK_CREATE_THREAD + lock_ret = pthread_mutex_unlock(&create_thread_lock); + gc_assert(lock_ret == 0); +#endif + FSHOW_SIGNAL((stderr,"/gc_start_the_world:end\n")); } #endif + +int +thread_yield() +{ +#ifdef LISP_FEATURE_SB_THREAD + return sched_yield(); +#else + return 0; +#endif +} + +/* If the thread id given does not belong to a running thread (it has + * exited or never even existed) pthread_kill _may_ fail with ESRCH, + * but it is also allowed to just segfault, see + * . + * + * Relying on thread ids can easily backfire since ids are recycled + * (NPTL recycles them extremely fast) so a signal can be sent to + * another process if the one it was sent to exited. + * + * We send signals in two places: signal_interrupt_thread sends a + * signal that's harmless if delivered to another thread, but + * SIG_STOP_FOR_GC is fatal. + * + * For these reasons, we must make sure that the thread is still alive + * when the pthread_kill is called and return if the thread is + * exiting. */ +int +kill_safely(os_thread_t os_thread, int signal) +{ +#ifdef LISP_FEATURE_SB_THREAD + sigset_t oldset; + struct thread *thread; + /* pthread_kill is not async signal safe and we don't want to be + * interrupted while holding the lock. */ + thread_sigmask(SIG_BLOCK, &deferrable_sigset, &oldset); + pthread_mutex_lock(&all_threads_lock); + for (thread = all_threads; thread; thread = thread->next) { + if (thread->os_thread == os_thread) { + int status = pthread_kill(os_thread, signal); + if (status) + lose("kill_safely: pthread_kill failed with %d\n", status); + break; + } + } + pthread_mutex_unlock(&all_threads_lock); + thread_sigmask(SIG_SETMASK,&oldset,0); + if (thread) + return 0; + else + return -1; +#else + int status; + if (os_thread != 0) + lose("kill_safely: who do you want to kill? %d?\n", os_thread); + status = raise(signal); + if (status == 0) { + return 0; + } else { + lose("cannot raise signal %d, %d %s\n", + signal, status, strerror(errno)); + } +#endif +}