X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fruntime%2Fthread.c;h=ab0db0886eab31ea383d5a85b60349a046e63e4d;hb=2805aa2c24f28ea664658d274789a1644fe16f9b;hp=ddcc8fdb3bb8f59b11ad5c67fc2d2a8280b7bcc0;hpb=e365f2f7a9c66d307b48fee70778f4eaa84bdcc0;p=sbcl.git diff --git a/src/runtime/thread.c b/src/runtime/thread.c index ddcc8fd..ab0db08 100644 --- a/src/runtime/thread.c +++ b/src/runtime/thread.c @@ -1,271 +1,541 @@ #include #include +#include #include +#include #include -#ifndef CLONE_PARENT /* lameass glibc 2.2 doesn't define this */ -#define CLONE_PARENT 0x00008000 /* even though the manpage documents it */ -#endif -#include "runtime.h" +#include +#include +#include + #include "sbcl.h" -#include "validate.h" /* for CONTROL_STACK_SIZE etc */ +#include "runtime.h" +#include "validate.h" /* for CONTROL_STACK_SIZE etc */ +#include "alloc.h" #include "thread.h" #include "arch.h" #include "target-arch-os.h" #include "os.h" #include "globals.h" -#ifdef LISP_FEATURE_GENCGC -#include "gencgc.h" -#endif #include "dynbind.h" #include "genesis/cons.h" +#include "genesis/fdefn.h" +#include "interr.h" /* for lose() */ +#include "gc-internal.h" + #define ALIEN_STACK_SIZE (1*1024*1024) /* 1Mb size chosen at random */ -int dynamic_values_bytes=4096*sizeof(lispobj); /* same for all threads */ -struct thread *all_threads; -lispobj all_threads_lock; +int dynamic_values_bytes=4096*sizeof(lispobj); /* same for all threads */ +struct thread * volatile all_threads; extern struct interrupt_data * global_interrupt_data; +extern int linux_no_threads_p; -void get_spinlock(lispobj *word,int value); +#ifdef LISP_FEATURE_SB_THREAD -/* this is the first thing that clone() runs in the child (which is - * why the silly calling convention). Basically it calls the user's - * requested lisp function after doing arch_os_thread_init and - * whatever other bookkeeping needs to be done - */ +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); \ + } +#endif + + +#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64) +extern lispobj call_into_lisp_first_time(lispobj fun, lispobj *args, int nargs); +#endif + +static int +initial_thread_trampoline(struct thread *th) +{ + lispobj function; +#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64) + lispobj *args = NULL; +#endif + function = th->no_tls_value_marker; + th->no_tls_value_marker = NO_TLS_VALUE_MARKER_WIDETAG; + if(arch_os_thread_init(th)==0) return 1; -/* set go to 0 to stop the thread before it starts. Convenient if you -* want to attach a debugger to it before it does anything */ -volatile int go=1; + if(th->os_thread < 1) lose("th->os_thread not set up right"); + th->state=STATE_RUNNING; +#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64) + return call_into_lisp_first_time(function,args,0); +#else + return funcall0(function); +#endif +} + +#ifdef LISP_FEATURE_SB_THREAD +/* this is the first thing that runs in the child (which is why the + * silly calling convention). Basically it calls the user's requested + * lisp function after doing arch_os_thread_init and whatever other + * bookkeeping needs to be done + */ int new_thread_trampoline(struct thread *th) { lispobj function; - lispobj *args = NULL; - function = th->unbound_marker; - if(go==0) { - fprintf(stderr, "/pausing 0x%lx(%d,%d) before new_thread_trampoline(0x%lx)\n", - (unsigned long)th,th->pid,getpid(),(unsigned long)function); - while(go==0) ; - fprintf(stderr, "/continue\n"); + int result; + function = th->no_tls_value_marker; + th->no_tls_value_marker = NO_TLS_VALUE_MARKER_WIDETAG; + if(arch_os_thread_init(th)==0) { + /* FIXME: handle error */ + lose("arch_os_thread_init failed\n"); } - th->unbound_marker = UNBOUND_MARKER_WIDETAG; + /* wait here until our thread is linked into all_threads: see below */ - while(th->pid<1) sched_yield(); + { + volatile os_thread_t *tid=&th->os_thread; + while(*tid<1) sched_yield(); + } - if(arch_os_thread_init(th)==0) - return 1; /* failure. no, really */ -#ifdef LISP_FEATURE_SB_THREAD - return call_into_lisp(function,args,0); -#else - return call_into_lisp_first_time(function,args,0); -#endif + th->state=STATE_RUNNING; + result = funcall0(function); + th->state=STATE_DEAD; + return result; +} +#endif /* LISP_FEATURE_SB_THREAD */ + +#define THREAD_STRUCT_SIZE (THREAD_CONTROL_STACK_SIZE + BINDING_STACK_SIZE + \ + ALIEN_STACK_SIZE + dynamic_values_bytes + \ + 32 * SIGSTKSZ) + +static void +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, + THREAD_STRUCT_SIZE); } /* 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 */ -pid_t create_thread(lispobj initial_function) { +static struct thread * +create_thread_struct(lispobj initial_function) { union per_thread_data *per_thread; - struct thread *th=0; /* subdue gcc */ + struct thread *th=0; /* subdue gcc */ void *spaces=0; - pid_t kid_pid; /* 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 */ - spaces=os_validate(0, - THREAD_CONTROL_STACK_SIZE+ - BINDING_STACK_SIZE+ - ALIEN_STACK_SIZE+ - dynamic_values_bytes+ - 32*SIGSTKSZ - ); - if(!spaces) goto cleanup; + spaces=os_validate(0, THREAD_STRUCT_SIZE); + if(!spaces) + return NULL; per_thread=(union per_thread_data *) - (spaces+ - THREAD_CONTROL_STACK_SIZE+ - BINDING_STACK_SIZE+ - ALIEN_STACK_SIZE); + (spaces+ + THREAD_CONTROL_STACK_SIZE+ + BINDING_STACK_SIZE+ + ALIEN_STACK_SIZE); - th=&per_thread->thread; if(all_threads) { - memcpy(per_thread,arch_os_get_current_thread(), - dynamic_values_bytes); + memcpy(per_thread,arch_os_get_current_thread(), + dynamic_values_bytes); } else { - 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) - SetSymbolValue - (FREE_TLS_INDEX, - make_fixnum(MAX_INTERRUPTS+ - sizeof(struct thread)/sizeof(lispobj)), - 0); #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; + if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG) { + SetSymbolValue + (FREE_TLS_INDEX, + make_fixnum(MAX_INTERRUPTS+ + sizeof(struct thread)/sizeof(lispobj)), + 0); + SetSymbolValue(TLS_INDEX_LOCK,make_fixnum(0),0); + } #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); - STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer); - STATIC_TLS_INIT(PSEUDO_ATOMIC_ATOMIC,pseudo_atomic_atomic); - STATIC_TLS_INIT(PSEUDO_ATOMIC_INTERRUPTED,pseudo_atomic_interrupted); + + 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); + 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); +#endif #undef STATIC_TLS_INIT #endif } + th=&per_thread->thread; th->control_stack_start = 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); + (lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE); th->binding_stack_pointer=th->binding_stack_start; th->this=th; - th->pid=0; + th->os_thread=0; + th->interrupt_fun=NIL; + th->interrupt_fun_lock=0; + th->state=STATE_STARTING; #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD th->alien_stack_pointer=((void *)th->alien_stack_start - + ALIEN_STACK_SIZE-4); /* naked 4. FIXME */ + + ALIEN_STACK_SIZE-N_WORD_BYTES); #else 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; - /* runtime.c used to set PSEUDO_ATOMIC_ATOMIC =1 globally. I'm not - * sure why, but it appears to help */ - th->pseudo_atomic_atomic=make_fixnum(1); + th->pseudo_atomic_atomic=0; +#endif +#ifdef LISP_FEATURE_GENCGC gc_set_region_empty(&th->alloc_region); +#endif #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 */ - SetSymbolValue(BINDING_STACK_START,th->binding_stack_start,th); - SetSymbolValue(BINDING_STACK_POINTER,th->binding_stack_pointer,th); - SetSymbolValue(CONTROL_STACK_START,th->control_stack_start,th); - SetSymbolValue(ALIEN_STACK,th->alien_stack_pointer,th); - SetSymbolValue(PSEUDO_ATOMIC_ATOMIC,th->pseudo_atomic_atomic,th); + SetSymbolValue(BINDING_STACK_START,(lispobj)th->binding_stack_start,th); + SetSymbolValue(CONTROL_STACK_START,(lispobj)th->control_stack_start,th); + SetSymbolValue(CONTROL_STACK_END,(lispobj)th->control_stack_end,th); +#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); +#else + current_binding_stack_pointer=th->binding_stack_pointer; + current_control_stack_pointer=th->control_stack_start; +#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=malloc(sizeof (struct interrupt_data)); - if(all_threads) - memcpy(th->interrupt_data,arch_os_get_current_thread()->interrupt_data, - sizeof (struct interrupt_data)); - else - memcpy(th->interrupt_data,global_interrupt_data, - sizeof (struct interrupt_data)); - - th->unbound_marker=initial_function; + bind_variable(GC_PENDING,NIL,th); #ifdef LISP_FEATURE_SB_THREAD -#if defined(LISP_FEATURE_X86) && defined (LISP_FEATURE_LINUX) - kid_pid= - clone(new_thread_trampoline, - (((void*)th->control_stack_start)+THREAD_CONTROL_STACK_SIZE-4), - (((getpid()!=parent_pid)?(CLONE_PARENT):0) - |CLONE_FILES|SIGALRM|CLONE_VM),th); - if(kid_pid<=0) - goto cleanup; -#else -#error this stuff presently only works on x86 Linux -#endif -#else - kid_pid=getpid(); + bind_variable(STOP_FOR_GC_PENDING,NIL,th); #endif - get_spinlock(&all_threads_lock,kid_pid); + + th->interrupt_data = (struct interrupt_data *) + os_validate(0,(sizeof (struct interrupt_data))); + if (!th->interrupt_data) { + free_thread_struct(th); + return 0; + } + th->interrupt_data->pending_handler = 0; + th->no_tls_value_marker=initial_function; + return th; +} + +static void +link_thread(struct thread *th,os_thread_t kid_tid) +{ + if (all_threads) all_threads->prev=th; th->next=all_threads; + th->prev=0; all_threads=th; - /* note that th->pid is 0 at this time. We rely on all_threads_lock - * to ensure that we don't have >1 thread with pid=0 on the list at once + /* note that th->os_thread is 0 at this time. We rely on + * 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->pid,1); - all_threads_lock=0; - th->pid=kid_pid; /* child will not start until this is set */ -#ifndef LISP_FEATURE_SB_THREAD - new_thread_trampoline(all_threads); /* call_into_lisp */ - lose("Clever child? Idiot savant, verging on the."); -#endif - - return th->pid; - cleanup: - /* if(th && th->tls_cookie>=0) os_free_tls_pointer(th); */ - if(spaces) os_invalidate(spaces, - THREAD_CONTROL_STACK_SIZE+BINDING_STACK_SIZE+ - ALIEN_STACK_SIZE+dynamic_values_bytes); - return 0; + protect_control_stack_guard_page(th,1); + /* child will not start until this is set */ + th->os_thread=kid_tid; + FSHOW((stderr,"/created thread %lu\n",kid_tid)); } -void destroy_thread (struct thread *th) -{ - /* precondition: the unix task has already been killed and exited. - * This is called by the parent */ - gc_alloc_update_page_tables(0, &th->alloc_region); - get_spinlock(&all_threads_lock,th->pid); - if(th==all_threads) - all_threads=th->next; - else { - struct thread *th1=all_threads; - while(th1->next!=th) th1=th1->next; - th1->next=th->next; /* unlink */ - } - all_threads_lock=0; - if(th && th->tls_cookie>=0) arch_os_thread_cleanup(th); - os_invalidate((os_vm_address_t) th->control_stack_start, - THREAD_CONTROL_STACK_SIZE+BINDING_STACK_SIZE+ - ALIEN_STACK_SIZE+dynamic_values_bytes+ - 32*SIGSTKSZ); +void create_initial_thread(lispobj initial_function) { + struct thread *th=create_thread_struct(initial_function); + os_thread_t kid_tid=thread_self(); + if(th && kid_tid>0) { + link_thread(th,kid_tid); + initial_thread_trampoline(all_threads); /* no return */ + } else lose("can't create initial thread"); } +#ifdef LISP_FEATURE_SB_THREAD + +#ifndef __USE_XOPEN2K +extern int pthread_attr_setstack (pthread_attr_t *__attr, void *__stackaddr, + size_t __stacksize); +#endif -struct thread *find_thread_by_pid(pid_t pid) +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); + /* Blocking deferrable signals is enough, since gc_stop_the_world + * waits until the child leaves STATE_STARTING. And why not let gc + * proceed as soon as possible? */ + 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))) + r=0; + thread_sigmask(SIG_SETMASK,&oldset,0); + return r; +} + +struct thread *create_thread(lispobj initial_function) { struct thread *th; - for_each_thread(th) - if(th->pid==pid) return th; - return 0; + os_thread_t kid_tid=0; + boolean success; + + if(linux_no_threads_p) return 0; + + th=create_thread_struct(initial_function); + if(th==0) return 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); + else + free_thread_struct(th); + + RELEASE_ALL_THREADS_LOCK("create_thread") + + if (success) + return th; + else + return 0; } +/* called from lisp from the thread object finalizer */ +void reap_dead_thread(struct thread *th) +{ + if(th->state!=STATE_DEAD) + lose("thread %p is not joinable, state=%d\n",th,th->state); +#ifdef LISP_FEATURE_GENCGC + { + sigset_t newset,oldset; + sigemptyset(&newset); + sigaddset_blockable(&newset); + thread_sigmask(SIG_BLOCK, &newset, &oldset); + gc_alloc_update_page_tables(0, &th->alloc_region); + thread_sigmask(SIG_SETMASK,&oldset,0); + } +#endif + GET_ALL_THREADS_LOCK("reap_dead_thread") + FSHOW((stderr,"/reap_dead_thread: reaping %lu\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); + free_thread_struct(th); +} -void get_spinlock(lispobj *word,int value) +/* 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) { - u32 eax=0; - do { - asm ("xor %0,%0;cmpxchg %1,%2" - : "=a" (eax) - : "r" (value), "m" (*word) - : "memory", "cc"); - } while(eax!=0); + 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; } -void block_sigcont(void) +int interrupt_thread(struct thread *th, lispobj function) { - /* don't allow ourselves to receive SIGCONT while we're in the - * "ambiguous" state of being on the queue but not actually stopped. + /* 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. */ - sigset_t newset; + lispobj c=alloc_cons(function,NIL); + sigset_t newset,oldset; sigemptyset(&newset); - sigaddset(&newset,SIGCONT); - sigprocmask(SIG_BLOCK, &newset, 0); + /* interrupt_thread_handler locks this spinlock with blockables + * blocked (it does so for the sake of + * arrange_return_to_lisp_function), so we must also block them or + * else SIG_STOP_FOR_GC and all_threads_lock will find a way to + * deadlock. */ + sigaddset_blockable(&newset); + thread_sigmask(SIG_BLOCK, &newset, &oldset); + if (th == arch_os_get_current_thread()) + lose("cannot interrupt current thread"); + get_spinlock(&th->interrupt_fun_lock, + (long)arch_os_get_current_thread()); + ((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); + /* Called from lisp with the thread object as a parameter. Thus, + * the object cannot be garbage collected and consequently reaped + * and joined. Because it's not joined, kill should work (even if + * the thread has died/exited). */ + { + int status=kill_thread_safely(th->os_thread,SIG_INTERRUPT_THREAD); + if (status==0) { + return 0; + } else if (status==ESRCH) { + /* This thread has exited. */ + th->interrupt_fun=NIL; + errno=ESRCH; + return -1; + } else { + lose("cannot send SIG_INTERRUPT_THREAD to thread=%lu: %d, %s", + th->os_thread,status,strerror(status)); + } + } } -void unblock_sigcont_and_sleep(void) +/* 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 + * 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() { - sigset_t set; - sigemptyset(&set); - sigaddset(&set,SIGCONT); - sigwaitinfo(&set,0); - sigprocmask(SIG_UNBLOCK,&set,0); + 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)); + /* 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)); + /* 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->state==STATE_RUNNING)) { + FSHOW_SIGNAL((stderr,"/gc_stop_the_world: suspending %lu\n", + p->os_thread)); + status=kill_thread_safely(p->os_thread,SIG_STOP_FOR_GC); + if (status==ESRCH) { + /* This thread has exited. */ + gc_assert(p->state==STATE_DEAD); + } else if (status) { + lose("cannot send suspend thread=%lu: %d, %s", + p->os_thread,status,strerror(status)); + } + } + } + FSHOW_SIGNAL((stderr,"/gc_stop_the_world:signals sent\n")); + /* wait for the running threads to stop or finish */ + for(p=all_threads;p;) { + 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; + } else { + sched_yield(); + } + } + FSHOW_SIGNAL((stderr,"/gc_stop_the_world:end\n")); } +void gc_start_the_world() +{ + struct thread *p,*th=arch_os_get_current_thread(); + int status; + /* 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 */ + 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", + p->os_thread,status,strerror(status)); + } + } + } + /* 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); \ + FSHOW_SIGNAL((stderr,"/gc_start_the_world:end\n")); +} +#endif