diff options
Diffstat (limited to 'libpthread/linuxthreads/manager.c')
| -rw-r--r-- | libpthread/linuxthreads/manager.c | 100 |
1 files changed, 70 insertions, 30 deletions
diff --git a/libpthread/linuxthreads/manager.c b/libpthread/linuxthreads/manager.c index 1b513ca92..f1c9b93af 100644 --- a/libpthread/linuxthreads/manager.c +++ b/libpthread/linuxthreads/manager.c @@ -18,6 +18,8 @@ #define __getpid getpid #define __getpagesize getpagesize +#include <features.h> +#define __USE_GNU #include <errno.h> #include <sched.h> #include <stddef.h> @@ -50,8 +52,8 @@ /* Array of active threads. Entry 0 is reserved for the initial thread. */ struct pthread_handle_struct __pthread_handles[PTHREAD_THREADS_MAX] = -{ { LOCK_INITIALIZER, &__pthread_initial_thread, 0}, - { LOCK_INITIALIZER, &__pthread_manager_thread, 0}, /* All NULLs */ }; +{ { __LOCK_INITIALIZER, &__pthread_initial_thread, 0}, + { __LOCK_INITIALIZER, &__pthread_manager_thread, 0}, /* All NULLs */ }; /* For debugging purposes put the maximum number of threads in a variable. */ const int __linuxthreads_pthread_threads_max = PTHREAD_THREADS_MAX; @@ -120,7 +122,7 @@ int __pthread_manager(void *arg) #else struct pollfd ufd; #endif - sigset_t mask; + sigset_t manager_mask; int n; struct pthread_request request; @@ -131,15 +133,19 @@ int __pthread_manager(void *arg) /* Set the error variable. */ __pthread_manager_thread.p_errnop = &__pthread_manager_thread.p_errno; __pthread_manager_thread.p_h_errnop = &__pthread_manager_thread.p_h_errno; + /* Block all signals except __pthread_sig_cancel and SIGTRAP */ - sigfillset(&mask); - sigdelset(&mask, __pthread_sig_cancel); /* for thread termination */ - sigdelset(&mask, SIGTRAP); /* for debugging purposes */ - sigprocmask(SIG_SETMASK, &mask, NULL); + sigfillset(&manager_mask); + sigdelset(&manager_mask, __pthread_sig_cancel); /* for thread termination */ + sigdelset(&manager_mask, SIGTRAP); /* for debugging purposes */ + if (__pthread_threads_debug && __pthread_sig_debug > 0) + sigdelset(&manager_mask, __pthread_sig_debug); + sigprocmask(SIG_SETMASK, &manager_mask, NULL); /* Raise our priority to match that of main thread */ __pthread_manager_adjust_prio(__pthread_main_thread->p_priority); /* Synchronize debugging of the thread manager */ - n = __libc_read(reqfd, (char *)&request, sizeof(request)); + n = TEMP_FAILURE_RETRY(__libc_read(reqfd, (char *)&request, + sizeof(request))); ASSERT(n == sizeof(request) && request.req_kind == REQ_DEBUG); #ifndef USE_SELECT ufd.fd = reqfd; @@ -201,17 +207,25 @@ PDEBUG("got REQ_FREE\n"); break; case REQ_PROCESS_EXIT: PDEBUG("got REQ_PROCESS_EXIT from %d, exit code = %d\n", - request.req_thread, request.req_args.exit.code); + request.req_thread, request.req_args.exit.code); pthread_handle_exit(request.req_thread, request.req_args.exit.code); break; case REQ_MAIN_THREAD_EXIT: PDEBUG("got REQ_MAIN_THREAD_EXIT\n"); main_thread_exiting = 1; + /* Reap children in case all other threads died and the signal handler + went off before we set main_thread_exiting to 1, and therefore did + not do REQ_KICK. */ + pthread_reap_children(); + if (__pthread_main_thread->p_nextlive == __pthread_main_thread) { restart(__pthread_main_thread); - return 0; - } + /* The main thread will now call exit() which will trigger an + __on_exit handler, which in turn will send REQ_PROCESS_EXIT + to the thread manager. In case you are wondering how the + manager terminates from its loop here. */ + } break; case REQ_POST: PDEBUG("got REQ_POST\n"); @@ -221,10 +235,14 @@ PDEBUG("got REQ_POST\n"); PDEBUG("got REQ_DEBUG\n"); /* Make gdb aware of new thread and gdb will restart the new thread when it is ready to handle the new thread. */ - if (__pthread_threads_debug && __pthread_sig_debug > 0) + if (__pthread_threads_debug && __pthread_sig_debug > 0) { PDEBUG("about to call raise(__pthread_sig_debug)\n"); raise(__pthread_sig_debug); - break; + } + case REQ_KICK: + /* This is just a prod to get the manager to reap some + threads right away, avoiding a potential delay at shutdown. */ + break; } } } @@ -246,8 +264,9 @@ int __pthread_manager_event(void *arg) } /* Process creation */ - -static int pthread_start_thread(void *arg) +static int +__attribute__ ((noreturn)) +pthread_start_thread(void *arg) { pthread_descr self = (pthread_descr) arg; struct pthread_request request; @@ -282,8 +301,8 @@ PDEBUG("\n"); if (__pthread_threads_debug && __pthread_sig_debug > 0) { request.req_thread = self; request.req_kind = REQ_DEBUG; - __libc_write(__pthread_manager_request, - (char *) &request, sizeof(request)); + TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request, + (char *) &request, sizeof(request))); suspend(self); } /* Run the thread code */ @@ -291,10 +310,11 @@ PDEBUG("\n"); p_start_args.arg)); /* Exit with the given return value */ pthread_exit(outcome); - return 0; } -static int pthread_start_thread_event(void *arg) +static int +__attribute__ ((noreturn)) +pthread_start_thread_event(void *arg) { pthread_descr self = (pthread_descr) arg; @@ -310,7 +330,7 @@ static int pthread_start_thread_event(void *arg) __pthread_unlock (THREAD_GETMEM(self, p_lock)); /* Continue with the real function. */ - return pthread_start_thread (arg); + pthread_start_thread (arg); } static int pthread_allocate_stack(const pthread_attr_t *attr, @@ -454,6 +474,7 @@ static int pthread_handle_create(pthread_t *thread, const pthread_attr_t *attr, char *guardaddr = NULL; size_t guardsize = 0; int pagesize = __getpagesize(); + int saved_errno = 0; /* First check whether we have to change the policy and if yes, whether we can do this. Normally this should be done by examining the @@ -549,8 +570,10 @@ static int pthread_handle_create(pthread_t *thread, const pthread_attr_t *attr, /* We have to report this event. */ pid = clone(pthread_start_thread_event, (void **) new_thread, - CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | - __pthread_sig_cancel, new_thread); + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | + __pthread_sig_cancel, new_thread); + + saved_errno = errno; if (pid != -1) { /* Now fill in the information about the new thread in @@ -577,9 +600,10 @@ static int pthread_handle_create(pthread_t *thread, const pthread_attr_t *attr, if (pid == 0) { PDEBUG("cloning new_thread = %p\n", new_thread); - pid = clone(pthread_start_thread, (void **) new_thread, - CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | - __pthread_sig_cancel, new_thread); + pid = clone(pthread_start_thread, (void **) new_thread, + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | + __pthread_sig_cancel, new_thread); + saved_errno = errno; } /* Check if cloning succeeded */ if (pid == -1) { @@ -714,15 +738,15 @@ static void pthread_exited(pid_t pid) /* If we have to signal this event do it now. */ if (th->p_report_events) { - /* See whether TD_DEATH is in any of the mask. */ + /* See whether TD_REAP is in any of the mask. */ int idx = __td_eventword (TD_REAP); uint32_t mask = __td_eventmask (TD_REAP); if ((mask & (__pthread_threads_events.event_bits[idx] | th->p_eventbuf.eventmask.event_bits[idx])) != 0) { - /* Yep, we have to signal the death. */ - th->p_eventbuf.eventnum = TD_DEATH; + /* Yep, we have to signal the reapage. */ + th->p_eventbuf.eventnum = TD_REAP; th->p_eventbuf.eventdata = th; __pthread_last_event = th; @@ -742,7 +766,7 @@ static void pthread_exited(pid_t pid) if (main_thread_exiting && __pthread_main_thread->p_nextlive == __pthread_main_thread) { restart(__pthread_main_thread); - _exit(0); + /* Same logic as REQ_MAIN_THREAD_EXIT. */ } } @@ -837,7 +861,23 @@ static void pthread_handle_exit(pthread_descr issuing_thread, int exitcode) void __pthread_manager_sighandler(int sig) { - terminated_children = 1; + int kick_manager = terminated_children == 0 && main_thread_exiting; + terminated_children = 1; + + /* If the main thread is terminating, kick the thread manager loop + each time some threads terminate. This eliminates a two second + shutdown delay caused by the thread manager sleeping in the + call to __poll(). Instead, the thread manager is kicked into + action, reaps the outstanding threads and resumes the main thread + so that it can complete the shutdown. */ + + if (kick_manager) { + struct pthread_request request; + request.req_thread = 0; + request.req_kind = REQ_KICK; + TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request, + (char *) &request, sizeof(request))); + } } /* Adjust priority of thread manager so that it always run at a priority |