From b8a2313263d0f120dacbe82ced5c99545bbd15a3 Mon Sep 17 00:00:00 2001 From: Lukas Larsson Date: Thu, 4 Dec 2014 11:04:23 +0100 Subject: erts: Introduce thread suspend functions These functions allow any thread to suspend any other thread immediately and then resume all threads. This is useful when doing a crash dump in order to get a more accurate picture of what state the system is in. --- erts/emulator/beam/erl_threads.h | 15 +++++++++ erts/emulator/beam/sys.h | 5 +++ erts/emulator/sys/unix/sys.c | 69 +++++++++++++++++++++++++++++++++++++--- 3 files changed, 85 insertions(+), 4 deletions(-) (limited to 'erts/emulator') diff --git a/erts/emulator/beam/erl_threads.h b/erts/emulator/beam/erl_threads.h index 1ab5418741..463271252d 100644 --- a/erts/emulator/beam/erl_threads.h +++ b/erts/emulator/beam/erl_threads.h @@ -621,11 +621,17 @@ ERTS_GLB_INLINE void erts_thr_set_main_status(int, int); ERTS_GLB_INLINE int erts_thr_get_main_status(void); ERTS_GLB_INLINE void erts_thr_yield(void); + #ifdef ETHR_HAVE_ETHR_SIG_FUNCS #define ERTS_THR_HAVE_SIG_FUNCS 1 ERTS_GLB_INLINE void erts_thr_sigmask(int how, const sigset_t *set, sigset_t *oset); ERTS_GLB_INLINE void erts_thr_sigwait(const sigset_t *set, int *sig); + +#ifdef USE_THREADS +ERTS_GLB_INLINE void erts_thr_kill(erts_tid_t tid, int sig); +#endif + #endif /* #ifdef HAVE_ETHR_SIG_FUNCS */ #ifdef USE_THREADS @@ -2848,6 +2854,15 @@ ERTS_GLB_INLINE void erts_thr_yield(void) #ifdef ETHR_HAVE_ETHR_SIG_FUNCS +ERTS_GLB_INLINE void +erts_thr_kill(erts_tid_t tid, int sig) { +#ifdef USE_THREADS + int res = ethr_kill((ethr_tid)tid, sig); + if (res) + erts_thr_fatal_error(res, "killing thread"); +#endif +} + ERTS_GLB_INLINE void erts_thr_sigmask(int how, const sigset_t *set, sigset_t *oset) { diff --git a/erts/emulator/beam/sys.h b/erts/emulator/beam/sys.h index c29d4b3777..bdc5237815 100644 --- a/erts/emulator/beam/sys.h +++ b/erts/emulator/beam/sys.h @@ -784,6 +784,11 @@ int erts_sys_unsetenv(char *key); char *erts_read_env(char *key); void erts_free_read_env(void *value); +#if defined(ERTS_THR_HAVE_SIG_FUNCS) && !defined(ETHR_UNUSABLE_SIGUSRX) +extern void sys_thr_resume(erts_tid_t tid); +extern void sys_thr_suspend(erts_tid_t tid); +#endif + /* utils.c */ /* Options to sys_alloc_opt */ diff --git a/erts/emulator/sys/unix/sys.c b/erts/emulator/sys/unix/sys.c index 81ed5626c2..841f0c7575 100644 --- a/erts/emulator/sys/unix/sys.c +++ b/erts/emulator/sys/unix/sys.c @@ -216,6 +216,9 @@ static erts_smp_atomic_t sys_misc_mem_sz; #if defined(ERTS_SMP) static void smp_sig_notify(char c); static int sig_notify_fds[2] = {-1, -1}; + +static int sig_suspend_fds[2] = {-1, -1}; +#define ERTS_SYS_SUSPEND_SIGNAL SIGUSR2 #elif defined(USE_THREADS) static int async_fd[2]; #endif @@ -789,6 +792,9 @@ prepare_crash_dump(int secs) /* We don't want to close the signal notification pipe... */ if (i == sig_notify_fds[0] || i == sig_notify_fds[1]) continue; + /* We don't want to close the signal syspend pipe... */ + if (i == sig_suspend_fds[0] || i == sig_suspend_fds[1]) + continue; #elif defined(USE_THREADS) /* We don't want to close the async notification pipe... */ if (i == async_fd[0] || i == async_fd[1]) @@ -877,9 +883,23 @@ sigusr1_exit(void) #ifdef ETHR_UNUSABLE_SIGUSRX #warning "Unusable SIGUSR1 & SIGUSR2. Disabling use of these signals" -#endif -#ifndef ETHR_UNUSABLE_SIGUSRX +#else + +#ifdef ERTS_SMP +void +sys_thr_suspend(erts_tid_t tid) { + erts_thr_kill(tid, ERTS_SYS_SUSPEND_SIGNAL); +} + +void +sys_thr_resume(erts_tid_t tid) { + int i = 0, res; + do { + res = write(sig_suspend_fds[1],&i,sizeof(i)); + } while (res < 0 && errno == EAGAIN); +} +#endif #if (defined(SIG_SIGSET) || defined(SIG_SIGNAL)) static RETSIGTYPE user_signal1(void) @@ -894,6 +914,21 @@ static RETSIGTYPE user_signal1(int signum) #endif } +#ifdef ERTS_SMP +#if (defined(SIG_SIGSET) || defined(SIG_SIGNAL)) +static RETSIGTYPE suspend_signal(void) +#else +static RETSIGTYPE suspend_signal(int signum) +#endif +{ + int res; + int buf[1]; + do { + res = read(sig_suspend_fds[0], buf, sizeof(int)); + } while (res < 0 && errno == EINTR); +} +#endif /* #ifdef ERTS_SMP */ + #endif /* #ifndef ETHR_UNUSABLE_SIGUSRX */ static void @@ -944,7 +979,10 @@ void init_break_handler(void) { sys_sigset(SIGINT, request_break); #ifndef ETHR_UNUSABLE_SIGUSRX - sys_sigset(SIGUSR1, user_signal1); + sys_signal(SIGUSR1, user_signal1); +#ifdef ERTS_SMP + sys_signal(ERTS_SYS_SUSPEND_SIGNAL, suspend_signal); +#endif /* #ifdef ERTS_SMP */ #endif /* #ifndef ETHR_UNUSABLE_SIGUSRX */ sys_sigset(SIGQUIT, do_quit); } @@ -963,8 +1001,13 @@ static void block_signals(void) sys_sigblock(SIGINT); #ifndef ETHR_UNUSABLE_SIGUSRX sys_sigblock(SIGUSR1); +#endif /* #ifndef ETHR_UNUSABLE_SIGUSRX */ +#endif /* #ifndef ERTS_SMP */ + +#if defined(ERTS_SMP) && !defined(ETHR_UNUSABLE_SIGUSRX) + sys_sigblock(ERTS_SYS_SUSPEND_SIGNAL); #endif -#endif + } static void unblock_signals(void) @@ -978,8 +1021,14 @@ static void unblock_signals(void) #ifndef ETHR_UNUSABLE_SIGUSRX sys_sigrelease(SIGUSR1); #endif /* #ifndef ETHR_UNUSABLE_SIGUSRX */ +#endif /* #ifndef ERTS_SMP */ + +#if defined(ERTS_SMP) && !defined(ETHR_UNUSABLE_SIGUSRX) + sys_sigrelease(ERTS_SYS_SUSPEND_SIGNAL); #endif + } + /************************** Time stuff **************************/ #ifdef HAVE_GETHRTIME #ifdef GETHRTIME_WITH_CLOCK_GETTIME @@ -3221,6 +3270,17 @@ init_smp_sig_notify(void) NULL, &thr_opts); } + +static void +init_smp_sig_suspend(void) { + if (pipe(sig_suspend_fds) < 0) { + erl_exit(ERTS_ABORT_EXIT, + "Failed to create sig_suspend pipe: %s (%d)\n", + erl_errno_id(errno), + errno); + } +} + #ifdef __DARWIN__ int erts_darwin_main_thread_pipe[2]; @@ -3371,6 +3431,7 @@ erl_sys_args(int* argc, char** argv) #ifdef ERTS_SMP init_smp_sig_notify(); + init_smp_sig_suspend(); #endif /* Handled arguments have been marked with NULL. Slide arguments -- cgit v1.2.3