diff options
| -rw-r--r-- | configure.ac | 2 | ||||
| -rw-r--r-- | rts/posix/Itimer.c | 91 |
2 files changed, 81 insertions, 12 deletions
diff --git a/configure.ac b/configure.ac index cc162e7c08..adc22dd019 100644 --- a/configure.ac +++ b/configure.ac @@ -766,7 +766,7 @@ dnl off_t, because it will affect the result of that test. AC_SYS_LARGEFILE dnl ** check for specific header (.h) files that we are interested in -AC_CHECK_HEADERS([ctype.h dirent.h dlfcn.h errno.h fcntl.h grp.h limits.h locale.h nlist.h pthread.h pwd.h signal.h sys/param.h sys/mman.h sys/resource.h sys/select.h sys/time.h sys/timeb.h sys/timers.h sys/times.h sys/utsname.h sys/wait.h termios.h time.h utime.h windows.h winsock.h sched.h]) +AC_CHECK_HEADERS([ctype.h dirent.h dlfcn.h errno.h fcntl.h grp.h limits.h locale.h nlist.h pthread.h pwd.h signal.h sys/param.h sys/mman.h sys/resource.h sys/select.h sys/time.h sys/timeb.h sys/timerfd.h sys/timers.h sys/times.h sys/utsname.h sys/wait.h termios.h time.h utime.h windows.h winsock.h sched.h]) dnl sys/cpuset.h needs sys/param.h to be included first on FreeBSD 9.1; #7708 AC_CHECK_HEADERS([sys/cpuset.h], [], [], diff --git a/rts/posix/Itimer.c b/rts/posix/Itimer.c index 57c7741cc7..f6c00a6007 100644 --- a/rts/posix/Itimer.c +++ b/rts/posix/Itimer.c @@ -53,6 +53,31 @@ #define USE_PTHREAD_FOR_ITIMER #endif +/* + * On Linux in the threaded RTS we can use timerfd_* (introduced in Linux + * 2.6.25) and a thread instead of alarm signals. It avoids the risk of + * interrupting syscalls (see #10840) and the risk of being accidentally + * modified in user code using signals. + */ +#if defined(linux_HOST_OS) && defined(THREADED_RTS) && HAVE_SYS_TIMERFD_H +#include <sys/timerfd.h> +#include <fcntl.h> +#define USE_PTHREAD_FOR_ITIMER +#define USE_TIMERFD_FOR_ITIMER 1 +#undef USE_TIMER_CREATE +#else +#define USE_TIMERFD_FOR_ITIMER 0 +#endif + +/* + * TFD_CLOEXEC has been added in Linux 2.6.26. + * If it is not available, we use fcntl(F_SETFD). + */ +#ifndef TFD_CLOEXEC +#define TFD_CLOEXEC 0 +#endif + + #if defined(USE_PTHREAD_FOR_ITIMER) #include <pthread.h> #include <unistd.h> @@ -150,15 +175,50 @@ static void install_vtalrm_handler(TickProc handle_tick) #endif #if defined(USE_PTHREAD_FOR_ITIMER) -static volatile int itimer_enabled; +enum ItimerState {STOPPED, RUNNING, STOPPING, EXITED}; +static volatile enum ItimerState itimer_state = STOPPED; static void *itimer_thread_func(void *_handle_tick) { TickProc handle_tick = _handle_tick; + uint64_t nticks; + int timerfd = -1; + +#if USE_TIMERFD_FOR_ITIMER + struct itimerspec it; + it.it_value.tv_sec = TimeToSeconds(itimer_interval); + it.it_value.tv_nsec = TimeToNS(itimer_interval) % 1000000000; + it.it_interval = it.it_value; + + timerfd = timerfd_create(CLOCK_MONOTONIC,TFD_CLOEXEC); + if (timerfd == -1) { + sysErrorBelch("timerfd_create"); + stg_exit(EXIT_FAILURE); + } + if (!TFD_CLOEXEC) { + fcntl(timerfd, F_SETFD, FD_CLOEXEC); + } + timerfd_settime(timerfd,0,&it,NULL); +#endif + while (1) { - usleep(TimeToUS(itimer_interval)); - switch (itimer_enabled) { - case 1: handle_tick(0); break; - case 2: itimer_enabled = 0; + if (USE_TIMERFD_FOR_ITIMER) { + read(timerfd, &nticks, sizeof(nticks)); + } else { + usleep(TimeToUS(itimer_interval)); + } + switch (itimer_state) { + case RUNNING: + handle_tick(0); + break; + case STOPPED: + break; + case STOPPING: + itimer_state = STOPPED; + break; + case EXITED: + if (USE_TIMERFD_FOR_ITIMER) + close(timerfd); + return NULL; } } return NULL; @@ -172,7 +232,13 @@ initTicker (Time interval, TickProc handle_tick) #if defined(USE_PTHREAD_FOR_ITIMER) pthread_t tid; - pthread_create(&tid, NULL, itimer_thread_func, (void*)handle_tick); + int r = pthread_create(&tid, NULL, itimer_thread_func, (void*)handle_tick); + if (!r) { + pthread_detach(tid); +#if HAVE_PTHREAD_SETNAME_NP + pthread_setname_np(tid, "ghc_ticker"); +#endif + } #elif defined(USE_TIMER_CREATE) { struct sigevent ev; @@ -198,7 +264,7 @@ void startTicker(void) { #if defined(USE_PTHREAD_FOR_ITIMER) - itimer_enabled = 1; + itimer_state = RUNNING; #elif defined(USE_TIMER_CREATE) { struct itimerspec it; @@ -232,10 +298,11 @@ void stopTicker(void) { #if defined(USE_PTHREAD_FOR_ITIMER) - if (itimer_enabled == 1) { - itimer_enabled = 2; + if (itimer_state == RUNNING) { + itimer_state = STOPPING; /* Wait for the thread to confirm it won't generate another tick. */ - while (itimer_enabled != 0) + write_barrier(); + while (itimer_state != STOPPED) sched_yield(); } #elif defined(USE_TIMER_CREATE) @@ -266,7 +333,9 @@ stopTicker(void) void exitTicker (rtsBool wait STG_UNUSED) { -#if defined(USE_TIMER_CREATE) +#if defined(USE_PTHREAD_FOR_ITIMER) + itimer_state = EXITED; +#elif defined(USE_TIMER_CREATE) // Before deleting the timer set the signal to ignore to avoid the // possibility of the signal being delivered after the timer is deleted. signal(ITIMER_SIGNAL, SIG_IGN); |