From: Paul Eggert Date: Thu, 31 Jul 2014 20:17:01 +0000 (-0700) Subject: Simplify timerfd configuration and fix some minor glitches. X-Git-Tag: emacs-25.0.90~2636^3 X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=5c6476b48a2d00bef6ada92fa210ac7cd1bc9a77;p=emacs.git Simplify timerfd configuration and fix some minor glitches. * configure.ac (HAVE_TIMERFD): Define only if TFD_CLOEXEC works, since the code leaked file descriptors to children when !TFD_CLOEXEC. (HAVE_TIMERFD_CLOEXEC): Remove; no longer used. * m4/clock_time.m4 (gl_CLOCK_TIME): Don't check for clock_getres. This reverts the previous change to this file, so it matches gnulib again. * src/atimer.c (TIMERFD_CREATE_FLAGS): Remove; we now assume TFD_CLOEXEC. (alarm_timer, alarm_timer_ok, set_alarm, init_atimer): Fall back on timer_create if timerfd_create fails at runtime. (resolution) [HAVE_CLOCK_GETRES]: Remove; we now rely on the kernel primitives to do resolution. All uses removed. (timerfd) [!HAVE_TIMERFD]: Define to be -1, for convenience. (turn_on_atimers): Clear timer_create-based timers too, for consistency. --- diff --git a/ChangeLog b/ChangeLog index c7fd47636a5..2dfef7037fe 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,13 @@ +2014-07-31 Paul Eggert + + Simplify timerfd configuration and fix some minor glitches. + * configure.ac (HAVE_TIMERFD): Define only if TFD_CLOEXEC works, + since the code leaked file descriptors to children when !TFD_CLOEXEC. + (HAVE_TIMERFD_CLOEXEC): Remove; no longer used. + * m4/clock_time.m4 (gl_CLOCK_TIME): Don't check for clock_getres. + This reverts the previous change to this file, so it matches + gnulib again. + 2014-07-28 Dmitry Antipov * configure.ac (toplevel): Check whether GNU/Linux-specific diff --git a/configure.ac b/configure.ac index 89440446ee5..4f3fde56af2 100644 --- a/configure.ac +++ b/configure.ac @@ -1539,7 +1539,7 @@ if test "$ac_cv_header_sys_sysinfo_h" = yes; then AC_DEFINE(LINUX_SYSINFO_UNIT, 1, [Define to 1 if Linux sysinfo sizes are in multiples of mem_unit bytes.])) fi -fi +fi dnl On Solaris 8 there's a compilation warning for term.h because dnl it doesn't define `bool'. @@ -3711,25 +3711,18 @@ AC_SUBST(LIBS_TERMCAP) AC_SUBST(TERMCAP_OBJ) # GNU/Linux-specific timer functions. -if test $opsys = gnu-linux; then - AC_MSG_CHECKING([whether Linux timerfd functions are supported]) - AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include ]], - [[timerfd_create (CLOCK_REALTIME, 0); - timerfd_settime (0, 0, NULL, NULL)]])], - emacs_cv_linux_timerfd=yes, emacs_cv_linux_timerfd=no) - AC_MSG_RESULT([$emacs_cv_linux_timerfd]) - if test $emacs_cv_linux_timerfd = yes; then - AC_DEFINE(HAVE_TIMERFD, 1, [Define to 1 if Linux timerfd functions are supported.]) - AC_MSG_CHECKING([whether TFD_CLOEXEC is defined]) - AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include ]], - [[timerfd_create (CLOCK_REALTIME, TFD_CLOEXEC)]])], - emacs_cv_tfd_cloexec=yes, emacs_cv_tfd_cloexec=no) - AC_MSG_RESULT([$emacs_cv_tfd_cloexec]) - if test $emacs_cv_tfd_cloexec = yes; then - AC_DEFINE(HAVE_TIMERFD_CLOEXEC, 1, [Define to 1 if TFD_CLOEXEC is defined.]) - fi - fi -fi +AC_CACHE_CHECK([for timerfd interface], [emacs_cv_have_timerfd], + [AC_COMPILE_IFELSE( + [AC_LANG_PROGRAM([[#include + ]], + [[timerfd_create (CLOCK_REALTIME, TFD_CLOEXEC); + timerfd_settime (0, TFD_TIMER_ABSTIME, 0, 0);]])], + [emacs_cv_have_timerfd=yes], + [emacs_cv_have_timerfd=no])]) +if test "$emacs_cv_have_timerfd" = yes; then + AC_DEFINE([HAVE_TIMERFD], 1, + [Define to 1 if timerfd functions are supported as in GNU/Linux.]) +fi # Do we have res_init, for detecting changes in /etc/resolv.conf? # On Darwin, res_init appears not to be useful: see bug#562 and diff --git a/m4/clock_time.m4 b/m4/clock_time.m4 index 8513c6d781a..6c4a637dc62 100644 --- a/m4/clock_time.m4 +++ b/m4/clock_time.m4 @@ -26,6 +26,6 @@ AC_DEFUN([gl_CLOCK_TIME], AC_SEARCH_LIBS([clock_gettime], [rt posix4], [test "$ac_cv_search_clock_gettime" = "none required" || LIB_CLOCK_GETTIME=$ac_cv_search_clock_gettime]) - AC_CHECK_FUNCS([clock_getres clock_gettime clock_settime]) + AC_CHECK_FUNCS([clock_gettime clock_settime]) LIBS=$gl_saved_libs ]) diff --git a/src/ChangeLog b/src/ChangeLog index 985e3b33e06..f3ab7f9b990 100644 --- a/src/ChangeLog +++ b/src/ChangeLog @@ -1,5 +1,15 @@ 2014-07-31 Paul Eggert + Simplify timerfd configuration and fix some minor glitches. + * atimer.c (TIMERFD_CREATE_FLAGS): Remove; we now assume TFD_CLOEXEC. + (alarm_timer, alarm_timer_ok, set_alarm, init_atimer): + Fall back on timer_create if timerfd_create fails at runtime. + (resolution) [HAVE_CLOCK_GETRES]: Remove; we now rely on the + kernel primitives to do resolution. All uses removed. + (timerfd) [!HAVE_TIMERFD]: Define to be -1, for convenience. + (turn_on_atimers): Clear timer_create-based timers too, + for consistency. + * frame.c (x_set_frame_parameters): Don't use uninitialized locals. Without this change, the code can access the local variable 'width' even when it has not been initialized, and likewise for 'height'; diff --git a/src/atimer.c b/src/atimer.c index c03ac96c6da..daac32f19b4 100644 --- a/src/atimer.c +++ b/src/atimer.c @@ -27,13 +27,8 @@ along with GNU Emacs. If not, see . */ #include #ifdef HAVE_TIMERFD -#include -#ifdef HAVE_TIMERFD_CLOEXEC -#define TIMERFD_CREATE_FLAGS TFD_CLOEXEC -#else -#define TIMERFD_CREATE_FLAGS 0 -#endif /* HAVE_TIMERFD_CLOEXEC */ -#endif /* HAVE_TIMERFD */ +# include +#endif /* Free-list of atimer structures. */ @@ -49,23 +44,18 @@ static struct atimer *stopped_atimers; static struct atimer *atimers; -#if defined (HAVE_TIMERFD) -/* File descriptor returned by timerfd_create. GNU/Linux-specific. */ -static int timerfd; -#elif defined (HAVE_ITIMERSPEC) -/* The alarm timer used if POSIX timers are available. */ +#ifdef HAVE_ITIMERSPEC +/* The alarm timer and whether it was properly initialized, if + POSIX timers are available. */ static timer_t alarm_timer; -#endif - -#if defined (HAVE_TIMERFD) || defined (HAVE_ITIMERSPEC) -/* Non-zero if one of the above was successfully initialized. Do not - use bool due to special treatment if HAVE_TIMERFD, see below. */ -static int special_timer_available; -#endif +static bool alarm_timer_ok; -#ifdef HAVE_CLOCK_GETRES -/* Resolution of CLOCK_REALTIME clock. */ -static struct timespec resolution; +# ifdef HAVE_TIMERFD +/* File descriptor for timer, or -1 if it could not be created. */ +static int timerfd; +# else +enum { timerfd = -1 }; +# endif #endif /* Block/unblock SIGALRM. */ @@ -92,20 +82,20 @@ static void schedule_atimer (struct atimer *); static struct atimer *append_atimer_lists (struct atimer *, struct atimer *); -/* Start a new atimer of type TYPE. TIME specifies when the timer is +/* Start a new atimer of type TYPE. TIMESTAMP specifies when the timer is ripe. FN is the function to call when the timer fires. CLIENT_DATA is stored in the client_data member of the atimer structure returned and so made available to FN when it is called. - If TYPE is ATIMER_ABSOLUTE, TIME is the absolute time at which the + If TYPE is ATIMER_ABSOLUTE, TIMESTAMP is the absolute time at which the timer fires. - If TYPE is ATIMER_RELATIVE, the timer is ripe TIME s/us in the + If TYPE is ATIMER_RELATIVE, the timer is ripe TIMESTAMP seconds in the future. In both cases, the timer is automatically freed after it has fired. - If TYPE is ATIMER_CONTINUOUS, the timer fires every TIME s/us. + If TYPE is ATIMER_CONTINUOUS, the timer fires every TIMESTAMP seconds. Value is a pointer to the atimer started. It can be used in calls to cancel_atimer; don't free it yourself. */ @@ -117,16 +107,10 @@ start_atimer (enum atimer_type type, struct timespec timestamp, struct atimer *t; sigset_t oldset; -#if !defined (HAVE_SETITIMER) - /* Round TIME up to the next full second if we don't have itimers. */ + /* Round TIMESTAMP up to the next full second if we don't have itimers. */ +#ifndef HAVE_SETITIMER if (timestamp.tv_nsec != 0 && timestamp.tv_sec < TYPE_MAXIMUM (time_t)) timestamp = make_timespec (timestamp.tv_sec + 1, 0); -#elif defined (HAVE_CLOCK_GETRES) - /* Check that the system clock is precise enough. If - not, round TIME up to the system clock resolution. */ - if (timespec_valid_p (resolution) - && timespec_cmp (timestamp, resolution) < 0) - timestamp = resolution; #endif /* not HAVE_SETITIMER */ /* Get an atimer structure from the free-list, or allocate @@ -311,25 +295,24 @@ set_alarm (void) #endif struct timespec now, interval; -#if defined (HAVE_TIMERFD) || defined (HAVE_ITIMERSPEC) - if (special_timer_available) +#ifdef HAVE_ITIMERSPEC + if (0 <= timerfd || alarm_timer_ok) { struct itimerspec ispec; ispec.it_value = atimers->expiration; ispec.it_interval.tv_sec = ispec.it_interval.tv_nsec = 0; -#if defined (HAVE_TIMERFD) - if (special_timer_available == 1) +# ifdef HAVE_TIMERFD + if (timerfd_settime (timerfd, TFD_TIMER_ABSTIME, &ispec, 0) == 0) { add_timer_wait_descriptor (timerfd); - special_timer_available++; + return; } - if (timerfd_settime (timerfd, TFD_TIMER_ABSTIME, &ispec, 0) == 0) -#elif defined (HAVE_ITIMERSPEC) - if (timer_settime (alarm_timer, TIMER_ABSTIME, &ispec, 0) == 0) -#endif +# endif + if (alarm_timer_ok + && timer_settime (alarm_timer, TIMER_ABSTIME, &ispec, 0) == 0) return; } -#endif /* HAVE_TIMERFD || HAVE_ITIMERSPEC */ +#endif /* Determine interval till the next timer is ripe. Don't set the interval to 0; this disables the timer. */ @@ -453,15 +436,15 @@ turn_on_atimers (bool on) set_alarm (); else { -#ifdef HAVE_TIMERFD - if (special_timer_available > 1) - { - struct itimerspec ispec; - memset (&ispec, 0, sizeof (ispec)); - /* Writing zero expiration time should disarm it. */ - timerfd_settime (timerfd, TFD_TIMER_ABSTIME, &ispec, 0); - } -#endif /* HAVE_TIMERFD */ +#ifdef HAVE_ITIMERSPEC + struct itimerspec ispec; + memset (&ispec, 0, sizeof ispec); + if (alarm_timer_ok) + timer_settime (alarm_timer, TIMER_ABSTIME, &ispec, 0); +# ifdef HAVE_TIMERFD + timerfd_settime (timerfd, TFD_TIMER_ABSTIME, &ispec, 0); +# endif +#endif alarm (0); } } @@ -494,14 +477,14 @@ debug_timer_callback (struct atimer *t) r->intime = 0; else if (result >= 0) { -#ifdef HAVE_SETITIMER +#ifdef HAVE_SETITIMER struct timespec delta = timespec_sub (now, r->expected); /* Too late if later than expected + 0.01s. FIXME: this should depend from system clock resolution. */ if (timespec_cmp (delta, make_timespec (0, 10000000)) > 0) r->intime = 0; else -#endif /* HAVE_SETITIMER */ +#endif /* HAVE_SETITIMER */ r->intime = 1; } } @@ -543,21 +526,20 @@ Return t if all self-tests are passed, nil otherwise. */) void init_atimer (void) { -#if defined (HAVE_TIMERFD) - timerfd = timerfd_create (CLOCK_REALTIME, TIMERFD_CREATE_FLAGS); - special_timer_available = !!(timerfd != -1); -#elif defined (HAVE_ITIMERSPEC) - struct sigevent sigev; - sigev.sigev_notify = SIGEV_SIGNAL; - sigev.sigev_signo = SIGALRM; - sigev.sigev_value.sival_ptr = &alarm_timer; - special_timer_available - = timer_create (CLOCK_REALTIME, &sigev, &alarm_timer) == 0; -#endif /* HAVE_TIMERFD */ -#ifdef HAVE_CLOCK_GETRES - if (clock_getres (CLOCK_REALTIME, &resolution)) - resolution = invalid_timespec (); -#endif +#ifdef HAVE_ITIMERSPEC +# ifdef HAVE_TIMERFD + timerfd = timerfd_create (CLOCK_REALTIME, TFD_CLOEXEC); +# endif + if (timerfd < 0) + { + struct sigevent sigev; + sigev.sigev_notify = SIGEV_SIGNAL; + sigev.sigev_signo = SIGALRM; + sigev.sigev_value.sival_ptr = &alarm_timer; + alarm_timer_ok + = timer_create (CLOCK_REALTIME, &sigev, &alarm_timer) == 0; + } +#endif free_atimers = stopped_atimers = atimers = NULL; /* pending_signals is initialized in init_keyboard. */ @@ -567,5 +549,5 @@ init_atimer (void) #ifdef ENABLE_CHECKING defsubr (&Sdebug_timer_check); -#endif +#endif }