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authorMike Gabriel <mike.gabriel@das-netzwerkteam.de>2017-02-16 15:21:34 +0000
committerMike Gabriel <mike.gabriel@das-netzwerkteam.de>2017-03-21 10:58:01 +0100
commit366067b7c3678148bff858239e3c16e0d6043e03 (patch)
tree1255b80c1e0ec86aab2a07f509129c8d9ba44f4e /nx-X11/programs/Xserver/os/utils.c
parentf14f738a627b5a6f6c1242f4fe123e4cc9e9c811 (diff)
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dix/os: backport various signal handling and smart scheduler changes from X.org
Backported from X.org: commit 6178b1c91cfc9e860914acc6f0be2f2d2e07a124 Author: Adam Jackson <ajax@redhat.com> Date: Tue Jun 7 15:52:11 2016 -0400 dix: Use OsSignal() not signal() As the man page for the latter states: The effects of signal() in a multithreaded process are unspecified. We already have an interface to call sigaction() instead, use it. Signed-off-by: Adam Jackson <ajax@redhat.com> Reviewed-by: Keith Packard <keithp@keithp.com> commit e10ba9e4b52269b2ac75c4802dce4ca47d169657 Author: Keith Packard <keithp@keithp.com> Date: Wed Nov 11 22:02:01 2015 -0800 Remove non-smart scheduler. Don't require setitimer. This allows the server to call GetTimeInMillis() after each request is processed to avoid needing setitimer. -dumbSched now turns off the setitimer. Reviewed-by: Adam Jackson <ajax@redhat.com> Signed-off-by: Keith Packard <keithp@keithp.com> commit 1f915e8b524dd02011158aa038935970684c7630 Author: Daniel Drake <drake@endlessm.com> Date: Wed May 20 13:16:12 2015 -0600 Keep SIGALRM restart flag after Popen Commit 94ab7455 added SA_RESTART to the SIGALRM handler. However, the Popen code tears down and recreates the SIGALRM handler via OsSignal(), and this flag is dropped at this time. Clean the code to use just a single codepath for creating this signal handler, always applying SA_RESTART. [ajax: Fixed commit id] Reviewed-by: Adam Jackson <ajax@redhat.com> Signed-off-by: Daniel Drake <drake@endlessm.com> commit 94ab7455abc213fc96760e29ab2e943ec682fb22 Author: Daniel Drake <drake@endlessm.com> Date: Tue May 12 16:39:22 2015 -0600 Allow system call restarts upon signal interruption The X server frequently deals with SIGIO and SIGALRM interruptions. If process execution is inside certain blocking system calls when these signals arrive, e.g. with the kernel blocked on a contended semaphore, the system calls will be interrupted. Some system calls are automatically restartable (the kernel re-executes them with the same parameters once the signal handler returns) but only if the signal handler allows it. Set SA_RESTART on the signal handlers to enable this convenient behaviour. Reviewed-by: Adam Jackson <ajax@redhat.com> Signed-off-by: Daniel Drake <drake@endlessm.com> commit a6c71ce5d2d2fe89e07a2ef5041c915acc3dc686 Author: Tiago Vignatti <tiago.vignatti@nokia.com> Date: Mon Mar 28 19:21:28 2011 +0300 os: fix memory and fd leaks in Popen Signed-off-by: Tiago Vignatti <tiago.vignatti@nokia.com> Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net> Reviewed-by: Nicolas Peninguy <nico@lostgeeks.org> commit c9051b684b524549eab6d5b88ee3e195a6f6fbe8 Author: Alan Coopersmith <alan.coopersmith@sun.com> Date: Wed Nov 5 18:25:57 2008 -0800 Use OsSignal in Popen/Pclose to avoid SysV signal() stupidity commit 0e9ef65fa583bf2393dd0fda82df6f092387b425 Author: Keith Packard <keithp@koto.keithp.com> Date: Wed Nov 7 16:33:10 2007 -0800 Don't frob timers unless SmartSchedule is running commit 2338d5c9914e2a43c3a4f7ee0f4355ad0a1ad9e7 Author: Arjan van de Ven <arjan@linux.intel.com> Date: Sun Oct 28 09:37:52 2007 +0100 reduce wakeups from smart scheduler The smart scheduler itimer currently always fires after each request (which in turn causes the CPU to wake out of idle, burning precious power). Rather than doing this, just stop the timer before going into the select() portion of the WaitFor loop. It's a cheap system call, and it will only get called if there's no more commands batched up from the active fd. This change also allows some of the functions to be simplified; setitimer() will only fail if it's passed invalid data, and we don't do that... so make it void and remove all the conditional code that deals with failure. The change also allows us to remove a few variables that were used for housekeeping between the signal handler and the main loop. Signed-off-by: Keith Packard <keithp@koto.keithp.com> **Note**: The above change also required ABI changes in hw/nxagent/. commit abe0a51f3f790f8c055289465e130177c4b647cc Author: Ben Byer <bbyer@bbyer.apple.com> Date: Fri Sep 21 17:07:36 2007 -0700 So, like, checking return codes of system calls (signal, etc) is good. Also, only restore an old signal handler if one was actually set (prevents the server from dying on OS X). commit 6da39c67905500ab2db00a45cda4a9f756cdde96 Author: Eric Anholt <eric@anholt.net> Date: Wed Sep 12 13:23:13 2007 +0000 Fix build on FreeBSD after Popen changes. commit a5b8053606d6e786cdcf6734f271acc05f9cc588 Author: Adam Jackson <ajax@benzedrine.nwnk.net> Date: Tue Sep 11 11:37:06 2007 -0400 Ignore - not just block - SIGALRM around Popen()/Pclose(). Because our "popen" implementation uses stdio, and because nobody's stdio library is capable of surviving signals, we need to make absolutely sure that we hide the SIGALRM from the smart scheduler. Otherwise, when you open a menu in openoffice, and it recompiles XKB to deal with the accelerators, and you popen xkbcomp because we suck, then the scheduler will tell you you're taking forever doing something stupid, and the wait() code will get confused, and input will hang and your CPU usage slams to 100%. Down, not across. Backported-to-NX-by: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>
Diffstat (limited to 'nx-X11/programs/Xserver/os/utils.c')
-rw-r--r--nx-X11/programs/Xserver/os/utils.c164
1 files changed, 93 insertions, 71 deletions
diff --git a/nx-X11/programs/Xserver/os/utils.c b/nx-X11/programs/Xserver/os/utils.c
index af793454f..25cbb1e87 100644
--- a/nx-X11/programs/Xserver/os/utils.c
+++ b/nx-X11/programs/Xserver/os/utils.c
@@ -290,7 +290,8 @@ OsSignal(sig, handler)
sigaddset(&act.sa_mask, sig);
act.sa_flags = 0;
act.sa_handler = handler;
- sigaction(sig, &act, &oact);
+ if (sigaction(sig, &act, &oact))
+ perror("sigaction");
return oact.sa_handler;
#endif
}
@@ -1026,10 +1027,12 @@ ProcessCommandLine(int argc, char *argv[])
i = skip - 1;
}
#endif
+#if HAVE_SETITIMER
else if ( strcmp( argv[i], "-dumbSched") == 0)
{
- SmartScheduleDisable = TRUE;
+ SmartScheduleSignalEnable = FALSE;
}
+#endif
else if ( strcmp( argv[i], "-schedInterval") == 0)
{
if (++i < argc)
@@ -1353,30 +1356,15 @@ XNFstrdup(const char *s)
return ret;
}
-unsigned long SmartScheduleIdleCount;
-Bool SmartScheduleIdle;
-Bool SmartScheduleTimerStopped;
-
-#ifdef SIGVTALRM
-#define SMART_SCHEDULE_POSSIBLE
-#endif
-
-#ifdef SMART_SCHEDULE_POSSIBLE
-#define SMART_SCHEDULE_SIGNAL SIGALRM
-#define SMART_SCHEDULE_TIMER ITIMER_REAL
-#endif
-
-#ifdef NX_TRANS_SOCKET
void
SmartScheduleStopTimer (void)
-#else
-static void
-SmartScheduleStopTimer (void)
-#endif
{
-#ifdef SMART_SCHEDULE_POSSIBLE
+#if HAVE_SETITIMER
struct itimerval timer;
+ if (!SmartScheduleSignalEnable)
+ return;
+
#ifdef NX_TRANS_TEST
fprintf(stderr, "SmartScheduleStopTimer: Stopping timer.\n");
#endif
@@ -1386,96 +1374,101 @@ SmartScheduleStopTimer (void)
timer.it_value.tv_sec = 0;
timer.it_value.tv_usec = 0;
(void) setitimer (ITIMER_REAL, &timer, 0);
- SmartScheduleTimerStopped = TRUE;
#endif
}
-Bool
+void
SmartScheduleStartTimer (void)
{
-#ifdef SMART_SCHEDULE_POSSIBLE
+#if HAVE_SETITIMER
struct itimerval timer;
- #ifdef NX_TRANS_SOCKET
-
- if (SmartScheduleDisable)
- {
- return FALSE;
- }
-
- #endif
+ if (!SmartScheduleSignalEnable)
+ return;
#ifdef NX_TRANS_TEST
fprintf(stderr, "SmartScheduleStartTimer: Starting timer with [%ld] ms.\n",
SmartScheduleInterval);
#endif
- SmartScheduleTimerStopped = FALSE;
timer.it_interval.tv_sec = 0;
timer.it_interval.tv_usec = SmartScheduleInterval * 1000;
timer.it_value.tv_sec = 0;
timer.it_value.tv_usec = SmartScheduleInterval * 1000;
- return setitimer (ITIMER_REAL, &timer, 0) >= 0;
+ setitimer (ITIMER_REAL, &timer, 0);
#endif
- return FALSE;
}
-#ifdef SMART_SCHEDULE_POSSIBLE
+#if HAVE_SETITIMER
static void
SmartScheduleTimer (int sig)
{
- int olderrno = errno;
-
SmartScheduleTime += SmartScheduleInterval;
#ifdef NX_TRANS_TEST
fprintf(stderr, "SmartScheduleTimer: Got timer with time [%ld] ms.\n",
SmartScheduleTime);
#endif
-
- if (SmartScheduleIdle)
- {
- SmartScheduleStopTimer ();
- }
- errno = olderrno;
}
-#endif
-Bool
-SmartScheduleInit (void)
+int
+SmartScheduleEnable (void)
{
-#ifdef SMART_SCHEDULE_POSSIBLE
+ int ret = 0;
struct sigaction act;
- if (SmartScheduleDisable)
- return TRUE;
-
+ if (!SmartScheduleSignalEnable)
+ return 0;
+
#ifdef NX_TRANS_TEST
- fprintf(stderr, "SmartScheduleInit: Initializing the smart scheduler.\n");
+ fprintf(stderr, "SmartScheduleEnable: Enabling the smart scheduler.\n");
#endif
- bzero ((char *) &act, sizeof(struct sigaction));
+ memset((char *) &act, 0, sizeof(struct sigaction));
/* Set up the timer signal function */
+ act.sa_flags = SA_RESTART;
act.sa_handler = SmartScheduleTimer;
sigemptyset (&act.sa_mask);
- sigaddset (&act.sa_mask, SMART_SCHEDULE_SIGNAL);
- if (sigaction (SMART_SCHEDULE_SIGNAL, &act, 0) < 0)
- {
- perror ("sigaction for smart scheduler");
- return FALSE;
- }
- /* Set up the virtual timer */
- if (!SmartScheduleStartTimer ())
- {
- perror ("scheduling timer");
- return FALSE;
+ sigaddset (&act.sa_mask, SIGALRM);
+ ret = sigaction(SIGALRM, &act, 0);
+ return ret;
+}
+
+static int
+SmartSchedulePause(void)
+{
+ int ret = 0;
+ struct sigaction act;
+
+ if (!SmartScheduleSignalEnable)
+ return 0;
+
+ #ifdef NX_TRANS_TEST
+ fprintf(stderr, "SmartSchedulePause: Pausing the smart scheduler.\n");
+ #endif
+
+ memset((char *) &act, 0, sizeof(struct sigaction));
+
+ act.sa_handler = SIG_IGN;
+ sigemptyset(&act.sa_mask);
+ ret = sigaction(SIGALRM, &act, 0);
+ return ret;
+}
+#endif
+
+void
+SmartScheduleInit(void)
+{
+#if HAVE_SETITIMER
+ #ifdef NX_TRANS_TEST
+ fprintf(stderr, "SmartScheduleInit: Initializing the smart scheduler.\n");
+ #endif
+
+ if (SmartScheduleEnable() < 0) {
+ perror("sigaction for smart scheduler");
+ SmartScheduleSignalEnable = FALSE;
}
- /* stop the timer and wait for WaitForSomething to start it */
- SmartScheduleStopTimer ();
- return TRUE;
-#else
- return FALSE;
#endif
}
@@ -1558,7 +1551,11 @@ System(char *command)
return(1);
#ifdef SIGCHLD
- csig = signal(SIGCHLD, SIG_DFL);
+ csig = OsSignal(SIGCHLD, SIG_DFL);
+ if (csig == SIG_ERR) {
+ perror("signal");
+ return -1;
+ }
#endif
#ifdef DEBUG
@@ -1596,7 +1593,10 @@ System(char *command)
#endif
#ifdef SIGCHLD
- signal(SIGCHLD, csig);
+ if (OsSignal(SIGCHLD, csig) == SIG_ERR) {
+ perror("signal");
+ return -1;
+ }
#endif
return p == -1 ? -1 : status;
@@ -1629,6 +1629,17 @@ Popen(char *command, char *type)
return NULL;
}
+ /* Ignore the smart scheduler while this is going on */
+#if HAVE_SETITIMER
+ if (SmartSchedulePause() < 0) {
+ close(pdes[0]);
+ close(pdes[1]);
+ free(cur);
+ perror("signal");
+ return NULL;
+ }
+#endif
+
#ifdef NX_TRANS_EXIT
if (OsVendorStartRedirectErrorFProc != NULL) {
OsVendorStartRedirectErrorFProc();
@@ -1640,6 +1651,10 @@ Popen(char *command, char *type)
close(pdes[0]);
close(pdes[1]);
free(cur);
+#if HAVE_SETITIMER
+ if (SmartScheduleEnable() < 0)
+ perror("signal");
+#endif
#ifdef NX_TRANS_EXIT
if (OsVendorEndRedirectErrorFProc != NULL) {
OsVendorEndRedirectErrorFProc();
@@ -1714,6 +1729,13 @@ Popen(char *command, char *type)
OsReleaseSignals ();
#endif
+#if HAVE_SETITIMER
+ if (SmartScheduleEnable() < 0) {
+ perror("signal");
+ return NULL;
+ }
+#endif
+
execl("/bin/sh", "sh", "-c", command, (char *)NULL);
_exit(127);
}