Messages in this thread Patch in this message | | | From | Stanislaw Gruszka <> | Subject | [PATCH 4/6 -mm] cpu-timers: change SIGEV_NONE timer implementation | Date | Wed, 20 Jan 2010 13:34:26 +0100 |
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When user will setup timer without associated signal and process does not use any other cpu timers and does not exit, tsk->signal->cputimer is enabled and running forever, change that.
I used below program to check patch does not break current user space visible behavior.
#include <sys/time.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <time.h> #include <unistd.h> #include <assert.h>
void consume_cpu(void) { int i = 0; int count = 0;
for(i=0; i<100000000; i++) count++; }
int main(void) { int i; struct sigaction act; struct sigevent evt = { }; timer_t tid; struct itimerspec spec = { };
evt.sigev_notify = SIGEV_NONE; assert(timer_create(CLOCK_PROCESS_CPUTIME_ID, &evt, &tid) == 0);
spec.it_value.tv_sec = 10; assert(timer_settime(tid, 0, &spec, NULL) == 0);
for (i = 0; i < 30; i++) { consume_cpu(); memset(&spec, 0, sizeof(spec)); assert(timer_gettime(tid, &spec) == 0); printf("%lu.%09lu\n", (unsigned long) spec.it_value.tv_sec, (unsigned long) spec.it_value.tv_nsec); }
assert(timer_delete(tid) == 0); return 0; }
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> --- kernel/posix-cpu-timers.c | 28 ++++++---------------------- 1 files changed, 6 insertions(+), 22 deletions(-)
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index e9aa4dc..faa0b42 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -614,7 +614,12 @@ static void arm_timer(struct k_itimer *timer) */ static void cpu_timer_fire(struct k_itimer *timer) { - if (unlikely(timer->sigq == NULL)) { + if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) { + /* + * User don't want any signal. + */ + timer->it.cpu.expires.sched = 0; + } else if (unlikely(timer->sigq == NULL)) { /* * This a special case for clock_nanosleep, * not a normal timer from sys_timer_create. @@ -783,7 +788,6 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, */ timer->it.cpu.expires = new_expires; if (new_expires.sched != 0 && - (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE && cpu_time_before(timer->it_clock, val, new_expires)) { arm_timer(timer); } @@ -808,7 +812,6 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, timer->it_overrun = -1; if (new_expires.sched != 0 && - (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE && !cpu_time_before(timer->it_clock, val, new_expires)) { /* * The designated time already passed, so we notify @@ -882,25 +885,6 @@ void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp) read_unlock(&tasklist_lock); } - if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) { - if (timer->it.cpu.incr.sched == 0 && - cpu_time_before(timer->it_clock, - timer->it.cpu.expires, now)) { - /* - * Do-nothing timer expired and has no reload, - * so it's as if it was never set. - */ - timer->it.cpu.expires.sched = 0; - itp->it_value.tv_sec = itp->it_value.tv_nsec = 0; - return; - } - /* - * Account for any expirations and reloads that should - * have happened. - */ - bump_cpu_timer(timer, now); - } - if (unlikely(clear_dead)) { /* * We've noticed that the thread is dead, but -- 1.6.2.5
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