From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751938Ab0ATMiO (ORCPT ); Wed, 20 Jan 2010 07:38:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752481Ab0ATMiJ (ORCPT ); Wed, 20 Jan 2010 07:38:09 -0500 Received: from mx1.redhat.com ([209.132.183.28]:29630 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932128Ab0ATMh4 (ORCPT ); Wed, 20 Jan 2010 07:37:56 -0500 From: Stanislaw Gruszka To: Thomas Gleixner , Andrew Morton Cc: Ingo Molnar , Oleg Nesterov , Peter Zijlstra , Hidetoshi Seto , Balbir Singh , linux-kernel@vger.kernel.org, Stanislaw Gruszka Subject: [PATCH 4/6 -mm] cpu-timers: change SIGEV_NONE timer implementation Date: Wed, 20 Jan 2010 13:34:26 +0100 Message-Id: <1263990868-8119-5-git-send-email-sgruszka@redhat.com> In-Reply-To: <1263990868-8119-4-git-send-email-sgruszka@redhat.com> References: <1263990868-8119-1-git-send-email-sgruszka@redhat.com> <1263990868-8119-2-git-send-email-sgruszka@redhat.com> <1263990868-8119-3-git-send-email-sgruszka@redhat.com> <1263990868-8119-4-git-send-email-sgruszka@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 #include #include #include #include #include #include #include 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 --- 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