From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754967Ab1HOPxq (ORCPT ); Mon, 15 Aug 2011 11:53:46 -0400 Received: from mail-vw0-f46.google.com ([209.85.212.46]:46598 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754932Ab1HOPxm (ORCPT ); Mon, 15 Aug 2011 11:53:42 -0400 From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Andrew Morton , Anton Blanchard , Avi Kivity , Ingo Molnar , Lai Jiangshan , "Paul E . McKenney" , Paul Menage , Peter Zijlstra , Stephen Hemminger , Thomas Gleixner , Tim Pepper Subject: [PATCH 18/32] nohz/cpuset: Don't stop the tick if posix cpu timers are running Date: Mon, 15 Aug 2011 17:52:15 +0200 Message-Id: <1313423549-27093-19-git-send-email-fweisbec@gmail.com> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1313423549-27093-1-git-send-email-fweisbec@gmail.com> References: <1313423549-27093-1-git-send-email-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If either a per thread or a per process posix cpu timer is running, don't stop the tick. TODO: restart the tick if it is stopped and a posix cpu timer is enqueued. Check we probably need a memory barrier for the per process posix timer that can be enqueued from another task of the group. Signed-off-by: Frederic Weisbecker Cc: Andrew Morton Cc: Anton Blanchard Cc: Avi Kivity Cc: Ingo Molnar Cc: Lai Jiangshan Cc: Paul E . McKenney Cc: Paul Menage Cc: Peter Zijlstra Cc: Stephen Hemminger Cc: Thomas Gleixner Cc: Tim Pepper --- include/linux/posix-timers.h | 1 + kernel/posix-cpu-timers.c | 12 ++++++++++++ kernel/sched.c | 4 ++++ 3 files changed, 17 insertions(+), 0 deletions(-) diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h index 959c141..5092cfd 100644 --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -116,6 +116,7 @@ int posix_timer_event(struct k_itimer *timr, int si_private); void posix_cpu_timer_schedule(struct k_itimer *timer); void run_posix_cpu_timers(struct task_struct *task); +bool posix_cpu_timers_running(struct task_struct *tsk); void posix_cpu_timers_exit(struct task_struct *task); void posix_cpu_timers_exit_group(struct task_struct *task); diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index 58f405b..f284fa4 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include @@ -1300,6 +1301,17 @@ static inline int fastpath_timer_check(struct task_struct *tsk) return 0; } +bool posix_cpu_timers_running(struct task_struct *tsk) +{ + if (!task_cputime_zero(&tsk->cputime_expires)) + return true; + + if (tsk->signal->cputimer.running) + return true; + + return false; +} + /* * This is called from the timer interrupt handler. The irq handler has * already updated our counts. We need to check if any timers fire now. diff --git a/kernel/sched.c b/kernel/sched.c index 8bf8280..78ea0a5 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -71,6 +71,7 @@ #include #include #include +#include #include #include @@ -2491,6 +2492,9 @@ bool cpuset_nohz_can_stop_tick(void) if (rcu_pending(cpu)) return false; + if (posix_cpu_timers_running(current)) + return false; + return true; } -- 1.7.5.4