Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031219AbbD1UBV (ORCPT ); Tue, 28 Apr 2015 16:01:21 -0400 Received: from g9t5008.houston.hp.com ([15.240.92.66]:37080 "EHLO g9t5008.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030826AbbD1UBQ (ORCPT ); Tue, 28 Apr 2015 16:01:16 -0400 From: Jason Low To: Peter Zijlstra , Ingo Molnar , Thomas Gleixner Cc: linux-kernel@vger.kernel.org, "Paul E. McKenney" , Andrew Morton , Oleg Nesterov , Frederic Weisbecker , Mel Gorman , Rik van Riel , Steven Rostedt , Preeti U Murthy , Mike Galbraith , Davidlohr Bueso , Waiman Long , Aswin Chandramouleeswaran , Scott J Norton , Jason Low Subject: [PATCH v2 5/5] sched, timer: Use the atomic task_cputime in thread_group_cputimer Date: Tue, 28 Apr 2015 13:00:24 -0700 Message-Id: <1430251224-5764-6-git-send-email-jason.low2@hp.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1430251224-5764-1-git-send-email-jason.low2@hp.com> References: <1430251224-5764-1-git-send-email-jason.low2@hp.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5838 Lines: 151 Recent optimizations were made to thread_group_cputimer to improve its scalability by keeping track of cputime stats without a lock. However, the values were open coded to the structure, causing them to be at a different abstraction level from the regular task_cputime structure. Furthermore, any subsequent similar optimizations would not be able to share the new code, since they are specific to thread_group_cputimer. This patch adds the new task_cputime_atomic data structure (introduced in the previous patch in the series) to thread_group_cputimer for keeping track of the cputime atomically, which also helps generalize the code. Suggested-by: Ingo Molnar Signed-off-by: Jason Low --- include/linux/init_task.h | 6 ++---- include/linux/sched.h | 4 +--- kernel/sched/stats.h | 6 +++--- kernel/time/posix-cpu-timers.c | 26 +++++++++++++------------- 4 files changed, 19 insertions(+), 23 deletions(-) diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 7b9d8b5..bb9b075 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -50,10 +50,8 @@ extern struct fs_struct init_fs; .cpu_timers = INIT_CPU_TIMERS(sig.cpu_timers), \ .rlim = INIT_RLIMITS, \ .cputimer = { \ - .utime = ATOMIC64_INIT(0), \ - .stime = ATOMIC64_INIT(0), \ - .sum_exec_runtime = ATOMIC64_INIT(0), \ - .running = 0 \ + .cputime_atomic = INIT_CPUTIME_ATOMIC, \ + .running = 0, \ }, \ .cred_guard_mutex = \ __MUTEX_INITIALIZER(sig.cred_guard_mutex), \ diff --git a/include/linux/sched.h b/include/linux/sched.h index 7092192..80ce921c 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -618,9 +618,7 @@ struct task_cputime_atomic { * used for thread group CPU timer calculations. */ struct thread_group_cputimer { - atomic64_t utime; - atomic64_t stime; - atomic64_t sum_exec_runtime; + struct task_cputime_atomic cputime_atomic; int running; }; diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h index c6d1c7d..077ebbd 100644 --- a/kernel/sched/stats.h +++ b/kernel/sched/stats.h @@ -216,7 +216,7 @@ static inline void account_group_user_time(struct task_struct *tsk, if (!cputimer_running(tsk)) return; - atomic64_add(cputime, &cputimer->utime); + atomic64_add(cputime, &cputimer->cputime_atomic.utime); } /** @@ -237,7 +237,7 @@ static inline void account_group_system_time(struct task_struct *tsk, if (!cputimer_running(tsk)) return; - atomic64_add(cputime, &cputimer->stime); + atomic64_add(cputime, &cputimer->cputime_atomic.stime); } /** @@ -258,5 +258,5 @@ static inline void account_group_exec_runtime(struct task_struct *tsk, if (!cputimer_running(tsk)) return; - atomic64_add(ns, &cputimer->sum_exec_runtime); + atomic64_add(ns, &cputimer->cputime_atomic.sum_exec_runtime); } diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index d857306..892e3da 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -211,20 +211,20 @@ retry: } } -static void update_gt_cputime(struct thread_group_cputimer *cputimer, struct task_cputime *sum) +static void update_gt_cputime(struct task_cputime_atomic *cputime_atomic, struct task_cputime *sum) { - __update_gt_cputime(&cputimer->utime, sum->utime); - __update_gt_cputime(&cputimer->stime, sum->stime); - __update_gt_cputime(&cputimer->sum_exec_runtime, sum->sum_exec_runtime); + __update_gt_cputime(&cputime_atomic->utime, sum->utime); + __update_gt_cputime(&cputime_atomic->stime, sum->stime); + __update_gt_cputime(&cputime_atomic->sum_exec_runtime, sum->sum_exec_runtime); } -/* Sample thread_group_cputimer values in "cputimer", store results in "times". */ -static inline void sample_group_cputimer(struct task_cputime *times, - struct thread_group_cputimer *cputimer) +/* Sample task_cputime_atomic values in "atomic_timers", store results in "times". */ +static inline void sample_cputime_atomic(struct task_cputime *times, + struct task_cputime_atomic *atomic_times) { - times->utime = atomic64_read(&cputimer->utime); - times->stime = atomic64_read(&cputimer->stime); - times->sum_exec_runtime = atomic64_read(&cputimer->sum_exec_runtime); + times->utime = atomic64_read(&atomic_times->utime); + times->stime = atomic64_read(&atomic_times->stime); + times->sum_exec_runtime = atomic64_read(&atomic_times->sum_exec_runtime); } void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times) @@ -240,7 +240,7 @@ void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times) * to synchronize the timer to the clock every time we start it. */ thread_group_cputime(tsk, &sum); - update_gt_cputime(cputimer, &sum); + update_gt_cputime(&cputimer->cputime_atomic, &sum); /* * We're setting cputimer->running without a lock. Ensure @@ -251,7 +251,7 @@ void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times) */ WRITE_ONCE(cputimer->running, 1); } - sample_group_cputimer(times, cputimer); + sample_cputime_atomic(times, &cputimer->cputime_atomic); } /* @@ -1137,7 +1137,7 @@ static inline int fastpath_timer_check(struct task_struct *tsk) if (READ_ONCE(sig->cputimer.running)) { struct task_cputime group_sample; - sample_group_cputimer(&group_sample, &sig->cputimer); + sample_cputime_atomic(&group_sample, &sig->cputimer.cputime_atomic); if (task_cputime_expired(&group_sample, &sig->cputime_expires)) return 1; -- 1.7.2.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/