Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753609AbbFXO6Q (ORCPT ); Wed, 24 Jun 2015 10:58:16 -0400 Received: from shelob.surriel.com ([74.92.59.67]:32786 "EHLO shelob.surriel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752196AbbFXO6J (ORCPT ); Wed, 24 Jun 2015 10:58:09 -0400 From: riel@redhat.com To: linux-kernel@vger.kernel.org Cc: fweisbec@redhat.com, peterz@infradead.org, mingo@kernel.org, tglx@linutronix.de, luto@amacapital.net Subject: [RFC PATCH 08/11] nohz,timer: have housekeeper call account_process_tick for nohz cpus Date: Wed, 24 Jun 2015 10:57:57 -0400 Message-Id: <1435157880-22925-9-git-send-email-riel@redhat.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1435157880-22925-1-git-send-email-riel@redhat.com> References: <1435157880-22925-1-git-send-email-riel@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2142 Lines: 71 From: Rik van Riel Have the housekeeper CPU call account_process_tick to do tick based accounting for remote nohz_full CPUs. Signed-off-by: Rik van Riel --- kernel/time/timer.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 2ece3aa5069c..6adebb373317 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -42,6 +42,7 @@ #include #include #include +#include "../sched/sched.h" #include #include @@ -1382,6 +1383,29 @@ unsigned long get_next_timer_interrupt(unsigned long now) } #endif +#ifdef CONFIG_NO_HZ_FULL +static void account_remote_process_ticks(void) +{ + int cpu; + + /* + * The current task on another CPU can get rescheduled while + * we are updating the statistics. The rcu read lock ensures + * the task does not get freed, so at worst the statistics will + * be off a little bit, which is expected with tick based sampling. + */ + rcu_read_lock(); + for_each_cpu_and(cpu, tick_nohz_full_mask, cpu_online_mask) { + struct task_struct *p = cpu_curr(cpu); + int user_tick = (per_cpu(context_tracking.state, cpu) == + CONTEXT_USER); + + account_process_tick(p, user_tick); + } + rcu_read_unlock(); +} +#endif + /* * Called from the timer interrupt handler to charge one tick to the current * process. user_tick is 1 if the tick is user time, 0 for system. @@ -1392,6 +1416,10 @@ void update_process_times(int user_tick) /* Note: this timer irq context must be accounted for as well. */ account_process_tick(p, user_tick); +#ifdef CONFIG_NO_HZ_FULL + if (is_timer_housekeeping_cpu(smp_processor_id())) + account_remote_process_ticks(); +#endif run_local_timers(); rcu_check_callbacks(user_tick); #ifdef CONFIG_IRQ_WORK -- 2.1.0 -- 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/