From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752037Ab2KFKjU (ORCPT ); Tue, 6 Nov 2012 05:39:20 -0500 Received: from service87.mimecast.com ([91.220.42.44]:41225 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751467Ab2KFKjF (ORCPT ); Tue, 6 Nov 2012 05:39:05 -0500 From: Viresh Kumar To: pjt@google.com, paul.mckenney@linaro.org, tglx@linutronix.de, tj@kernel.org, suresh.b.siddha@intel.com, venki@google.com, mingo@redhat.com, peterz@infradead.org, rostedt@goodmis.org Cc: Arvind.Chauhan@arm.com, linaro-dev@lists.linaro.org, patches@linaro.org, pdsw-power-team@arm.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, Viresh Kumar Subject: [PATCH V2 Resend 2/4] timer: hrtimer: Don't check idle_cpu() before calling get_nohz_timer_target() Date: Tue, 6 Nov 2012 16:08:44 +0530 Message-Id: <5caa3dab5feb7cc3d78b4f9a19dbb24401796b53.1352196505.git.viresh.kumar@linaro.org> X-Mailer: git-send-email 1.7.12.rc2.18.g61b472e In-Reply-To: References: In-Reply-To: References: X-OriginalArrivalTime: 06 Nov 2012 10:38:55.0124 (UTC) FILETIME=[EB8DB540:01CDBC0A] X-MC-Unique: 112110610385633701 Content-Type: text/plain; charset=WINDOWS-1252 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id qA6AdOpM014379 Check for current cpu's idleness already done in implementation of sched_select_cpu() which is called by get_nohz_timer_target(). So, no need to call idle_cpu() twice, once from sched_select_cpu() and once from timer and hrtimer before calling get_nohz_timer_target(). This patch removes calls to idle_cpu() from timer and hrtimer. This also reduces an extra call to smp_processor_id() when get_nohz_timer_target() is called. Signed-off-by: Viresh Kumar --- kernel/hrtimer.c | 2 +- kernel/timer.c | 8 +++++--- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 6db7a5e..74bdaf6 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -159,7 +159,7 @@ struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer, static int hrtimer_get_target(int this_cpu, int pinned) { #ifdef CONFIG_NO_HZ - if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu)) + if (!pinned && get_sysctl_timer_migration()) return get_nohz_timer_target(); #endif return this_cpu; diff --git a/kernel/timer.c b/kernel/timer.c index 367d008..1170ece 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -735,11 +735,13 @@ __mod_timer(struct timer_list *timer, unsigned long expires, debug_activate(timer, expires); - cpu = smp_processor_id(); - #if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP) - if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu)) + if (!pinned && get_sysctl_timer_migration()) cpu = get_nohz_timer_target(); + else + cpu = smp_processor_id(); +#else + cpu = smp_processor_id(); #endif new_base = per_cpu(tvec_bases, cpu); -- 1.7.12.rc2.18.g61b472e