From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757937AbZBTNBw (ORCPT ); Fri, 20 Feb 2009 08:01:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753837AbZBTNBn (ORCPT ); Fri, 20 Feb 2009 08:01:43 -0500 Received: from e28smtp03.in.ibm.com ([59.145.155.3]:52773 "EHLO e28smtp03.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752880AbZBTNBn (ORCPT ); Fri, 20 Feb 2009 08:01:43 -0500 Date: Fri, 20 Feb 2009 18:31:31 +0530 From: Arun R Bharadwaj To: linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org, a.p.zijlstra@chello.nl, ego@in.ibm.com, tglx@linutronix.de, mingo@elte.hu, andi@firstfloor.org, venkatesh.pallipadi@intel.com, vatsa@linux.vnet.ibm.com, arjan@infradead.org Subject: [RFC PATCH 4/4] timers: logic to enable timer migration. Message-ID: <20090220130131.GD19762@linux.vnet.ibm.com> Reply-To: arun@linux.vnet.ibm.com Mail-Followup-To: linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org, a.p.zijlstra@chello.nl, ego@in.ibm.com, tglx@linutronix.de, mingo@elte.hu, andi@firstfloor.org, venkatesh.pallipadi@intel.com, vatsa@linux.vnet.ibm.com, arjan@infradead.org References: <20090220125516.GB10232@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20090220125516.GB10232@linux.vnet.ibm.com> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Arun R Bharadwaj [2009-02-20 18:25:16]: This patch migrates all non pinned timers and hrtimers to the target CPU. Timer migration is enabled by setting the sysfs entry of the particular CPU. At the time of queuing a timer, it is checked to see if migration is enabled for that particular CPU. If so, the target CPU base is set as the new timer base and the timer is queued on that CPU. Signed-off-by: Arun R Bharadwaj --- kernel/hrtimer.c | 12 +++++++++++- kernel/timer.c | 15 ++++++++++++++- 2 files changed, 25 insertions(+), 2 deletions(-) Index: git-2.6/kernel/timer.c =================================================================== --- git-2.6.orig/kernel/timer.c +++ git-2.6/kernel/timer.c @@ -616,7 +616,7 @@ int __mod_timer(struct timer_list *timer { struct tvec_base *base, *new_base; unsigned long flags; - int ret = 0; + int ret = 0, target_cpu; timer_stats_timer_set_start_info(timer); BUG_ON(!timer->function); @@ -631,6 +631,18 @@ int __mod_timer(struct timer_list *timer debug_timer_activate(timer); new_base = __get_cpu_var(tvec_bases); + /* + * @target_cpu: The CPU to which timers are to be migrated. + * If timer migration is disabled, target_cpu = this_cpu. + */ + target_cpu = __get_cpu_var(enable_timer_migration); + if (!tbase_get_pinned(timer->base) && cpu_online(target_cpu)) { + new_base = per_cpu(tvec_bases, target_cpu); + timer_set_base(timer, new_base); + timer->expires = expires; + internal_add_timer(new_base, timer); + goto out; + } if (base != new_base) { /* @@ -652,6 +664,7 @@ int __mod_timer(struct timer_list *timer timer->expires = expires; internal_add_timer(base, timer); +out: spin_unlock_irqrestore(&base->lock, flags); return ret; Index: git-2.6/kernel/hrtimer.c =================================================================== --- git-2.6.orig/kernel/hrtimer.c +++ git-2.6/kernel/hrtimer.c @@ -198,8 +198,18 @@ int pinned) { struct hrtimer_clock_base *new_base; struct hrtimer_cpu_base *new_cpu_base; + int target_cpu; + + /* + * @target_cpu: CPU to which the timers are to be migrated. + * If timer migration is disabled, target_cpu = this_cpu + */ + target_cpu = __get_cpu_var(enable_timer_migration); + if (cpu_online(target_cpu) && !pinned) + new_cpu_base = &per_cpu(hrtimer_bases, target_cpu); + else + new_cpu_base = &__get_cpu_var(hrtimer_bases); - new_cpu_base = &__get_cpu_var(hrtimer_bases); new_base = &new_cpu_base->clock_base[base->index]; if (base != new_base) {