From patchwork Tue Sep 6 18:00:23 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Paul E. McKenney" X-Patchwork-Id: 3922 Return-Path: X-Original-To: patchwork@peony.canonical.com Delivered-To: patchwork@peony.canonical.com Received: from fiordland.canonical.com (fiordland.canonical.com [91.189.94.145]) by peony.canonical.com (Postfix) with ESMTP id AC39323FC9 for ; Wed, 7 Sep 2011 06:20:57 +0000 (UTC) Received: from mail-fx0-f52.google.com (mail-fx0-f52.google.com [209.85.161.52]) by fiordland.canonical.com (Postfix) with ESMTP id 9D98FA186A3 for ; Wed, 7 Sep 2011 06:20:57 +0000 (UTC) Received: by fxd18 with SMTP id 18so398985fxd.11 for ; Tue, 06 Sep 2011 23:20:57 -0700 (PDT) Received: by 10.223.22.16 with SMTP id l16mr664994fab.62.1315376457382; Tue, 06 Sep 2011 23:20:57 -0700 (PDT) X-Forwarded-To: linaro-patchwork@canonical.com X-Forwarded-For: patch@linaro.org linaro-patchwork@canonical.com Delivered-To: patches@linaro.org Received: by 10.152.11.8 with SMTP id m8cs127787lab; Tue, 6 Sep 2011 23:20:57 -0700 (PDT) Received: by 10.150.239.8 with SMTP id m8mr4611994ybh.74.1315376456329; Tue, 06 Sep 2011 23:20:56 -0700 (PDT) Received: from e3.ny.us.ibm.com (e3.ny.us.ibm.com [32.97.182.143]) by mx.google.com with ESMTPS id 7si2507983ybn.65.2011.09.06.23.20.54 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 06 Sep 2011 23:20:55 -0700 (PDT) Received-SPF: pass (google.com: domain of paulmck@linux.vnet.ibm.com designates 32.97.182.143 as permitted sender) client-ip=32.97.182.143; Authentication-Results: mx.google.com; spf=pass (google.com: domain of paulmck@linux.vnet.ibm.com designates 32.97.182.143 as permitted sender) smtp.mail=paulmck@linux.vnet.ibm.com Received: from d01relay07.pok.ibm.com (d01relay07.pok.ibm.com [9.56.227.147]) by e3.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p875u7iw022917 for ; Wed, 7 Sep 2011 01:56:07 -0400 Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay07.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p876KqlI2555942 for ; Wed, 7 Sep 2011 02:20:52 -0400 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p876Kjdm005998 for ; Wed, 7 Sep 2011 02:20:52 -0400 Received: from paulmck-ThinkPad-W500 (dyn9050016039.mts.ibm.com [9.50.16.39] (may be forged)) by d01av01.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id p876KfpK004973; Wed, 7 Sep 2011 02:20:42 -0400 Received: by paulmck-ThinkPad-W500 (Postfix, from userid 1000) id 729F613F885; Tue, 6 Sep 2011 11:00:52 -0700 (PDT) From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, patches@linaro.org, "Shi, Alex" , "Paul E. McKenney" Subject: [PATCH tip/core/rcu 29/55] nohz: Remove nohz_cpu_mask Date: Tue, 6 Sep 2011 11:00:23 -0700 Message-Id: <1315332049-2604-29-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.3.2 In-Reply-To: <20110906180015.GA2560@linux.vnet.ibm.com> References: <20110906180015.GA2560@linux.vnet.ibm.com> From: Shi, Alex RCU no longer uses this global variable, nor does anyone else. This commit therefore removes this variable. This reduces memory footprint and also removes some atomic instructions and memory barriers from the dyntick-idle path. Signed-off-by: Alex Shi Signed-off-by: Paul E. McKenney --- include/linux/sched.h | 1 - kernel/sched.c | 11 ----------- kernel/time/tick-sched.c | 6 ------ 3 files changed, 0 insertions(+), 18 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 14a6c7b..d1a1533 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -270,7 +270,6 @@ extern void init_idle_bootup_task(struct task_struct *idle); extern int runqueue_is_locked(int cpu); -extern cpumask_var_t nohz_cpu_mask; #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ) extern void select_nohz_load_balancer(int stop_tick); extern int get_nohz_timer_target(void); diff --git a/kernel/sched.c b/kernel/sched.c index 1c87917..313c0f6 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5940,15 +5940,6 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu) } /* - * In a system that switches off the HZ timer nohz_cpu_mask - * indicates which cpus entered this state. This is used - * in the rcu update to wait only for active cpus. For system - * which do not switch off the HZ timer nohz_cpu_mask should - * always be CPU_BITS_NONE. - */ -cpumask_var_t nohz_cpu_mask; - -/* * Increase the granularity value when there are more CPUs, * because with more CPUs the 'effective latency' as visible * to users decreases. But the relationship is not linear, @@ -8167,8 +8158,6 @@ void __init sched_init(void) */ current->sched_class = &fair_sched_class; - /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */ - zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT); #ifdef CONFIG_SMP zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); #ifdef CONFIG_NO_HZ diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index d5097c4..eb98e55 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -139,7 +139,6 @@ static void tick_nohz_update_jiffies(ktime_t now) struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); unsigned long flags; - cpumask_clear_cpu(cpu, nohz_cpu_mask); ts->idle_waketime = now; local_irq_save(flags); @@ -389,9 +388,6 @@ void tick_nohz_stop_sched_tick(int inidle) else expires.tv64 = KTIME_MAX; - if (delta_jiffies > 1) - cpumask_set_cpu(cpu, nohz_cpu_mask); - /* Skip reprogram of event if its not changed */ if (ts->tick_stopped && ktime_equal(expires, dev->next_event)) goto out; @@ -441,7 +437,6 @@ void tick_nohz_stop_sched_tick(int inidle) * softirq. */ tick_do_update_jiffies64(ktime_get()); - cpumask_clear_cpu(cpu, nohz_cpu_mask); } raise_softirq_irqoff(TIMER_SOFTIRQ); out: @@ -524,7 +519,6 @@ void tick_nohz_restart_sched_tick(void) /* Update jiffies first */ select_nohz_load_balancer(0); tick_do_update_jiffies64(now); - cpumask_clear_cpu(cpu, nohz_cpu_mask); #ifndef CONFIG_VIRT_CPU_ACCOUNTING /*