Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752781Ab0FOGP7 (ORCPT ); Tue, 15 Jun 2010 02:15:59 -0400 Received: from mail-bw0-f46.google.com ([209.85.214.46]:46238 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750855Ab0FOGP5 (ORCPT ); Tue, 15 Jun 2010 02:15:57 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=eosOmyPJv2W415QxHp6vhj/lAyYFm45dlYLKKodoWwN3pPa9JYP1dORywbpTHFDTiP +Q3aaXDzRQ6UkJ3FqtgiG2IE8HXSQuZqcMc+JlqhzB/RVlplIE36AjSiTAzJXHN+Fv7H owRJM4Af5QQhfch3xcqAhEtBT0rWJPD3s6UnQ= Date: Tue, 15 Jun 2010 09:19:27 +0300 From: Sergey Senozhatsky To: Arjan van de Ven Cc: "Rafael J. Wysocki" , Maxim Levitsky , Len Brown , Pavel Machek , Jiri Slaby , Andrew Morton , linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: [PATCH] avoid using smp_processor_id() in preemptible code (nr_iowait_cpu) Message-ID: <20100615061927.GA3312@swordfish> References: <20100613203352.GA3577@swordfish> <1276461183.2659.4.camel@maxim-laptop> <201006140136.18652.rjw@sisk.pl> <20100614140941.GA3581@swordfish.minsk.epam.com> <20100614073853.6fa2f91f@infradead.org> <20100614145439.GA3448@swordfish.minsk.epam.com> <20100614080154.7d6a71fc@infradead.org> <20100614151735.GB3448@swordfish.minsk.epam.com> <20100614204021.52c50cdc@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100614204021.52c50cdc@infradead.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4438 Lines: 140 Fixing BUG: using smp_processor_id() in preemptible [00000000] code: s2disk/3392 caller is nr_iowait_cpu+0xe/0x1e Pid: 3392, comm: s2disk Not tainted 2.6.35-rc3-dbg-00106-ga75e02b #2 Call Trace: [] debug_smp_processor_id+0xa5/0xbc [] nr_iowait_cpu+0xe/0x1e [] update_ts_time_stats+0x32/0x6c [] get_cpu_idle_time_us+0x36/0x58 [] get_cpu_idle_time+0x12/0x74 [] cpufreq_governor_dbs+0xc3/0x2dc [] __cpufreq_governor+0x51/0x85 [] __cpufreq_set_policy+0x10c/0x13d [] cpufreq_add_dev_interface+0x212/0x233 [] ? handle_update+0x0/0xd [] cpufreq_add_dev+0x34b/0x35a [] ? schedule_delayed_work_on+0x11/0x13 [] cpufreq_cpu_callback+0x59/0x63 [] notifier_call_chain+0x26/0x48 [] __raw_notifier_call_chain+0xe/0x10 [] __cpu_notify+0x15/0x29 [] cpu_notify+0xd/0xf [] _cpu_up+0xaf/0xd2 [] enable_nonboot_cpus+0x3d/0x94 [] hibernation_snapshot+0x104/0x1a2 [] snapshot_ioctl+0x24b/0x53e [] ? sub_preempt_count+0x7c/0x89 [] vfs_ioctl+0x2e/0x8c [] ? snapshot_ioctl+0x0/0x53e [] do_vfs_ioctl+0x42f/0x45a [] ? fsnotify_modify+0x4f/0x5a [] ? tty_write+0x0/0x1d0 [] ? vfs_write+0xa2/0xda [] sys_ioctl+0x41/0x62 [] sysenter_do_call+0x12/0x2d Initially fix was to use get_cpu/put_cpu in nr_iowait_cpu. However, Arjan van de Ven stated that "the bug is that it needs to be nr_iowait_cpu(int cpu)". This patch introduces nr_iowait_cpu(int cpu) and changes to it callers. Signed-off-by: Sergey Senozhatsky --- diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 52ff8aa..4871ed5 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -137,14 +137,17 @@ static inline int which_bucket(unsigned int duration) { int bucket = 0; + int cpu = get_cpu(); /* * We keep two groups of stats; one with no * IO pending, one without. * This allows us to calculate * E(duration)|iowait */ - if (nr_iowait_cpu()) + if (nr_iowait_cpu(cpu)) bucket = BUCKETS/2; + + put_cpu(); if (duration < 10) return bucket; @@ -169,14 +172,17 @@ static inline int which_bucket(unsigned int duration) static inline int performance_multiplier(void) { int mult = 1; - + int cpu = get_cpu(); + /* for higher loadavg, we are more reluctant */ mult += 2 * get_loadavg(); /* for IO wait tasks (per cpu!) we add 5x each */ - mult += 10 * nr_iowait_cpu(); + mult += 10 * nr_iowait_cpu(cpu); + put_cpu(); + return mult; } diff --git a/include/linux/sched.h b/include/linux/sched.h index f118809..747fcae 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -139,7 +139,7 @@ extern int nr_processes(void); extern unsigned long nr_running(void); extern unsigned long nr_uninterruptible(void); extern unsigned long nr_iowait(void); -extern unsigned long nr_iowait_cpu(void); +extern unsigned long nr_iowait_cpu(int cpu); extern unsigned long this_cpu_load(void); diff --git a/kernel/sched.c b/kernel/sched.c index f8b8996..f61b48e 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2864,9 +2864,9 @@ unsigned long nr_iowait(void) return sum; } -unsigned long nr_iowait_cpu(void) +unsigned long nr_iowait_cpu(int cpu) { - struct rq *this = this_rq(); + struct rq *this = cpu_rq(cpu); return atomic_read(&this->nr_iowait); } diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 1d7b9bc..101e8aa 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -159,10 +159,12 @@ update_ts_time_stats(struct tick_sched *ts, ktime_t now, u64 *last_update_time) ktime_t delta; if (ts->idle_active) { + int cpu = get_cpu(); delta = ktime_sub(now, ts->idle_entrytime); ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); - if (nr_iowait_cpu() > 0) + if (nr_iowait_cpu(cpu) > 0) ts->iowait_sleeptime = ktime_add(ts->iowait_sleeptime, delta); + put_cpu(); ts->idle_entrytime = now; } -- 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/