Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:60708 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932155Ab0FPUnV (ORCPT ); Wed, 16 Jun 2010 16:43:21 -0400 Date: Wed, 16 Jun 2010 13:42:31 -0700 From: Andrew Morton To: "Rafael J. Wysocki" Cc: sedat.dilek@gmail.com, Linux Kernel Mailing List , Maciej Rutecki , Linus Torvalds , Kernel Testers List , Network Development , Linux ACPI , Linux PM List , Linux SCSI List , Linux Wireless List , DRI , dmonakhov@openvz.org Subject: Re: 2.6.35-rc2-git2: Reported regressions from 2.6.34 Message-Id: <20100616134231.23ff30da.akpm@linux-foundation.org> In-Reply-To: <201006091122.35304.rjw@sisk.pl> References:

<201006091122.35304.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, 9 Jun 2010 11:22:35 +0200 "Rafael J. Wysocki" wrote: > On Wednesday 09 June 2010, Sedat Dilek wrote: > > The patch from [1] is still missing. > > > > "cpufreq-call-nr_iowait_cpu-with-disabled-preemption.patch" from > > Dmitry Monakhoc > > > > Tested-by: Sedat Dilek > > Tested-by Maciej Rutecki > > > > I have already reported this issue on LKML [2] and cpufreq ML [3]. > > > > - Sedat - > > > > [1] http://www.spinics.net/lists/cpufreq/msg01631.html > > [2] http://lkml.org/lkml/2010/5/31/77 > > [3] http://www.spinics.net/lists/cpufreq/msg01637.html > > Thanks, added. I just merged a different patch whcih should address this: From: Sergey Senozhatsky Fix 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 The initial fix was to use get_cpu/put_cpu in nr_iowait_cpu. However, Arjan 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. akpm: addresses about 30,000,000 different bug reports. Signed-off-by: Sergey Senozhatsky Cc: Arjan van de Ven Cc: "Rafael J. Wysocki" Cc: Maxim Levitsky Cc: Len Brown Cc: Pavel Machek Cc: Jiri Slaby Signed-off-by: Andrew Morton --- drivers/cpuidle/governors/menu.c | 10 ++++++++-- include/linux/sched.h | 2 +- kernel/sched.c | 4 ++-- kernel/time/tick-sched.c | 4 +++- 4 files changed, 14 insertions(+), 6 deletions(-) diff -puN drivers/cpuidle/governors/menu.c~cpuidle-avoid-using-smp_processor_id-in-preemptible-code-nr_iowait_cpu drivers/cpuidle/governors/menu.c --- a/drivers/cpuidle/governors/menu.c~cpuidle-avoid-using-smp_processor_id-in-preemptible-code-nr_iowait_cpu +++ a/drivers/cpuidle/governors/menu.c @@ -137,15 +137,18 @@ static inline int which_bucket(unsigned { 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; if (duration < 100) @@ -169,13 +172,16 @@ static inline int which_bucket(unsigned 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 -puN include/linux/sched.h~cpuidle-avoid-using-smp_processor_id-in-preemptible-code-nr_iowait_cpu include/linux/sched.h --- a/include/linux/sched.h~cpuidle-avoid-using-smp_processor_id-in-preemptible-code-nr_iowait_cpu +++ a/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 -puN kernel/sched.c~cpuidle-avoid-using-smp_processor_id-in-preemptible-code-nr_iowait_cpu kernel/sched.c --- a/kernel/sched.c~cpuidle-avoid-using-smp_processor_id-in-preemptible-code-nr_iowait_cpu +++ a/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 -puN kernel/time/tick-sched.c~cpuidle-avoid-using-smp_processor_id-in-preemptible-code-nr_iowait_cpu kernel/time/tick-sched.c --- a/kernel/time/tick-sched.c~cpuidle-avoid-using-smp_processor_id-in-preemptible-code-nr_iowait_cpu +++ a/kernel/time/tick-sched.c @@ -159,10 +159,12 @@ update_ts_time_stats(struct tick_sched * 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; } _