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* Re: [patch]mm: fix a memcg warning
  2011-08-01  6:41 [patch]mm: fix a memcg warning Shaohua Li
@ 2011-08-01  6:37 ` KAMEZAWA Hiroyuki
  2011-08-01  6:57   ` Shaohua Li
  2011-08-01 12:12 ` Michal Hocko
  1 sibling, 1 reply; 4+ messages in thread
From: KAMEZAWA Hiroyuki @ 2011-08-01  6:37 UTC (permalink / raw)
  To: Shaohua Li; +Cc: Andrew Morton, linux-mm

On Mon, 01 Aug 2011 14:41:18 +0800
Shaohua Li <shaohua.li@intel.com> wrote:

> I get below warning:
> BUG: using smp_processor_id() in preemptible [00000000] code: bash/739
> caller is drain_local_stock+0x1a/0x55
> Pid: 739, comm: bash Tainted: G        W   3.0.0+ #255
> Call Trace:
>  [<ffffffff813435c6>] debug_smp_processor_id+0xc2/0xdc
>  [<ffffffff8114ae9b>] drain_local_stock+0x1a/0x55
>  [<ffffffff8114b076>] drain_all_stock+0x98/0x13a
>  [<ffffffff8114f04c>] mem_cgroup_force_empty+0xa3/0x27a
>  [<ffffffff8114ff1d>] ? sys_close+0x38/0x138
>  [<ffffffff811a7631>] ? environ_read+0x1d/0x159
>  [<ffffffff8114f253>] mem_cgroup_force_empty_write+0x17/0x19
>  [<ffffffff810c72fb>] cgroup_file_write+0xa8/0xba
>  [<ffffffff811522ce>] vfs_write+0xb3/0x138
>  [<ffffffff81152416>] sys_write+0x4a/0x71
>  [<ffffffff8114ffd5>] ? sys_close+0xf0/0x138
>  [<ffffffff8176deab>] system_call_fastpath+0x16/0x1b
> 
> drain_local_stock() should be run with preempt disabled.
> 
> Signed-off-by: Shaohua Li <shaohua.li@intel.com>
> 

Thanks,
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

IIUC, I myself didn't see this warning when I wrote codes.
Do I need to set some CONFIG ?


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^ permalink raw reply	[flat|nested] 4+ messages in thread

* [patch]mm: fix a memcg warning
@ 2011-08-01  6:41 Shaohua Li
  2011-08-01  6:37 ` KAMEZAWA Hiroyuki
  2011-08-01 12:12 ` Michal Hocko
  0 siblings, 2 replies; 4+ messages in thread
From: Shaohua Li @ 2011-08-01  6:41 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-mm, KAMEZAWA Hiroyuki

I get below warning:
BUG: using smp_processor_id() in preemptible [00000000] code: bash/739
caller is drain_local_stock+0x1a/0x55
Pid: 739, comm: bash Tainted: G        W   3.0.0+ #255
Call Trace:
 [<ffffffff813435c6>] debug_smp_processor_id+0xc2/0xdc
 [<ffffffff8114ae9b>] drain_local_stock+0x1a/0x55
 [<ffffffff8114b076>] drain_all_stock+0x98/0x13a
 [<ffffffff8114f04c>] mem_cgroup_force_empty+0xa3/0x27a
 [<ffffffff8114ff1d>] ? sys_close+0x38/0x138
 [<ffffffff811a7631>] ? environ_read+0x1d/0x159
 [<ffffffff8114f253>] mem_cgroup_force_empty_write+0x17/0x19
 [<ffffffff810c72fb>] cgroup_file_write+0xa8/0xba
 [<ffffffff811522ce>] vfs_write+0xb3/0x138
 [<ffffffff81152416>] sys_write+0x4a/0x71
 [<ffffffff8114ffd5>] ? sys_close+0xf0/0x138
 [<ffffffff8176deab>] system_call_fastpath+0x16/0x1b

drain_local_stock() should be run with preempt disabled.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5f84d23..11d5671 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2169,13 +2169,7 @@ static void drain_all_stock(struct mem_cgroup *root_mem, bool sync)
 
 	/* Notify other cpus that system-wide "drain" is running */
 	get_online_cpus();
-	/*
-	 * Get a hint for avoiding draining charges on the current cpu,
-	 * which must be exhausted by our charging.  It is not required that
-	 * this be a precise check, so we use raw_smp_processor_id() instead of
-	 * getcpu()/putcpu().
-	 */
-	curcpu = raw_smp_processor_id();
+	curcpu = get_cpu();
 	for_each_online_cpu(cpu) {
 		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
 		struct mem_cgroup *mem;
@@ -2192,6 +2186,7 @@ static void drain_all_stock(struct mem_cgroup *root_mem, bool sync)
 				schedule_work_on(cpu, &stock->work);
 		}
 	}
+	put_cpu();
 
 	if (!sync)
 		goto out;


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^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [patch]mm: fix a memcg warning
  2011-08-01  6:37 ` KAMEZAWA Hiroyuki
@ 2011-08-01  6:57   ` Shaohua Li
  0 siblings, 0 replies; 4+ messages in thread
From: Shaohua Li @ 2011-08-01  6:57 UTC (permalink / raw)
  To: KAMEZAWA Hiroyuki; +Cc: Andrew Morton, linux-mm

On Mon, 2011-08-01 at 14:37 +0800, KAMEZAWA Hiroyuki wrote:
> On Mon, 01 Aug 2011 14:41:18 +0800
> Shaohua Li <shaohua.li@intel.com> wrote:
> 
> > I get below warning:
> > BUG: using smp_processor_id() in preemptible [00000000] code: bash/739
> > caller is drain_local_stock+0x1a/0x55
> > Pid: 739, comm: bash Tainted: G        W   3.0.0+ #255
> > Call Trace:
> >  [<ffffffff813435c6>] debug_smp_processor_id+0xc2/0xdc
> >  [<ffffffff8114ae9b>] drain_local_stock+0x1a/0x55
> >  [<ffffffff8114b076>] drain_all_stock+0x98/0x13a
> >  [<ffffffff8114f04c>] mem_cgroup_force_empty+0xa3/0x27a
> >  [<ffffffff8114ff1d>] ? sys_close+0x38/0x138
> >  [<ffffffff811a7631>] ? environ_read+0x1d/0x159
> >  [<ffffffff8114f253>] mem_cgroup_force_empty_write+0x17/0x19
> >  [<ffffffff810c72fb>] cgroup_file_write+0xa8/0xba
> >  [<ffffffff811522ce>] vfs_write+0xb3/0x138
> >  [<ffffffff81152416>] sys_write+0x4a/0x71
> >  [<ffffffff8114ffd5>] ? sys_close+0xf0/0x138
> >  [<ffffffff8176deab>] system_call_fastpath+0x16/0x1b
> > 
> > drain_local_stock() should be run with preempt disabled.
> > 
> > Signed-off-by: Shaohua Li <shaohua.li@intel.com>
> > 
> 
> Thanks,
> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> 
> IIUC, I myself didn't see this warning when I wrote codes.
> Do I need to set some CONFIG ?
I thought it's CONFIG_DEBUG_PREEMPT=y


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^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [patch]mm: fix a memcg warning
  2011-08-01  6:41 [patch]mm: fix a memcg warning Shaohua Li
  2011-08-01  6:37 ` KAMEZAWA Hiroyuki
@ 2011-08-01 12:12 ` Michal Hocko
  1 sibling, 0 replies; 4+ messages in thread
From: Michal Hocko @ 2011-08-01 12:12 UTC (permalink / raw)
  To: Shaohua Li; +Cc: Andrew Morton, linux-mm, KAMEZAWA Hiroyuki

On Mon 01-08-11 14:41:18, Shaohua Li wrote:
> I get below warning:
> BUG: using smp_processor_id() in preemptible [00000000] code: bash/739
> caller is drain_local_stock+0x1a/0x55
> Pid: 739, comm: bash Tainted: G        W   3.0.0+ #255
> Call Trace:
>  [<ffffffff813435c6>] debug_smp_processor_id+0xc2/0xdc
>  [<ffffffff8114ae9b>] drain_local_stock+0x1a/0x55
>  [<ffffffff8114b076>] drain_all_stock+0x98/0x13a
>  [<ffffffff8114f04c>] mem_cgroup_force_empty+0xa3/0x27a
>  [<ffffffff8114ff1d>] ? sys_close+0x38/0x138
>  [<ffffffff811a7631>] ? environ_read+0x1d/0x159
>  [<ffffffff8114f253>] mem_cgroup_force_empty_write+0x17/0x19
>  [<ffffffff810c72fb>] cgroup_file_write+0xa8/0xba
>  [<ffffffff811522ce>] vfs_write+0xb3/0x138
>  [<ffffffff81152416>] sys_write+0x4a/0x71
>  [<ffffffff8114ffd5>] ? sys_close+0xf0/0x138
>  [<ffffffff8176deab>] system_call_fastpath+0x16/0x1b
> 
> drain_local_stock() should be run with preempt disabled.

Ahh, yes. This got in with d1a05b69 (memcg: do not try to drain per-cpu
caches without pages) which started calling drain_local_stock directly
rather than from a kernel thread.

> Signed-off-by: Shaohua Li <shaohua.li@intel.com>

Acked-by: Michal Hocko <mhocko@suse.cz>

Thanks for catching this.

> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 5f84d23..11d5671 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2169,13 +2169,7 @@ static void drain_all_stock(struct mem_cgroup *root_mem, bool sync)
>  
>  	/* Notify other cpus that system-wide "drain" is running */
>  	get_online_cpus();
> -	/*
> -	 * Get a hint for avoiding draining charges on the current cpu,
> -	 * which must be exhausted by our charging.  It is not required that
> -	 * this be a precise check, so we use raw_smp_processor_id() instead of
> -	 * getcpu()/putcpu().
> -	 */
> -	curcpu = raw_smp_processor_id();
> +	curcpu = get_cpu();
>  	for_each_online_cpu(cpu) {
>  		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
>  		struct mem_cgroup *mem;
> @@ -2192,6 +2186,7 @@ static void drain_all_stock(struct mem_cgroup *root_mem, bool sync)
>  				schedule_work_on(cpu, &stock->work);
>  		}
>  	}
> +	put_cpu();
>  
>  	if (!sync)
>  		goto out;
> 
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2011-08-01 12:12 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2011-08-01  6:41 [patch]mm: fix a memcg warning Shaohua Li
2011-08-01  6:37 ` KAMEZAWA Hiroyuki
2011-08-01  6:57   ` Shaohua Li
2011-08-01 12:12 ` Michal Hocko

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