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From: "Hillf Danton" <hillf.zj@alibaba-inc.com>
To: "'Michal Hocko'" <mhocko@kernel.org>
Cc: <linux-mm@kvack.org>,
	"'Andrew Morton'" <akpm@linux-foundation.org>,
	"'Johannes Weiner'" <hannes@cmpxchg.org>,
	"'Mel Gorman'" <mgorman@suse.de>,
	"'Tetsuo Handa'" <penguin-kernel@I-love.SAKURA.ne.jp>,
	"'LKML'" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: warn about allocations which stall for too long
Date: Fri, 23 Sep 2016 16:44:26 +0800	[thread overview]
Message-ID: <007a01d21576$b12ac4a0$13804de0$@alibaba-inc.com> (raw)
In-Reply-To: <20160923083224.GF4478@dhcp22.suse.cz>

On Friday, September 23, 2016 4:32 PM, Michal Hocko wrote
> On Fri 23-09-16 16:29:36, Hillf Danton wrote:
> [...]
> > > @@ -3659,6 +3661,15 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
> > >  	else
> > >  		no_progress_loops++;
> > >
> > > +	/* Make sure we know about allocations which stall for too long */
> > > +	if (!(gfp_mask & __GFP_NOWARN) && time_after(jiffies, alloc_start + stall_timeout)) {
> > > +		pr_warn("%s: page alloction stalls for %ums: order:%u mode:%#x(%pGg)\n",
> > > +				current->comm, jiffies_to_msecs(jiffies-alloc_start),
> >
> > Better if pid is also printed.
> 
> I've tried to be consistent with warn_alloc_failed and that doesn't
> print pid either. Maybe both of them should. Dunno
> 
With pid imho we can distinguish two tasks with same name in a simpler way. 

> > > +				order, gfp_mask, &gfp_mask);
> > > +		stall_timeout += 10 * HZ;
> >
> > Alternatively	 alloc_start = jiffies;
> 
> Then we would lose the cumulative time in the output which is imho
> helpful because you cannot tell whether the new warning is a new request
> or the old one still looping.
> 
Fair.

thanks
Hillf

WARNING: multiple messages have this Message-ID (diff)
From: "Hillf Danton" <hillf.zj@alibaba-inc.com>
To: 'Michal Hocko' <mhocko@kernel.org>
Cc: linux-mm@kvack.org, 'Andrew Morton' <akpm@linux-foundation.org>,
	'Johannes Weiner' <hannes@cmpxchg.org>,
	'Mel Gorman' <mgorman@suse.de>,
	'Tetsuo Handa' <penguin-kernel@I-love.SAKURA.ne.jp>,
	'LKML' <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: warn about allocations which stall for too long
Date: Fri, 23 Sep 2016 16:44:26 +0800	[thread overview]
Message-ID: <007a01d21576$b12ac4a0$13804de0$@alibaba-inc.com> (raw)
In-Reply-To: <20160923083224.GF4478@dhcp22.suse.cz>

On Friday, September 23, 2016 4:32 PM, Michal Hocko wrote
> On Fri 23-09-16 16:29:36, Hillf Danton wrote:
> [...]
> > > @@ -3659,6 +3661,15 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
> > >  	else
> > >  		no_progress_loops++;
> > >
> > > +	/* Make sure we know about allocations which stall for too long */
> > > +	if (!(gfp_mask & __GFP_NOWARN) && time_after(jiffies, alloc_start + stall_timeout)) {
> > > +		pr_warn("%s: page alloction stalls for %ums: order:%u mode:%#x(%pGg)\n",
> > > +				current->comm, jiffies_to_msecs(jiffies-alloc_start),
> >
> > Better if pid is also printed.
> 
> I've tried to be consistent with warn_alloc_failed and that doesn't
> print pid either. Maybe both of them should. Dunno
> 
With pid imho we can distinguish two tasks with same name in a simpler way. 

> > > +				order, gfp_mask, &gfp_mask);
> > > +		stall_timeout += 10 * HZ;
> >
> > Alternatively	 alloc_start = jiffies;
> 
> Then we would lose the cumulative time in the output which is imho
> helpful because you cannot tell whether the new warning is a new request
> or the old one still looping.
> 
Fair.

thanks
Hillf

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  reply	other threads:[~2016-09-23  8:50 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-23  8:15 [PATCH] mm: warn about allocations which stall for too long Michal Hocko
2016-09-23  8:15 ` Michal Hocko
2016-09-23  8:29 ` Hillf Danton
2016-09-23  8:29   ` Hillf Danton
2016-09-23  8:32   ` Michal Hocko
2016-09-23  8:32     ` Michal Hocko
2016-09-23  8:44     ` Hillf Danton [this message]
2016-09-23  8:44       ` Hillf Danton
2016-09-23  9:15       ` Michal Hocko
2016-09-23  9:15         ` Michal Hocko
2016-09-23 14:36 ` Tetsuo Handa
2016-09-23 14:36   ` Tetsuo Handa
2016-09-23 15:02   ` Michal Hocko
2016-09-23 15:02     ` Michal Hocko
2016-09-24  3:00     ` Tetsuo Handa
2016-09-24  3:00       ` Tetsuo Handa
2016-09-26  8:17       ` Michal Hocko
2016-09-26  8:17         ` Michal Hocko
2016-09-27 12:57         ` Tetsuo Handa
2016-09-27 12:57           ` Tetsuo Handa
2016-09-29  8:48           ` Michal Hocko
2016-09-29  8:48             ` Michal Hocko
2016-09-23 17:34 ` Dave Hansen
2016-09-23 17:34   ` Dave Hansen
2016-09-24 13:19   ` Balbir Singh
2016-09-24 13:19     ` Balbir Singh
2016-09-26  8:13     ` Michal Hocko
2016-09-26  8:13       ` Michal Hocko
2016-09-26  8:12   ` Michal Hocko
2016-09-26  8:12     ` Michal Hocko
2016-09-29  8:44 ` [PATCH 0/2] " Michal Hocko
2016-09-29  8:44   ` Michal Hocko
2016-09-29  8:44   ` [PATCH 1/2] mm: consolidate warn_alloc_failed users Michal Hocko
2016-09-29  8:44     ` Michal Hocko
2016-09-29  9:23     ` Vlastimil Babka
2016-09-29  9:23       ` Vlastimil Babka
2016-09-29  8:44   ` [PATCH 2/2] mm: warn about allocations which stall for too long Michal Hocko
2016-09-29  8:44     ` Michal Hocko
2016-09-29  9:02     ` Tetsuo Handa
2016-09-29  9:02       ` Tetsuo Handa
2016-09-29  9:10       ` Michal Hocko
2016-09-29  9:10         ` Michal Hocko

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