From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Jens Axboe <jens.axboe@oracle.com>,
akpm@linux-foundation.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Ingo Molnar <mingo@elte.hu>,
thomas.pi@arcor.dea, Yuriy Lalym <ylalym@gmail.com>,
ltt-dev@lists.casi.polymtl.ca, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH] mm fix page writeback accounting to fix oom condition under heavy I/O
Date: Tue, 10 Feb 2009 16:56:13 +1100 [thread overview]
Message-ID: <200902101656.13792.nickpiggin@yahoo.com.au> (raw)
In-Reply-To: <alpine.LFD.2.00.0902092120450.3048@localhost.localdomain>
On Tuesday 10 February 2009 16:23:56 Linus Torvalds wrote:
> On Mon, 9 Feb 2009, Mathieu Desnoyers wrote:
> > So this patch fixes this behavior by only decrementing the page
> > accounting _after_ the block I/O writepage has been done.
>
> This makes no sense, really.
>
> Or rather, I don't mind the notion of updating the counters only after IO
> per se, and _that_ part of it probably makes sense. But why is it that you
> only then fix up two of the call-sites. There's a lot more call-sites than
> that for this function.
Well if you do that, then I'd think you also have to change some
calculations that today use dirty+writeback.
In some ways it does make sense, but OTOH it is natural in the
pagecache since it was introduced to treat writeback as basically
equivalent to dirty. So writeback && !dirty pages shouldn't cause
things to blow up, or if it does then hopefully it is a simple
bug somewhere.
WARNING: multiple messages have this Message-ID (diff)
From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Jens Axboe <jens.axboe@oracle.com>,
akpm@linux-foundation.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Ingo Molnar <mingo@elte.hu>,
thomas.pi@arcor.dea, Yuriy Lalym <ylalym@gmail.com>,
ltt-dev@lists.casi.polymtl.ca, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH] mm fix page writeback accounting to fix oom condition under heavy I/O
Date: Tue, 10 Feb 2009 16:56:13 +1100 [thread overview]
Message-ID: <200902101656.13792.nickpiggin@yahoo.com.au> (raw)
In-Reply-To: <alpine.LFD.2.00.0902092120450.3048@localhost.localdomain>
On Tuesday 10 February 2009 16:23:56 Linus Torvalds wrote:
> On Mon, 9 Feb 2009, Mathieu Desnoyers wrote:
> > So this patch fixes this behavior by only decrementing the page
> > accounting _after_ the block I/O writepage has been done.
>
> This makes no sense, really.
>
> Or rather, I don't mind the notion of updating the counters only after IO
> per se, and _that_ part of it probably makes sense. But why is it that you
> only then fix up two of the call-sites. There's a lot more call-sites than
> that for this function.
Well if you do that, then I'd think you also have to change some
calculations that today use dirty+writeback.
In some ways it does make sense, but OTOH it is natural in the
pagecache since it was introduced to treat writeback as basically
equivalent to dirty. So writeback && !dirty pages shouldn't cause
things to blow up, or if it does then hopefully it is a simple
bug somewhere.
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next prev parent reply other threads:[~2009-02-10 5:56 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-17 0:44 [Regression] High latency when doing large I/O Mathieu Desnoyers
2009-01-17 16:26 ` [RFC PATCH] block: Fix bio merge induced high I/O latency Mathieu Desnoyers
2009-01-17 16:50 ` Leon Woestenberg
2009-01-17 17:15 ` Mathieu Desnoyers
2009-01-17 19:04 ` Jens Axboe
2009-01-18 21:12 ` Mathieu Desnoyers
2009-01-18 21:27 ` Mathieu Desnoyers
2009-01-19 18:26 ` Jens Axboe
2009-01-20 2:10 ` Mathieu Desnoyers
2009-01-20 7:37 ` Jens Axboe
2009-01-20 12:28 ` Jens Axboe
2009-01-20 14:22 ` [ltt-dev] " Mathieu Desnoyers
2009-01-20 14:24 ` Jens Axboe
2009-01-20 15:42 ` Mathieu Desnoyers
2009-01-20 23:06 ` Mathieu Desnoyers
2009-01-20 23:27 ` Mathieu Desnoyers
2009-01-21 0:25 ` Mathieu Desnoyers
2009-01-21 4:38 ` Ben Gamari
2009-01-21 4:54 ` [ltt-dev] " Mathieu Desnoyers
2009-01-21 6:17 ` Ben Gamari
2009-01-22 22:59 ` Mathieu Desnoyers
2009-01-23 3:21 ` [ltt-dev] " KOSAKI Motohiro
2009-01-23 4:03 ` Mathieu Desnoyers
2009-02-10 3:36 ` [PATCH] mm fix page writeback accounting to fix oom condition under heavy I/O Mathieu Desnoyers
2009-02-10 3:36 ` Mathieu Desnoyers
2009-02-10 3:55 ` Nick Piggin
2009-02-10 3:55 ` Nick Piggin
2009-02-10 5:23 ` Linus Torvalds
2009-02-10 5:23 ` Linus Torvalds
2009-02-10 5:56 ` Nick Piggin [this message]
2009-02-10 5:56 ` Nick Piggin
2009-02-10 6:12 ` Mathieu Desnoyers
2009-02-10 6:12 ` Mathieu Desnoyers
2009-02-02 2:08 ` [RFC PATCH] block: Fix bio merge induced high I/O latency Mathieu Desnoyers
2009-02-02 11:26 ` Jens Axboe
2009-02-03 0:46 ` Mathieu Desnoyers
2009-01-20 13:45 ` [ltt-dev] " Mathieu Desnoyers
2009-01-20 20:22 ` Ben Gamari
2009-01-20 22:23 ` Ben Gamari
2009-01-20 23:05 ` Mathieu Desnoyers
2009-01-22 2:35 ` Ben Gamari
2009-01-19 15:45 ` Nikanth K
2009-01-19 18:23 ` Jens Axboe
2009-01-17 20:03 ` Ben Gamari
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