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From: nickpiggin@yahoo.com.au (Nick Piggin)
Subject: [ltt-dev] [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.





  reply	other threads:[~2009-02-10  5:56 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-17  0:44 [ltt-dev] [Regression] High latency when doing large I/O Mathieu Desnoyers
2009-01-17 16:26 ` [ltt-dev] [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               ` 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                     ` Mathieu Desnoyers
2009-01-21  6:17                       ` Ben Gamari
2009-01-22 22:59                   ` Mathieu Desnoyers
2009-01-23  3:21                 ` KOSAKI Motohiro
2009-01-23  4:03                   ` Mathieu Desnoyers
2009-02-10  3:36                   ` [ltt-dev] [PATCH] mm fix page writeback accounting to fix oom condition under heavy I/O Mathieu Desnoyers
2009-02-10  3:55                     ` Nick Piggin
2009-02-10  5:23                     ` Linus Torvalds
2009-02-10  5:56                       ` Nick Piggin [this message]
2009-02-10  6:12                       ` Mathieu Desnoyers
2009-02-02  2:08               ` [ltt-dev] [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             ` 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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