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From: Peter Zijlstra <peterz@infradead.org>
To: Nikanth Karthikesan <knikanth@suse.de>
Cc: Wu Fengguang <fengguang.wu@intel.com>,
	Bill Davidsen <davidsen@tmr.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Jens Axboe <axboe@kernel.dk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jan Kara <jack@suse.cz>
Subject: Re: [RFC][PATCH] Per file dirty limit throttling
Date: Tue, 17 Aug 2010 10:24:35 +0200	[thread overview]
Message-ID: <1282033475.1926.2093.camel@laptop> (raw)
In-Reply-To: <201008171039.23701.knikanth@suse.de>

On Tue, 2010-08-17 at 10:39 +0530, Nikanth Karthikesan wrote:
> Oh, nice.  Per-task limit is an elegant solution, which should help during 
> most of the common cases.
> 
> But I just wonder what happens, when
> 1. The dirtier is multiple co-operating processes
> 2. Some app like a shell script, that repeatedly calls dd with seek and skip? 
> People do this for data deduplication, sparse skipping etc..
> 3. The app dies and comes back again. Like a VM that is rebooted, and 
> continues writing to a disk backed by a file on the host.
> 
> Do you think, in those cases this might still be useful? 

Those cases do indeed defeat the current per-task-limit, however I think
the solution to that is to limit the amount of writeback done by each
blocked process.

Jan Kara had some good ideas in that department.

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  reply	other threads:[~2010-08-17  8:25 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-16  4:19 [RFC][PATCH] Per file dirty limit throttling Nikanth Karthikesan
2010-08-16 11:05 ` Peter Zijlstra
2010-08-17  5:09   ` Nikanth Karthikesan
2010-08-17  8:24     ` Peter Zijlstra [this message]
2010-08-18  9:22       ` Nikanth Karthikesan
2010-08-18  9:58         ` Peter Zijlstra
2010-08-18 14:08           ` Balbir Singh
2010-08-18 14:25             ` Peter Zijlstra
2010-08-18 14:48               ` Balbir Singh
2010-08-23 12:19           ` Nikanth Karthikesan
2010-08-16 16:53 ` Bill Davidsen
2010-08-17  2:53   ` Wu Fengguang
2010-08-17  2:41 ` Wu Fengguang

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