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From: Mel Gorman <mel@csn.ul.ie>
To: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Minchan Kim <minchan.kim@gmail.com>,
	KOSAKI Motohiro <kosaki.motohiro@gmail.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Adrian Drzewieki <z@drze.net>
Subject: Re: [PATCH v4 -mm] make swapin readahead skip over holes
Date: Wed, 25 Jan 2012 10:51:38 +0000	[thread overview]
Message-ID: <20120125105138.GA3901@csn.ul.ie> (raw)
In-Reply-To: <20120124141400.6d33b7c4@annuminas.surriel.com>

On Tue, Jan 24, 2012 at 02:14:00PM -0500, Rik van Riel wrote:
> Ever since abandoning the virtual scan of processes, for scalability
> reasons, swap space has been a little more fragmented than before.
> This can lead to the situation where a large memory user is killed,
> swap space ends up full of "holes" and swapin readahead is totally
> ineffective.
> 
> On my home system, after killing a leaky firefox it took over an
> hour to page just under 2GB of memory back in, slowing the virtual
> machines down to a crawl.
> 
> This patch makes swapin readahead simply skip over holes, instead
> of stopping at them.  This allows the system to swap things back in
> at rates of several MB/second, instead of a few hundred kB/second.
> 
> The checks done in valid_swaphandles are already done in 
> read_swap_cache_async as well, allowing us to remove a fair amount
> of code.
> 
> Signed-off-by: Rik van Riel <riel@redhat.com>

Acked-by: Mel Gorman <mgorman@suse.de>

-- 
Mel Gorman
SUSE Labs

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  parent reply	other threads:[~2012-01-25 10:51 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-24 18:13 [PATCH v3 " Rik van Riel
2012-01-24 19:14 ` [PATCH v4 " Rik van Riel
2012-01-25 10:31   ` Johannes Weiner
2012-01-25 10:51   ` Mel Gorman [this message]
2012-01-26  1:23   ` Andrew Morton
2012-01-26  1:26     ` Rik van Riel
2012-01-26  1:30       ` Andrew Morton

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