From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx111.postini.com [74.125.245.111]) by kanga.kvack.org (Postfix) with SMTP id C0F906B004D for ; Wed, 25 Jan 2012 05:51:48 -0500 (EST) Date: Wed, 25 Jan 2012 10:51:38 +0000 From: Mel Gorman Subject: Re: [PATCH v4 -mm] make swapin readahead skip over holes Message-ID: <20120125105138.GA3901@csn.ul.ie> References: <20120124131351.05309a2a@annuminas.surriel.com> <20120124141400.6d33b7c4@annuminas.surriel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20120124141400.6d33b7c4@annuminas.surriel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Rik van Riel Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Minchan Kim , KOSAKI Motohiro , Johannes Weiner , Adrian Drzewieki 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 Acked-by: Mel Gorman -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org