Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758067Ab3CYJNs (ORCPT ); Mon, 25 Mar 2013 05:13:48 -0400 Received: from mail-ee0-f54.google.com ([74.125.83.54]:36837 "EHLO mail-ee0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757777Ab3CYJNr (ORCPT ); Mon, 25 Mar 2013 05:13:47 -0400 Message-ID: <51501545.50908@suse.cz> Date: Mon, 25 Mar 2013 10:13:41 +0100 From: Jiri Slaby User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:19.0) Gecko/20130124 Thunderbird/19.0 MIME-Version: 1.0 To: Michal Hocko , Mel Gorman CC: Linux-MM , Valdis Kletnieks , Rik van Riel , Zlatko Calusic , Johannes Weiner , dormando , Satoru Moriya , LKML Subject: Re: [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority References: <1363525456-10448-1-git-send-email-mgorman@suse.de> <1363525456-10448-2-git-send-email-mgorman@suse.de> <20130325090758.GO2154@dhcp22.suse.cz> In-Reply-To: <20130325090758.GO2154@dhcp22.suse.cz> X-Enigmail-Version: 1.6a1pre Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1899 Lines: 39 On 03/25/2013 10:07 AM, Michal Hocko wrote: > On Sun 17-03-13 13:04:07, Mel Gorman wrote: >> The number of pages kswapd can reclaim is bound by the number of pages it >> scans which is related to the size of the zone and the scanning priority. In >> many cases the priority remains low because it's reset every SWAP_CLUSTER_MAX >> reclaimed pages but in the event kswapd scans a large number of pages it >> cannot reclaim, it will raise the priority and potentially discard a large >> percentage of the zone as sc->nr_to_reclaim is ULONG_MAX. The user-visible >> effect is a reclaim "spike" where a large percentage of memory is suddenly >> freed. It would be bad enough if this was just unused memory but because >> of how anon/file pages are balanced it is possible that applications get >> pushed to swap unnecessarily. >> >> This patch limits the number of pages kswapd will reclaim to the high >> watermark. Reclaim will will overshoot due to it not being a hard limit as >> shrink_lruvec() will ignore the sc.nr_to_reclaim at DEF_PRIORITY but it >> prevents kswapd reclaiming the world at higher priorities. The number of >> pages it reclaims is not adjusted for high-order allocations as kswapd will >> reclaim excessively if it is to balance zones for high-order allocations. >> >> Signed-off-by: Mel Gorman > > It seems I forgot to add > Reviewed-by: Michal Hocko Thanks, now I applied all ten. BTW I very pray this will fix also the issue I have when I run ltp tests (highly I/O intensive, esp. `growfiles') in a VM while playing a movie on the host resulting in a stuttered playback ;). -- js suse labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/