From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx150.postini.com [74.125.245.150]) by kanga.kvack.org (Postfix) with SMTP id 7A0606B0006 for ; Thu, 11 Apr 2013 22:45:25 -0400 (EDT) Message-ID: <5167752C.6010703@redhat.com> Date: Thu, 11 Apr 2013 22:45:00 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 03/10] mm: vmscan: Flatten kswapd priority loop References: <1365505625-9460-1-git-send-email-mgorman@suse.de> <1365505625-9460-4-git-send-email-mgorman@suse.de> In-Reply-To: <1365505625-9460-4-git-send-email-mgorman@suse.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Andrew Morton , Jiri Slaby , Valdis Kletnieks , Zlatko Calusic , Johannes Weiner , dormando , Satoru Moriya , Michal Hocko , Linux-MM , LKML On 04/09/2013 07:06 AM, Mel Gorman wrote: > kswapd stops raising the scanning priority when at least SWAP_CLUSTER_MAX > pages have been reclaimed or the pgdat is considered balanced. It then > rechecks if it needs to restart at DEF_PRIORITY and whether high-order > reclaim needs to be reset. This is not wrong per-se but it is confusing > to follow and forcing kswapd to stay at DEF_PRIORITY may require several > restarts before it has scanned enough pages to meet the high watermark even > at 100% efficiency. This patch irons out the logic a bit by controlling > when priority is raised and removing the "goto loop_again". > > This patch has kswapd raise the scanning priority until it is scanning > enough pages that it could meet the high watermark in one shrink of the > LRU lists if it is able to reclaim at 100% efficiency. It will not raise > the scanning prioirty higher unless it is failing to reclaim any pages. > > To avoid infinite looping for high-order allocation requests kswapd will > not reclaim for high-order allocations when it has reclaimed at least > twice the number of pages as the allocation request. > > Signed-off-by: Mel Gorman Reviewed-by: Rik van Riel It looks like this patch could lead to near-infinite reclaiming when higher-order reclaim is being done, but patch 4/10 should fix that... -- All rights reversed -- 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/ . Don't email: email@kvack.org