From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id A3BA98D0030 for ; Mon, 1 Nov 2010 03:06:49 -0400 (EDT) Date: Mon, 1 Nov 2010 16:06:12 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH 1/2] mm: page allocator: Adjust the per-cpu counter threshold when memory is low In-Reply-To: <1288169256-7174-2-git-send-email-mel@csn.ul.ie> References: <1288169256-7174-1-git-send-email-mel@csn.ul.ie> <1288169256-7174-2-git-send-email-mel@csn.ul.ie> Message-Id: <20101101023957.606E.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton , Shaohua Li , Christoph Lameter , David Rientjes , KAMEZAWA Hiroyuki , LKML , Linux-MM List-ID: > To ensure that kswapd wakes up, a safe version of zone_watermark_ok() > is introduced that takes a more accurate reading of NR_FREE_PAGES when > called from wakeup_kswapd, when deciding whether it is really safe to go > back to sleep in sleeping_prematurely() and when deciding if a zone is > really balanced or not in balance_pgdat(). We are still using an expensive > function but limiting how often it is called. > > When the test case is reproduced, the time spent in the watermark functions > is reduced. The following report is on the percentage of time spent > cumulatively spent in the functions zone_nr_free_pages(), zone_watermark_ok(), > __zone_watermark_ok(), zone_watermark_ok_safe(), zone_page_state_snapshot(), > zone_page_state(). > > vanilla 11.6615% > disable-threshold 0.2584% > > Reported-by: Shaohua Li > Signed-off-by: Mel Gorman Except kamezawa-san pointed piece Reviewed-by: KOSAKI Motohiro -- 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 policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org