Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753824Ab0KAHHI (ORCPT ); Mon, 1 Nov 2010 03:07:08 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:36231 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753539Ab0KAHHF (ORCPT ); Mon, 1 Nov 2010 03:07:05 -0400 Date: Mon, 1 Nov 2010 16:06:12 +0900 (JST) X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Mel Gorman Subject: Re: [PATCH 1/2] mm: page allocator: Adjust the per-cpu counter threshold when memory is low Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton , Shaohua Li , Christoph Lameter , David Rientjes , KAMEZAWA Hiroyuki , LKML , Linux-MM 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 X-Mailer: Becky! ver. 2.50.07 [ja] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1273 Lines: 29 > 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 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/