From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752883Ab0DOELm (ORCPT ); Thu, 15 Apr 2010 00:11:42 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:39863 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751872Ab0DOELl (ORCPT ); Thu, 15 Apr 2010 00:11:41 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: KOSAKI Motohiro Subject: [PATCH 1/4] vmscan: delegate pageout io to flusher thread if current is kswapd Cc: kosaki.motohiro@jp.fujitsu.com, Dave Chinner , Mel Gorman , Chris Mason , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org In-Reply-To: <20100415130212.D16E.A69D9226@jp.fujitsu.com> References: <20100415013436.GO2493@dastard> <20100415130212.D16E.A69D9226@jp.fujitsu.com> Message-Id: <20100415131106.D174.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Thu, 15 Apr 2010 13:11:37 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Now, vmscan pageout() is one of IO throuput degression source. Some IO workload makes very much order-0 allocation and reclaim and pageout's 4K IOs are making annoying lots seeks. At least, kswapd can avoid such pageout() because kswapd don't need to consider OOM-Killer situation. that's no risk. Signed-off-by: KOSAKI Motohiro --- mm/vmscan.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 3ff3311..d392a50 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -614,6 +614,13 @@ static enum page_references page_check_references(struct page *page, if (referenced_page) return PAGEREF_RECLAIM_CLEAN; + /* + * Delegate pageout IO to flusher thread. They can make more + * effective IO pattern. + */ + if (current_is_kswapd()) + return PAGEREF_RECLAIM_CLEAN; + return PAGEREF_RECLAIM; } -- 1.6.5.2