Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756937Ab0DOITB (ORCPT ); Thu, 15 Apr 2010 04:19:01 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:54919 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751925Ab0DOIS7 (ORCPT ); Thu, 15 Apr 2010 04:18:59 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: KOSAKI Motohiro Subject: Re: [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: <20100415131106.D174.A69D9226@jp.fujitsu.com> References: <20100415130212.D16E.A69D9226@jp.fujitsu.com> <20100415131106.D174.A69D9226@jp.fujitsu.com> Message-Id: <20100415171750.D195.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 17:18:56 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1347 Lines: 49 > 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. I've found one bug in this patch myself. flusher thread don't pageout anon pages. then, we need PageAnon() check ;) > > 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 > > > -- 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/