Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756028Ab0K3BK0 (ORCPT ); Mon, 29 Nov 2010 20:10:26 -0500 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:58968 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755812Ab0K3BKZ (ORCPT ); Mon, 29 Nov 2010 20:10:25 -0500 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Minchan Kim Subject: Re: [PATCH 2/3] Reclaim invalidated page ASAP Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton , linux-mm , LKML , Ben Gamari , Wu Fengguang , Johannes Weiner , Nick Piggin , Mel Gorman In-Reply-To: <053e6a3308160a8992af5a47fb4163796d033b08.1291043274.git.minchan.kim@gmail.com> References: <053e6a3308160a8992af5a47fb4163796d033b08.1291043274.git.minchan.kim@gmail.com> Message-Id: <20101130100933.82E9.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Tue, 30 Nov 2010 10:10:20 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1741 Lines: 41 > invalidate_mapping_pages is very big hint to reclaimer. > It means user doesn't want to use the page any more. > So in order to prevent working set page eviction, this patch > move the page into tail of inactive list by PG_reclaim. > > Please, remember that pages in inactive list are working set > as well as active list. If we don't move pages into inactive list's > tail, pages near by tail of inactive list can be evicted although > we have a big clue about useless pages. It's totally bad. > > Now PG_readahead/PG_reclaim is shared. > fe3cba17 added ClearPageReclaim into clear_page_dirty_for_io for > preventing fast reclaiming readahead marker page. > > In this series, PG_reclaim is used by invalidated page, too. > If VM find the page is invalidated and it's dirty, it sets PG_reclaim > to reclaim asap. Then, when the dirty page will be writeback, > clear_page_dirty_for_io will clear PG_reclaim unconditionally. > It disturbs this serie's goal. > > I think it's okay to clear PG_readahead when the page is dirty, not > writeback time. So this patch moves ClearPageReadahead. > > Signed-off-by: Minchan Kim > Acked-by: Rik van Riel > Cc: Wu Fengguang > Cc: KOSAKI Motohiro > Cc: Johannes Weiner > Cc: Nick Piggin > Cc: Mel Gorman I still dislike this one. I doubt this trick makes much benefit in real world workload. -- 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/