From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id E50C66B004A for ; Mon, 29 Nov 2010 02:29:59 -0500 (EST) Date: Mon, 29 Nov 2010 15:29:51 +0800 From: Wu Fengguang Subject: Re: [PATCH v2 2/3] move ClearPageReclaim Message-ID: <20101129072951.GA22803@localhost> References: <7b50614882592047dfd96f6ca2bb2d0baa8f5367.1290956059.git.minchan.kim@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: Andrew Morton , linux-mm , LKML , Ben Gamari , Rik van Riel , KOSAKI Motohiro , Johannes Weiner , Nick Piggin , Mel Gorman List-ID: On Sun, Nov 28, 2010 at 11:02:56PM +0800, Minchan Kim wrote: > 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. > This patch needs Wu's opinion. It's a safe change. The possibility and consequence of races are both small enough. However the patch could be simplified as follows? Thanks, Fengguang --- --- linux-next.orig/mm/page-writeback.c 2010-11-29 15:14:54.000000000 +0800 +++ linux-next/mm/page-writeback.c 2010-11-29 15:15:02.000000000 +0800 @@ -1330,6 +1330,7 @@ int set_page_dirty(struct page *page) { struct address_space *mapping = page_mapping(page); + ClearPageReclaim(page); if (likely(mapping)) { int (*spd)(struct page *) = mapping->a_ops->set_page_dirty; #ifdef CONFIG_BLOCK @@ -1387,7 +1388,6 @@ int clear_page_dirty_for_io(struct page BUG_ON(!PageLocked(page)); - ClearPageReclaim(page); if (mapping && mapping_cap_account_dirty(mapping)) { /* * Yes, Virginia, this is indeed insane. -- 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