From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id 417AD6B004A for ; Mon, 29 Nov 2010 03:16:03 -0500 (EST) Received: by iwn9 with SMTP id 9so707011iwn.14 for ; Mon, 29 Nov 2010 00:16:01 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20101129072951.GA22803@localhost> References: <7b50614882592047dfd96f6ca2bb2d0baa8f5367.1290956059.git.minchan.kim@gmail.com> <20101129072951.GA22803@localhost> Date: Mon, 29 Nov 2010 17:16:01 +0900 Message-ID: Subject: Re: [PATCH v2 2/3] move ClearPageReclaim From: Minchan Kim Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: Andrew Morton , linux-mm , LKML , Ben Gamari , Rik van Riel , KOSAKI Motohiro , Johannes Weiner , Nick Piggin , Mel Gorman List-ID: On Mon, Nov 29, 2010 at 4:29 PM, Wu Fengguang wrot= e: > 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? If all of file systems use it, I don't mind it. Do all of filesystems use it when the page is dirtied? I was not sure it.(It's why I added Cc. :) If it doesn't have a problem, I hope so. Thanks, Wu. > > Thanks, > Fengguang > --- > > --- linux-next.orig/mm/page-writeback.c 2010-11-29 15:14:54.000000000 +08= 00 > +++ linux-next/mm/page-writeback.c =A0 =A0 =A02010-11-29 15:15:02.0000000= 00 +0800 > @@ -1330,6 +1330,7 @@ int set_page_dirty(struct page *page) > =A0{ > =A0 =A0 =A0 =A0struct address_space *mapping =3D page_mapping(page); > > + =A0 =A0 =A0 ClearPageReclaim(page); > =A0 =A0 =A0 =A0if (likely(mapping)) { > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0int (*spd)(struct page *) =3D mapping->a_o= ps->set_page_dirty; > =A0#ifdef CONFIG_BLOCK > @@ -1387,7 +1388,6 @@ int clear_page_dirty_for_io(struct page > > =A0 =A0 =A0 =A0BUG_ON(!PageLocked(page)); > > - =A0 =A0 =A0 ClearPageReclaim(page); > =A0 =A0 =A0 =A0if (mapping && mapping_cap_account_dirty(mapping)) { > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0/* > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 * Yes, Virginia, this is indeed insane. > --=20 Kind regards, Minchan Kim -- 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