From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 975196B003D for ; Wed, 29 Apr 2009 07:28:31 -0400 (EDT) Subject: Re: [PATCH] [13/16] POISON: The high level memory error handler in the VM II From: Chris Mason In-Reply-To: <20090429090501.GB15488@localhost> References: <20090407509.382219156@firstfloor.org> <20090407151010.E72A91D0471@basil.firstfloor.org> <1239210239.28688.15.camel@think.oraclecorp.com> <20090409072949.GF14687@one.firstfloor.org> <20090409075805.GG14687@one.firstfloor.org> <1239283829.23150.34.camel@think.oraclecorp.com> <20090409140257.GI14687@one.firstfloor.org> <1239287859.23150.57.camel@think.oraclecorp.com> <20090429081616.GA8339@localhost> <20090429083655.GA23223@one.firstfloor.org> <20090429090501.GB15488@localhost> Content-Type: text/plain Date: Wed, 29 Apr 2009 07:27:36 -0400 Message-Id: <1241004456.15136.91.camel@think.oraclecorp.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: Andi Kleen , "hugh@veritas.com" , "npiggin@suse.de" , "riel@redhat.com" , "lee.schermerhorn@hp.com" , "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "x86@kernel.org" List-ID: On Wed, 2009-04-29 at 17:05 +0800, Wu Fengguang wrote: > On Wed, Apr 29, 2009 at 04:36:55PM +0800, Andi Kleen wrote: > > > > I'll have to read harder next week, the FS invalidatepage may expect > > > > truncate to be the only caller. > > > > > > If direct de-dirty is hard for some pages, how about just ignore them? > > > > You mean just ignoring it for the pages where it is hard? > > Yes. > > > Yes that is what it is essentially doing right now. But at least > > some dirty pages need to be handled because most user space > > pages tend to be dirty. > > Sure. There are three types of dirty pages: > > A. now dirty, can be de-dirty in the current code > B. now dirty, cannot be de-dirty > C. now dirty and writeback, cannot be de-dirty > > I mean B and C can be handled in one single place - the block layer. > > If B is hard to be de-dirtied now, ignore them for now and they will > eventually be going to IO and become C. > > > > There are the PG_writeback pages anyway. We can inject code to > > > intercept them at the last stage of IO request dispatching. > > > > That would require adding error out code through all the file systems, > > right? > > Not necessarily. The file systems deal with buffer head, extend map > and bios, they normally won't touch the poisoned page content at all. > They often do when zeroing parts of the page that straddle i_size. At least for btrfs its enough to change grab_cache_page and find_get_page (and friends) to do the poison magic, along with the functions uses by write_cache_pages. -chris -- 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/ . Don't email: email@kvack.org