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 ESMTP id E62A76B004F for ; Wed, 12 Aug 2009 06:16:55 -0400 (EDT) Date: Wed, 12 Aug 2009 12:16:58 +0200 From: Andi Kleen Subject: Re: [PATCH] [16/19] HWPOISON: Enable .remove_error_page for migration aware file systems Message-ID: <20090812101658.GF28848@basil.fritz.box> References: <200908051136.682859934@firstfloor.org> <20090805093643.E0C00B15D8@basil.firstfloor.org> <4A7FBFD1.2010208@hitachi.com> <20090810074421.GA6838@basil.fritz.box> <4A80EAA3.7040107@hitachi.com> <20090811071756.GC14368@basil.fritz.box> <4A822DD4.1050202@hitachi.com> <20090812074611.GC28848@basil.fritz.box> <4A8290CE.7000904@hitachi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A8290CE.7000904@hitachi.com> Sender: owner-linux-mm@kvack.org To: Hidehiro Kawai Cc: Andi Kleen , tytso@mit.edu, hch@infradead.org, mfasheh@suse.com, aia21@cantab.net, hugh.dickins@tiscali.co.uk, swhiteho@redhat.com, akpm@linux-foundation.org, npiggin@suse.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org, fengguang.wu@intel.com, Satoshi OSHIMA , Taketoshi Sakuraba List-ID: On Wed, Aug 12, 2009 at 06:52:14PM +0900, Hidehiro Kawai wrote: > Andi Kleen wrote: > > >>Generally, dropping unwritten dirty page caches is considered to be > >>risky. So the "panic on IO error" policy has been used as usual > >>practice for some systems. I just suggested that we adopted > >>this policy into machine check errors. > > > > Hmm, what we could possibly do -- as followon patches -- would be to > > let error_remove_page check the per file system panic-on-io-error > > super block setting for dirty pages and panic in this case too. > > Unfortunately this setting is currently per file system, not generic, > > so it would need to be a fs specific check (or the flag would need > > to be moved into a generic fs superblock field first) > > A generic setting would be better, so I suggested > panic_on_dirty_page_cache_corruption flag which would be checked > before invoking error_remove_page(). If we check per-filesystem > settings, we might want to notify EIO to the filesystem. You mean remounting ro if that is set? That makes sense, but I'm not sure how complicated it would be. I still would prefer to unify it with the file system settings. > > The problem is memory_failure() would then need to start distingushing > > between AR=1 and AR=0 which it doesn't today. > > > > It could be done, but would need some more work. > > It's my understanding that memory_failure() are never called in > AR=1 case. Is it wrong? Today yes, but we don't want to hardcode that assumption. e.g. for IA64 they will definitely need the equivalent of AR=1 handling. -Andi -- ak@linux.intel.com -- Speaking for myself only. -- 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