From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 00A6F6B004F for ; Thu, 4 Jun 2009 01:20:25 -0400 (EDT) Date: Thu, 4 Jun 2009 07:27:38 +0200 From: Andi Kleen Subject: Re: [PATCH] [10/16] HWPOISON: Handle poisoned pages in set_page_dirty() Message-ID: <20090604052738.GR1065@one.firstfloor.org> References: <20090603846.816684333@firstfloor.org> <20090603184644.190E71D0281@basil.firstfloor.org> <20090604003621.GA12210@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090604003621.GA12210@localhost> Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: Andi Kleen , "akpm@linux-foundation.org" , "npiggin@suse.de" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" List-ID: On Thu, Jun 04, 2009 at 08:36:21AM +0800, Wu Fengguang wrote: > On Thu, Jun 04, 2009 at 02:46:43AM +0800, Andi Kleen wrote: > > > > Bail out early in set_page_dirty for poisoned pages. We don't want any > > of the dirty accounting done or file system write back started, because > > the page will be just thrown away. > > I'm afraid this patch is not necessary and could be harmful. > > It is not necessary because a poisoned page will normally already be > isolated from page cache, or likely cannot be isolated because it has > dirty buffers. Hmm I think I had a case when I originally wrote the code where it was needed. But I can't clearly remember now what it was. But you're right the page cache isolation should normally take care of it. > It is harmful because it put the page into dirty state without queuing > it for IO by moving it to s_io. When more normal pages are dirtied > later, __set_page_dirty_nobuffers() won't move the inode into s_io, > hence delaying the writeback of good pages for arbitrary long time. That's a good point. I dropped the patch for now. -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