From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id 4D8FF6B004F for ; Wed, 3 Jun 2009 10:34:27 -0400 (EDT) Date: Tue, 2 Jun 2009 15:41:26 +0200 From: Andi Kleen Subject: Re: [PATCH] [13/16] HWPOISON: The high level memory error handler in the VM v3 Message-ID: <20090602134126.GM1065@one.firstfloor.org> References: <20090528095934.GA10678@localhost> <20090528122357.GM6920@wotan.suse.de> <20090528135428.GB16528@localhost> <20090601115046.GE5018@wotan.suse.de> <20090601183225.GS1065@one.firstfloor.org> <20090602120042.GB1392@wotan.suse.de> <20090602124757.GG1065@one.firstfloor.org> <20090602125713.GG1392@wotan.suse.de> <20090602132538.GK1065@one.firstfloor.org> <20090602132441.GC6262@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090602132441.GC6262@wotan.suse.de> Sender: owner-linux-mm@kvack.org To: Nick Piggin Cc: Andi Kleen , Wu Fengguang , "hugh@veritas.com" , "riel@redhat.com" , "akpm@linux-foundation.org" , "chris.mason@oracle.com" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" List-ID: On Tue, Jun 02, 2009 at 03:24:41PM +0200, Nick Piggin wrote: > On Tue, Jun 02, 2009 at 03:25:38PM +0200, Andi Kleen wrote: > > On Tue, Jun 02, 2009 at 02:57:13PM +0200, Nick Piggin wrote: > > > > > not a big deal and just avoids duplicating code. I attached an > > > > > (untested) patch. > > > > > > > > Thanks. But the function in the patch is not doing the same what > > > > the me_pagecache_clean/dirty are doing. For once there is no error > > > > checking, as in the second try_to_release_page() > > > > > > > > Then it doesn't do all the IO error and missing mapping handling. > > > > > > Obviously I don't mean just use that single call for the entire > > > handler. You can set the EIO bit or whatever you like. The > > > "error handling" you have there also seems strange. You could > > > retain it, but the page is assured to be removed from pagecache. > > > > The reason this code double checks is that someone could have > > a reference (remember we can come in any time) we cannot kill immediately. > > Can't kill what? The page is gone from pagecache. It may remain > other kernel references, but I don't see why this code will > consider this as a failure (and not, for example, a raised error > count). It's a failure because the page was still used and not successfully isolated. > + * remove_from_page_cache assumes (mapping && !mapped) > + */ > + if (page_mapping(p) && !page_mapped(p)) { Ok you're right. That one is not needed. I will remove it. > > > > User page tables was on the todo list, these are actually relatively > > easy. The biggest issue is to detect them. > > > > Metadata would likely need file system callbacks, which I would like to > > avoid at this point. > > So I just don't know why you argue the point that you have lots > of large holes left. I didn't argue that. My point was just that I currently don't have data what holes are the worst on given workloads. If I figure out at some point that writeback pages are a significant part of some important workload I would be interested in tackling them. That said I think that's unlikely, but I'm not ruling it out. -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