From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Schwidefsky Subject: Re: [PATCH] [11/19] HWPOISON: Refactor truncate to allow direct truncating of page v2 Date: Thu, 6 Aug 2009 13:48:30 +0200 Message-ID: <20090806134830.4f3931d2@skybase> References: <200908051136.682859934@firstfloor.org> <20090805093638.D3754B15D8@basil.firstfloor.org> <20090805102008.GB17190@wotan.suse.de> <20090805134607.GH11385@basil.fritz.box> <20090805140145.GB28563@wotan.suse.de> <20090805141001.GJ11385@basil.fritz.box> <20090805141642.GB23992@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mtagate8.de.ibm.com ([195.212.29.157]:57166 "EHLO mtagate8.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752911AbZHFLsi (ORCPT ); Thu, 6 Aug 2009 07:48:38 -0400 In-Reply-To: <20090805141642.GB23992@wotan.suse.de> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Nick Piggin Cc: Andi Kleen , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, fengguang.wu@intel.com, hidehiro.kawai.ez@hitachi.com, linux-arch@vger.kernel.org On Wed, 5 Aug 2009 16:16:42 +0200 Nick Piggin wrote: > On Wed, Aug 05, 2009 at 04:10:01PM +0200, Andi Kleen wrote: > > > I haven't brought up the caller at this point, but IIRC you had > > > the page locked and mapping confirmed at this point anyway so > > > it would never be an error for your code. > > > > > > Probably it would be nice to just force callers to verify the page. > > > Normally IMO it is much nicer and clearer to do it at the time the > > > page gets locked, unless there is good reason otherwise. > > > > Ok. I think I'll just keep it as it is for now. > > > > The only reason I added the error code was to make truncate_inode_page > > fit into .error_remove_page, but then latter I did another wrapper > > so it could be removed again. But it won't hurt to have it either. > > OK, it's more of a cleanup/nit. > > One question I had for the others (Andrew? other mm guys?) what is the > feelings of merging this feature? Leaving aside exact implementation > and just considering the high level design and cost/benefit. Last time > there were some people objecting, so I wonder the situation now? So > does anybody need more convincing? :) > > Also I will just cc linux-arch. It would be interesting to know whether > powerpc, ia64, or s390 or others would be interested to use this feature? This is not relevant for s390, as current machines do transparent memory sparing if a memory module goes bad. Really old machines reported bad memory to the OS by means of a machine check (storage error uncorrected and storage error corrected). I have never seen this happen, the level below the OS deals with these errors for us. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin.