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 SMTP id D4EB06B0055 for ; Thu, 28 May 2009 12:55:43 -0400 (EDT) Date: Thu, 28 May 2009 11:56:25 -0500 From: Russ Anderson Subject: Re: [PATCH] [13/16] HWPOISON: The high level memory error handler in the VM v3 Message-ID: <20090528165625.GA17572@sgi.com> Reply-To: Russ Anderson References: <200905271012.668777061@firstfloor.org> <20090527201239.C2C9C1D0294@basil.firstfloor.org> <20090528082616.GG6920@wotan.suse.de> <20090528093141.GD1065@one.firstfloor.org> <20090528120854.GJ6920@wotan.suse.de> <20090528134520.GH1065@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090528134520.GH1065@one.firstfloor.org> Sender: owner-linux-mm@kvack.org To: Andi Kleen Cc: Nick Piggin , hugh@veritas.com, riel@redhat.com, akpm@linux-foundation.org, chris.mason@oracle.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, fengguang.wu@intel.com, rja@sgi.com List-ID: On Thu, May 28, 2009 at 03:45:20PM +0200, Andi Kleen wrote: > On Thu, May 28, 2009 at 02:08:54PM +0200, Nick Piggin wrote: > > > > > + printk(KERN_ERR "MCE: Out of memory while machine check handling\n"); > > > > > + return; > > > > > + } > > > > > + } > > > > > + tk->addr = page_address_in_vma(p, vma); > > > > > + if (tk->addr == -EFAULT) { > > > > > + printk(KERN_INFO "MCE: Failed to get address in VMA\n"); > > > > > > > > I don't know if this is very helpful message. I could legitimately happen and > > > > nothing anybody can do about it... > > > > > > Can you suggest a better message? > > > > Well, for userspace, nothing? At the very least ratelimited, and preferably > > telling a more high level of what the problem and consequences are. > > I changed it to > > "MCE: Unable to determine user space address during error handling\n") > > Still not perfect, but hopefully better. Is it even worth having a message at all? Does the fact that page_address_in_vma() failed change the behavior in any way? (Does tk->addr == 0 matter?) From a quick scan of the code I do not believe it does. If the message is for developers/debugging, it would be nice to have more information, such as why did page_address_in_vma() return -EFAULT. If that is important, page_address_in_vma() sould return a different failure status for each of the three failing conditions. But that would only be needed if the code (potentially) was going to do some additional handling. Thanks, -- Russ Anderson, OS RAS/Partitioning Project Lead SGI - Silicon Graphics Inc rja@sgi.com -- 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