From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx160.postini.com [74.125.245.160]) by kanga.kvack.org (Postfix) with SMTP id BD1556B003B for ; Wed, 17 Apr 2013 02:43:03 -0400 (EDT) Received: by mail-ia0-f182.google.com with SMTP id u20so1131796iag.41 for ; Tue, 16 Apr 2013 23:43:03 -0700 (PDT) Message-ID: <516E446B.5060006@gmail.com> Date: Wed, 17 Apr 2013 14:42:51 +0800 From: Simon Jeons MIME-Version: 1.0 Subject: Re: [RFC Patch 0/2] mm: Add parameters to make kernel behavior at memory error on dirty cache selectable References: <51662D5B.3050001@hitachi.com> <20130411134915.GH16732@two.firstfloor.org> <1365693788-djsd2ymu-mutt-n-horiguchi@ah.jp.nec.com> In-Reply-To: <1365693788-djsd2ymu-mutt-n-horiguchi@ah.jp.nec.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Naoya Horiguchi Cc: Andi Kleen , Mitsuhiro Tanino , linux-kernel , linux-mm Hi Naoya, On 04/11/2013 11:23 PM, Naoya Horiguchi wrote: > On Thu, Apr 11, 2013 at 03:49:16PM +0200, Andi Kleen wrote: >>> As a result, if the dirty cache includes user data, the data is lost, >>> and data corruption occurs if an application uses old data. >> The application cannot use old data, the kernel code kills it if it >> would do that. And if it's IO data there is an EIO triggered. >> >> iirc the only concern in the past was that the application may miss >> the asynchronous EIO because it's cleared on any fd access. >> >> This is a general problem not specific to memory error handling, >> as these asynchronous IO errors can happen due to other reason >> (bad disk etc.) >> >> If you're really concerned about this case I think the solution >> is to make the EIO more sticky so that there is a higher chance >> than it gets returned. This will make your data much more safe, >> as it will cover all kinds of IO errors, not just the obscure memory >> errors. > I'm interested in this topic, and in previous discussion, what I was said > is that we can't expect user applications to change their behaviors when > they get EIO, so globally changing EIO's stickiness is not a great approach. The user applications will get EIO firstly or get SIG_KILL firstly? > I'm working on a new pagecache tag based mechanism to solve this. > But it needs time and more discussions. > So I guess Tanino-san suggests giving up on dirty pagecache errors > as a quick solution. > > Thanks, > Naoya > > -- > 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 -- 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