From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx111.postini.com [74.125.245.111]) by kanga.kvack.org (Postfix) with SMTP id D89616B0044 for ; Fri, 10 Aug 2012 21:01:28 -0400 (EDT) From: Naoya Horiguchi Subject: Re: [PATCH 3/3] HWPOISON: improve handling/reporting of memory error on dirty pagecache Date: Fri, 10 Aug 2012 21:01:15 -0400 Message-Id: <1344646875-17935-1-git-send-email-n-horiguchi@ah.jp.nec.com> In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Andi Kleen Cc: Naoya Horiguchi , Andi Kleen , Wu Fengguang , Andrew Morton , Tony Luck , Rik van Riel , Jun'ichi Nomura , linux-mm@kvack.org, linux-kernel@vger.kernel.org Hello, On Fri, Aug 10, 2012 at 04:13:03PM -0700, Andi Kleen wrote: > Naoya Horiguchi writes: > > > Current error reporting of memory errors on dirty pagecache has silent > > data lost problem because AS_EIO in struct address_space is cleared > > once checked. > > Seems very complicated. I think I would prefer something simpler > if possible, especially unless it's proven the case is common. > It's hard to maintain rarely used error code when it's complicated. I'm not sure if memory error is a rare event, because I don't have any numbers about that on real systems. But assuming that hwpoison events are not rare, dirty pagecache error is not an ignorable case because dirty page ratio is typically ~10% of total physical memory in average systems. It may be small but not negligible. > Maybe try Fengguang's simple proposal first? That would fix other IO > errors too. In my understanding, Fengguang's patch (specified in this patch's description) only fixes memory error reporting. And I'm not sure that similar appoarch (like making AS_EIO sticky) really fixes the IO errors because this change can break userspace applications which expect the current behavior. Anyway, OK, I agree to start with Fengguang's one and separate out the additional suggestion about "making dirty pagecache error recoverable". And if possible, I want your feedback about the additional part of my idea. Can I ask a favor? 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