From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id A84976B009F for ; Mon, 28 Sep 2009 12:23:04 -0400 (EDT) Date: Mon, 28 Sep 2009 04:57:41 +0200 From: Nick Piggin Subject: Re: [RFC][PATCH] HWPOISON: remove the unsafe __set_page_locked() Message-ID: <20090928025741.GI6327@wotan.suse.de> References: <20090926031537.GA10176@localhost> <20090926190645.GB14368@wotan.suse.de> <20090926213204.GX30185@one.firstfloor.org> <20090927192251.GB6327@wotan.suse.de> <20090927230118.GH6327@wotan.suse.de> <20090928011943.GB1656@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090928011943.GB1656@one.firstfloor.org> Sender: owner-linux-mm@kvack.org To: Andi Kleen Cc: Hugh Dickins , Wu Fengguang , Andrew Morton , linux-mm@kvack.org, LKML List-ID: On Mon, Sep 28, 2009 at 03:19:43AM +0200, Andi Kleen wrote: > > There is no real rush AFAIKS to fix this one single pagecache site > > while we have problems with slab allocators and all other unaudited > > places that nonatomically modify page flags with an elevated > > hwpoison ignores slab pages. "ignores" them *after* it has already written to page flags? By that time it's too late. > > page reference ... just mark HWPOISON as broken for the moment, or > > cut it down to do something much simpler I guess? > > Erm no. These cases are *EXTREMLY* unlikely to hit. Well it's fundamentally badly buggy, rare or not. We could avoid lots of nasty atomic operations if we just care that it works most of the time. I guess it's a matter of perspective but I won't push for one thing or the other in hwpoison code so long as it stays out of core code for the most part. -- 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