Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752740AbZI1C5m (ORCPT ); Sun, 27 Sep 2009 22:57:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752466AbZI1C5l (ORCPT ); Sun, 27 Sep 2009 22:57:41 -0400 Received: from cantor.suse.de ([195.135.220.2]:45511 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752211AbZI1C5l (ORCPT ); Sun, 27 Sep 2009 22:57:41 -0400 Date: Mon, 28 Sep 2009 04:57:41 +0200 From: Nick Piggin To: Andi Kleen Cc: Hugh Dickins , Wu Fengguang , Andrew Morton , linux-mm@kvack.org, LKML 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> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1123 Lines: 27 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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/