From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 22 Dec 2007 23:29:32 -0800 From: Andrew Morton Subject: Re: [patch] mm: fix PageUptodate memory ordering bug Message-Id: <20071222232932.590e2b6c.akpm@linux-foundation.org> In-Reply-To: <20071223071529.GC29288@wotan.suse.de> References: <20071218012632.GA23110@wotan.suse.de> <20071222005737.2675c33b.akpm@linux-foundation.org> <20071223055730.GA29288@wotan.suse.de> <20071222223234.7f0fbd8a.akpm@linux-foundation.org> <20071223071529.GC29288@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Hugh Dickins , Linux Memory Management List , Benjamin Herrenschmidt , Linus Torvalds List-ID: On Sun, 23 Dec 2007 08:15:29 +0100 Nick Piggin wrote: > > That's just speculation. Please find out why such a small patch caused > > such a large code size increase and see if it can be fixed. > > It's not actually increasing size by that much here... hmm, do you have > CONFIG_X86_PPRO_FENCE defined, by any chance? I expect it was just allmodconfig, so: yes It's a quite repeatable experiment though. > It looks like this gets defined by default for i386, and also probably for > distro configs. Linus? This is a fairly heavy hammer for such an unlikely bug on > such a small number of systems (that admittedly doesn't even fix the bug in all > cases anyway). It's not only heavy for my proposed patch, but it also halves the > speed of spinlocks. Can we have some special config option for this instead? Sounds worthwhile, if we can't do it via altinstructions. -- 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