From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id 9FFA4600794 for ; Mon, 3 May 2010 12:36:09 -0400 (EDT) Date: Mon, 3 May 2010 09:34:14 -0700 (PDT) From: Linus Torvalds Subject: Re: [PATCH 2/2] mm: fix race between shift_arg_pages and rmap_walk In-Reply-To: <20100503121929.260ed5ee@annuminas.surriel.com> Message-ID: References: <20100503121743.653e5ecc@annuminas.surriel.com> <20100503121929.260ed5ee@annuminas.surriel.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Rik van Riel Cc: akpm@linux-foundation.org, Mel Gorman , Linux-MM , LKML , Minchan Kim , KAMEZAWA Hiroyuki , Andrea Arcangeli , Christoph Lameter List-ID: On Mon, 3 May 2010, Rik van Riel wrote: > > migrate.c requires rmap to be able to find all ptes mapping a page at > all times, otherwise the migration entry can be instantiated, but it > can't be removed if the second rmap_walk fails to find the page. Please correct me if I'm wrong, but this patch looks like pure and utter garbage. It looks like it makes execve() do a totally insane "create and then immediately destroy temporary vma and anon_vma chain" for a case that is unlikely to ever matter. In fact, for a case that isn't even normally _enabled_, namely migration. Why would we want to slow down execve() for that? Linus -- 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