From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 93C686200BD for ; Sun, 9 May 2010 16:09:06 -0400 (EDT) Date: Sun, 9 May 2010 13:06:30 -0700 (PDT) From: Linus Torvalds Subject: Re: [PATCH 2/2] mm,migration: Fix race between shift_arg_pages and rmap_walk by guaranteeing rmap_walk finds PTEs created within the temporary stack In-Reply-To: Message-ID: References: <1273188053-26029-1-git-send-email-mel@csn.ul.ie> <1273188053-26029-3-git-send-email-mel@csn.ul.ie> <20100507105712.18fc90c4.kamezawa.hiroyu@jp.fujitsu.com> <20100509192145.GI4859@csn.ul.ie> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: KAMEZAWA Hiroyuki , Andrew Morton , Linux-MM , LKML , Minchan Kim , Christoph Lameter , Andrea Arcangeli , Rik van Riel , Peter Zijlstra List-ID: On Sun, 9 May 2010, Linus Torvalds wrote: > > IOW, a patch like this (this is a pseudo-patch, totally untested, won't > compile, yadda yadda - you need to actually make the people who call > "move_page_tables()" call that prepare function first etc etc) Btw, that pseudo-patch is also likely the least efficient way to do this, since it re-walks the page directories for each pmd it creates. Also - the thing is, we can easily choose to do this _just_ for the case of shifting argument pages, which really is a special case (the generic case of "mremap()" is a lot more complicated, and doesn't have the issue with rmap because it's doing all the "new vma" setup etc). 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