From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 283EB6B0248 for ; Mon, 10 May 2010 15:06:38 -0400 (EDT) Date: Mon, 10 May 2010 21:05:59 +0200 From: Andrea Arcangeli Subject: Re: [PATCH 2/2] mm,migration: Avoid race between shift_arg_pages() and rmap_walk() during migration by not migrating temporary stacks Message-ID: <20100510190559.GD22632@random.random> References: <1272529930-29505-1-git-send-email-mel@csn.ul.ie> <1272529930-29505-3-git-send-email-mel@csn.ul.ie> <20100504094522.GA20979@csn.ul.ie> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org To: Christoph Lameter Cc: Mel Gorman , Andrew Morton , Linux-MM , LKML , Minchan Kim , KAMEZAWA Hiroyuki , Rik van Riel List-ID: On Mon, May 10, 2010 at 12:41:07PM -0500, Christoph Lameter wrote: > A simple way to disallow migration of pages is to increment the refcount > of a page. Ok for migrate but it won't prevent to crash in split_huge_page rmap walk, nor the PG_lock. Why for a rmap bug have a migrate specific fix? The fix that makes execve the only special place to handle in every rmap walk, is at least more maintainable than a fix that makes one of the rmap walk users special and won't fix the others, as there will be more than just 1 user that requires this. My fix didn't make execve special and it didn't require execve knowledge into the every rmap walk like migrate (split_huge_page etc...) but as long as the kernel doesn't crash I'm fine ;). -- 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