From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 457256B0276 for ; Sun, 9 May 2010 21:44:50 -0400 (EDT) Received: from m5.gw.fujitsu.co.jp ([10.0.50.75]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o4A1il8c004861 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Mon, 10 May 2010 10:44:47 +0900 Received: from smail (m5 [127.0.0.1]) by outgoing.m5.gw.fujitsu.co.jp (Postfix) with ESMTP id 6D70845DE51 for ; Mon, 10 May 2010 10:44:47 +0900 (JST) Received: from s5.gw.fujitsu.co.jp (s5.gw.fujitsu.co.jp [10.0.50.95]) by m5.gw.fujitsu.co.jp (Postfix) with ESMTP id 4C35C45DE4F for ; Mon, 10 May 2010 10:44:47 +0900 (JST) Received: from s5.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s5.gw.fujitsu.co.jp (Postfix) with ESMTP id 368C11DB803F for ; Mon, 10 May 2010 10:44:47 +0900 (JST) Received: from m108.s.css.fujitsu.com (m108.s.css.fujitsu.com [10.249.87.108]) by s5.gw.fujitsu.co.jp (Postfix) with ESMTP id E76981DB8038 for ; Mon, 10 May 2010 10:44:46 +0900 (JST) Date: Mon, 10 May 2010 10:40:39 +0900 From: KAMEZAWA Hiroyuki 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 Message-Id: <20100510104039.98332e67.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: 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> <20100510094050.8cb79143.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Linus Torvalds Cc: Mel Gorman , Andrew Morton , Linux-MM , LKML , Minchan Kim , Christoph Lameter , Andrea Arcangeli , Rik van Riel , Peter Zijlstra List-ID: On Sun, 9 May 2010 18:32:32 -0700 (PDT) Linus Torvalds wrote: > > > On Sun, 9 May 2010, Linus Torvalds wrote: > > > > So I never disliked that patch. I'm perfectly happy with a "don't migrate > > these pages at all, because they are in a half-way state in the middle of > > execve stack magic". > > Btw, I also think that Mel's patch could be made a lot _less_ magic by > just marking that initial stack vma with a VM_STACK_INCOMPLETE_SETUP bit, > instead of doing that "maybe_stack" thing. We could easily make that > initial vma setup very explicit indeed, and then just clear that bit when > we've moved the stack to its final position. > Hmm. vm_flags is still 32bit..(I think it should be long long) Using combination of existing flags... #define VM_STACK_INCOMPLETE_SETUP (VM_RAND_READ | VM_SEC_READ) Can be used instead of checking mapcount, I think. Thanks, -Kame -- 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