From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m4.gw.fujitsu.co.jp ([10.0.50.74]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id m9H5gpxR009192 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Fri, 17 Oct 2008 14:42:51 +0900 Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 0CF2A2AC02D for ; Fri, 17 Oct 2008 14:41:42 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id D856C12C044 for ; Fri, 17 Oct 2008 14:41:41 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 206B01DB803C for ; Fri, 17 Oct 2008 14:41:38 +0900 (JST) Received: from ml10.s.css.fujitsu.com (ml10.s.css.fujitsu.com [10.249.87.100]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 17D021DB8037 for ; Fri, 17 Oct 2008 14:41:33 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [patch][rfc] mm: have expand_stack honour VM_LOCKED In-Reply-To: <20081017050120.GA28605@wotan.suse.de> References: <20081017050120.GA28605@wotan.suse.de> Message-Id: <20081017142346.FAA6.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Fri, 17 Oct 2008 14:41:31 +0900 (JST) Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: kosaki.motohiro@jp.fujitsu.com, Hugh Dickins , Linux Memory Management List List-ID: Hi Nick, > Is this valid? > > > It appears that direct callers of expand_stack may not properly lock the newly > expanded stack if they don't call make_pages_present (page fault handlers do > this). When happend this issue? I think... case 1. explit mlock to stack 1. mlock to stack -> make_pages_present is called via mlock(2). 2. stack increased -> no page fault happened. case 2. swapout and mlock stack 1. stack swap out 2. mlock to stack -> the page doesn't swap in at the time. 3. page fault in the stack -> the page swap in (no need make_present_page()) So, it seems this patch isn't necessary. -- 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