From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m1.gw.fujitsu.co.jp ([10.0.50.71]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id m9H9W9Cm026407 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Fri, 17 Oct 2008 18:32:09 +0900 Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 724BC240047 for ; Fri, 17 Oct 2008 18:32:09 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 49A872DC078 for ; Fri, 17 Oct 2008 18:32:09 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 15A691DB8046 for ; Fri, 17 Oct 2008 18:32:09 +0900 (JST) Received: from m105.s.css.fujitsu.com (m105.s.css.fujitsu.com [10.249.87.105]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id C5EA61DB803E for ; Fri, 17 Oct 2008 18:32:08 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [patch][rfc] mm: have expand_stack honour VM_LOCKED In-Reply-To: <20081017090813.GA32554@wotan.suse.de> References: <20081017142346.FAA6.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20081017090813.GA32554@wotan.suse.de> Message-Id: <20081017182737.E23C.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 18:32:07 +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. > > What if you you page fault the stack further than a single page down? > I see. thanks. But unfortunately, this patch conflicted against unevictable patch series. I'll make for -mm version patch few days after if you don't like do that. -- 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