From mboxrd@z Thu Jan 1 00:00:00 1970 From: KOSAKI Motohiro Subject: Re: [PATCH 30/30] nfs: fix various memory recursions possible with swap over NFS. Date: Fri, 25 Jul 2008 20:15:52 +0900 Message-ID: <20080725201324.86BE.KOSAKI.MOTOHIRO@jp.fujitsu.com> References: <20080725194517.86BB.KOSAKI.MOTOHIRO@jp.fujitsu.com> <1216983472.7257.365.camel@twins> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Cc: kosaki.motohiro@jp.fujitsu.com, Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, trond.myklebust@fys.uio.no, Daniel Lezcano , Pekka Enberg , Neil Brown To: Peter Zijlstra Return-path: Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:35887 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755821AbYGYLUk (ORCPT ); Fri, 25 Jul 2008 07:20:40 -0400 In-Reply-To: <1216983472.7257.365.camel@twins> Sender: netdev-owner@vger.kernel.org List-ID: > On Fri, 2008-07-25 at 19:46 +0900, KOSAKI Motohiro wrote: > > > GFP_NOFS is not enough, since swap traffic is IO, hence fall back to GFP_NOIO. > > > > this comment imply turn on GFP_NOIO, but the code is s/NOFS/NOIO/. why? > > Does the misunderstanding stem from the use of 'enough'? > > GFP_NOFS is _more_ permissive than GFP_NOIO in that it will initiate IO, > just not of any filesystem data. > > The problem is that previuosly NOFS was correct because that avoids > recursion into the NFS code, it now is not, because also IO (swap) can > lead to this recursion. Thanks nicer explain. So, I hope add above 3 line to patch description. Cheers!