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 CB1E86B004D for ; Wed, 18 Nov 2009 00:55:57 -0500 (EST) Received: from m6.gw.fujitsu.co.jp ([10.0.50.76]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id nAI5ttSk029170 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Wed, 18 Nov 2009 14:55:55 +0900 Received: from smail (m6 [127.0.0.1]) by outgoing.m6.gw.fujitsu.co.jp (Postfix) with ESMTP id 89B0B45DE4E for ; Wed, 18 Nov 2009 14:55:55 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (s6.gw.fujitsu.co.jp [10.0.50.96]) by m6.gw.fujitsu.co.jp (Postfix) with ESMTP id 6E2B145DE4C for ; Wed, 18 Nov 2009 14:55:55 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id 577791DB8037 for ; Wed, 18 Nov 2009 14:55:55 +0900 (JST) Received: from ml13.s.css.fujitsu.com (ml13.s.css.fujitsu.com [10.249.87.103]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id 079B71DB8042 for ; Wed, 18 Nov 2009 14:55:52 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH 0/7] Kill PF_MEMALLOC abuse In-Reply-To: <1258491379.3918.48.camel@laptop> References: <20091117172802.3DF4.A69D9226@jp.fujitsu.com> <1258491379.3918.48.camel@laptop> Message-Id: <20091118144418.3E17.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Date: Wed, 18 Nov 2009 14:55:51 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Peter Zijlstra Cc: kosaki.motohiro@jp.fujitsu.com, David Rientjes , linux-mm , LKML , Andrew Morton List-ID: > On Tue, 2009-11-17 at 17:33 +0900, KOSAKI Motohiro wrote: > > > > if there is so such reason. we might need to implement another MM trick. > > but keeping this strage usage is not a option. All memory freeing activity > > (e.g. page out, task killing) need some memory. we need to protect its > > emergency memory. otherwise linux reliability decrease dramatically when > > the system face to memory stress. > > In general PF_MEMALLOC is a particularly bad idea, even for the VM when > not coupled with limiting the consumption. That is one should make an > upper-bound estimation of the memory needed for a writeout-path per > page, and reserve a small multiple thereof, and limit the number of > pages written out so as to never exceed this estimate. > > If the current mempool interface isn't sufficient (not hard to imagine), > look at the swap over NFS patch-set, that includes a much more able > reservation scheme, and accounting framework. Yes, I agree. In this discussion, some people explained why their subsystem need emergency memory, but nobody claim sharing memory pool against VM and surely want to stop reclaim (PF_MEMALLOC's big side effect). OK. I try to review your patch carefully and remake this patch series on top your reservation framework in swap-over-nfs patch series. -- 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