From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759253AbZCBGHm (ORCPT ); Mon, 2 Mar 2009 01:07:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750879AbZCBGHe (ORCPT ); Mon, 2 Mar 2009 01:07:34 -0500 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:59677 "EHLO e23smtp07.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750786AbZCBGHd (ORCPT ); Mon, 2 Mar 2009 01:07:33 -0500 Date: Mon, 2 Mar 2009 11:37:26 +0530 From: Balbir Singh To: KAMEZAWA Hiroyuki Cc: linux-mm@kvack.org, Sudhir Kumar , YAMAMOTO Takashi , Bharata B Rao , Paul Menage , lizf@cn.fujitsu.com, linux-kernel@vger.kernel.org, KOSAKI Motohiro , David Rientjes , Pavel Emelianov , Dhaval Giani , Rik van Riel , Andrew Morton Subject: Re: [PATCH 2/4] Memory controller soft limit interface (v3) Message-ID: <20090302060726.GH11421@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <20090301062959.31557.31079.sendpatchset@localhost.localdomain> <20090301063011.31557.42094.sendpatchset@localhost.localdomain> <20090302110323.1a9b9e6b.kamezawa.hiroyu@jp.fujitsu.com> <20090302044631.GE11421@balbir.in.ibm.com> <20090302143518.43f5fcc2.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20090302143518.43f5fcc2.kamezawa.hiroyu@jp.fujitsu.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * KAMEZAWA Hiroyuki [2009-03-02 14:35:18]: > On Mon, 2 Mar 2009 10:16:31 +0530 > Balbir Singh wrote: > > > * KAMEZAWA Hiroyuki [2009-03-02 11:03:23]: > > > > > On Sun, 01 Mar 2009 12:00:11 +0530 > > > Balbir Singh wrote: > > > > > > > > > > > From: Balbir Singh > > > > > > > > Changelog v2...v1 > > > > 1. Add support for res_counter_check_soft_limit_locked. This is used > > > > by the hierarchy code. > > > > > > > > Add an interface to allow get/set of soft limits. Soft limits for memory plus > > > > swap controller (memsw) is currently not supported. Resource counters have > > > > been enhanced to support soft limits and new type RES_SOFT_LIMIT has been > > > > added. Unlike hard limits, soft limits can be directly set and do not > > > > need any reclaim or checks before setting them to a newer value. > > > > > > > > Kamezawa-San raised a question as to whether soft limit should belong > > > > to res_counter. Since all resources understand the basic concepts of > > > > hard and soft limits, it is justified to add soft limits here. Soft limits > > > > are a generic resource usage feature, even file system quotas support > > > > soft limits. > > > > > > > I don't convice adding more logics to res_counter is a good to do, yet. > > > > > > > Even though it is extensible and you pay the cost only when soft > > limits is turned on? Can you show me why you are not convinced? > > > Inserting more codes (like "if") to res_counter itself is not welcome.. > I think res_counter is too complex as counter already. > Darn.. we better stop all code development! > I'm now searching a way to reduce res_counter->lock ping-pong but have no > good idea. > I've been doing some detailed analysis on the memory controller overhead. I have a set of patches that I am testing right now. I'll share the details once I am done with them. -- Balbir