From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751157Ab1CPE3W (ORCPT ); Wed, 16 Mar 2011 00:29:22 -0400 Received: from e31.co.us.ibm.com ([32.97.110.149]:33871 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750823Ab1CPE3Q (ORCPT ); Wed, 16 Mar 2011 00:29:16 -0400 Date: Tue, 15 Mar 2011 21:29:09 -0700 From: "Paul E. McKenney" To: Lai Jiangshan Cc: Ingo Molnar , LKML , Manfred Spraul Subject: Re: [PATCH V4 1/1] rcu: introduce kfree_rcu() Message-ID: <20110316042909.GG2273@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <4D7F356C.8020903@cn.fujitsu.com> <20110315113038.GB2167@linux.vnet.ibm.com> <4D802578.8050603@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D802578.8050603@cn.fujitsu.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 16, 2011 at 10:50:32AM +0800, Lai Jiangshan wrote: > On 03/15/2011 07:30 PM, Paul E. McKenney wrote: > > On Tue, Mar 15, 2011 at 05:46:20PM +0800, Lai Jiangshan wrote: > >> kfree_rcu() which was original proposed by Lai 2.5 years ago is one of > >> the most important RCU TODO list entries, Lai and Manfred have worked on > >> patches for this. This V4 patch is based on the Manfred's patch and > >> the V1 of Lai's patch. (These two patches are almost the same > >> in implementation, and this patch is mainly based on the Manfred's). > >> > >> Lai's V1 patch: http://lkml.org/lkml/2008/9/18/1 > >> Manfred's patch: http://lkml.org/lkml/2009/1/2/115 > >> RCU TODO list: http://www.kernel.org/pub/linux/kernel/people/paulmck/rcutodo.html > >> > >> This new introduced API kfree_rcu() primitive kfree()s the specified memory > >> after a RCU grace period elapses. > >> > >> It replaces many simple "call_rcu(head, simple_kfree_callback)"; > >> These many simple_kfree_callback() instances just does > >> > >> kfree(containerof(head,struct whatever_struct,rcu_member)); > >> > >> These simple_kfree_callback() instances are just duplicate code, we need > >> a generic function for them. > >> > >> And kfree_rcu() is also help for unloadable modules, kfree_rcu() does not > >> queue any function which belong to the module, so a rcu_barrier() can > >> be avoid when module exit. (If we queue any other function by call_rcu(), > >> rcu_barrier() is still needed.) > > > > Thank you for putting this together! It does represent a nice > > reduction in code size. > > > > Once it settles out a bit, I intend to queue this patch. It would be > > best if the subsystems queue their own patches using kfree_rcu() once > > this patch reaches mainline. > > > > It seems that the subsystems maintainers just Ack the patches. > I hope Ingo queue the Acked using kfree_rcu() patches into -tip, > it will help the kfree_rcu() reaches mainline earlier. Yep, I am comfortable pushing the patches that have received acks. Thanx, Paul