From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752769Ab3KYL36 (ORCPT ); Mon, 25 Nov 2013 06:29:58 -0500 Received: from merlin.infradead.org ([205.233.59.134]:38282 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750767Ab3KYL35 (ORCPT ); Mon, 25 Nov 2013 06:29:57 -0500 Date: Mon, 25 Nov 2013 12:29:49 +0100 From: Peter Zijlstra To: Xiao Guangrong Cc: Marcelo Tosatti , gleb@redhat.com, avi.kivity@gmail.com, pbonzini@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Eric Dumazet Subject: Re: [PATCH v3 07/15] KVM: MMU: introduce nulls desc Message-ID: <20131125112949.GJ3694@twins.programming.kicks-ass.net> References: <1382534973-13197-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> <1382534973-13197-8-git-send-email-xiaoguangrong@linux.vnet.ibm.com> <20131122191429.GA13308@amt.cnet> <20131125093157.GU10022@twins.programming.kicks-ass.net> <52932D8C.2080308@linux.vnet.ibm.com> <20131125110500.GV3866@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131125110500.GV3866@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 25, 2013 at 12:05:00PM +0100, Peter Zijlstra wrote: > On Mon, Nov 25, 2013 at 06:59:24PM +0800, Xiao Guangrong wrote: > > I guess Marcelo was talking about rculist_nulls.h > > (Documentation/RCU/rculist_nulls.txt). > > Oh, let me have a look, I don't think I've really looked at that yet. Egads, that's far too clever ;-) Yes, if that's what Marcello was referencing to he's right, it doesn't have a proper termination condition in the face of unlimited modification. And it can indeed use SLAB_DESTROY_BY_RCU as you alluded to -- although the documentation is a tad scarce explaining why this is so.