Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756681Ab1CGWvQ (ORCPT ); Mon, 7 Mar 2011 17:51:16 -0500 Received: from flusers.ccur.com ([173.221.59.2]:43176 "EHLO gamx.iccur.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755527Ab1CGWvP (ORCPT ); Mon, 7 Mar 2011 17:51:15 -0500 Date: Mon, 7 Mar 2011 17:51:10 -0500 From: Joe Korty To: "Paul E. McKenney" Cc: Frederic Weisbecker , linux-kernel@vger.kernel.org Subject: Re: [PATCH] An RCU for SMP with a single CPU garbage collector Message-ID: <20110307225110.GA19414@tsunami.ccur.com> Reply-To: Joe Korty References: <1289410271.2084.25.camel@laptop> <20101111041920.GD3134@linux.vnet.ibm.com> <20101113223046.GB5445@nowhere> <20101116012846.GV2555@linux.vnet.ibm.com> <20101116135230.GA5362@nowhere> <20101116155104.GB2497@linux.vnet.ibm.com> <20101117005229.GC26243@nowhere> <20110307203106.GA23002@tsunami.ccur.com> <20110307210157.GG3104@linux.vnet.ibm.com> <20110307211613.GA26455@tsunami.ccur.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110307211613.GA26455@tsunami.ccur.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1140 Lines: 25 On Mon, Mar 07, 2011 at 04:16:13PM -0500, Joe Korty wrote: > On Mon, Mar 07, 2011 at 04:01:57PM -0500, Paul E. McKenney wrote: >> But I would really prefer leveraging the existing RCU implementations >> to the extent possible. Are the user-dedicated CPUs able to invoke >> system calls? If so, something like Frederic's approach should permit >> the existing RCU implementations to operate normally. If not, what is >> doing the RCU read-side critical sections on the dedicated CPUs? > > I thought about the system call approach but rejected it. > Some (maybe many) customers needing dedicated CPUs will > have apps that never make any system calls at all. Hi Paul, Thinking about it some more, the tap-into-syscall approach might work in my implementation, in which case the tap-into-preempt-enable code could go away. Nice thing about RCU, the algorithms are infinitely mallable :) Joe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/