From owner-cvs-all@FreeBSD.ORG Tue Nov 2 21:11:18 2004 Return-Path: Delivered-To: cvs-all@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0A35016A501 for ; Tue, 2 Nov 2004 21:11:18 +0000 (GMT) Received: from mail5.speakeasy.net (mail5.speakeasy.net [216.254.0.205]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8B88043D1D for ; Tue, 2 Nov 2004 21:11:15 +0000 (GMT) (envelope-from jhb@FreeBSD.org) Received: (qmail 2218 invoked from network); 2 Nov 2004 21:11:15 -0000 Received: from dsl027-160-063.atl1.dsl.speakeasy.net (HELO server.baldwin.cx) ([216.27.160.63]) (envelope-sender ) encrypted SMTP for ; 2 Nov 2004 21:11:14 -0000 Received: from [10.50.41.235] (gw1.twc.weather.com [216.133.140.1]) (authenticated bits=0) by server.baldwin.cx (8.12.11/8.12.11) with ESMTP id iA2LAuYQ070948; Tue, 2 Nov 2004 16:11:10 -0500 (EST) (envelope-from jhb@FreeBSD.org) From: John Baldwin To: Andre Oppermann Date: Tue, 2 Nov 2004 15:50:25 -0500 User-Agent: KMail/1.6.2 References: <200410291910.i9TJAlNf089795@repoman.freebsd.org> <200411011434.28141.jhb@FreeBSD.org> <41874ED1.662A02@freebsd.org> In-Reply-To: <41874ED1.662A02@freebsd.org> MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200411021550.25945.jhb@FreeBSD.org> X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on server.baldwin.cx cc: Alan Cox cc: cvs-src@FreeBSD.org cc: Mike Silbersack cc: src-committers@FreeBSD.org cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/i386/i386 pmap.c X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 02 Nov 2004 21:11:18 -0000 On Tuesday 02 November 2004 04:09 am, Andre Oppermann wrote: > John Baldwin wrote: > > That's very easy, it's just critical_enter/exit() without the > > cpu_critical_*(). As mentioned in the SMP "design doc", the > > cpu_critical_*() are only needed for spin mutexes that are used in both > > top-half and bottom-half code (where ithreads are top-half, but "fast" > > interrupts and the code that schedules ithreads are bottom-half). I've > > thought about shoving cpu_critical_*() off into another API that spin > > mutexes would use, but that not all critical sections would use, this > > would give us critical sections that don't block interrupts, but just > > block preempting. For idle page zeroing though, I'm not sure we really > > want to use even a cheap critical section since it would still defer an > > ithread from running, and ithreads are more important than idle page > > zeroing. > > > > Note that you can easily pin the current thread to its current CPU via > > sched_pin/unpin() and that that works across preemptions. > > Does this involve any mutexes or so? This is very interesting for a couple > of cases in the network stack which uses a lot of heavy-weight mutexes at > the moment. No, pin/unpin just bounce a per-thread private counter with no locks needed. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org