From owner-freebsd-current@FreeBSD.ORG Tue Oct 26 21:15:46 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8C40E16A4DA for ; Tue, 26 Oct 2004 21:15:46 +0000 (GMT) Received: from mail6.speakeasy.net (mail6.speakeasy.net [216.254.0.206]) by mx1.FreeBSD.org (Postfix) with ESMTP id 354EC43D2D for ; Tue, 26 Oct 2004 21:15:46 +0000 (GMT) (envelope-from john@baldwin.cx) Received: (qmail 11040 invoked from network); 26 Oct 2004 21:15:46 -0000 Received: from dsl027-160-063.atl1.dsl.speakeasy.net (HELO server.baldwin.cx) ([216.27.160.63]) (envelope-sender ) encrypted SMTP for ; 26 Oct 2004 21:15:45 -0000 Received: from zion.baldwin.cx (zion.baldwin.cx [192.168.0.7]) by server.baldwin.cx (8.12.11/8.12.11) with ESMTP id i9QLFe7C009574; Tue, 26 Oct 2004 17:15:40 -0400 (EDT) (envelope-from john@baldwin.cx) Received: from zion.baldwin.cx (localhost [127.0.0.1]) by zion.baldwin.cx (8.12.10/8.12.10) with ESMTP id i9QLFe8h015300; Tue, 26 Oct 2004 17:15:40 -0400 (EDT) (envelope-from john@zion.baldwin.cx) Received: from localhost (localhost [[UNIX: localhost]]) by zion.baldwin.cx (8.12.10/8.12.10/Submit) id i9QLFecP015299; Tue, 26 Oct 2004 17:15:40 -0400 (EDT) (envelope-from john) From: John Baldwin To: Stephan Uphoff Date: Tue, 26 Oct 2004 17:07:09 -0400 User-Agent: KMail/1.6 References: <20041020221659.33824.qmail@web21124.mail.yahoo.com> <200410211705.45147.jhb@FreeBSD.org> <1098811105.20390.16988.camel@palm.tree.com> In-Reply-To: <1098811105.20390.16988.camel@palm.tree.com> MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200410261707.09293.jhb@FreeBSD.org> X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on server.baldwin.cx cc: Nik Azim Azam cc: freebsd-current@FreeBSD.org Subject: Re: number of CPUs and IPI panic X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 26 Oct 2004 21:15:46 -0000 On Tuesday 26 October 2004 01:18 pm, Stephan Uphoff wrote: > On Thu, 2004-10-21 at 17:05, John Baldwin wrote: > > On Wednesday 20 October 2004 09:05 pm, Stephan Uphoff wrote: > > > Can you try the attached patch? > > > ( Hope it still applies since it is a few weeks old) > > > > > > If this does not work I have a few more questions next week. > > > > Unfortunately it can enable interrupts with sched_lock held which can > > result in deadlocks due to ithread preemption (IIRC, maybe not as badly > > with the newer preemption code.) > > The code only enables interrupts for TLB shootdowns. > In this case it is guaranteed that it holds the smp_ipi_mtx that as a > side effect protects it against preemption and holds no other spin > mutex. > I don't see the problem. I must have missed the TLB shootdown detail then when I looked over it. We send some other IPI's such as IPI_AST while holding sched_lock and if we enabled interrupts during that we could have problems. > I am thinking about implementing the bitmap based stuff be talked about > a few weeks ago to avoid having more than one queued IPI of the same > type. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/