From owner-freebsd-arch@FreeBSD.ORG Thu May 24 00:11:24 2007 Return-Path: X-Original-To: arch@freebsd.org Delivered-To: freebsd-arch@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 5EFD416A421 for ; Thu, 24 May 2007 00:11:24 +0000 (UTC) (envelope-from jroberson@chesapeake.net) Received: from webaccess-cl.virtdom.com (webaccess-cl.virtdom.com [216.240.101.25]) by mx1.freebsd.org (Postfix) with ESMTP id 29EFC13C48A for ; Thu, 24 May 2007 00:11:24 +0000 (UTC) (envelope-from jroberson@chesapeake.net) Received: from [192.168.1.101] (c-71-231-138-78.hsd1.or.comcast.net [71.231.138.78]) (authenticated bits=0) by webaccess-cl.virtdom.com (8.13.6/8.13.6) with ESMTP id l4O0BLF1035696 (version=TLSv1/SSLv3 cipher=DHE-DSS-AES256-SHA bits=256 verify=NO); Wed, 23 May 2007 20:11:22 -0400 (EDT) (envelope-from jroberson@chesapeake.net) Date: Wed, 23 May 2007 17:11:15 -0700 (PDT) From: Jeff Roberson X-X-Sender: jroberson@10.0.0.1 To: Marcel Moolenaar In-Reply-To: <38601004-BB95-4B8B-87A6-26E2D52B89BA@mac.com> Message-ID: <20070523170449.L9443@10.0.0.1> References: <20070520155103.K632@10.0.0.1> <20070523155236.U9443@10.0.0.1> <6A9BD12D-D93C-4AE8-B4F4-D59A0327032D@mac.com> <20070523163109.X9443@10.0.0.1> <38601004-BB95-4B8B-87A6-26E2D52B89BA@mac.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: arch@freebsd.org Subject: Re: sched_lock && thread_lock() X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 May 2007 00:11:24 -0000 On Wed, 23 May 2007, Marcel Moolenaar wrote: > >>> The old patch was missing PowerPC & ia64. Will the final version >>> include those as well? >> >> There are a couple of uses of the global scheduler lock in some >> architecture specific locations. They will continue to be safe with the >> 4BSD scheduler. I intended to work on these issues with the architecture >> maintainers after the threadlock patch goes in. Can you suggest some >> alternative to sched_lock for pmap_switch in ia64? > > pmap_switch() is called from cpu_switch() and from pmap_install(). > So, currently, pmap_install() grabs sched_lock to mimic the > cpu_switch() path and we assert having sched_lock in pmap_switch(). > Basically, any lock that serializes cpu_switch() would work, because > we don't want to switch the thread while in the middle of setting up > the region registers. We could simply use thread_lock() now if this serialization only applies to preventing multiple access to the same thread. > >> There are a couple of these small issues that should be perfectly safe that >> I was hoping to address outside of this patch so that it didn't get too >> big. > > I noticed you introduced sched_throw(). Would it harm if ia64 > doesn't yet use sched_throw() and instead has the sequence it > replaces? In other words: is the initial implementation of > sched_throw() the same as the current code? The problem is that sched_throw() must acquire the correct scheduler lock before entering cpu_throw(). That's why I moved it into the per-scheduler code. sched_smp, which is the updated ule, acquires the correct lock for the current cpu. Jeff > > -- > Marcel Moolenaar > xcllnt@mac.com >