From owner-svn-src-all@FreeBSD.ORG Thu May 24 22:46:15 2012 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 958D9106564A; Thu, 24 May 2012 22:46:15 +0000 (UTC) (envelope-from nwhitehorn@freebsd.org) Received: from adsum.doit.wisc.edu (adsum.doit.wisc.edu [144.92.197.210]) by mx1.freebsd.org (Postfix) with ESMTP id 602068FC0A; Thu, 24 May 2012 22:46:15 +0000 (UTC) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; CHARSET=US-ASCII; format=flowed Received: from avs-daemon.smtpauth1.wiscmail.wisc.edu by smtpauth1.wiscmail.wisc.edu (Sun Java(tm) System Messaging Server 7u2-7.05 32bit (built Jul 30 2009)) id <0M4J00100TWXSV00@smtpauth1.wiscmail.wisc.edu>; Thu, 24 May 2012 17:46:09 -0500 (CDT) Received: from wanderer.tachypleus.net (i3-user-nat.icecube.wisc.edu [128.104.255.12]) by smtpauth1.wiscmail.wisc.edu (Sun Java(tm) System Messaging Server 7u2-7.05 32bit (built Jul 30 2009)) with ESMTPSA id <0M4J00C29TWW1J30@smtpauth1.wiscmail.wisc.edu>; Thu, 24 May 2012 17:46:09 -0500 (CDT) Date: Thu, 24 May 2012 17:46:08 -0500 From: Nathan Whitehorn In-reply-to: <358A54BA-6B8E-4685-8CDD-CCAC305ACA2B@xcllnt.net> To: Marcel Moolenaar Message-id: <4FBEBA30.6050901@freebsd.org> X-Spam-Report: AuthenticatedSender=yes, SenderIP=128.104.255.12 X-Spam-PmxInfo: Server=avs-16, Version=5.6.1.2065439, Antispam-Engine: 2.7.2.376379, Antispam-Data: 2012.5.24.223633, SenderIP=128.104.255.12 References: <201205242045.q4OKjipb059398@svn.freebsd.org> <4FBEA493.4020702@freebsd.org> <4FBEB2F3.4060405@freebsd.org> <358A54BA-6B8E-4685-8CDD-CCAC305ACA2B@xcllnt.net> User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:12.0) Gecko/20120502 Thunderbird/12.0 Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, Marcel Moolenaar , src-committers@freebsd.org Subject: Re: svn commit: r235931 - head/sys/powerpc/include X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 May 2012 22:46:15 -0000 On 05/24/12 17:22, Marcel Moolenaar wrote: > > On May 24, 2012, at 3:15 PM, Nathan Whitehorn wrote: > >>>> Summary: >>>> 1. *mb() must be lwsync or sync on all machines, except for wmb() which could be eieio >>>> 2. __ATOMIC_ACQ() must be isync (though could be reduced to lwsync with bus_space changes) >>>> 3. __ATOMIC_REL() must be lwsync or sync >>> >>> This is absolutely not what I concluded from our discussions. I have no idea >>> how we could end up so out of sync... >>> >> >> Thanks for the quick change. No idea how we got out of sync. I find all of this synchronization stuff a little mind-bending, so sorry for any miscommunication. __ATOMIC_ACQ() needed to also be isync on ppc64, so I've fixed that up. Things should be good now. > > Ok. I didn't change wmb() to eieio as I wanted to avoid a pendulum effect. > I'll reread our emails and make sure wmb() is what we think it is and if > so I'll do a followup commit. > FYI, > I don't think it really makes a difference. Basically nothing uses wmb(), and those things that do mostly use it wrong and need sync. So it should probably stay as [lw]sync. -Nathan