From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [v3,11/41] mips: reuse asm-generic/barrier.h Date: Fri, 15 Jan 2016 14:01:47 -0800 Message-ID: <20160115220147.GD3818@linux.vnet.ibm.com> References: <20160113104516.GE25458@arm.com> <5696CF08.8080700@imgtec.com> <20160114121449.GC15828@arm.com> <5697F6D2.60409@imgtec.com> <20160114203430.GC3818@linux.vnet.ibm.com> <56980C91.1010403@imgtec.com> <20160114212913.GF3818@linux.vnet.ibm.com> <20160115085554.GF3421@worktop> <20160115173912.GU3818@linux.vnet.ibm.com> <20160115212912.GN3421@worktop> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20160115212912.GN3421@worktop> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Peter Zijlstra Cc: linux-mips@linux-mips.org, linux-ia64@vger.kernel.org, "Michael S. Tsirkin" , Will Deacon , virtualization@lists.linux-foundation.org, "H. Peter Anvin" , sparclinux@vger.kernel.org, Ingo Molnar , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Russell King - ARM Linux , user-mode-linux-devel@lists.sourceforge.net, linux-sh@vger.kernel.org, Michael Ellerman , x86@kernel.org, xen-devel@lists.xenproject.org, Ingo Molnar , linux-xtensa@linux-xtensa.org, james.hogan@imgtec.com, Arnd Bergmann , Stefano Stabellini , adi-buildroot-devel@lists.sourceforge.net, Leonid Yegoshin , ddaney.cavm@gmail.com, Thomas Gleixner , linux-metag@vger.kernel.org List-Id: linux-arch.vger.kernel.org On Fri, Jan 15, 2016 at 10:29:12PM +0100, Peter Zijlstra wrote: > On Fri, Jan 15, 2016 at 09:39:12AM -0800, Paul E. McKenney wrote: > > Should we start putting litmus tests for the various examples > > somewhere, perhaps in a litmus-tests directory within each participating > > architecture? I have a pile of powerpc-related litmus tests on my laptop, > > but they probably aren't doing all that much good there. > > Yeah, or a version of them in C that we can 'compile'? That would be good as well. I am guessing that architecture-specific litmus tests will also be needed, but you are right that architecture-independent versions are higher priority. > > commit 2cb4e83a1b5c89c8e39b8a64bd89269d05913e41 > > Author: Paul E. McKenney > > Date: Fri Jan 15 09:30:42 2016 -0800 > > > > documentation: Distinguish between local and global transitivity > > > > The introduction of smp_load_acquire() and smp_store_release() had > > the side effect of introducing a weaker notion of transitivity: > > The transitivity of full smp_mb() barriers is global, but that > > of smp_store_release()/smp_load_acquire() chains is local. This > > commit therefore introduces the notion of local transitivity and > > gives an example. > > > > Reported-by: Peter Zijlstra > > Reported-by: Will Deacon > > Signed-off-by: Paul E. McKenney > > I think it fails to mention smp_mb__after_release_acquire(), although I > suspect we didn't actually introduce the primitive yet, which raises the > point, do we want to? Well, it is not in v4.4. I believe that we need good use cases before we add it. Thanx, Paul From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e33.co.us.ibm.com ([32.97.110.151]:32886 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752383AbcAOWIb (ORCPT ); Fri, 15 Jan 2016 17:08:31 -0500 Received: from localhost by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 15 Jan 2016 15:08:31 -0700 Date: Fri, 15 Jan 2016 14:01:47 -0800 From: "Paul E. McKenney" Subject: Re: [v3,11/41] mips: reuse asm-generic/barrier.h Message-ID: <20160115220147.GD3818@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20160113104516.GE25458@arm.com> <5696CF08.8080700@imgtec.com> <20160114121449.GC15828@arm.com> <5697F6D2.60409@imgtec.com> <20160114203430.GC3818@linux.vnet.ibm.com> <56980C91.1010403@imgtec.com> <20160114212913.GF3818@linux.vnet.ibm.com> <20160115085554.GF3421@worktop> <20160115173912.GU3818@linux.vnet.ibm.com> <20160115212912.GN3421@worktop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160115212912.GN3421@worktop> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Peter Zijlstra Cc: Leonid Yegoshin , Will Deacon , "Michael S. Tsirkin" , linux-kernel@vger.kernel.org, Arnd Bergmann , linux-arch@vger.kernel.org, Andrew Cooper , Russell King - ARM Linux , virtualization@lists.linux-foundation.org, Stefano Stabellini , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Joe Perches , David Miller , linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-metag@vger.kernel.org, linux-mips@linux-mips.org, x86@kernel.org, user-mode-linux-devel@lists.sourceforge.net, adi-buildroot-devel@lists.sourceforge.net, linux-sh@vger.kernel.org, linux-xtensa@linux-xtensa.org, xen-devel@lists.xenproject.org, Ralf Baechle , Ingo Molnar , ddaney.cavm@gmail.com, james.hogan@imgtec.com, Michael Ellerman Message-ID: <20160115220147.0IujTf-XLwxvwylt3afHhlWfRyS4DZPpJa6w6zIYSZU@z> On Fri, Jan 15, 2016 at 10:29:12PM +0100, Peter Zijlstra wrote: > On Fri, Jan 15, 2016 at 09:39:12AM -0800, Paul E. McKenney wrote: > > Should we start putting litmus tests for the various examples > > somewhere, perhaps in a litmus-tests directory within each participating > > architecture? I have a pile of powerpc-related litmus tests on my laptop, > > but they probably aren't doing all that much good there. > > Yeah, or a version of them in C that we can 'compile'? That would be good as well. I am guessing that architecture-specific litmus tests will also be needed, but you are right that architecture-independent versions are higher priority. > > commit 2cb4e83a1b5c89c8e39b8a64bd89269d05913e41 > > Author: Paul E. McKenney > > Date: Fri Jan 15 09:30:42 2016 -0800 > > > > documentation: Distinguish between local and global transitivity > > > > The introduction of smp_load_acquire() and smp_store_release() had > > the side effect of introducing a weaker notion of transitivity: > > The transitivity of full smp_mb() barriers is global, but that > > of smp_store_release()/smp_load_acquire() chains is local. This > > commit therefore introduces the notion of local transitivity and > > gives an example. > > > > Reported-by: Peter Zijlstra > > Reported-by: Will Deacon > > Signed-off-by: Paul E. McKenney > > I think it fails to mention smp_mb__after_release_acquire(), although I > suspect we didn't actually introduce the primitive yet, which raises the > point, do we want to? Well, it is not in v4.4. I believe that we need good use cases before we add it. Thanx, Paul