From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leonid Yegoshin Subject: Re: [v3,11/41] mips: reuse asm-generic/barrier.h Date: Thu, 14 Jan 2016 11:42:02 -0800 Message-ID: <5697FA0A.6040601@imgtec.com> References: <20160112092711.GP6344@twins.programming.kicks-ass.net> <20160112102555.GV6373@twins.programming.kicks-ass.net> <20160112104012.GW6373@twins.programming.kicks-ass.net> <20160112114111.GB15737@arm.com> <569565DA.2010903@imgtec.com> <20160113104516.GE25458@arm.com> <56969F4B.7070001@imgtec.com> <20160113204844.GV6357@twins.programming.kicks-ass.net> <5696BA6E.4070508@imgtec.com> <20160114120445.GB15828@arm.com> <20160114161604.GT3818@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160114161604.GT3818@linux.vnet.ibm.com> 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: paulmck@linux.vnet.ibm.com, Will Deacon Cc: linux-mips@linux-mips.org, linux-ia64@vger.kernel.org, "Michael S. Tsirkin" , Peter Zijlstra , 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, ddaney.cavm@gmail.com, Thomas Gleixner , linux-metag@vger.kernel.org, linux-arm-kernel@lists.infradead.org, And List-Id: linux-arch.vger.kernel.org On 01/14/2016 08:16 AM, Paul E. McKenney wrote: > On Thu, Jan 14, 2016 at 12:04:45PM +0000, Will Deacon wrote: >> On Wed, Jan 13, 2016 at 12:58:22PM -0800, Leonid Yegoshin wrote: >>> On 01/13/2016 12:48 PM, Peter Zijlstra wrote: >>>> On Wed, Jan 13, 2016 at 11:02:35AM -0800, Leonid Yegoshin wrote: >>>> >>>>> I ask HW team about it but I have a question - has it any relationship with >>>>> replacing MIPS SYNC with lightweight SYNCs (SYNC_WMB etc)? >>>> Of course. If you cannot explain the semantics of the primitives you >>>> introduce, how can we judge the patch. >>>> >>>> >>> You missed a point - it is a question about replacement of SYNC with >>> lightweight primitives. It is NOT a question about multithread system >>> behavior without any SYNC. The answer on a latest Will's question lies in >>> different area. > What Will said! > > Yes, you can cut corners within MIPS architecture-specific code, > but primitives that are used in the core kernel really do need to > work as expected. > > Thanx, Paul > > Absolutelly! Please use SYNC - right now it is not. An the only point - please use an appropriate SYNC_* barriers instead of heavy bold hammer. That stuff was design explicitly to support the requirements of Documentation/memory-barriers.txt It is easy - just use smp_acquire instead of plain smp_mb insmp_load_acquire, at least for MIPS. - Leonid. - Leonid. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from [195.59.15.196] ([195.59.15.196]:11439 "EHLO mailapp01.imgtec.com" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754194AbcANTmb (ORCPT ); Thu, 14 Jan 2016 14:42:31 -0500 Message-ID: <5697FA0A.6040601@imgtec.com> Date: Thu, 14 Jan 2016 11:42:02 -0800 From: Leonid Yegoshin MIME-Version: 1.0 Subject: Re: [v3,11/41] mips: reuse asm-generic/barrier.h References: <20160112092711.GP6344@twins.programming.kicks-ass.net> <20160112102555.GV6373@twins.programming.kicks-ass.net> <20160112104012.GW6373@twins.programming.kicks-ass.net> <20160112114111.GB15737@arm.com> <569565DA.2010903@imgtec.com> <20160113104516.GE25458@arm.com> <56969F4B.7070001@imgtec.com> <20160113204844.GV6357@twins.programming.kicks-ass.net> <5696BA6E.4070508@imgtec.com> <20160114120445.GB15828@arm.com> <20160114161604.GT3818@linux.vnet.ibm.com> In-Reply-To: <20160114161604.GT3818@linux.vnet.ibm.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: paulmck@linux.vnet.ibm.com, Will Deacon Cc: Peter Zijlstra , "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: <20160114194202.QevAF4jTY0zaLqdSt2R2wiJjIUfx6eW1SK8hTa1M9uQ@z> On 01/14/2016 08:16 AM, Paul E. McKenney wrote: > On Thu, Jan 14, 2016 at 12:04:45PM +0000, Will Deacon wrote: >> On Wed, Jan 13, 2016 at 12:58:22PM -0800, Leonid Yegoshin wrote: >>> On 01/13/2016 12:48 PM, Peter Zijlstra wrote: >>>> On Wed, Jan 13, 2016 at 11:02:35AM -0800, Leonid Yegoshin wrote: >>>> >>>>> I ask HW team about it but I have a question - has it any relationship with >>>>> replacing MIPS SYNC with lightweight SYNCs (SYNC_WMB etc)? >>>> Of course. If you cannot explain the semantics of the primitives you >>>> introduce, how can we judge the patch. >>>> >>>> >>> You missed a point - it is a question about replacement of SYNC with >>> lightweight primitives. It is NOT a question about multithread system >>> behavior without any SYNC. The answer on a latest Will's question lies in >>> different area. > What Will said! > > Yes, you can cut corners within MIPS architecture-specific code, > but primitives that are used in the core kernel really do need to > work as expected. > > Thanx, Paul > > Absolutelly! Please use SYNC - right now it is not. An the only point - please use an appropriate SYNC_* barriers instead of heavy bold hammer. That stuff was design explicitly to support the requirements of Documentation/memory-barriers.txt It is easy - just use smp_acquire instead of plain smp_mb insmp_load_acquire, at least for MIPS. - Leonid. - Leonid. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leonid Yegoshin Date: Thu, 14 Jan 2016 19:42:02 +0000 Subject: Re: [v3,11/41] mips: reuse asm-generic/barrier.h Message-Id: <5697FA0A.6040601@imgtec.com> List-Id: References: <20160112092711.GP6344@twins.programming.kicks-ass.net> <20160112102555.GV6373@twins.programming.kicks-ass.net> <20160112104012.GW6373@twins.programming.kicks-ass.net> <20160112114111.GB15737@arm.com> <569565DA.2010903@imgtec.com> <20160113104516.GE25458@arm.com> <56969F4B.7070001@imgtec.com> <20160113204844.GV6357@twins.programming.kicks-ass.net> <5696BA6E.4070508@imgtec.com> <20160114120445.GB15828@arm.com> <20160114161604.GT3818@linux.vnet.ibm.com> In-Reply-To: <20160114161604.GT3818@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: paulmck@linux.vnet.ibm.com, Will Deacon Cc: linux-mips@linux-mips.org, linux-ia64@vger.kernel.org, "Michael S. Tsirkin" , Peter Zijlstra , 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, ddaney.cavm@gmail.com, Thomas Gleixner , linux-metag@vger.kernel.org, linux-arm-kernel@lists.infradead.org, And On 01/14/2016 08:16 AM, Paul E. McKenney wrote: > On Thu, Jan 14, 2016 at 12:04:45PM +0000, Will Deacon wrote: >> On Wed, Jan 13, 2016 at 12:58:22PM -0800, Leonid Yegoshin wrote: >>> On 01/13/2016 12:48 PM, Peter Zijlstra wrote: >>>> On Wed, Jan 13, 2016 at 11:02:35AM -0800, Leonid Yegoshin wrote: >>>> >>>>> I ask HW team about it but I have a question - has it any relationship with >>>>> replacing MIPS SYNC with lightweight SYNCs (SYNC_WMB etc)? >>>> Of course. If you cannot explain the semantics of the primitives you >>>> introduce, how can we judge the patch. >>>> >>>> >>> You missed a point - it is a question about replacement of SYNC with >>> lightweight primitives. It is NOT a question about multithread system >>> behavior without any SYNC. The answer on a latest Will's question lies in >>> different area. > What Will said! > > Yes, you can cut corners within MIPS architecture-specific code, > but primitives that are used in the core kernel really do need to > work as expected. > > Thanx, Paul > > Absolutelly! Please use SYNC - right now it is not. An the only point - please use an appropriate SYNC_* barriers instead of heavy bold hammer. That stuff was design explicitly to support the requirements of Documentation/memory-barriers.txt It is easy - just use smp_acquire instead of plain smp_mb insmp_load_acquire, at least for MIPS. - Leonid. - Leonid. From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 14 Jan 2016 20:42:16 +0100 (CET) Received: from mailapp01.imgtec.com ([195.59.15.196]:54449 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S27009970AbcANTmOWuV5Z (ORCPT ); Thu, 14 Jan 2016 20:42:14 +0100 Received: from HHMAIL01.hh.imgtec.org (unknown [10.100.10.19]) by Websense Email Security Gateway with ESMTPS id C3DACC6C086BF; Thu, 14 Jan 2016 19:42:04 +0000 (GMT) Received: from BAMAIL02.ba.imgtec.org (10.20.40.28) by HHMAIL01.hh.imgtec.org (10.100.10.19) with Microsoft SMTP Server (TLS) id 14.3.235.1; Thu, 14 Jan 2016 19:42:07 +0000 Received: from [10.20.3.92] (10.20.3.92) by bamail02.ba.imgtec.org (10.20.40.28) with Microsoft SMTP Server (TLS) id 14.3.174.1; Thu, 14 Jan 2016 11:42:03 -0800 Message-ID: <5697FA0A.6040601@imgtec.com> Date: Thu, 14 Jan 2016 11:42:02 -0800 From: Leonid Yegoshin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: , Will Deacon CC: Peter Zijlstra , "Michael S. Tsirkin" , , Arnd Bergmann , , Andrew Cooper , Russell King - ARM Linux , , Stefano Stabellini , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Joe Perches , David Miller , , , , , , , , , , , , , , "Ralf Baechle" , Ingo Molnar , , , Michael Ellerman Subject: Re: [v3,11/41] mips: reuse asm-generic/barrier.h References: <20160112092711.GP6344@twins.programming.kicks-ass.net> <20160112102555.GV6373@twins.programming.kicks-ass.net> <20160112104012.GW6373@twins.programming.kicks-ass.net> <20160112114111.GB15737@arm.com> <569565DA.2010903@imgtec.com> <20160113104516.GE25458@arm.com> <56969F4B.7070001@imgtec.com> <20160113204844.GV6357@twins.programming.kicks-ass.net> <5696BA6E.4070508@imgtec.com> <20160114120445.GB15828@arm.com> <20160114161604.GT3818@linux.vnet.ibm.com> In-Reply-To: <20160114161604.GT3818@linux.vnet.ibm.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.20.3.92] Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 51124 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: Leonid.Yegoshin@imgtec.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips On 01/14/2016 08:16 AM, Paul E. McKenney wrote: > On Thu, Jan 14, 2016 at 12:04:45PM +0000, Will Deacon wrote: >> On Wed, Jan 13, 2016 at 12:58:22PM -0800, Leonid Yegoshin wrote: >>> On 01/13/2016 12:48 PM, Peter Zijlstra wrote: >>>> On Wed, Jan 13, 2016 at 11:02:35AM -0800, Leonid Yegoshin wrote: >>>> >>>>> I ask HW team about it but I have a question - has it any relationship with >>>>> replacing MIPS SYNC with lightweight SYNCs (SYNC_WMB etc)? >>>> Of course. If you cannot explain the semantics of the primitives you >>>> introduce, how can we judge the patch. >>>> >>>> >>> You missed a point - it is a question about replacement of SYNC with >>> lightweight primitives. It is NOT a question about multithread system >>> behavior without any SYNC. The answer on a latest Will's question lies in >>> different area. > What Will said! > > Yes, you can cut corners within MIPS architecture-specific code, > but primitives that are used in the core kernel really do need to > work as expected. > > Thanx, Paul > > Absolutelly! Please use SYNC - right now it is not. An the only point - please use an appropriate SYNC_* barriers instead of heavy bold hammer. That stuff was design explicitly to support the requirements of Documentation/memory-barriers.txt It is easy - just use smp_acquire instead of plain smp_mb insmp_load_acquire, at least for MIPS. - Leonid. - Leonid. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leonid.Yegoshin@imgtec.com (Leonid Yegoshin) Date: Thu, 14 Jan 2016 11:42:02 -0800 Subject: [v3,11/41] mips: reuse asm-generic/barrier.h In-Reply-To: <20160114161604.GT3818@linux.vnet.ibm.com> References: <20160112092711.GP6344@twins.programming.kicks-ass.net> <20160112102555.GV6373@twins.programming.kicks-ass.net> <20160112104012.GW6373@twins.programming.kicks-ass.net> <20160112114111.GB15737@arm.com> <569565DA.2010903@imgtec.com> <20160113104516.GE25458@arm.com> <56969F4B.7070001@imgtec.com> <20160113204844.GV6357@twins.programming.kicks-ass.net> <5696BA6E.4070508@imgtec.com> <20160114120445.GB15828@arm.com> <20160114161604.GT3818@linux.vnet.ibm.com> Message-ID: <5697FA0A.6040601@imgtec.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 01/14/2016 08:16 AM, Paul E. McKenney wrote: > On Thu, Jan 14, 2016 at 12:04:45PM +0000, Will Deacon wrote: >> On Wed, Jan 13, 2016 at 12:58:22PM -0800, Leonid Yegoshin wrote: >>> On 01/13/2016 12:48 PM, Peter Zijlstra wrote: >>>> On Wed, Jan 13, 2016 at 11:02:35AM -0800, Leonid Yegoshin wrote: >>>> >>>>> I ask HW team about it but I have a question - has it any relationship with >>>>> replacing MIPS SYNC with lightweight SYNCs (SYNC_WMB etc)? >>>> Of course. If you cannot explain the semantics of the primitives you >>>> introduce, how can we judge the patch. >>>> >>>> >>> You missed a point - it is a question about replacement of SYNC with >>> lightweight primitives. It is NOT a question about multithread system >>> behavior without any SYNC. The answer on a latest Will's question lies in >>> different area. > What Will said! > > Yes, you can cut corners within MIPS architecture-specific code, > but primitives that are used in the core kernel really do need to > work as expected. > > Thanx, Paul > > Absolutelly! Please use SYNC - right now it is not. An the only point - please use an appropriate SYNC_* barriers instead of heavy bold hammer. That stuff was design explicitly to support the requirements of Documentation/memory-barriers.txt It is easy - just use smp_acquire instead of plain smp_mb insmp_load_acquire, at least for MIPS. - Leonid. - Leonid.