From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Date: Wed, 9 Mar 2016 13:22:17 +0100 Message-ID: <20160309122217.GK6356@twins.programming.kicks-ass.net> References: <1457447457-25878-1-git-send-email-vgupta@synopsys.com> <56DEF3D3.6080008@synopsys.com> <56DFC604.6070407@synopsys.com> <20160309101349.GJ6344@twins.programming.kicks-ass.net> <56E0024F.4070401@synopsys.com> <20160309114054.GJ6356@twins.programming.kicks-ass.net> <56E00EB6.4000201@synopsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <56E00EB6.4000201@synopsys.com> Sender: owner-linux-mm@kvack.org To: Vineet Gupta Cc: "linux-arch@vger.kernel.org" , linux-parisc@vger.kernel, Helge Deller , linux-kernel@vger.kernel.org, stable@vger.kernel.org, "James E.J. Bottomley" , Pekka Enberg , linux-mm@kvack.org, Noam Camus , David Rientjes , Joonsoo Kim , Andrew Morton , linux-snps-arc@lists.infradead.org, Christoph Lameter List-Id: linux-arch.vger.kernel.org On Wed, Mar 09, 2016 at 05:23:26PM +0530, Vineet Gupta wrote: > > I did not follow through the maze, I think the few archs implementing > > this simply do not include this file at all. > > > > I'll let the first person that cares about this worry about that :-) > > Ok - that's be me :-) although I really don't see much gains in case of ARC LLSC. > > For us, LD + BCLR + ST is very similar to LLOCK + BCLR + SCOND atleast in terms of > cache coherency transactions ! The win would be in not having to ever retry the SCOND. Although in this case, the contending CPU would be doing reads -- which I assume will not cause a SCOND to fail, so it might indeed not make any difference. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from casper.infradead.org ([85.118.1.10]:59643 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751487AbcCIMWX (ORCPT ); Wed, 9 Mar 2016 07:22:23 -0500 Date: Wed, 9 Mar 2016 13:22:17 +0100 From: Peter Zijlstra Subject: Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Message-ID: <20160309122217.GK6356@twins.programming.kicks-ass.net> References: <1457447457-25878-1-git-send-email-vgupta@synopsys.com> <56DEF3D3.6080008@synopsys.com> <56DFC604.6070407@synopsys.com> <20160309101349.GJ6344@twins.programming.kicks-ass.net> <56E0024F.4070401@synopsys.com> <20160309114054.GJ6356@twins.programming.kicks-ass.net> <56E00EB6.4000201@synopsys.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56E00EB6.4000201@synopsys.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Vineet Gupta Cc: "linux-arch@vger.kernel.org" , linux-parisc@vger.kernel, Helge Deller , linux-kernel@vger.kernel.org, stable@vger.kernel.org, "James E.J. Bottomley" , Pekka Enberg , linux-mm@kvack.org, Noam Camus , David Rientjes , Joonsoo Kim , Andrew Morton , linux-snps-arc@lists.infradead.org, Christoph Lameter Message-ID: <20160309122217.cGLxJh_H_xhZPdsL_ZfL_wji4coNl2bCpnMY4wJ-5cg@z> On Wed, Mar 09, 2016 at 05:23:26PM +0530, Vineet Gupta wrote: > > I did not follow through the maze, I think the few archs implementing > > this simply do not include this file at all. > > > > I'll let the first person that cares about this worry about that :-) > > Ok - that's be me :-) although I really don't see much gains in case of ARC LLSC. > > For us, LD + BCLR + ST is very similar to LLOCK + BCLR + SCOND atleast in terms of > cache coherency transactions ! The win would be in not having to ever retry the SCOND. Although in this case, the contending CPU would be doing reads -- which I assume will not cause a SCOND to fail, so it might indeed not make any difference.