From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933189AbcGLM2X (ORCPT ); Tue, 12 Jul 2016 08:28:23 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:36215 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932974AbcGLM2W (ORCPT ); Tue, 12 Jul 2016 08:28:22 -0400 Date: Tue, 12 Jul 2016 14:28:17 +0200 From: Daniel Vetter To: Thomas Hellstrom Cc: Dave Airlie , "Jason A. Donenfeld" , Paul McKenney , LKML , "dri-devel@lists.freedesktop.org" Subject: Re: Patch for drm-next WAS Re: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless Message-ID: <20160712122817.GT23520@phenom.ffwll.local> Mail-Followup-To: Thomas Hellstrom , Dave Airlie , "Jason A. Donenfeld" , Paul McKenney , LKML , "dri-devel@lists.freedesktop.org" References: <1444474594-28359-1-git-send-email-Jason@zx2c4.com> <561ABFA6.8050102@vmware.com> <842a1a37-7c57-ed57-7a80-97fb8a3c3f88@vmware.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <842a1a37-7c57-ed57-7a80-97fb8a3c3f88@vmware.com> X-Operating-System: Linux phenom 4.6.0-rc5+ User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 01, 2016 at 09:08:34AM +0200, Thomas Hellstrom wrote: > Dave, > > Since kref_get_unless_zero() was brought in by drm, could we add this to > drm-next? Sure can do, but I can't find the raw patch anywhere (I suck, I know). Care to resend? Thanks, Daniel > > Thanks, > Thomas > > > On 06/30/2016 12:52 AM, Jason A. Donenfeld wrote: > > This was positively reviewed by maintainers but never picked up. Can > > someone queue this for 4.7 or 4.8? > > > > Thanks, > > Jason > > > > On Mon, Feb 1, 2016 at 10:53 PM, Jason A. Donenfeld wrote: > >> This was positively reviewed but never picked up. Can someone queue > >> this for rc3? > >> > >> Thanks, > >> Jason > >> > >> On Sun, Oct 11, 2015 at 9:59 PM, Thomas Hellstrom wrote: > >>> Reviewed-by: Thomas Hellstrom > >>> > >>> > >>> On 10/10/2015 12:56 PM, Jason A. Donenfeld wrote: > >>>> On most platforms, there exists this ifdef: > >>>> > >>>> #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) > >>>> > >>>> This makes this patch functionally useless. However, on PPC, there is > >>>> actually an explicit definition of atomic_inc_not_zero with its own > >>>> assembly that is slightly more optimized than atomic_add_unless. So, > >>>> this patch changes kref to use atomic_inc_not_zero instead, for PPC and > >>>> any future platforms that might provide an explicit implementation. > >>>> > >>>> This also puts this usage of kref more in line with a verbatim reading > >>>> of the examples in Paul McKenney's paper [1] in the section titled "2.4 > >>>> Atomic Counting With Check and Release Memory Barrier", which uses > >>>> atomic_inc_not_zero. > >>>> > >>>> [1] https://urldefense.proofpoint.com/v2/url?u=http-3A__open-2Dstd.org_jtc1_sc22_wg21_docs_papers_2007_n2167.pdf&d=BQIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=vpukPkBtpoNQp2IUKuFviOmPNYWVKmen3Jeeu55zmEA&m=z5Nd9sYiJMKiphNjyZp6XT5CbayXMBlcb903f260pDY&s=HEHX3CuXRs2GRRQWuC4Vef6iJMwdilKVRkiZgJpjEpA&e= > >>>> > >>>> Signed-off-by: Jason A. Donenfeld > >>>> --- > >>>> include/linux/kref.h | 2 +- > >>>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>>> > >>>> diff --git a/include/linux/kref.h b/include/linux/kref.h > >>>> index 484604d..83d1f94 100644 > >>>> --- a/include/linux/kref.h > >>>> +++ b/include/linux/kref.h > >>>> @@ -166,6 +166,6 @@ static inline int kref_put_mutex(struct kref *kref, > >>>> */ > >>>> static inline int __must_check kref_get_unless_zero(struct kref *kref) > >>>> { > >>>> - return atomic_add_unless(&kref->refcount, 1, 0); > >>>> + return atomic_inc_not_zero(&kref->refcount); > >>>> } > >>>> #endif /* _KREF_H_ */ > > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: Patch for drm-next WAS Re: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless Date: Tue, 12 Jul 2016 14:28:17 +0200 Message-ID: <20160712122817.GT23520@phenom.ffwll.local> References: <1444474594-28359-1-git-send-email-Jason@zx2c4.com> <561ABFA6.8050102@vmware.com> <842a1a37-7c57-ed57-7a80-97fb8a3c3f88@vmware.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from mail-wm0-x244.google.com (mail-wm0-x244.google.com [IPv6:2a00:1450:400c:c09::244]) by gabe.freedesktop.org (Postfix) with ESMTPS id 299716E53C for ; Tue, 12 Jul 2016 12:28:22 +0000 (UTC) Received: by mail-wm0-x244.google.com with SMTP id i5so1873508wmg.2 for ; Tue, 12 Jul 2016 05:28:22 -0700 (PDT) Content-Disposition: inline In-Reply-To: <842a1a37-7c57-ed57-7a80-97fb8a3c3f88@vmware.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Thomas Hellstrom Cc: Dave Airlie , "Jason A. 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