From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752555AbcFAXQi (ORCPT ); Wed, 1 Jun 2016 19:16:38 -0400 Received: from mail-oi0-f68.google.com ([209.85.218.68]:34269 "EHLO mail-oi0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752313AbcFAXQK (ORCPT ); Wed, 1 Jun 2016 19:16:10 -0400 Date: Thu, 2 Jun 2016 07:19:43 +0800 From: Boqun Feng To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, manfred@colorfullife.com, dave@stgolabs.net, paulmck@linux.vnet.ibm.com, will.deacon@arm.com, Waiman.Long@hpe.com, tj@kernel.org, pablo@netfilter.org, kaber@trash.net, davem@davemloft.net, oleg@redhat.com, netfilter-devel@vger.kernel.org, sasha.levin@oracle.com, hofrat@osadl.org Subject: Re: [PATCH -v3 3/8] locking: Introduce smp_acquire__after_ctrl_dep Message-ID: <20160601231943.GD30064@insomnia> References: <20160531094134.606249808@infradead.org> <20160531094844.037298593@infradead.org> <20160601135214.GC30064@insomnia> <20160601162255.GT3190@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="k4f25fnPtRuIRUb3" Content-Disposition: inline In-Reply-To: <20160601162255.GT3190@twins.programming.kicks-ass.net> User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --k4f25fnPtRuIRUb3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jun 01, 2016 at 06:22:55PM +0200, Peter Zijlstra wrote: > On Wed, Jun 01, 2016 at 09:52:14PM +0800, Boqun Feng wrote: > > On Tue, May 31, 2016 at 11:41:37AM +0200, Peter Zijlstra wrote: >=20 > > > @@ -292,7 +282,7 @@ static void sem_wait_array(struct sem_ar > > > sem =3D sma->sem_base + i; > > > spin_unlock_wait(&sem->lock); > > > } > > > - ipc_smp_acquire__after_spin_is_unlocked(); > > > + smp_acquire__after_ctrl_dep(); > >=20 > > I wonder whether we can kill this barrier after updating > > spin_unlock_wait() to ACQUIRE? >=20 > See patch 5 doing that :-) Oops, right ;-) Regards, Boqun --k4f25fnPtRuIRUb3 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAABCAAGBQJXT22JAAoJEEl56MO1B/q4+W0H/1GIqudmMPVieC/ebtu3mySs LER03q8exkKgnD9sdLENokyjCTxEvyaQ2JLqDT98an9Cza5SmOFV7fumMDZikf1V zL/kAaQnTd/OXfpiN9YmmTr5Uyyeav8JfE0DcZVaidk8ohyXJeEvvI0l9z7UEPoi zPyiMkxYdfcXTqTemH2/8LpRdxvvohDpPDsiDbzFBY5AZ0N8jif2+7EMcKxqD+Ur qRFKsOwUUmAlnYYxfv07Zdfd4lPUr8LefAfEtk1PYhCCmT83F9kNnG4XU0w0jlkF +mwiHW6FqMuUS6tqhBGYpnGT/sUOCZarEo8UkxdY0Wl2kUJ5CdYdTlnw5i63suA= =g+US -----END PGP SIGNATURE----- --k4f25fnPtRuIRUb3--