From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752214AbdLDW6N (ORCPT ); Mon, 4 Dec 2017 17:58:13 -0500 Received: from merlin.infradead.org ([205.233.59.134]:55514 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751711AbdLDW6K (ORCPT ); Mon, 4 Dec 2017 17:58:10 -0500 Date: Mon, 4 Dec 2017 23:57:54 +0100 From: Peter Zijlstra To: David Howells Cc: "Paul E. McKenney" , linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, rostedt@goodmis.org, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com Subject: Re: [PATCH tip/core/rcu 01/21] doc: READ_ONCE() now implies smp_barrier_depends() Message-ID: <20171204225754.GE20227@worktop.programming.kicks-ass.net> References: <20171204215448.GY3326@worktop> <1512157876-24665-1-git-send-email-paulmck@linux.vnet.ibm.com> <20171201195053.GA23494@linux.vnet.ibm.com> <15076.1512401936@warthog.procyon.org.uk> <20171204185215.GB7829@linux.vnet.ibm.com> <27500.1512427145@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <27500.1512427145@warthog.procyon.org.uk> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 04, 2017 at 10:39:05PM +0000, David Howells wrote: > Peter Zijlstra wrote: > > > > Good point! How about as shown in the updated patch below? > > > > Humm, I thought the idea was to completely remove read_barrier_depends > > from the lkmm and memory-barriers.txt, making it an Alpha implementation > > detail. > > memory-barriers.txt explains how the barriers used by the kernel work, amongst > other things. The thing is, read-barrier-depends will no longer be used. read-read dependencies will henceforth be assumed to 'just work'. > Don't forget, btw, that Blackfin uses it also. We should delete that blackfin code, its beyond insane.