From mboxrd@z Thu Jan 1 00:00:00 1970 From: "tip-bot for Michael S. Tsirkin" Subject: [tip:locking/core] locking/x86: Tweak the comment about use of wmb() for IO Date: Fri, 29 Jan 2016 03:32:52 -0800 Message-ID: References: <1453921746-16178-4-git-send-email-mst@redhat.com> Reply-To: dvlasenk@redhat.com, bp@suse.de, luto@amacapital.net, luto@kernel.org, virtualization@lists.linux-foundation.org, mingo@kernel.org, akpm@linux-foundation.org, mst@redhat.com, torvalds@linux-foundation.org, brgerst@gmail.com, dave@stgolabs.net, paulmck@linux.vnet.ibm.com, peterz@infradead.org, bp@alien8.de, dbueso@suse.de, linux-kernel@vger.kernel.org, andreyknvl@google.com, hpa@zytor.com, tglx@linutronix.de Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1453921746-16178-4-git-send-email-mst@redhat.com> Content-Disposition: inline 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: linux-tip-commits@vger.kernel.org Cc: dave@stgolabs.net, dvlasenk@redhat.com, akpm@linux-foundation.org, brgerst@gmail.com, dbueso@suse.de, peterz@infradead.org, andreyknvl@google.com, mst@redhat.com, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, luto@amacapital.net, bp@alien8.de, bp@suse.de, luto@kernel.org, hpa@zytor.com, tglx@linutronix.de, paulmck@linux.vnet.ibm.com, torvalds@linux-foundation.org, mingo@kernel.org List-Id: virtualization@lists.linuxfoundation.org Commit-ID: 57d9b1b43433a6ba7267c80b87d8e8f6e86edceb Gitweb: http://git.kernel.org/tip/57d9b1b43433a6ba7267c80b87d8e8f6e86edceb Author: Michael S. Tsirkin AuthorDate: Thu, 28 Jan 2016 19:02:44 +0200 Committer: Ingo Molnar CommitDate: Fri, 29 Jan 2016 09:40:10 +0100 locking/x86: Tweak the comment about use of wmb() for IO On x86, we *do* still use the non-NOP rmb()/wmb() for IO barriers, but even that is generally questionable. Leave them around as historial unless somebody can point to a case where they care about the performance, but tweak the comment so people don't think they are strictly required in all cases. Signed-off-by: Michael S. Tsirkin Acked-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Andrey Konovalov Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Davidlohr Bueso Cc: Davidlohr Bueso Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: virtualization Link: http://lkml.kernel.org/r/1453921746-16178-4-git-send-email-mst@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/barrier.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h index a291745..bfb28ca 100644 --- a/arch/x86/include/asm/barrier.h +++ b/arch/x86/include/asm/barrier.h @@ -6,7 +6,7 @@ /* * Force strict CPU ordering. - * And yes, this is required on UP too when we're talking + * And yes, this might be required on UP too when we're talking * to devices. */