From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753446AbaKRBFB (ORCPT ); Mon, 17 Nov 2014 20:05:01 -0500 Received: from gate.crashing.org ([63.228.1.57]:60963 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752880AbaKRBE7 (ORCPT ); Mon, 17 Nov 2014 20:04:59 -0500 Message-ID: <1416271412.18381.20.camel@kernel.crashing.org> Subject: Re: [PATCH 2/4] arch: Add lightweight memory barriers fast_rmb() and fast_wmb() From: Benjamin Herrenschmidt To: Alexander Duyck Cc: Linus Torvalds , "linux-arch@vger.kernel.org" , Network Development , Linux Kernel Mailing List , Mathieu Desnoyers , Peter Zijlstra , Heiko Carstens , Ingo Molnar , Michael Neuling , Russell King - ARM Linux , donald.c.skidmore@intel.com, matthew.vick@intel.com, Geert Uytterhoeven , Jeff Kirsher , Francois Romieu , Paul McKenney , nic_swsd@realtek.com, Will Deacon , Michael Ellerman , Tony Luck , Oleg Nesterov , Martin Schwidefsky , =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , David Miller Date: Tue, 18 Nov 2014 11:43:32 +1100 In-Reply-To: <546A6EB2.6020304@redhat.com> References: <20141117171005.22333.96544.stgit@ahduyck-server> <20141117171812.22333.90395.stgit@ahduyck-server> <546A6EB2.6020304@redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.7-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2014-11-17 at 13:54 -0800, Alexander Duyck wrote: > What would you think of the name "coherent_*mb()"? I would prefer to > avoid dma in the name since, at least in my mind, that implies MMIO. I'm lazy, I like typing less, so I like dma_* but I don't object to coherent_* if at least one more person thinks it makes the semantics clearer :) > It also ties in well with dma_alloc_coherent/dma_free_coherent which is > what would typically be used to allocate the memory we would be using > the barrier to protect anyway. Agreed. > > And yes, in the same spirit, it would probably be good to try to > > eventually get rid of the plain "*mb()" functions, and perhaps call > > them "mmio_*mb()" to clarify that they are about ordering memory wrt > > mmio. > > > > Hmm? > > > > Linus > > I will work on pulling all of the coherent barrier cases out of using > the plain "*mb()" calls first. We need to sort that out before we could > look at renaming the plain barrier functions. Makes sense. Cheers, Ben. > - Alex > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH 2/4] arch: Add lightweight memory barriers fast_rmb() and fast_wmb() Date: Tue, 18 Nov 2014 11:43:32 +1100 Message-ID: <1416271412.18381.20.camel@kernel.crashing.org> References: <20141117171005.22333.96544.stgit@ahduyck-server> <20141117171812.22333.90395.stgit@ahduyck-server> <546A6EB2.6020304@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Linus Torvalds , "linux-arch@vger.kernel.org" , Network Development , Linux Kernel Mailing List , Mathieu Desnoyers , Peter Zijlstra , Heiko Carstens , Ingo Molnar , Michael Neuling , Russell King - ARM Linux , donald.c.skidmore@intel.com, matthew.vick@intel.com, Geert Uytterhoeven , Jeff Kirsher , Francois Romieu , Paul McKenney , nic_swsd@realtek.com, Will Deacon , Michael Ellerman , Tony Luck , Oleg Nesterov , Martin Schwidefsky Return-path: In-Reply-To: <546A6EB2.6020304@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Mon, 2014-11-17 at 13:54 -0800, Alexander Duyck wrote: > What would you think of the name "coherent_*mb()"? I would prefer to > avoid dma in the name since, at least in my mind, that implies MMIO. I'm lazy, I like typing less, so I like dma_* but I don't object to coherent_* if at least one more person thinks it makes the semantics clearer :) > It also ties in well with dma_alloc_coherent/dma_free_coherent which is > what would typically be used to allocate the memory we would be using > the barrier to protect anyway. Agreed. > > And yes, in the same spirit, it would probably be good to try to > > eventually get rid of the plain "*mb()" functions, and perhaps call > > them "mmio_*mb()" to clarify that they are about ordering memory wrt > > mmio. > > > > Hmm? > > > > Linus > > I will work on pulling all of the coherent barrier cases out of using > the plain "*mb()" calls first. We need to sort that out before we could > look at renaming the plain barrier functions. Makes sense. Cheers, Ben. > - Alex > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH 2/4] arch: Add lightweight memory barriers fast_rmb() and fast_wmb() Date: Tue, 18 Nov 2014 11:43:32 +1100 Message-ID: <1416271412.18381.20.camel@kernel.crashing.org> References: <20141117171005.22333.96544.stgit@ahduyck-server> <20141117171812.22333.90395.stgit@ahduyck-server> <546A6EB2.6020304@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <546A6EB2.6020304@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Alexander Duyck Cc: Linus Torvalds , "linux-arch@vger.kernel.org" , Network Development , Linux Kernel Mailing List , Mathieu Desnoyers , Peter Zijlstra , Heiko Carstens , Ingo Molnar , Michael Neuling , Russell King - ARM Linux , donald.c.skidmore@intel.com, matthew.vick@intel.com, Geert Uytterhoeven , Jeff Kirsher , Francois Romieu , Paul McKenney , nic_swsd@realtek.com, Will Deacon , Michael Ellerman , Tony Luck , Oleg Nesterov , Martin Schwidefsky List-Id: linux-arch.vger.kernel.org On Mon, 2014-11-17 at 13:54 -0800, Alexander Duyck wrote: > What would you think of the name "coherent_*mb()"? I would prefer to > avoid dma in the name since, at least in my mind, that implies MMIO. I'm lazy, I like typing less, so I like dma_* but I don't object to coherent_* if at least one more person thinks it makes the semantics clearer :) > It also ties in well with dma_alloc_coherent/dma_free_coherent which is > what would typically be used to allocate the memory we would be using > the barrier to protect anyway. Agreed. > > And yes, in the same spirit, it would probably be good to try to > > eventually get rid of the plain "*mb()" functions, and perhaps call > > them "mmio_*mb()" to clarify that they are about ordering memory wrt > > mmio. > > > > Hmm? > > > > Linus > > I will work on pulling all of the coherent barrier cases out of using > the plain "*mb()" calls first. We need to sort that out before we could > look at renaming the plain barrier functions. Makes sense. Cheers, Ben. > - Alex > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/