Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751349AbaFELvM (ORCPT ); Thu, 5 Jun 2014 07:51:12 -0400 Received: from mail-ig0-f170.google.com ([209.85.213.170]:61420 "EHLO mail-ig0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750840AbaFELvL (ORCPT ); Thu, 5 Jun 2014 07:51:11 -0400 MIME-Version: 1.0 In-Reply-To: <20140604174902.GC20812@kroah.com> References: <1401287192-14701-1-git-send-email-thierry.reding@gmail.com> <20140528205145.GB10468@kroah.com> <20140530081504.GA16669@ulmo> <20140530160831.GA11182@kroah.com> <20140604132831.GC28484@ulmo> <20140604174902.GC20812@kroah.com> Date: Thu, 5 Jun 2014 07:51:10 -0400 Message-ID: Subject: Re: [PATCH] fence: Use smp_mb__before_atomic() From: Rob Clark To: Greg Kroah-Hartman Cc: Thierry Reding , Sumit Semwal , Maarten Lankhorst , LKML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 4, 2014 at 1:49 PM, Greg Kroah-Hartman wrote: > On Wed, Jun 04, 2014 at 03:28:33PM +0200, Thierry Reding wrote: >> On Wed, Jun 04, 2014 at 04:57:07PM +0530, Sumit Semwal wrote: >> > Hi Greg, >> > >> > >> > On 30 May 2014 21:38, Greg Kroah-Hartman wrote: >> > > On Fri, May 30, 2014 at 10:15:05AM +0200, Thierry Reding wrote: >> > >> On Wed, May 28, 2014 at 01:51:45PM -0700, Greg Kroah-Hartman wrote: >> > >> > On Wed, May 28, 2014 at 04:26:32PM +0200, Thierry Reding wrote: >> > >> > > From: Thierry Reding >> > >> > > >> > >> > > Commit febdbfe8a91c (arch: Prepare for smp_mb__{before,after}_atomic()) >> > >> > > deprecated the smp_mb__{before,after}_{atomic,clear}_{dec,inc,bit}*() >> > >> > > functions in favour of the unified smp_mb__{before,after}_atomic(). >> > >> > > >> > >> > > Signed-off-by: Thierry Reding >> > >> > > --- >> > >> > > drivers/base/fence.c | 4 ++-- >> > >> > >> > >> > Where does this file come from? I've not seen it before, and it's not >> > >> > in my tree. >> > >> >> > >> I think it came in through Sumit's tree and it's only in linux-next I >> > >> believe. >> > > >> > > Odd, linux-next is for merging things in Linus's next release. >> > > >> > > And as I have never seen this code that will end up being my >> > > responsibility to maintain, it seems strange that it will be merged in >> > > the next kernel development cycle. >> > > >> > > What broke down here with our review process that required something to >> > > be merged without at least a cc: to me? >> > >> > This is a new file added by Maarten's patches [1], that got reviewed >> > on dri-devel and other mailing lists. Since it was quite closely >> > associated with dma-buf, I figured I should take it through the >> > dma-buf tree. >> > >> > I am sorry I didn't notice that you weren't CC'ed on these patches - >> > Sincere apologies, since I should've noticed that during the patch >> > review process - I would take part of the blame here as well :( >> > >> > I do realize now that atleast on my part, I should've asked you before >> > taking it through the dma-buf tree - I will make sure things like this >> > don't happen again through me. >> > >> > May I request you to help us handle this - would it help if we add >> > Maarten as the maintainer for this file? Any other suggestions? >> >> Perhaps something like the following would help? >> >> diff --git a/MAINTAINERS b/MAINTAINERS >> index fb39c9c3f0c1..d582f54adec8 100644 >> --- a/MAINTAINERS >> +++ b/MAINTAINERS >> @@ -2867,7 +2867,9 @@ L: linux-media@vger.kernel.org >> L: dri-devel@lists.freedesktop.org >> L: linaro-mm-sig@lists.linaro.org >> F: drivers/base/dma-buf* >> +F: drivers/base/fence.c >> F: include/linux/dma-buf* >> +F: include/linux/fence.h >> F: Documentation/dma-buf-sharing.txt >> T: git git://git.linaro.org/people/sumitsemwal/linux-dma-buf.git >> @@ -2936,6 +2938,8 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git >> S: Supported >> F: Documentation/kobject.txt >> F: drivers/base/ >> +X: drivers/base/dma-buf* >> +X: drivers/base/fence.c >> F: fs/sysfs/ >> F: fs/debugfs/ >> F: include/linux/kobj* >> >> That removes Greg from the list generated by get_maintainer.pl for >> anything that touches the DMA-BUF files. > > That doesn't really work for most people, I'll still be "responsible" > for the code. > >> Thinking about it, perhaps moving DMA-BUF into its own subdirectory >> would be an option too, to make the separation more obvious. > > That might be best for some of this. > > But again, why is the fence.c code needed at all anyway? I'm not sold > on that. Fence serves as a way to synchronize between (for example) multiple asynchronous gpu's. There is definitely a need for this. Otherwise performance for optimus/prime type setups is going to suck. I thought we had added something under Documentation/ about it, but I can't find it now (although possibly looking at the wrong trees).. there is at least a bit of a description in the commit msg: https://lkml.org/lkml/2014/2/24/602 I don't think the question about whether we need something like fence to augment dma-buf is really in doubt. Maybe it should live somewhere else, I'm not sure. But it makes sense for it to live wherever dma-buf does, as they are intended to work together. BR, -R > greg k-h > -- > 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/ -- 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/