From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S966392AbcHDVTC (ORCPT <rfc822;w@1wt.eu>);
	Thu, 4 Aug 2016 17:19:02 -0400
Received: from mail-qk0-f194.google.com ([209.85.220.194]:36475 "EHLO
	mail-qk0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S965712AbcHDVS7 (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 4 Aug 2016 17:18:59 -0400
Date: Thu, 4 Aug 2016 18:18:53 -0300
From: Gustavo Padovan <gustavo@padovan.org>
To: Chris Wilson <chris@chris-wilson.co.uk>, dri-devel@lists.freedesktop.org,
        marcheu@google.com, Daniel Stone <daniels@collabora.com>,
        seanpaul@google.com, Daniel Vetter <daniel.vetter@ffwll.ch>,
        linux-kernel@vger.kernel.org, laurent.pinchart@ideasonboard.com,
        Gustavo Padovan <gustavo.padovan@collabora.co.uk>,
        John Harrison <John.C.Harrison@Intel.com>, m.chehab@samsung.com
Subject: Re: [PATCH v4 5/5] dma-buf/sync_file: only enable fence signalling
 on poll()
Message-ID: <20160804211853.GA2478@joana>
Mail-Followup-To: Gustavo Padovan <gustavo@padovan.org>,
	Chris Wilson <chris@chris-wilson.co.uk>,
	dri-devel@lists.freedesktop.org, marcheu@google.com,
	Daniel Stone <daniels@collabora.com>, seanpaul@google.com,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	linux-kernel@vger.kernel.org, laurent.pinchart@ideasonboard.com,
	Gustavo Padovan <gustavo.padovan@collabora.co.uk>,
	John Harrison <John.C.Harrison@Intel.com>, m.chehab@samsung.com
References: <1468346925-12774-1-git-send-email-gustavo@padovan.org>
 <1468346925-12774-5-git-send-email-gustavo@padovan.org>
 <20160803114328.GI20686@nuc-i3427.alporthouse.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20160803114328.GI20686@nuc-i3427.alporthouse.com>
User-Agent: Mutt/1.6.2 (2016-07-01)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

2016-08-03 Chris Wilson <chris@chris-wilson.co.uk>:

> On Tue, Jul 12, 2016 at 03:08:45PM -0300, Gustavo Padovan wrote:
> > From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
> > 
> > Signalling doesn't need to be enabled at sync_file creation, it is only
> > required if userspace waiting the fence to signal through poll().
> > 
> > Thus we delay fence_add_callback() until poll is called. It only adds the
> > callback the first time poll() is called. This avoid re-adding the same
> > callback multiple times.
> > 
> > v2: rebase and update to work with new fence support for sync_file
> > 
> > v3: use atomic operation to set enabled and protect fence_add_callback()
> 
> There's actually a spare bit in fence->flags you can use for this.
> 
> #define POLL_ENABLED FENCE_FLAG_USER_BITS

Wouldn't it be better to add a new bit to fence_flags_bit?

	Gustavo