From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesse Barnes Subject: Re: [PATCH 2/4] drm/i915: Only apply the mb() when flushing the GTT domain during a finish Date: Thu, 11 Oct 2012 12:43:42 -0700 Message-ID: <20121011124342.4102105a@jbarnes-desktop> References: <6c3329lntgg@orsmga002.jf.intel.com> <1349807080-9005-1-git-send-email-chris@chris-wilson.co.uk> <1349807080-9005-2-git-send-email-chris@chris-wilson.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from oproxy12-pub.bluehost.com (oproxy12-pub.bluehost.com [50.87.16.10]) by gabe.freedesktop.org (Postfix) with SMTP id A7FFF9E836 for ; Thu, 11 Oct 2012 12:43:02 -0700 (PDT) In-Reply-To: <1349807080-9005-2-git-send-email-chris@chris-wilson.co.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: Chris Wilson Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Tue, 9 Oct 2012 19:24:38 +0100 Chris Wilson wrote: > Now that we seem to have brought order to the GTT barriers, the last one > to review is the terminal barrier before we unbind the buffer from the > GTT. This needs to only be performed if the buffer still resides in the > GTT domain, and so we can skip some needless barriers otherwise. > > Signed-off-by: Chris Wilson > --- > drivers/gpu/drm/i915/i915_gem.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c > index 3c4577b..ed8d21a 100644 > --- a/drivers/gpu/drm/i915/i915_gem.c > +++ b/drivers/gpu/drm/i915/i915_gem.c > @@ -2526,15 +2526,15 @@ static void i915_gem_object_finish_gtt(struct drm_i915_gem_object *obj) > { > u32 old_write_domain, old_read_domains; > > - /* Act a barrier for all accesses through the GTT */ > - mb(); > - > /* Force a pagefault for domain tracking on next user access */ > i915_gem_release_mmap(obj); > > if ((obj->base.read_domains & I915_GEM_DOMAIN_GTT) == 0) > return; > > + /* Wait for any direct GTT access to complete */ > + mb(); > + > old_read_domains = obj->base.read_domains; > old_write_domain = obj->base.write_domain; > Yeah this looks like a better place to put it. You're trying to serialize this against a subsequent fence or map operation? Reviewed-by: Jesse Barnes -- Jesse Barnes, Intel Open Source Technology Center