From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: [PATCH 2/2] drm/i915: Unpin stolen pages Date: Mon, 3 Jun 2013 09:36:48 +0100 Message-ID: <20130603083648.GC17485@cantiga.alporthouse.com> References: <20130531184616.GD11399@cantiga.alporthouse.com> <1370036780-13482-1-git-send-email-ben@bwidawsk.net> <1370036780-13482-2-git-send-email-ben@bwidawsk.net> <20130531235102.GA1097@cantiga.alporthouse.com> <20130601113405.GF11399@cantiga.alporthouse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from fireflyinternet.com (s16502780.onlinehome-server.info [87.106.93.118]) by gabe.freedesktop.org (Postfix) with ESMTP id B19BDE5CC5 for ; Mon, 3 Jun 2013 01:36:51 -0700 (PDT) Content-Disposition: inline In-Reply-To: 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: Daniel Vetter Cc: Ben Widawsky , Intel GFX List-Id: intel-gfx@lists.freedesktop.org On Sat, Jun 01, 2013 at 03:13:04PM +0200, Daniel Vetter wrote: > On Sat, Jun 1, 2013 at 1:34 PM, Chris Wilson wrote: > > On Sat, Jun 01, 2013 at 11:17:10AM +0200, Daniel Vetter wrote: > >> On Sat, Jun 1, 2013 at 1:51 AM, Chris Wilson wrote: > >> > That neatly explains the WARN. Not too happy about accumulating lots of > >> > backing storage specific processing into free_object, but that can be > >> > fixed up later (there is an obj->ops->release() pending). > >> > >> I'm more irked with the semantic overloading of object pinning. Might > >> be cleaner to otherwise mark stolen obejcts as not shrinkable instead > >> of pinning them for their entire lifetime. But we can bikeshed that > >> later on ;-) > > > > Some merit to that argument, but it still feels correct to say that the > > stolen pages are pinned for their lifetime. Given obj->ops->release(), > > it does actually become simpler to not mess around with pin_count. So > > later it is. > > I was more unhappy that pin_count has different meanings, until I've > noticed that we've fixed that up already with the introduction of > ->pages_pin_count. Shouldn't stolen mem just hold a reference on that > one? After all unbinding from the gtt is ok with stolen memory, but > dropping the backing storage in the shrinker won't work. Not that we > currently use stolen for anything else than permanently pinned bos. As mentioned on irc, stolen does use the pages_pin_count for its purposes. The purpose of this patch is purely to allow sanity checking the pages_pin_count with a WARN_ON during free which seems sensible but not strictly required. -Chris -- Chris Wilson, Intel Open Source Technology Centre