From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: [PATCH 2/2] drm/i915: Disable page-faults around the fast pwrite/pread paths Date: Sat, 09 Jul 2011 22:23:28 +0100 Message-ID: References: <1310200731-18086-1-git-send-email-chris@chris-wilson.co.uk> <1310200731-18086-2-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 mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTP id AFEB99F4E1 for ; Sat, 9 Jul 2011 14:23:33 -0700 (PDT) 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: Keith Packard , intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Sat, 09 Jul 2011 14:06:23 -0700, Keith Packard wrote: > On Sat, 09 Jul 2011 21:50:26 +0100, Chris Wilson wrote: > Sure, it's permitted, so ideally we'd detect this abuse and fall back to > the slow path, but we need a cheap check which takes the slow path, > perhaps pessimistically. If we prefault every page, then we only hit the slow path under system load combined or severe memory pressure. I don't think that is too bad a compromise. I can stick some counters in there and find out what the impact actually is. -Chris -- Chris Wilson, Intel Open Source Technology Centre