From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH 2/2] drm/i915: Use remap_pfn_range() to prefault all PTE in a single pass Date: Thu, 12 Jun 2014 09:15:22 +0200 Message-ID: <20140612071522.GP5821@phenom.ffwll.local> References: <1402398881-14425-1-git-send-email-chris@chris-wilson.co.uk> <1402398881-14425-2-git-send-email-chris@chris-wilson.co.uk> <20140611211721.GB25454@bdvolkin-ubuntu-desktop> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wg0-f48.google.com (mail-wg0-f48.google.com [74.125.82.48]) by gabe.freedesktop.org (Postfix) with ESMTP id 2D86D89DE3 for ; Thu, 12 Jun 2014 00:15:29 -0700 (PDT) Received: by mail-wg0-f48.google.com with SMTP id n12so781355wgh.7 for ; Thu, 12 Jun 2014 00:15:28 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20140611211721.GB25454@bdvolkin-ubuntu-desktop> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: "Volkin, Bradley D" Cc: "intel-gfx@lists.freedesktop.org" List-Id: intel-gfx@lists.freedesktop.org On Wed, Jun 11, 2014 at 02:17:21PM -0700, Volkin, Bradley D wrote: > On Tue, Jun 10, 2014 at 04:14:41AM -0700, Chris Wilson wrote: > > On an Ivybridge i7-3720qm with 1600MHz DDR3, with 32 fences, > > Upload rate for 2 linear surfaces: 8134MiB/s -> 8154MiB/s > > Upload rate for 2 tiled surfaces: 8625MiB/s -> 8632MiB/s > > Upload rate for 4 linear surfaces: 8127MiB/s -> 8134MiB/s > > Upload rate for 4 tiled surfaces: 8602MiB/s -> 8629MiB/s > > Upload rate for 8 linear surfaces: 8124MiB/s -> 8137MiB/s > > Upload rate for 8 tiled surfaces: 8603MiB/s -> 8624MiB/s > > Upload rate for 16 linear surfaces: 8123MiB/s -> 8128MiB/s > > Upload rate for 16 tiled surfaces: 8606MiB/s -> 8618MiB/s > > Upload rate for 32 linear surfaces: 8121MiB/s -> 8128MiB/s > > Upload rate for 32 tiled surfaces: 8605MiB/s -> 8614MiB/s > > Upload rate for 64 linear surfaces: 8121MiB/s -> 8127MiB/s > > Upload rate for 64 tiled surfaces: 3017MiB/s -> 5127MiB/s > > > > Signed-off-by: Chris Wilson > > The translation from vm_insert_pfn to remap_pfn_range looks correct. I don't know > these APIs particularly well though. I wonder if there's any reason it would be > unsafe to call remap_pfn_range from .fault() since it seems to only be used in > .mmap() handlers in other places. Reading their implementations, nothing jumped > out, so I'll say Most drivers just statically relocate their BAR to userspace, we manage it dynamically. Iirc vm_insert_pfn was more-or-less added for us, too. In any case I think we're safe. > > Reviewed-by: Brad Volkin > > with the note that you may want to take a look just in case. Thanks for the review, also added the Testcase: tag now that Chris pushed his igt patch. -Daniel > > > --- > > drivers/gpu/drm/i915/i915_gem.c | 28 +++++++++++++--------------- > > 1 file changed, 13 insertions(+), 15 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c > > index e1f68f06c2ef..7128d389a6ff 100644 > > --- a/drivers/gpu/drm/i915/i915_gem.c > > +++ b/drivers/gpu/drm/i915/i915_gem.c > > @@ -1709,21 +1709,19 @@ int i915_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) > > pfn >>= PAGE_SHIFT; > > > > if (!obj->fault_mappable) { > > - int i; > > - > > - for (i = 0; i < obj->base.size >> PAGE_SHIFT; i++) { > > - ret = vm_insert_pfn(vma, > > - (unsigned long)vma->vm_start + i * PAGE_SIZE, > > - pfn + i); > > - if (ret) > > - break; > > - } > > - > > - obj->fault_mappable = true; > > - } else > > - ret = vm_insert_pfn(vma, > > - (unsigned long)vmf->virtual_address, > > - pfn + page_offset); > > + ret = remap_pfn_range(vma, > > + vma->vm_start, > > + pfn, > > + obj->base.size, > > + vma->vm_page_prot); > > + obj->fault_mappable = ret == 0; > > + } else { > > + ret = remap_pfn_range(vma, > > + (unsigned long)vmf->virtual_address, > > + pfn + page_offset, > > + PAGE_SIZE, > > + vma->vm_page_prot); > > + } > > unpin: > > i915_gem_object_ggtt_unpin(obj); > > unlock: > > -- > > 2.0.0 > > > > _______________________________________________ > > Intel-gfx mailing list > > Intel-gfx@lists.freedesktop.org > > http://lists.freedesktop.org/mailman/listinfo/intel-gfx > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch