[Intel-gfx] [PATCH] drm/i915: fixup i915_gem_object_get_page inline helper

[Chris Wilson]

On Tue, 09 Oct 2012 23:16:02 +0100, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Tue,  9 Oct 2012 22:50:48 +0200, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> > The obj->pages to obj->pages->sgl rework introduced this helper, but
> > it doesn't actually work for n >= SG_MAX_SINGLE_ALLOC.
> > 
> > For simplicity (and since right now I seem to be too stupid to see
> > the bug), let's just grab the right page with a for_each_sg loop.
> > 
> > This is exercised by the improved hangman tests and the gem_exec_big
> > test in i-g-t.
> > 
> > v2: Compared to v1, don't try to be clever since I seemingly only
> > manage to prove that I'm not clever.
> 
> Only I expect that loop to show up on profiles even higher than the
> sg_next() from pwrite. :|
> 
> I expect it to have a measureable impact upon relocation throughput,
> so I should measure it...
> -Chris
> 
> -- 
> Chris Wilson, Intel Open Source Technology Centre
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> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
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From: Chris Wilson <chris at chris-wilson.co.uk>
Subject: Re: [PATCH] drm/i915: fixup i915_gem_object_get_page inline helper
To: Daniel Vetter <daniel.vetter at ffwll.ch>, Intel Graphics Development <intel-gfx at lists.freedesktop.org>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
In-Reply-To: <1349815848-1824-1-git-send-email-daniel.vetter at ffwll.ch>
References: <84c8a8$624sk4 at orsmga001.jf.intel.com> <1349815848-1824-1-git-send-email-daniel.vetter at ffwll.ch>

On Tue,  9 Oct 2012 22:50:48 +0200, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> The obj->pages to obj->pages->sgl rework introduced this helper, but
> it doesn't actually work for n >= SG_MAX_SINGLE_ALLOC.
> 
> For simplicity (and since right now I seem to be too stupid to see
> the bug), let's just grab the right page with a for_each_sg loop.
> 
> This is exercised by the improved hangman tests and the gem_exec_big
> test in i-g-t.
> 
> v2: Compared to v1, don't try to be clever since I seemingly only
> manage to prove that I'm not clever.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>

Looks like my worries are baseless. It can always be attacked latter if
need be. I'd still like to know what the mistake was...

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre