Re: [PATCH] drm/i915: optimize the shmem_pwrite slowpath handling

Daniel Vetter
2012-11-29T12:48:17Z

On Thu, Nov 15, 2012 at 04:07:45PM +0000, Chris Wilson wrote:
> On Thu, 15 Nov 2012 16:53:58 +0100, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> > Since we drop dev->struct_mutex when going through the slowpath, the
> > object might have been moved out of the cpu domain. Hence we need to
> > clflush the entire object to ensure that after the ioctl returns,
> > everything is coherent again (interwoven writes are ill-defined
> > anyway).
> >
> > But we only need to do this if we start in the cpu domain and the
> > object requires flushing for coherency. So don't do the flushing if
> > the object is coherent anyway or if we've done in-line clfushing
> > already.
> >
> > v2: i915_gem_clflush_object already checks whether the object is
> > coherent and if so, drops the flushing. Hence we don't need to check
> > that ourselves, simplifying the condition.
> >
> > v3: Reorder the checks for better clarify (and adjust the comment
> > accordingly), suggested by Chris Wilson.
> >
> > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>
> Yup, the comment makes much more sense now.
> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

Both patches merged to dinq, thanks a lot for the review comments.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch