Messages in this thread Patch in this message | | | Subject | Re: [PATCH 3/4] drm/i915: allow volatile buffers to use ttm pool allocator | From | Thomas Hellström <> | Date | Wed, 11 May 2022 14:42:51 +0200 |
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Hi, Bob,
On Tue, 2022-05-03 at 19:13 +0000, Robert Beckett wrote: > internal buffers should be shmem backed. > if a volatile buffer is requested, allow ttm to use the pool > allocator > to provide volatile pages as backing > > Signed-off-by: Robert Beckett <bob.beckett@collabora.com> > --- > drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c > b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c > index 4c25d9b2f138..fdb3a1c18cb6 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c > +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c > @@ -309,7 +309,8 @@ static struct ttm_tt *i915_ttm_tt_create(struct > ttm_buffer_object *bo, > page_flags |= TTM_TT_FLAG_ZERO_ALLOC; > > caching = i915_ttm_select_tt_caching(obj); > - if (i915_gem_object_is_shrinkable(obj) && caching == > ttm_cached) { > + if (i915_gem_object_is_shrinkable(obj) && caching == > ttm_cached && > + !i915_gem_object_is_volatile(obj)) { > page_flags |= TTM_TT_FLAG_EXTERNAL | > TTM_TT_FLAG_EXTERNAL_MAPPABLE; > i915_tt->is_shmem = true;
While this is ok, I think it also needs adjustment in the i915_ttm shrink callback. If someone creates a volatile smem object which then hits the shrinker, I think we might hit asserts that it's a is_shem ttm?
In this case, the shrink callback should just i915_ttm_purge().
/Thomas
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