On 11/05/2022 13:42, Thomas Hellström wrote:
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@xxxxxxxxxxxxx>
---
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().
agreed. nice catch.
I'll fix for v2
looks like we could maybe do with some extra shrinker testing too? looks
like nothing caught this during CI testing
/Thomas
