Re: [PATCH 3/4] drm/i915: allow volatile buffers to use ttm pool allocator

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





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





[Index of Archives]     [AMD Graphics]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux