| Message ID | 20240808063812.1293955-1-lincao12@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/buddy: fix issue that force_merge cannot free all roots | expand |
Hi, On 08/08/2024 07:38, Lin.Cao wrote: > If buddy manager have more than one roots and each root have sub-block > need to be free. When drm_buddy_fini called, the first loop of > force_merge will merge and free all of the sub block of first root, > which offset is 0x0 and size is biggest(more than have of the mm size). > In subsequent force_merge rounds, if we use 0 as start and use remaining > mm size as end, the block of other roots will be skipped in > __force_merge function. It will cause the other roots can not be freed. > > Solution: use roots' offset as the start could fix this issue. > > Signed-off-by: Lin.Cao <lincao12@amd.com> Nice catch. > --- > drivers/gpu/drm/drm_buddy.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c > index 94f8c34fc293..5379687552bc 100644 > --- a/drivers/gpu/drm/drm_buddy.c > +++ b/drivers/gpu/drm/drm_buddy.c > @@ -327,12 +327,14 @@ void drm_buddy_fini(struct drm_buddy *mm) > u64 root_size, size; > unsigned int order; > int i; > + u64 start = 0; Nit: We could maybe move this into root_size, size or even into the loop body below? Also no need to init. > > size = mm->size; > > for (i = 0; i < mm->n_roots; ++i) { > order = ilog2(size) - ilog2(mm->chunk_size); > - __force_merge(mm, 0, size, order); > + start = drm_buddy_block_offset(mm->roots[i]); > + __force_merge(mm, start, start + size, order); > > WARN_ON(!drm_buddy_block_is_free(mm->roots[i])); We do seem to have a testcase for this at the bottom of drm_test_buddy_alloc_clear(), so either it is not triggering the WARN_ON() here in which case we should maybe improve that. Or it is, but kunit doesn't treat that as a test failure? Maybe we can call something like kunit_fail_current_test() here if that WARN_ON is triggered? For reference our CI is just running all drm selftests with: /kernel/tools/testing/kunit/kunit.py run --kunitconfig /kernel/drivers/gpu/drm/tests/.kunitconfig > drm_block_free(mm, mm->roots[i]);
diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c index 94f8c34fc293..5379687552bc 100644 --- a/drivers/gpu/drm/drm_buddy.c +++ b/drivers/gpu/drm/drm_buddy.c @@ -327,12 +327,14 @@ void drm_buddy_fini(struct drm_buddy *mm) u64 root_size, size; unsigned int order; int i; + u64 start = 0; size = mm->size; for (i = 0; i < mm->n_roots; ++i) { order = ilog2(size) - ilog2(mm->chunk_size); - __force_merge(mm, 0, size, order); + start = drm_buddy_block_offset(mm->roots[i]); + __force_merge(mm, start, start + size, order); WARN_ON(!drm_buddy_block_is_free(mm->roots[i])); drm_block_free(mm, mm->roots[i]);
If buddy manager have more than one roots and each root have sub-block need to be free. When drm_buddy_fini called, the first loop of force_merge will merge and free all of the sub block of first root, which offset is 0x0 and size is biggest(more than have of the mm size). In subsequent force_merge rounds, if we use 0 as start and use remaining mm size as end, the block of other roots will be skipped in __force_merge function. It will cause the other roots can not be freed. Solution: use roots' offset as the start could fix this issue. Signed-off-by: Lin.Cao <lincao12@amd.com> --- drivers/gpu/drm/drm_buddy.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)