Am 29.03.22 um 13:28 schrieb Arunpravin Paneer Selvam:
On 23/03/22 1:15 pm, Christian König wrote:
Am 23.03.22 um 08:34 schrieb Arunpravin Paneer Selvam:
Add a simple check to reject any size not aligned to the
min_page_size.
handle instances when size is not aligned with the min_page_size.
Unigine Heaven has allocation requests for example required pages
are 257 and alignment request is 256. To allocate the left over 1
page, continues the iteration to find the order value which is 0
and when it compares with min_order = 8, triggers the BUG_ON(order
< min_order). To avoid this problem, we added a simple check to
return -EINVAL if size is not aligned to the min_page_size.
v2: Added more details to the commit description
Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@xxxxxxx>
Suggested-by: Matthew Auld <matthew.auld@xxxxxxxxx>
---
drivers/gpu/drm/drm_buddy.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
index 72f52f293249..b503c88786b0 100644
--- a/drivers/gpu/drm/drm_buddy.c
+++ b/drivers/gpu/drm/drm_buddy.c
@@ -661,6 +661,9 @@ int drm_buddy_alloc_blocks(struct drm_buddy *mm,
if (range_overflows(start, size, mm->size))
return -EINVAL;
+ if (WARN_ON(!IS_ALIGNED(size, min_page_size)))
+ return -EINVAL;
+
I'm not that happy with the handling here.
See a minimum page size larger than the requested size is perfectly
valid, it just means that the remaining pages needs to be trimmed.
In other words when the request is to allocate 1 page with an alignment
of 256 we just need to give the remaining 255 pages back to the allocator.
In one of the previous mail Matthew explained that i915 expects to
return -EINVAL error code if size is not aligned to min_page_size.
can we just modify in amdgpu code where we round_up the size to the
min_page_size value and keep this error handling in drm_buddy.c?
Yeah, I'm fine with that as well now.
I realized that this is probably the easiest option to check if an
allocation is contiguous or not between the alloc and trim.
So having two functions for that sounds like a good idea to me.
Thanks,
Christian.
Regards,
Christian.
/* Actual range allocation */
if (start + size == end)
return __drm_buddy_alloc_range(mm, start, size, blocks);
base-commit: 056d47eaf6ea753fa2e21da31f9cbd8b721bbb7b
