Am 2023-01-09 um 19:01 schrieb Philip Yang:
Use page aligned size to reserve VRAM usage because page aligned TTM BO
size is used to unreserve VRAM usage, otherwise this cause vram_used
accounting unbalanced.

Change vram_used definition type to int64_t to be able to trigger
WARN_ONCE(adev && adev->kfd.vram_used < 0, "..."), to help debug the
accouting issue with warning and backtrace.

Signed-off-by: Philip Yang <philip.y...@amd.com>
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h       | 2 +-
  drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 2 +-
  2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
index fb41869e357a..333780491867 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
@@ -97,7 +97,7 @@ struct amdgpu_amdkfd_fence {
struct amdgpu_kfd_dev {
        struct kfd_dev *dev;
-       uint64_t vram_used;
+       int64_t vram_used;
        uint64_t vram_used_aligned;
        bool init_complete;
        struct work_struct reset_work;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index 2a118669d0e3..f23d94e57762 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -151,7 +151,7 @@ int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device 
*adev,
                 * to avoid fragmentation caused by 4K allocations in the tail
                 * 2M BO chunk.
                 */
-               vram_needed = size;
+               vram_needed = PAGE_ALIGN(size);

This only solves part of the problem. size is used in other places in this function that should all use the page-aligned size. I think we should do the page-alignment at a much higher level, in kfd_ioctl_alloc_memory_of_gpu. That way all the kernel code can safely assume that buffer sizes are page aligned, and we avoid future surprises.

Regards,
  Felix


        } else if (alloc_flag & KFD_IOC_ALLOC_MEM_FLAGS_USERPTR) {
                system_mem_needed = size;
        } else if (!(alloc_flag &

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