Re: [PATCH v2] drm/amdkfd: Let VRAM allocations go to GTT domain on small APUs

[Felix Kuehling]

On 2024-04-30 6:08, Lang Yu wrote:

Small APUs(i.e., consumer, embedded products) usually have a small
carveout device memory which can't satisfy most compute workloads
memory allocation requirements.

We can't even run a Basic MNIST Example with a default 512MB carveout.
https://github.com/pytorch/examples/tree/main/mnist.
Error Log when running mnist:
"torch.cuda.OutOfMemoryError: HIP out of memory. Tried to allocate
84.00 MiB. GPU 0 has a total capacity of 512.00 MiB of which 0 bytes
is free. Of the allocated memory 103.83 MiB is allocated by PyTorch,
and 22.17 MiB is reserved by PyTorch but unallocated"

Though we can change BIOS settings to enlarge carveout size,
which is inflexible and may bring complaint. On the other hand,
the memory resource can't be effectively used between host and device.

The solution is MI300A approach, i.e., let VRAM allocations go to GTT.
Then device and host can effectively share system memory.

v2: Report local_mem_size_private as 0. (Felix)

Signed-off-by: Lang Yu <lang...@amd.com>

Reviewed-by: Felix Kuehling <felix.kuehl...@amd.com>

---
  drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c    |  5 +++++
  .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 20 ++++++++++---------
  drivers/gpu/drm/amd/amdkfd/kfd_migrate.c      |  2 +-
  drivers/gpu/drm/amd/amdkfd/kfd_svm.c          |  6 ++++--
  drivers/gpu/drm/amd/amdkfd/kfd_svm.h          |  3 ++-
  5 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
index 7ba05f030dd1..e3738d417245 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
@@ -455,6 +455,9 @@ void amdgpu_amdkfd_get_local_mem_info(struct amdgpu_device 
*adev,
                else
                        mem_info->local_mem_size_private =
                                        KFD_XCP_MEMORY_SIZE(adev, xcp->id);
+       } else if (adev->flags & AMD_IS_APU) {
+               mem_info->local_mem_size_public = (ttm_tt_pages_limit() << 
PAGE_SHIFT);
+               mem_info->local_mem_size_private = 0;
        } else {
                mem_info->local_mem_size_public = adev->gmc.visible_vram_size;
                mem_info->local_mem_size_private = adev->gmc.real_vram_size -
@@ -824,6 +827,8 @@ u64 amdgpu_amdkfd_xcp_memory_size(struct amdgpu_device 
*adev, int xcp_id)
                }
                do_div(tmp, adev->xcp_mgr->num_xcp_per_mem_partition);
                return ALIGN_DOWN(tmp, PAGE_SIZE);
+       } else if (adev->flags & AMD_IS_APU) {
+               return (ttm_tt_pages_limit() << PAGE_SHIFT);
        } else {
                return adev->gmc.real_vram_size;
        }
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index 4bdf59213384..5843c3d35cb9 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -196,7 +196,7 @@ int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device 
*adev,
                        return -EINVAL;

vram_size = KFD_XCP_MEMORY_SIZE(adev, xcp_id);

-               if (adev->gmc.is_app_apu) {
+               if (adev->gmc.is_app_apu || adev->flags & AMD_IS_APU) {
                        system_mem_needed = size;
                        ttm_mem_needed = size;
                }
@@ -232,7 +232,8 @@ int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device 
*adev,
                  "adev reference can't be null when vram is used");
        if (adev && xcp_id >= 0) {
                adev->kfd.vram_used[xcp_id] += vram_needed;
-               adev->kfd.vram_used_aligned[xcp_id] += adev->gmc.is_app_apu ?
+               adev->kfd.vram_used_aligned[xcp_id] +=
+                               (adev->gmc.is_app_apu || adev->flags & 
AMD_IS_APU) ?
                                vram_needed :
                                ALIGN(vram_needed, VRAM_AVAILABLITY_ALIGN);
        }
@@ -260,7 +261,7 @@ void amdgpu_amdkfd_unreserve_mem_limit(struct amdgpu_device 
*adev,

if (adev) {

                        adev->kfd.vram_used[xcp_id] -= size;
-                       if (adev->gmc.is_app_apu) {
+                       if (adev->gmc.is_app_apu || adev->flags & AMD_IS_APU) {
                                adev->kfd.vram_used_aligned[xcp_id] -= size;
                                kfd_mem_limit.system_mem_used -= size;
                                kfd_mem_limit.ttm_mem_used -= size;
@@ -889,7 +890,7 @@ static int kfd_mem_attach(struct amdgpu_device *adev, 
struct kgd_mem *mem,
         * if peer device has large BAR. In contrast, access over xGMI is
         * allowed for both small and large BAR configurations of peer device
         */
-       if ((adev != bo_adev && !adev->gmc.is_app_apu) &&
+       if ((adev != bo_adev && !(adev->gmc.is_app_apu || adev->flags & AMD_IS_APU)) 
&&
            ((mem->domain == AMDGPU_GEM_DOMAIN_VRAM) ||
             (mem->alloc_flags & KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL) ||
             (mem->alloc_flags & KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP))) {
@@ -1674,7 +1675,7 @@ size_t amdgpu_amdkfd_get_available_memory(struct 
amdgpu_device *adev,
                - atomic64_read(&adev->vram_pin_size)
                - reserved_for_pt;

- if (adev->gmc.is_app_apu) {

+       if (adev->gmc.is_app_apu || adev->flags & AMD_IS_APU) {
                system_mem_available = no_system_mem_limit ?
                                        kfd_mem_limit.max_system_mem_limit :
                                        kfd_mem_limit.max_system_mem_limit -
@@ -1722,7 +1723,7 @@ int amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu(
        if (flags & KFD_IOC_ALLOC_MEM_FLAGS_VRAM) {
                domain = alloc_domain = AMDGPU_GEM_DOMAIN_VRAM;

- if (adev->gmc.is_app_apu) {

+               if (adev->gmc.is_app_apu || adev->flags & AMD_IS_APU) {
                        domain = AMDGPU_GEM_DOMAIN_GTT;
                        alloc_domain = AMDGPU_GEM_DOMAIN_GTT;
                        alloc_flags = 0;
@@ -1973,7 +1974,7 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
        if (size) {
                if (!is_imported &&
                   (mem->bo->preferred_domains == AMDGPU_GEM_DOMAIN_VRAM ||
-                  (adev->gmc.is_app_apu &&
+                  ((adev->gmc.is_app_apu || adev->flags & AMD_IS_APU) &&
                    mem->bo->preferred_domains == AMDGPU_GEM_DOMAIN_GTT)))
                        *size = bo_size;
                else
@@ -2395,8 +2396,9 @@ static int import_obj_create(struct amdgpu_device *adev,
        (*mem)->dmabuf = dma_buf;
        (*mem)->bo = bo;
        (*mem)->va = va;
-       (*mem)->domain = (bo->preferred_domains & AMDGPU_GEM_DOMAIN_VRAM) && 
!adev->gmc.is_app_apu ?
-               AMDGPU_GEM_DOMAIN_VRAM : AMDGPU_GEM_DOMAIN_GTT;
+       (*mem)->domain = (bo->preferred_domains & AMDGPU_GEM_DOMAIN_VRAM) &&
+                        !(adev->gmc.is_app_apu || adev->flags & AMD_IS_APU) ?
+                        AMDGPU_GEM_DOMAIN_VRAM : AMDGPU_GEM_DOMAIN_GTT;

(*mem)->mapped_to_gpu_memory = 0;

        (*mem)->process_info = avm->process_info;
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index 4bcfbeac48fb..4816fcb9803a 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -1023,7 +1023,7 @@ int kgd2kfd_init_zone_device(struct amdgpu_device *adev)
        if (amdgpu_ip_version(adev, GC_HWIP, 0) < IP_VERSION(9, 0, 1))
                return -EINVAL;

- if (adev->gmc.is_app_apu)

+       if (adev->gmc.is_app_apu || adev->flags & AMD_IS_APU)
                return 0;

pgmap = &kfddev->pgmap;

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 386875e6eb96..069b81eeea03 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -2619,7 +2619,8 @@ svm_range_best_restore_location(struct svm_range *prange,
                return -1;
        }

- if (node->adev->gmc.is_app_apu)

+       if (node->adev->gmc.is_app_apu ||
+           node->adev->flags & AMD_IS_APU)
                return 0;

if (prange->preferred_loc == gpuid ||

@@ -3337,7 +3338,8 @@ svm_range_best_prefetch_location(struct svm_range *prange)
                goto out;
        }

- if (bo_node->adev->gmc.is_app_apu) {

+       if (bo_node->adev->gmc.is_app_apu ||
+           bo_node->adev->flags & AMD_IS_APU) {
                best_loc = 0;
                goto out;
        }
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h 
b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
index 026863a0abcd..9c37bd0567ef 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
@@ -201,7 +201,8 @@ void svm_range_list_lock_and_flush_work(struct 
svm_range_list *svms, struct mm_s
   * is initialized to not 0 when page migration register device memory.
   */
  #define KFD_IS_SVM_API_SUPPORTED(adev) ((adev)->kfd.pgmap.type != 0 ||\
-                                       (adev)->gmc.is_app_apu)
+                                       (adev)->gmc.is_app_apu ||\
+                                       ((adev)->flags & AMD_IS_APU))

void svm_range_bo_unref_async(struct svm_range_bo *svm_bo);