[PATCH 2/2] drm/amdkfd: track unified memory reservation with xnack off

Alex Sierra alex.sierra at amd.com
Tue May 17 23:11:08 UTC 2022


[WHY]
Unified memory with xnack off should be tracked, as userptr mappings
and legacy allocations do. To avoid oversuscribe system memory when
xnack off.
[How]
Exposing functions reserve_mem_limit and unreserve_mem_limit to SVM
API and call them on every prange creation and free.

Signed-off-by: Alex Sierra <alex.sierra at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h    |  4 +++
 .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 24 +++++++------
 drivers/gpu/drm/amd/amdkfd/kfd_svm.c          | 34 ++++++++++++++-----
 3 files changed, 43 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
index f8b9f27adcf5..f55f34af6480 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
@@ -301,6 +301,10 @@ bool amdgpu_amdkfd_bo_mapped_to_dev(struct amdgpu_device *adev, struct kgd_mem *
 void amdgpu_amdkfd_block_mmu_notifications(void *p);
 int amdgpu_amdkfd_criu_resume(void *p);
 bool amdgpu_amdkfd_ras_query_utcl2_poison_status(struct amdgpu_device *adev);
+int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device *adev,
+		uint64_t size, u32 alloc_flag);
+void amdgpu_amdkfd_unreserve_mem_limit(struct amdgpu_device *adev,
+		uint64_t size, u32 alloc_flag);
 
 #if IS_ENABLED(CONFIG_HSA_AMD)
 void amdgpu_amdkfd_gpuvm_init_mem_limits(void);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index e985cf9c7ec0..b2236159ff39 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -122,7 +122,7 @@ void amdgpu_amdkfd_reserve_system_mem(uint64_t size)
  *
  * Return: returns -ENOMEM in case of error, ZERO otherwise
  */
-static int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device *adev,
+int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device *adev,
 		uint64_t size, u32 alloc_flag)
 {
 	uint64_t reserved_for_pt =
@@ -157,8 +157,8 @@ static int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device *adev,
 	     kfd_mem_limit.max_system_mem_limit && !no_system_mem_limit) ||
 	    (kfd_mem_limit.ttm_mem_used + ttm_mem_needed >
 	     kfd_mem_limit.max_ttm_mem_limit) ||
-	    (adev->kfd.vram_used + vram_needed >
-	     adev->gmc.real_vram_size - reserved_for_pt)) {
+	    (adev && (adev->kfd.vram_used + vram_needed >
+	     adev->gmc.real_vram_size - reserved_for_pt))) {
 		ret = -ENOMEM;
 		goto release;
 	}
@@ -166,7 +166,8 @@ static int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device *adev,
 	/* Update memory accounting by decreasing available system
 	 * memory, TTM memory and GPU memory as computed above
 	 */
-	adev->kfd.vram_used += vram_needed;
+	if (adev)
+		adev->kfd.vram_used += vram_needed;
 	kfd_mem_limit.system_mem_used += system_mem_needed;
 	kfd_mem_limit.ttm_mem_used += ttm_mem_needed;
 
@@ -175,7 +176,7 @@ static int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device *adev,
 	return ret;
 }
 
-static void unreserve_mem_limit(struct amdgpu_device *adev,
+void amdgpu_amdkfd_unreserve_mem_limit(struct amdgpu_device *adev,
 		uint64_t size, u32 alloc_flag)
 {
 	spin_lock(&kfd_mem_limit.mem_limit_lock);
@@ -184,7 +185,8 @@ static void unreserve_mem_limit(struct amdgpu_device *adev,
 		kfd_mem_limit.system_mem_used -= size;
 		kfd_mem_limit.ttm_mem_used -= size;
 	} else if (alloc_flag & KFD_IOC_ALLOC_MEM_FLAGS_VRAM) {
-		adev->kfd.vram_used -= size;
+		if (adev)
+			adev->kfd.vram_used -= size;
 	} else if (alloc_flag & KFD_IOC_ALLOC_MEM_FLAGS_USERPTR) {
 		kfd_mem_limit.system_mem_used -= size;
 	} else if (!(alloc_flag &
@@ -193,9 +195,9 @@ static void unreserve_mem_limit(struct amdgpu_device *adev,
 		pr_err("%s: Invalid BO type %#x\n", __func__, alloc_flag);
 		goto release;
 	}
-
-	WARN_ONCE(adev->kfd.vram_used < 0,
-		  "KFD VRAM memory accounting unbalanced");
+	if (adev)
+		WARN_ONCE(adev->kfd.vram_used < 0,
+			"KFD VRAM memory accounting unbalanced");
 	WARN_ONCE(kfd_mem_limit.ttm_mem_used < 0,
 		  "KFD TTM memory accounting unbalanced");
 	WARN_ONCE(kfd_mem_limit.system_mem_used < 0,
@@ -211,7 +213,7 @@ void amdgpu_amdkfd_release_notify(struct amdgpu_bo *bo)
 	u32 alloc_flags = bo->kfd_bo->alloc_flags;
 	u64 size = amdgpu_bo_size(bo);
 
-	unreserve_mem_limit(adev, size, alloc_flags);
+	amdgpu_amdkfd_unreserve_mem_limit(adev, size, alloc_flags);
 
 	kfree(bo->kfd_bo);
 }
@@ -1601,7 +1603,7 @@ int amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu(
 	/* Don't unreserve system mem limit twice */
 	goto err_reserve_limit;
 err_bo_create:
-	unreserve_mem_limit(adev, size, flags);
+	amdgpu_amdkfd_unreserve_mem_limit(adev, size, flags);
 err_reserve_limit:
 	mutex_destroy(&(*mem)->lock);
 	if (gobj)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 5ed8d9b549a4..e7e9b388fea4 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -261,11 +261,21 @@ void svm_range_free_dma_mappings(struct svm_range *prange)
 
 static void svm_range_free(struct svm_range *prange)
 {
+	uint64_t size = (prange->last - prange->start + 1) << PAGE_SHIFT;
+	struct kfd_process *p;
+
 	pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx]\n", prange->svms, prange,
 		 prange->start, prange->last);
 
 	svm_range_vram_node_free(prange);
 	svm_range_free_dma_mappings(prange);
+
+	p = container_of(prange->svms, struct kfd_process, svms);
+	if (!p->xnack_enabled) {
+		pr_debug("unreserve mem limit: %lld\n", size);
+		amdgpu_amdkfd_unreserve_mem_limit(NULL, size,
+					KFD_IOC_ALLOC_MEM_FLAGS_USERPTR);
+	}
 	mutex_destroy(&prange->lock);
 	mutex_destroy(&prange->migrate_mutex);
 	kfree(prange);
@@ -284,7 +294,7 @@ svm_range_set_default_attributes(int32_t *location, int32_t *prefetch_loc,
 
 static struct
 svm_range *svm_range_new(struct svm_range_list *svms, uint64_t start,
-			 uint64_t last)
+			 uint64_t last, bool is_new_alloc)
 {
 	uint64_t size = last - start + 1;
 	struct svm_range *prange;
@@ -293,6 +303,15 @@ svm_range *svm_range_new(struct svm_range_list *svms, uint64_t start,
 	prange = kzalloc(sizeof(*prange), GFP_KERNEL);
 	if (!prange)
 		return NULL;
+
+	p = container_of(svms, struct kfd_process, svms);
+	if (!p->xnack_enabled && is_new_alloc &&
+	    amdgpu_amdkfd_reserve_mem_limit(NULL, size << PAGE_SHIFT,
+					    KFD_IOC_ALLOC_MEM_FLAGS_USERPTR)) {
+		pr_err("Failed to allocate usrptr memory\n");
+		kfree(prange);
+		return NULL;
+	}
 	prange->npages = size;
 	prange->svms = svms;
 	prange->start = start;
@@ -307,7 +326,6 @@ svm_range *svm_range_new(struct svm_range_list *svms, uint64_t start,
 	mutex_init(&prange->migrate_mutex);
 	mutex_init(&prange->lock);
 
-	p = container_of(svms, struct kfd_process, svms);
 	if (p->xnack_enabled)
 		bitmap_copy(prange->bitmap_access, svms->bitmap_supported,
 			    MAX_GPU_INSTANCE);
@@ -1000,9 +1018,9 @@ svm_range_split(struct svm_range *prange, uint64_t start, uint64_t last,
 
 	svms = prange->svms;
 	if (old_start == start)
-		*new = svm_range_new(svms, last + 1, old_last);
+		*new = svm_range_new(svms, last + 1, old_last, false);
 	else
-		*new = svm_range_new(svms, old_start, start - 1);
+		*new = svm_range_new(svms, old_start, start - 1, false);
 	if (!*new)
 		return -ENOMEM;
 
@@ -1825,7 +1843,7 @@ static struct svm_range *svm_range_clone(struct svm_range *old)
 {
 	struct svm_range *new;
 
-	new = svm_range_new(old->svms, old->start, old->last);
+	new = svm_range_new(old->svms, old->start, old->last, true);
 	if (!new)
 		return NULL;
 
@@ -1951,7 +1969,7 @@ svm_range_add(struct kfd_process *p, uint64_t start, uint64_t size,
 
 		/* insert a new node if needed */
 		if (node->start > start) {
-			prange = svm_range_new(svms, start, node->start - 1);
+			prange = svm_range_new(svms, start, node->start - 1, true);
 			if (!prange) {
 				r = -ENOMEM;
 				goto out;
@@ -1967,7 +1985,7 @@ svm_range_add(struct kfd_process *p, uint64_t start, uint64_t size,
 
 	/* add a final range at the end if needed */
 	if (start <= last) {
-		prange = svm_range_new(svms, start, last);
+		prange = svm_range_new(svms, start, last, true);
 		if (!prange) {
 			r = -ENOMEM;
 			goto out;
@@ -2585,7 +2603,7 @@ svm_range *svm_range_create_unregistered_range(struct amdgpu_device *adev,
 		last = addr;
 	}
 
-	prange = svm_range_new(&p->svms, start, last);
+	prange = svm_range_new(&p->svms, start, last, true);
 	if (!prange) {
 		pr_debug("Failed to create prange in address [0x%llx]\n", addr);
 		return NULL;
-- 
2.32.0



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