Does this really guarantee VRAM placement? The code doesn't say anything about that.

Marek

On Fri, May 6, 2022 at 7:23 AM Christian König <ckoenig.leichtzumerken@gmail.com> wrote:

Add a AMDGPU_GEM_CREATE_DISCARDABLE flag to note that the content of a BO
doesn't needs to be preserved during eviction.

KFD was already using a similar functionality for SVM BOs so replace the
internal flag with the new UAPI.

Only compile tested!

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c    | 4 ++--
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 1 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.h | 1 -
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    | 2 +-
 drivers/gpu/drm/amd/amdkfd/kfd_svm.c       | 2 +-
 include/uapi/drm/amdgpu_drm.h              | 4 ++++
 6 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index 2e16484bf606..bf97d8f07f57 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -302,8 +302,8 @@ int amdgpu_gem_create_ioctl(struct drm_device *dev, void *data,
                      AMDGPU_GEM_CREATE_VRAM_CLEARED |
                      AMDGPU_GEM_CREATE_VM_ALWAYS_VALID |
                      AMDGPU_GEM_CREATE_EXPLICIT_SYNC |
-                     AMDGPU_GEM_CREATE_ENCRYPTED))
-
+                     AMDGPU_GEM_CREATE_ENCRYPTED |
+                     AMDGPU_GEM_CREATE_DISCARDABLE))
                return -EINVAL;

        /* reject invalid gem domains */
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index 8b7ee1142d9a..1944ef37a61e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -567,6 +567,7 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
                bp->domain;
        bo->allowed_domains = bo->preferred_domains;
        if (bp->type != ttm_bo_type_kernel &&
+           !(bp->flags & AMDGPU_GEM_CREATE_DISCARDABLE) &&
            bo->allowed_domains == AMDGPU_GEM_DOMAIN_VRAM)
                bo->allowed_domains |= AMDGPU_GEM_DOMAIN_GTT;

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
index 4c9cbdc66995..147b79c10cbb 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
@@ -41,7 +41,6 @@

 /* BO flag to indicate a KFD userptr BO */
 #define AMDGPU_AMDKFD_CREATE_USERPTR_BO        (1ULL << 63)
-#define AMDGPU_AMDKFD_CREATE_SVM_BO    (1ULL << 62)

 #define to_amdgpu_bo_user(abo) container_of((abo), struct amdgpu_bo_user, bo)
 #define to_amdgpu_bo_vm(abo) container_of((abo), struct amdgpu_bo_vm, bo)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 41d6f604813d..ba3221a25e75 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -117,7 +117,7 @@ static void amdgpu_evict_flags(struct ttm_buffer_object *bo,
        }

        abo = ttm_to_amdgpu_bo(bo);
-       if (abo->flags & AMDGPU_AMDKFD_CREATE_SVM_BO) {
+       if (abo->flags & AMDGPU_GEM_CREATE_DISCARDABLE) {
                placement->num_placement = 0;
                placement->num_busy_placement = 0;
                return;
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 5ed8d9b549a4..835b5187f0b8 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -531,7 +531,7 @@ svm_range_vram_node_new(struct amdgpu_device *adev, struct svm_range *prange,
        bp.domain = AMDGPU_GEM_DOMAIN_VRAM;
        bp.flags = AMDGPU_GEM_CREATE_NO_CPU_ACCESS;
        bp.flags |= clear ? AMDGPU_GEM_CREATE_VRAM_CLEARED : 0;
-       bp.flags |= AMDGPU_AMDKFD_CREATE_SVM_BO;
+       bp.flags |= AMDGPU_GEM_CREATE_DISCARDABLE;
        bp.type = ttm_bo_type_device;
        bp.resv = NULL;

diff --git a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h
index 9a1d210d135d..57b9d8f0133a 100644
--- a/include/uapi/drm/amdgpu_drm.h
+++ b/include/uapi/drm/amdgpu_drm.h
@@ -140,6 +140,10 @@ extern "C" {
  * not require GTT memory accounting
  */
 #define AMDGPU_GEM_CREATE_PREEMPTIBLE          (1 << 11)
+/* Flag that BO can be discarded under memory pressure without keeping the
+ * content.
+ */
+#define AMDGPU_GEM_CREATE_DISCARDABLE          (1 << 12)

 struct drm_amdgpu_gem_create_in  {
        /** the requested memory size */
--
2.25.1