Am 18.03.24 um 22:40 schrieb Arunpravin Paneer Selvam:
Add clear page support in vram memory region.

v1(Christian):
   - Dont handle clear page as TTM flag since when moving the BO back
     in from GTT again we don't need that.
   - Make a specialized version of amdgpu_fill_buffer() which only
     clears the VRAM areas which are not already cleared
   - Drop the TTM_PL_FLAG_WIPE_ON_RELEASE check in
     amdgpu_object.c

v2:
   - Modify the function name amdgpu_ttm_* (Alex)
   - Drop the delayed parameter (Christian)
   - handle amdgpu_res_cleared(&cursor) just above the size
     calculation (Christian)
   - Use AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE for clearing the buffers
     in the free path to properly wait for fences etc.. (Christian)

v3(Christian):
   - Remove buffer clear code in VRAM manager instead change the
     AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE handling to set
     the DRM_BUDDY_CLEARED flag.
   - Remove ! from amdgpu_res_cleared(&cursor) check.

Signed-off-by: Arunpravin Paneer Selvam <arunpravin.paneersel...@amd.com>
Suggested-by: Christian König <christian.koe...@amd.com>
Acked-by: Felix Kuehling <felix.kuehl...@amd.com>

Just a few nit picks below, but in general already looks good to me.

---
  drivers/gpu/drm/amd/amdgpu/amdgpu_object.c    | 22 ++++---
  .../gpu/drm/amd/amdgpu/amdgpu_res_cursor.h    | 25 ++++++++
  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c       | 61 ++++++++++++++++++-
  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h       |  5 +-
  drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c  |  6 +-
  drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h  |  5 ++
  6 files changed, 111 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index 8bc79924d171..c92d92b28a57 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -39,6 +39,7 @@
  #include "amdgpu.h"
  #include "amdgpu_trace.h"
  #include "amdgpu_amdkfd.h"
+#include "amdgpu_vram_mgr.h"
/**
   * DOC: amdgpu_object
@@ -601,8 +602,7 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
        if (!amdgpu_bo_support_uswc(bo->flags))
                bo->flags &= ~AMDGPU_GEM_CREATE_CPU_GTT_USWC;
- if (adev->ras_enabled)
-               bo->flags |= AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE;
+       bo->flags |= AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE;
bo->tbo.bdev = &adev->mman.bdev;
        if (bp->domain & (AMDGPU_GEM_DOMAIN_GWS | AMDGPU_GEM_DOMAIN_OA |
@@ -632,15 +632,17 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
if (bp->flags & AMDGPU_GEM_CREATE_VRAM_CLEARED &&
            bo->tbo.resource->mem_type == TTM_PL_VRAM) {
-               struct dma_fence *fence;
+               struct dma_fence *fence = NULL;
- r = amdgpu_fill_buffer(bo, 0, bo->tbo.base.resv, &fence, true);
+               r = amdgpu_ttm_clear_buffer(bo, bo->tbo.base.resv, &fence);
                if (unlikely(r))
                        goto fail_unreserve;
- dma_resv_add_fence(bo->tbo.base.resv, fence,
-                                  DMA_RESV_USAGE_KERNEL);
-               dma_fence_put(fence);
+               if (fence) {
+                       dma_resv_add_fence(bo->tbo.base.resv, fence,
+                                          DMA_RESV_USAGE_KERNEL);
+                       dma_fence_put(fence);
+               }
        }
        if (!bp->resv)
                amdgpu_bo_unreserve(bo);
@@ -1365,8 +1367,12 @@ void amdgpu_bo_release_notify(struct ttm_buffer_object 
*bo)
        if (WARN_ON_ONCE(!dma_resv_trylock(bo->base.resv)))
                return;
- r = amdgpu_fill_buffer(abo, AMDGPU_POISON, bo->base.resv, &fence, true);
+       r = amdgpu_fill_buffer(abo, 0, bo->base.resv, &fence, true);
        if (!WARN_ON(r)) {
+               struct amdgpu_vram_mgr_resource *vres;
+
+               vres = to_amdgpu_vram_mgr_resource(bo->resource);
+               vres->flags |= DRM_BUDDY_CLEARED;

Those lines should probably be in the VRAM manager.

                amdgpu_bo_fence(abo, fence, false);
                dma_fence_put(fence);
        }
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
index 381101d2bf05..50fcd86e1033 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_res_cursor.h
@@ -164,4 +164,29 @@ static inline void amdgpu_res_next(struct 
amdgpu_res_cursor *cur, uint64_t size)
        }
  }
+/**
+ * amdgpu_res_cleared - check if blocks are cleared
+ *
+ * @cur: the cursor to extract the block
+ *
+ * Check if the @cur block is cleared
+ */
+static inline bool amdgpu_res_cleared(struct amdgpu_res_cursor *cur)
+{
+       struct drm_buddy_block *block;
+
+       switch (cur->mem_type) {
+       case TTM_PL_VRAM:
+               block = cur->node;
+
+               if (!amdgpu_vram_mgr_is_cleared(block))
+                       return false;
+               break;
+       default:
+               return false;
+       }
+
+       return true;
+}
+
  #endif
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 8722beba494e..bcbffe909b47 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -378,11 +378,15 @@ static int amdgpu_move_blit(struct ttm_buffer_object *bo,
            (abo->flags & AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE)) {
                struct dma_fence *wipe_fence = NULL;
- r = amdgpu_fill_buffer(abo, AMDGPU_POISON, NULL, &wipe_fence,
-                                       false);
+               r = amdgpu_fill_buffer(abo, 0, NULL, &wipe_fence,
+                                      false);
                if (r) {
                        goto error;
                } else if (wipe_fence) {
+                       struct amdgpu_vram_mgr_resource *vres;
+
+                       vres = to_amdgpu_vram_mgr_resource(bo->resource);
+                       vres->flags |= DRM_BUDDY_CLEARED;
                        dma_fence_put(fence);
                        fence = wipe_fence;
                }
@@ -2214,6 +2218,59 @@ static int amdgpu_ttm_fill_mem(struct amdgpu_ring *ring, 
uint32_t src_data,
        return 0;
  }

Some kerneldoc here what the function does would ne nice to have.

+int amdgpu_ttm_clear_buffer(struct amdgpu_bo *bo,
+                           struct dma_resv *resv,
+                           struct dma_fence **fence)
+{
+       struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
+       struct amdgpu_ring *ring = adev->mman.buffer_funcs_ring;
+       struct amdgpu_res_cursor cursor;
+       struct dma_fence *f = NULL;

It might be cleaner to just use the stub fence here (see dma_fence_get_stub()).

This would avoid to local variable init in the caller and the if which checks if the function returned a fence or not.

+       u64 addr;
+       int r;
+
+       if (!adev->mman.buffer_funcs_enabled)
+               return -EINVAL;
+
+       amdgpu_res_first(bo->tbo.resource, 0, amdgpu_bo_size(bo), &cursor);
+
+       mutex_lock(&adev->mman.gtt_window_lock);
+       while (cursor.remaining) {
+               struct dma_fence *next = NULL;
+               u64 size;
+
+               if (amdgpu_res_cleared(&cursor)) {
+                       amdgpu_res_next(&cursor, cursor.size);
+                       continue;
+               }
+
+               /* Never clear more than 256MiB at once to avoid timeouts */
+               size = min(cursor.size, 256ULL << 20);
+
+               r = amdgpu_ttm_map_buffer(&bo->tbo, bo->tbo.resource, &cursor,
+                                         1, ring, false, &size, &addr);
+               if (r)
+                       goto err;
+
+               r = amdgpu_ttm_fill_mem(ring, 0, addr, size, resv,
+                                       &next, true, true);
+               if (r)
+                       goto err;
+
+               dma_fence_put(f);
+               f = next;
+
+               amdgpu_res_next(&cursor, size);
+       }
+err:
+       mutex_unlock(&adev->mman.gtt_window_lock);
+       if (fence)

Just make fence a mandatory parameter and drop the if and the get/put dance.

+               *fence = dma_fence_get(f);
+       dma_fence_put(f);
+
+       return r;
+}
+
  int amdgpu_fill_buffer(struct amdgpu_bo *bo,
                        uint32_t src_data,
                        struct dma_resv *resv,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
index 65ec82141a8e..b404d89d52e5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
@@ -38,8 +38,6 @@
  #define AMDGPU_GTT_MAX_TRANSFER_SIZE  512
  #define AMDGPU_GTT_NUM_TRANSFER_WINDOWS       2
-#define AMDGPU_POISON 0xd0bed0be
-
  extern const struct attribute_group amdgpu_vram_mgr_attr_group;
  extern const struct attribute_group amdgpu_gtt_mgr_attr_group;
@@ -155,6 +153,9 @@ int amdgpu_ttm_copy_mem_to_mem(struct amdgpu_device *adev,
                               uint64_t size, bool tmz,
                               struct dma_resv *resv,
                               struct dma_fence **f);
+int amdgpu_ttm_clear_buffer(struct amdgpu_bo *bo,
+                           struct dma_resv *resv,
+                           struct dma_fence **fence);
  int amdgpu_fill_buffer(struct amdgpu_bo *bo,
                        uint32_t src_data,
                        struct dma_resv *resv,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
index c0c851409241..e494f5bf136a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
@@ -450,6 +450,7 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager 
*man,
  {
        struct amdgpu_vram_mgr *mgr = to_vram_mgr(man);
        struct amdgpu_device *adev = to_amdgpu_device(mgr);
+       struct amdgpu_bo *bo = ttm_to_amdgpu_bo(tbo);
        u64 vis_usage = 0, max_bytes, min_block_size;
        struct amdgpu_vram_mgr_resource *vres;
        u64 size, remaining_size, lpfn, fpfn;
@@ -501,6 +502,9 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager 
*man,
        if (place->flags & TTM_PL_FLAG_CONTIGUOUS)
                vres->flags |= DRM_BUDDY_CONTIGUOUS_ALLOCATION;
+ if (bo->flags & AMDGPU_GEM_CREATE_VRAM_CLEARED)
+               vres->flags |= DRM_BUDDY_CLEAR_ALLOCATION;
+

Mhm, you should probably *not* store this flags in the vres structure.

As soon as the BO is used the VRAM wouldn't be cleared any more.

Regards,
Christian.

        if (fpfn || lpfn != mgr->mm.size)
                /* Allocate blocks in desired range */
                vres->flags |= DRM_BUDDY_RANGE_ALLOCATION;
@@ -604,7 +608,7 @@ static void amdgpu_vram_mgr_del(struct ttm_resource_manager 
*man,
amdgpu_vram_mgr_do_reserve(man); - drm_buddy_free_list(mm, &vres->blocks, 0);
+       drm_buddy_free_list(mm, &vres->blocks, vres->flags);
        mutex_unlock(&mgr->lock);
atomic64_sub(vis_usage, &mgr->vis_usage);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h
index 0e04e42cf809..8478522d7366 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h
@@ -53,6 +53,11 @@ static inline u64 amdgpu_vram_mgr_block_size(struct 
drm_buddy_block *block)
        return (u64)PAGE_SIZE << drm_buddy_block_order(block);
  }
+static inline bool amdgpu_vram_mgr_is_cleared(struct drm_buddy_block *block)
+{
+       return drm_buddy_block_is_clear(block);
+}
+
  static inline struct amdgpu_vram_mgr_resource *
  to_amdgpu_vram_mgr_resource(struct ttm_resource *res)
  {

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