On 1/9/2024 2:05 PM, Philip Yang wrote:
After svm range partial migrating to system memory, unmap to cleanup the
corresponding dma_addr vram domain flag, otherwise the future split will
get incorrect vram_pages and actual loc.

After range spliting, set new range and old range actual_loc:
new range actual_loc is 0 if new->vram_pages is 0.
old range actual_loc is 0 if old->vram_pages - new->vram_pages == 0.

new range takes svm_bo ref only if vram_pages not equal to 0.

Signed-off-by: Philip Yang <philip.y...@amd.com>
---
  drivers/gpu/drm/amd/amdkfd/kfd_migrate.c |  3 ++
  drivers/gpu/drm/amd/amdkfd/kfd_svm.c     | 35 +++++++++++++++---------
  drivers/gpu/drm/amd/amdkfd/kfd_svm.h     |  3 +-
  3 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index f856901055d3..e85bcda29db6 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -839,6 +839,9 @@ int svm_migrate_vram_to_ram(struct svm_range *prange, 
struct mm_struct *mm,
                        prange->actual_loc = 0;
                        svm_range_vram_node_free(prange);
                }
+
+               svm_range_dma_unmap(prange, start_mgr - prange->start,
+                                   last_mgr - start_mgr + 1);

when come here we know some pages got migrated to sys ram, in theory we do not know if all pages got migrated. svm_range_dma_unmap does dma_unmap for all pages from  start_mgr - prange->start to  last_mgr - start_mgr + 1.

If there are pages not migrated due to some reason(though it is rare) we still need keep its dma_addr, I think only hmm can tell that.

        }
return r < 0 ? r : 0;
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index cc24f30f88fb..2202bdcde057 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -254,6 +254,10 @@ void svm_range_dma_unmap_dev(struct device *dev, 
dma_addr_t *dma_addr,
                return;
for (i = offset; i < offset + npages; i++) {
+               if (dma_addr[i] & SVM_RANGE_VRAM_DOMAIN) {
+                       dma_addr[i] = 0;
+                       continue;
+               }
same as above here set dma_addr[i]=0 unconditionally without knowing if the page is indeed in sys ram.
                if (!svm_is_valid_dma_mapping_addr(dev, dma_addr[i]))
                        continue;
                pr_debug_ratelimited("unmap 0x%llx\n", dma_addr[i] >> 
PAGE_SHIFT);
@@ -262,7 +266,8 @@ void svm_range_dma_unmap_dev(struct device *dev, dma_addr_t 
*dma_addr,
        }
  }
-void svm_range_dma_unmap(struct svm_range *prange)
+void svm_range_dma_unmap(struct svm_range *prange, unsigned long offset,
+                        unsigned long npages)
  {
        struct kfd_process_device *pdd;
        dma_addr_t *dma_addr;
@@ -284,7 +289,7 @@ void svm_range_dma_unmap(struct svm_range *prange)
                }
                dev = &pdd->dev->adev->pdev->dev;
- svm_range_dma_unmap_dev(dev, dma_addr, 0, prange->npages);
+               svm_range_dma_unmap_dev(dev, dma_addr, offset, npages);
        }
  }
@@ -299,7 +304,7 @@ static void svm_range_free(struct svm_range *prange, bool do_unmap) svm_range_vram_node_free(prange);
        if (do_unmap)
-               svm_range_dma_unmap(prange);
+               svm_range_dma_unmap(prange, 0, prange->npages);
if (do_unmap && !p->xnack_enabled) {
                pr_debug("unreserve prange 0x%p size: 0x%llx\n", prange, size);
@@ -362,7 +367,6 @@ svm_range *svm_range_new(struct svm_range_list *svms, 
uint64_t start,
        INIT_LIST_HEAD(&prange->child_list);
        atomic_set(&prange->invalid, 0);
        
-       prange->vram_pages = 0;

still want it as the last patch? I thought you want also remove

prange->validate_timestamp = 0;

and

atomic_set(&prange->invalid, 0);

that are not necessary to set afterkzalloc.

Regards

Xiaogang

        mutex_init(&prange->migrate_mutex);
        mutex_init(&prange->lock);
@@ -980,9 +984,14 @@ svm_range_split_pages(struct svm_range *new, struct svm_range *old,
                if (r)
                        return r;
        }
-       if (old->actual_loc)
+       if (old->actual_loc && new->vram_pages) {
                old->vram_pages -= new->vram_pages;
-
+               new->actual_loc = old->actual_loc;
+               if (!old->vram_pages)
+                       old->actual_loc = 0;
+       }
+       pr_debug("new->vram_pages 0x%llx loc 0x%x old->vram_pages 0x%llx loc 
0x%x\n",
+                new->vram_pages, new->actual_loc, old->vram_pages, 
old->actual_loc);
        return 0;
  }
@@ -1002,13 +1011,14 @@ svm_range_split_nodes(struct svm_range *new, struct svm_range *old,
                new->offset = old->offset + npages;
        }
- new->svm_bo = svm_range_bo_ref(old->svm_bo);
-       new->ttm_res = old->ttm_res;
-
-       spin_lock(&new->svm_bo->list_lock);
-       list_add(&new->svm_bo_list, &new->svm_bo->range_list);
-       spin_unlock(&new->svm_bo->list_lock);
+       if (new->vram_pages) {
+               new->svm_bo = svm_range_bo_ref(old->svm_bo);
+               new->ttm_res = old->ttm_res;
+ spin_lock(&new->svm_bo->list_lock);
+               list_add(&new->svm_bo_list, &new->svm_bo->range_list);
+               spin_unlock(&new->svm_bo->list_lock);
+       }
        return 0;
  }
@@ -1058,7 +1068,6 @@ svm_range_split_adjust(struct svm_range *new, struct svm_range *old,
        new->flags = old->flags;
        new->preferred_loc = old->preferred_loc;
        new->prefetch_loc = old->prefetch_loc;
-       new->actual_loc = old->actual_loc;
        new->granularity = old->granularity;
        new->mapped_to_gpu = old->mapped_to_gpu;
        bitmap_copy(new->bitmap_access, old->bitmap_access, MAX_GPU_INSTANCE);
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h 
b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
index 026863a0abcd..778f108911cd 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
@@ -182,7 +182,8 @@ void svm_range_add_list_work(struct svm_range_list *svms,
  void schedule_deferred_list_work(struct svm_range_list *svms);
  void svm_range_dma_unmap_dev(struct device *dev, dma_addr_t *dma_addr,
                         unsigned long offset, unsigned long npages);
-void svm_range_dma_unmap(struct svm_range *prange);
+void svm_range_dma_unmap(struct svm_range *prange, unsigned long offset,
+                        unsigned long npages);
  int svm_range_get_info(struct kfd_process *p, uint32_t *num_svm_ranges,
                       uint64_t *svm_priv_data_size);
  int kfd_criu_checkpoint_svm(struct kfd_process *p,

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