drm/amdkfd: evict svm bo worker handle error

Migrate vram to ram may fail to find the vma if process is exiting
and vma is removed, evict svm bo worker sets prange->svm_bo to NULL
and warn svm_bo ref count != 1 only if migrating vram to ram
successfully.

Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index 7f68909..3a29d85 100644 (file)
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -638,6 +638,22 @@ out_oom:
        return r;
 }
 
+/**
+ * svm_migrate_vma_to_ram - migrate range inside one vma from device to system
+ *
+ * @adev: amdgpu device to migrate from
+ * @prange: svm range structure
+ * @vma: vm_area_struct that range [start, end] belongs to
+ * @start: range start virtual address in pages
+ * @end: range end virtual address in pages
+ *
+ * Context: Process context, caller hold mmap read lock, prange->migrate_mutex
+ *
+ * Return:
+ *   0 - success with all pages migrated
+ *   negative values - indicate error
+ *   positive values - partial migration, number of pages not migrated
+ */
 static long
 svm_migrate_vma_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
                       struct vm_area_struct *vma, uint64_t start, uint64_t end)
@@ -709,8 +725,6 @@ out:
                pdd = svm_range_get_pdd_by_adev(prange, adev);
                if (pdd)
                        WRITE_ONCE(pdd->page_out, pdd->page_out + cpages);
-
-               return upages;
        }
        return r ? r : upages;
 }
@@ -720,7 +734,7 @@ out:
  * @prange: range structure
  * @mm: process mm, use current->mm if NULL
  *
- * Context: Process context, caller hold mmap read lock, svms lock, prange lock
+ * Context: Process context, caller hold mmap read lock, prange->migrate_mutex
  *
  * Return:
  * 0 - OK, otherwise error code
@@ -759,13 +773,16 @@ int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm)
                unsigned long next;
 
                vma = find_vma(mm, addr);
-               if (!vma || addr < vma->vm_start)
+               if (!vma || addr < vma->vm_start) {
+                       pr_debug("failed to find vma for prange %p\n", prange);
+                       r = -EFAULT;
                        break;
+               }
 
                next = min(vma->vm_end, end);
                r = svm_migrate_vma_to_ram(adev, prange, vma, addr, next);
                if (r < 0) {
-                       pr_debug("failed %ld to migrate\n", r);
+                       pr_debug("failed %ld to migrate prange %p\n", r, prange);
                        break;
                } else {
                        upages += r;
@@ -773,7 +790,7 @@ int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm)
                addr = next;
        }
 
-       if (!upages) {
+       if (r >= 0 && !upages) {
                svm_range_vram_node_free(prange);
                prange->actual_loc = 0;
        }

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 509d915..3b8856b 100644 (file)
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -3155,6 +3155,7 @@ static void svm_range_evict_svm_bo_worker(struct work_struct *work)
        struct svm_range_bo *svm_bo;
        struct kfd_process *p;
        struct mm_struct *mm;
+       int r = 0;
 
        svm_bo = container_of(work, struct svm_range_bo, eviction_work);
        if (!svm_bo_ref_unless_zero(svm_bo))
@@ -3170,7 +3171,7 @@ static void svm_range_evict_svm_bo_worker(struct work_struct *work)
 
        mmap_read_lock(mm);
        spin_lock(&svm_bo->list_lock);
-       while (!list_empty(&svm_bo->range_list)) {
+       while (!list_empty(&svm_bo->range_list) && !r) {
                struct svm_range *prange =
                                list_first_entry(&svm_bo->range_list,
                                                struct svm_range, svm_bo_list);
@@ -3184,15 +3185,18 @@ static void svm_range_evict_svm_bo_worker(struct work_struct *work)
 
                mutex_lock(&prange->migrate_mutex);
                do {
-                       svm_migrate_vram_to_ram(prange,
+                       r = svm_migrate_vram_to_ram(prange,
                                                svm_bo->eviction_fence->mm);
-               } while (prange->actual_loc && --retries);
-               WARN(prange->actual_loc, "Migration failed during eviction");
+               } while (!r && prange->actual_loc && --retries);
 
-               mutex_lock(&prange->lock);
-               prange->svm_bo = NULL;
-               mutex_unlock(&prange->lock);
+               if (!r && prange->actual_loc)
+                       pr_info_once("Migration failed during eviction");
 
+               if (!prange->actual_loc) {
+                       mutex_lock(&prange->lock);
+                       prange->svm_bo = NULL;
+                       mutex_unlock(&prange->lock);
+               }
                mutex_unlock(&prange->migrate_mutex);
 
                spin_lock(&svm_bo->list_lock);
@@ -3201,10 +3205,11 @@ static void svm_range_evict_svm_bo_worker(struct work_struct *work)
        mmap_read_unlock(mm);
 
        dma_fence_signal(&svm_bo->eviction_fence->base);
+
        /* This is the last reference to svm_bo, after svm_range_vram_node_free
         * has been called in svm_migrate_vram_to_ram
         */
-       WARN_ONCE(kref_read(&svm_bo->kref) != 1, "This was not the last reference\n");
+       WARN_ONCE(!r && kref_read(&svm_bo->kref) != 1, "This was not the last reference\n");
        svm_range_bo_unref(svm_bo);
 }