drm/amdkfd: handle svm partial migration cpages 0

migrate_vma_setup may return cpages 0, means 0 page can be migrated,
treat this as error case to skip the rest of vma migration steps.

Change svm_migrate_vma_to_vram and svm_migrate_vma_to_ram to return the
number of pages migrated successfully or error code. The caller add up
all the successful migration pages and update prange->actual_loc only if
the total migrated pages is not 0.

This also removes the warning message "VRAM BO missing during
validation" if migration cpages is 0.

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 b05c057..147300a 100644 (file)
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -376,7 +376,7 @@ out:
        return r;
 }
 
-static int
+static long
 svm_migrate_vma_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
                        struct vm_area_struct *vma, uint64_t start,
                        uint64_t end)
@@ -413,32 +413,37 @@ svm_migrate_vma_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
                        prange->start, prange->last);
                goto out_free;
        }
-       if (migrate.cpages != npages) {
-               pr_debug("Partial migration. 0x%lx/0x%llx pages can be migrated\n",
-                        migrate.cpages,
-                        npages);
-       }
 
-       if (migrate.cpages) {
-               r = svm_migrate_copy_to_vram(adev, prange, &migrate, &mfence,
-                                            scratch);
-               migrate_vma_pages(&migrate);
-               svm_migrate_copy_done(adev, mfence);
-               migrate_vma_finalize(&migrate);
+       if (migrate.cpages != npages)
+               pr_debug("partial migration, 0x%lx/0x%llx pages migrated\n",
+                        migrate.cpages, npages);
+       else
+               pr_debug("0x%lx pages migrated\n", migrate.cpages);
+
+       if (!migrate.cpages) {
+               pr_debug("failed collect migrate sys pages [0x%lx 0x%lx]\n",
+                        prange->start, prange->last);
+               goto out_free;
        }
 
+       r = svm_migrate_copy_to_vram(adev, prange, &migrate, &mfence, scratch);
+       migrate_vma_pages(&migrate);
+       svm_migrate_copy_done(adev, mfence);
+       migrate_vma_finalize(&migrate);
+
        svm_range_dma_unmap(adev->dev, scratch, 0, npages);
        svm_range_free_dma_mappings(prange);
 
 out_free:
        kvfree(buf);
 out:
-       if (!r) {
+       if (!r && migrate.cpages) {
                pdd = svm_range_get_pdd_by_adev(prange, adev);
                if (pdd)
                        WRITE_ONCE(pdd->page_in, pdd->page_in + migrate.cpages);
-       }
 
+               return migrate.cpages;
+       }
        return r;
 }
 
@@ -460,7 +465,8 @@ svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc,
        unsigned long addr, start, end;
        struct vm_area_struct *vma;
        struct amdgpu_device *adev;
-       int r = 0;
+       unsigned long cpages = 0;
+       long r = 0;
 
        if (prange->actual_loc == best_loc) {
                pr_debug("svms 0x%p [0x%lx 0x%lx] already on best_loc 0x%x\n",
@@ -492,17 +498,19 @@ svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc,
 
                next = min(vma->vm_end, end);
                r = svm_migrate_vma_to_vram(adev, prange, vma, addr, next);
-               if (r) {
-                       pr_debug("failed to migrate\n");
+               if (r < 0) {
+                       pr_debug("failed %ld to migrate\n", r);
                        break;
+               } else {
+                       cpages += r;
                }
                addr = next;
        }
 
-       if (!r)
+       if (cpages)
                prange->actual_loc = best_loc;
 
-       return r;
+       return r < 0 ? r : 0;
 }
 
 static void svm_migrate_page_free(struct page *page)
@@ -603,7 +611,7 @@ out_oom:
        return r;
 }
 
-static int
+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)
 {
@@ -640,29 +648,35 @@ svm_migrate_vma_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
                goto out_free;
        }
 
-       pr_debug("cpages %ld\n", migrate.cpages);
+       if (migrate.cpages != npages)
+               pr_debug("partial migration, 0x%lx/0x%llx pages migrated\n",
+                        migrate.cpages, npages);
+       else
+               pr_debug("0x%lx pages migrated\n", migrate.cpages);
 
-       if (migrate.cpages) {
-               r = svm_migrate_copy_to_ram(adev, prange, &migrate, &mfence,
-                                           scratch, npages);
-               migrate_vma_pages(&migrate);
-               svm_migrate_copy_done(adev, mfence);
-               migrate_vma_finalize(&migrate);
-       } else {
+       if (!migrate.cpages) {
                pr_debug("failed collect migrate device pages [0x%lx 0x%lx]\n",
                         prange->start, prange->last);
+               goto out_free;
        }
 
+       r = svm_migrate_copy_to_ram(adev, prange, &migrate, &mfence,
+                                   scratch, npages);
+       migrate_vma_pages(&migrate);
+       svm_migrate_copy_done(adev, mfence);
+       migrate_vma_finalize(&migrate);
        svm_range_dma_unmap(adev->dev, scratch, 0, npages);
 
 out_free:
        kvfree(buf);
 out:
-       if (!r) {
+       if (!r && migrate.cpages) {
                pdd = svm_range_get_pdd_by_adev(prange, adev);
                if (pdd)
                        WRITE_ONCE(pdd->page_out,
                                   pdd->page_out + migrate.cpages);
+
+               return migrate.cpages;
        }
        return r;
 }
@@ -684,7 +698,8 @@ int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm)
        unsigned long addr;
        unsigned long start;
        unsigned long end;
-       int r = 0;
+       unsigned long cpages = 0;
+       long r = 0;
 
        if (!prange->actual_loc) {
                pr_debug("[0x%lx 0x%lx] already migrated to ram\n",
@@ -715,18 +730,21 @@ int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm)
 
                next = min(vma->vm_end, end);
                r = svm_migrate_vma_to_ram(adev, prange, vma, addr, next);
-               if (r) {
-                       pr_debug("failed %d to migrate\n", r);
+               if (r < 0) {
+                       pr_debug("failed %ld to migrate\n", r);
                        break;
+               } else {
+                       cpages += r;
                }
                addr = next;
        }
 
-       if (!r) {
+       if (cpages) {
                svm_range_vram_node_free(prange);
                prange->actual_loc = 0;
        }
-       return r;
+
+       return r < 0 ? r : 0;
 }
 
 /**