[PATCH 07/10] drm/amdkfd: skip migration for pages already in VRAM

[Alex Sierra]

Migration skipped for pages that are already in VRAM
domain. These could be the result of previous partial
migrations to SYS RAM, and prefetch back to VRAM.
Ex. Coherent pages in VRAM that were not written/invalidated after
a copy-on-write.

Signed-off-by: Alex Sierra <alex.sierra at amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index 6fd68528c425..8a3f21d76915 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -329,14 +329,15 @@ svm_migrate_copy_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
 	for (i = j = 0; i < npages; i++) {
 		struct page *spage;
 
-		dst[i] = vram_addr + (j << PAGE_SHIFT);
-		migrate->dst[i] = svm_migrate_addr_to_pfn(adev, dst[i]);
-		svm_migrate_get_vram_page(prange, migrate->dst[i]);
-
-		migrate->dst[i] = migrate_pfn(migrate->dst[i]);
-		migrate->dst[i] |= MIGRATE_PFN_LOCKED;
-
-		if (migrate->src[i] & MIGRATE_PFN_VALID) {
+		spage = migrate_pfn_to_page(migrate->src[i]);
+		if (spage && !is_zone_device_page(spage)) {
+			dst[i] = vram_addr + (j << PAGE_SHIFT);
+			migrate->dst[i] = svm_migrate_addr_to_pfn(adev, dst[i]);
+			svm_migrate_get_vram_page(prange, migrate->dst[i]);
+			migrate->dst[i] = migrate_pfn(migrate->dst[i]);
+			migrate->dst[i] |= MIGRATE_PFN_LOCKED;
+		}
+		if (migrate->dst[i] & MIGRATE_PFN_VALID) {
 			spage = migrate_pfn_to_page(migrate->src[i]);
 			src[i] = dma_map_page(dev, spage, 0, PAGE_SIZE,
 					      DMA_TO_DEVICE);
-- 
2.32.0