drm/xe/madvise: Skip vma invalidation if mem attr are unchanged

If a VMA within the madvise input range already has the same memory
attribute as the one requested by the user, skip PTE zapping for that
VMA to avoid unnecessary invalidation.

v2 (Matthew Brost)
- fix skip_invalidation for new attributes
- s/u32/bool
- Remove unnecessary assignment for kzalloc'ed

Suggested-by: Matthew Brost <[e-mail]>
Reviewed-by: Matthew Brost <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Himal Prasad Ghimiray <[e-mail]>

drivers/gpu/drm/xe/xe_vm_madvise.c

···
 
 	for (i = 0; i < num_vmas; i++) {
 		/*TODO: Extend attributes to bo based vmas */
-		if (!xe_vma_is_cpu_addr_mirror(vmas[i]))
-			continue;
-
-		vmas[i]->attr.preferred_loc.devmem_fd = op->preferred_mem_loc.devmem_fd;
-
-		/* Till multi-device support is not added migration_policy
-		 * is of no use and can be ignored.
-		 */
-		vmas[i]->attr.preferred_loc.migration_policy =
+		if ((vmas[i]->attr.preferred_loc.devmem_fd == op->preferred_mem_loc.devmem_fd &&
+		     vmas[i]->attr.preferred_loc.migration_policy ==
+		     op->preferred_mem_loc.migration_policy) ||
+		    !xe_vma_is_cpu_addr_mirror(vmas[i])) {
+			vmas[i]->skip_invalidation = true;
+		} else {
+			vmas[i]->skip_invalidation = false;
+			vmas[i]->attr.preferred_loc.devmem_fd = op->preferred_mem_loc.devmem_fd;
+			/* Till multi-device support is not added migration_policy
+			 * is of no use and can be ignored.
+			 */
+			vmas[i]->attr.preferred_loc.migration_policy =
 						op->preferred_mem_loc.migration_policy;
+		}
 	}
 }
 
···
 	xe_assert(vm->xe, op->atomic.val <= DRM_XE_ATOMIC_CPU);
 
 	for (i = 0; i < num_vmas; i++) {
-		if ((xe_vma_is_userptr(vmas[i]) &&
-		     !(op->atomic.val == DRM_XE_ATOMIC_DEVICE &&
-		       xe->info.has_device_atomics_on_smem)))
+		if (xe_vma_is_userptr(vmas[i]) &&
+		    !(op->atomic.val == DRM_XE_ATOMIC_DEVICE &&
+		      xe->info.has_device_atomics_on_smem)) {
+			vmas[i]->skip_invalidation = true;
 			continue;
+		}
+
+		if (vmas[i]->attr.atomic_access == op->atomic.val) {
+			vmas[i]->skip_invalidation = true;
+		} else {
+			vmas[i]->skip_invalidation = false;
+			vmas[i]->attr.atomic_access = op->atomic.val;
+		}
 
 		vmas[i]->attr.atomic_access = op->atomic.val;
 
 		bo = xe_vma_bo(vmas[i]);
-		if (!bo)
+		if (!bo || bo->attr.atomic_access == op->atomic.val)
 			continue;
 
+		vmas[i]->skip_invalidation = false;
 		xe_bo_assert_held(bo);
 		bo->attr.atomic_access = op->atomic.val;
 
···
 
 	xe_assert(vm->xe, op->type == DRM_XE_MEM_RANGE_ATTR_PAT);
 
-	for (i = 0; i < num_vmas; i++)
-		vmas[i]->attr.pat_index = op->pat_index.val;
+	for (i = 0; i < num_vmas; i++) {
+		if (vmas[i]->attr.pat_index == op->pat_index.val) {
+			vmas[i]->skip_invalidation = true;
+		} else {
+			vmas[i]->skip_invalidation = false;
+			vmas[i]->attr.pat_index = op->pat_index.val;
+		}
+	}
 }
 
 typedef void (*madvise_func)(struct xe_device *xe, struct xe_vm *vm,
···
 {
 	struct drm_gpuva *gpuva;
 	struct xe_tile *tile;
-	u8 id, tile_mask;
+	u8 id, tile_mask = 0;
 
 	lockdep_assert_held_write(&vm->lock);
 
···
 				  false, MAX_SCHEDULE_TIMEOUT) <= 0)
 		XE_WARN_ON(1);
 
-	tile_mask = xe_svm_ranges_zap_ptes_in_range(vm, start, end);
-
 	drm_gpuvm_for_each_va_range(gpuva, &vm->gpuvm, start, end) {
 		struct xe_vma *vma = gpuva_to_vma(gpuva);
 
-		if (xe_vma_is_cpu_addr_mirror(vma) || xe_vma_is_null(vma))
+		if (vma->skip_invalidation || xe_vma_is_null(vma))
 			continue;
 
-		for_each_tile(tile, vm->xe, id) {
-			if (xe_pt_zap_ptes(tile, vma)) {
-				tile_mask |= BIT(id);
+		if (xe_vma_is_cpu_addr_mirror(vma)) {
+			tile_mask |= xe_svm_ranges_zap_ptes_in_range(vm,
+								      xe_vma_start(vma),
+								      xe_vma_end(vma));
+		} else {
+			for_each_tile(tile, vm->xe, id) {
+				if (xe_pt_zap_ptes(tile, vma)) {
+					tile_mask |= BIT(id);
 
 				/*
 				 * WRITE_ONCE pairs with READ_ONCE
···
 				 */
 				WRITE_ONCE(vma->tile_invalidated,
 					   vma->tile_invalidated | BIT(id));
+				}
 			}
 		}
 	}

drivers/gpu/drm/xe/xe_vm_types.h

···
 	u8 tile_staged;
 
 	/**
+	 * @skip_invalidation: Used in madvise to avoid invalidation
+	 * if mem attributes doesn't change
+	 */
+	bool skip_invalidation;
+
+	/**
 	 * @ufence: The user fence that was provided with MAP.
 	 * Needs to be signalled before UNMAP can be processed.
 	 */