[PATCH v2 2/2] drm/xe: Opportunistically skip TLB invalidaion on unbind

[Matthew Brost]

If a range or VMA is invalidated and scratch page is disabled, there
is no reason to issue a TLB invalidation on unbind, skip TLB
innvalidation is this condition is true. This is an opportunistic check
as it is done without the notifier lock, thus it possible for the range
or VMA to be invalidated after this check is performed.

This should improve performance of the SVM garbage collector, for
example, xe_exec_system_allocator --r many-stride-new-prefetch, went
~20s to ~9.5s on a BMG.

v2:
 - Use helper for valid check (Thomas)

Signed-off-by: Matthew Brost <matthew.brost at intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>>
---
 drivers/gpu/drm/xe/xe_pt.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c
index 59496c1a1e77..39947fd5c3a2 100644
--- a/drivers/gpu/drm/xe/xe_pt.c
+++ b/drivers/gpu/drm/xe/xe_pt.c
@@ -1988,7 +1988,9 @@ static int unbind_op_prepare(struct xe_tile *tile,
 					 xe_vma_end(vma));
 	++pt_update_ops->current_op;
 	pt_update_ops->needs_userptr_lock |= xe_vma_is_userptr(vma);
-	pt_update_ops->needs_invalidation = true;
+	pt_update_ops->needs_invalidation |= xe_vm_has_scratch(xe_vma_vm(vma)) ||
+		xe_vm_has_valid_gpu_pages(tile, vma->tile_present,
+					  vma->tile_invalidated);
 
 	xe_pt_commit_prepare_unbind(vma, pt_op->entries, pt_op->num_entries);
 
@@ -2023,7 +2025,9 @@ static int unbind_range_prepare(struct xe_vm *vm,
 					 range->base.itree.last + 1);
 	++pt_update_ops->current_op;
 	pt_update_ops->needs_svm_lock = true;
-	pt_update_ops->needs_invalidation = true;
+	pt_update_ops->needs_invalidation |= xe_vm_has_scratch(vm) ||
+		xe_vm_has_valid_gpu_pages(tile, range->tile_present,
+					  range->tile_invalidated);
 
 	xe_pt_commit_prepare_unbind(XE_INVALID_VMA, pt_op->entries,
 				    pt_op->num_entries);
-- 
2.34.1