Commit bcc28720 authored by Matthew Brost's avatar Matthew Brost
Browse files

drm/xe: Opportunistically skip TLB invalidaion on unbind 



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
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)
v3:
 - Avoid skipping TLB invalidation if PTEs are removed at a higher
   level than the range
 - Never skip TLB invalidations for VMA
 - Drop Himal's RB

Signed-off-by: default avatarMatthew Brost <matthew.brost@intel.com>
Reviewed-by: default avatarHimal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://lore.kernel.org/r/20250616063024.2059829-3-matthew.brost@intel.com
parent fab76ce5

drivers/gpu/drm/xe/xe_pt.c

+30 −1
Original line number Diff line number Diff line
@@ -1995,6 +1995,32 @@ static int unbind_op_prepare(struct xe_tile *tile, 
	return 0;

}



static bool

xe_pt_op_check_range_skip_invalidation(struct xe_vm_pgtable_update_op *pt_op,

				       struct xe_svm_range *range)

{

	struct xe_vm_pgtable_update *update = pt_op->entries;



	XE_WARN_ON(!pt_op->num_entries);



	/*

	 * We can't skip the invalidation if we are removing PTEs that span more

	 * than the range, do some checks to ensure we are removing PTEs that

	 * are invalid.

	 */



	if (pt_op->num_entries > 1)

		return false;



	if (update->pt->level == 0)

		return true;



	if (update->pt->level == 1)

		return xe_svm_range_size(range) >= SZ_2M;



	return false;

}



static int unbind_range_prepare(struct xe_vm *vm,

				struct xe_tile *tile,

				struct xe_vm_pgtable_update_ops *pt_update_ops,
@@ -2023,7 +2049,10 @@ 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_mapping(tile, range->tile_present,

					    range->tile_invalidated) ||

		!xe_pt_op_check_range_skip_invalidation(pt_op, range);



	xe_pt_commit_prepare_unbind(XE_INVALID_VMA, pt_op->entries,

				    pt_op->num_entries);