openwrt/target/linux/generic/backport-6.1/020-v6.3-28-mm-multi-gen-LRU-simplify-arch_has_hw_pte_young-chec.patch

From cf3297e4c7a928da8b2b2f0baff2f9c69ea57952 Mon Sep 17 00:00:00 2001
From: Yu Zhao <[email protected]>
Date: Wed, 21 Dec 2022 21:19:06 -0700
Subject: [PATCH 28/29] mm: multi-gen LRU: simplify arch_has_hw_pte_young()
 check

Scanning page tables when hardware does not set the accessed bit has
no real use cases.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Yu Zhao <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Michael Larabel <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Roman Gushchin <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
 mm/vmscan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4144,7 +4144,7 @@ static bool try_to_inc_max_seq(struct lr
 	 * handful of PTEs. Spreading the work out over a period of time usually
 	 * is less efficient, but it avoids bursty page faults.
 	 */
-	if (!force_scan && !(arch_has_hw_pte_young() && get_cap(LRU_GEN_MM_WALK))) {
+	if (!arch_has_hw_pte_young() || !get_cap(LRU_GEN_MM_WALK)) {
 		success = iterate_mm_list_nowalk(lruvec, max_seq);
 		goto done;
 	}