linux-kernel - [PATCH mm-unstable v2 8/8] mm: multi-gen LRU: simplify arch_has_hw_pte

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Message-Id: <20221221001207.1376119-9-yuzhao@google.com>
Date:   Tue, 20 Dec 2022 17:12:08 -0700
From:   Yu Zhao <yuzhao@...gle.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Johannes Weiner <hannes@...xchg.org>,
        Jonathan Corbet <corbet@....net>,
        Michael Larabel <michael@...haellarabel.com>,
        Michal Hocko <mhocko@...nel.org>,
        Mike Rapoport <rppt@...nel.org>,
        Roman Gushchin <roman.gushchin@...ux.dev>,
        Suren Baghdasaryan <surenb@...gle.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, linux-mm@...gle.com,
        Yu Zhao <yuzhao@...gle.com>
Subject: [PATCH mm-unstable v2 8/8] 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.

Signed-off-by: Yu Zhao <yuzhao@...gle.com>
Change-Id: I414310f1cf642d305a16045518517f09ce0eda23
---
 mm/vmscan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 308c3c16d81d..88948f4c8d18 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4430,7 +4430,7 @@ static bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long max_seq,
 	 * 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;
 	}
-- 
2.39.0.314.g84b9a713c41-goog