Re: [PATCH v3 1/4] mm: avoid unnecessary lru drain for wp_can_reuse_anon_folio()

["Barry Song (Xiaomi)" <baohua@kernel.org>]

On Tue, Jul 7, 2026 at 11:58 PM David Hildenbrand (Arm) <david@kernel.org> wrote:
>
> On 7/7/26 17:26, Kairui Song wrote:
> > On Mon, Jul 6, 2026 at 4:54 PM Barry Song <baohua@kernel.org> wrote:
> >>
> >> On Thu, Jul 2, 2026 at 4:05 PM David Hildenbrand (Arm) <david@kernel.org> wrote:
> >>>
> >>> The other folks should probably re-review this patch that changed quite a bit :)
> >>>
> >>>
> >>> Acked-by: David Hildenbrand (Arm) <david@kernel.org>
> >>
> >> Thanks!
> >>
> >> Hi Baoquan, Shakeel, and Kairui,
> >>
> >> Would you like to re-review the patches so I can re-collect your
> >> tags? If not, are you okay with me removing your tags when I
> >> send v4?
> >
> > Sure, no problem.
> >
> > The only complain from me, and a trivial one is that `in_lru_cache =
> > !folio_test_lru(folio)` looks a bit odd.
>
> I was debating with myself a bit, how to keep it short yet expressive.
>
> "maybe_in_lru_cache" could work.

yes. sounds very good to me. Thanks, Kairui and David.

Hi Andrew,

Would you like to squash the below change?


From 4ce3a8e95eaa58ca58291ac8c2986f00e0e4db12 Mon Sep 17 00:00:00 2001
From: "Barry Song (Xiaomi)" <baohua@kernel.org>
Date: Wed, 8 Jul 2026 22:46:43 +0800
Subject: [PATCH] mm: rename in_lru_cache to maybe_in_lru_cache

!folio_test_lru(folio) doesn't necessarily mean folio
is in lru cache. so let's put "maybe" prefix.

Suggested-by: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Barry Song (Xiaomi) <baohua@kernel.org>
---
 mm/memory.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 5689b7cff76c..631c170f812a 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4174,7 +4174,7 @@ static bool __wp_can_reuse_large_anon_folio(struct folio *folio,
 static bool wp_can_reuse_anon_folio(struct folio *folio,
 				    struct vm_area_struct *vma)
 {
-	const bool in_lru_cache = !folio_test_lru(folio);
+	const bool maybe_in_lru_cache = !folio_test_lru(folio);
 	const bool in_swapcache = folio_test_swapcache(folio);
 
 	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && folio_test_large(folio))
@@ -4188,9 +4188,9 @@ static bool wp_can_reuse_anon_folio(struct folio *folio,
 	 * KSM doesn't necessarily raise the folio refcount.
 	 */
 	if (folio_test_ksm(folio) ||
-	    folio_ref_count(folio) > 1 + in_lru_cache + in_swapcache)
+	    folio_ref_count(folio) > 1 + maybe_in_lru_cache + in_swapcache)
 		return false;
-	if (in_lru_cache)
+	if (maybe_in_lru_cache)
 		/*
 		 * We cannot easily detect+handle references from
 		 * remote LRU caches or references to LRU folios.
-- 
2.39.3 (Apple Git-146)


>
> --
> Cheers,
>
> David