Hi Andrew,

Thank you for revising this patch!

From: "andrew.yang" andrew.yang@mediatek.com

damon_get_folio() would always increase folio _refcount and folio_isolate_lru() would increase folio _refcount if the folio's lru flag is set.

If an unevictable folio isolated successfully, there will be two more _refcount. The one from folio_isolate_lru() will be decreased in folio_puback_lru(), but the other one from damon_get_folio() will be left behind. This causes a pin page.

Whatever the case, the _refcount from damon_get_folio() should be decreased.

Signed-off-by: andrew.yang andrew.yang@mediatek.com Fixes: 57223ac29584 ("mm/damon/paddr: support the pageout scheme") Cc: stable@vger.kernel.org # 5.16.x

Reviewed-by: SeongJae Park sj@kernel.org

This may not cleanly applicable on 6.1.y and 6.2.y. I would post backports once this is merged in the mainline, unless others do earlier than me.

Thanks, SJ

---

v3: add fixes tag and cc stable v2: according to David's suggestion 1. revise subject according to SeongJae's suggestions 1. rebase to mm-unstable tree 2. remove braces for th single statements

---

mm/damon/paddr.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c index 607bb69e526c..6c655d9b5639 100644 --- a/mm/damon/paddr.c +++ b/mm/damon/paddr.c @@ -250,12 +250,11 @@ static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s) folio_put(folio); continue; }

• if (folio_test_unevictable(folio)) {
  

• if (folio_test_unevictable(folio))
  folio_putback_lru(folio);
  

• } else {
  

• else
  list_add(&folio->lru, &folio_list);
  

• 	folio_put(folio);
  

• }
  

• folio_put(folio);
  

  } applied = reclaim_pages(&folio_list); cond_resched();

-- 2.18.0