mm/huge_memory: fix outdated comment about freeing subpages in __folio_split

The comment appears to be outdated.  add_to_swap() no longer exists,
and the explanation of why we need to call put_page() after splitting
could be made more general.

Link: https://lore.kernel.org/20260423034917.8234-1-baohua@kernel.org
Signed-off-by: Barry Song (Xiaomi) <baohua@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Youngjun Park <youngjun.park@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Barry Song (Xiaomi) 2026-04-23 11:49:17 +08:00 committed by Andrew Morton
parent eb92d97f7e
commit 085a7acf73

View File

@ -4190,11 +4190,10 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
folio_unlock(new_folio);
/*
* Subpages may be freed if there wasn't any mapping
* like if add_to_swap() is running on a lru page that
* had its mapping zapped. And freeing these pages
* requires taking the lru_lock so we do the put_page
* of the tail pages after the split is complete.
* Subpages whose mapping has been zapped may be freed
* earlier, but freeing them requires taking the
* lru_lock, so we defer put_page() on tail pages until
* after the split completes.
*/
free_folio_and_swap_cache(new_folio);
}