From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 67A8A469845 for ; Wed, 23 Sep 2026 22:32:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790202773; cv=none; b=uf9hyBk0U3zWUNS3eQ3o7dj2XcQHF+DYUfV9/CeBpLPzVwxwwajJ1yH8UGaNMnG+XPRJfBNQzz2etmvw2E60wyrrJJLbMn4/4p5AA0zfnw3Xq9lnI3ZNqXjBvqteMHqvCKZREQEUm9i17oKslwDkO18OMLdHJl2XtXDeHOzElIU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790202773; c=relaxed/simple; bh=KiJd9q9FCO3tboVZmnbwZf1UfKYdFdcUfBduo0BNgAA=; h=Date:To:From:Subject:Message-Id; b=FQslR/xW27LGKJNB3Bc/rpzePB6w4PqzGvCa2hatKH9lsQCIPBJG9oKjB2uLfgn7wRs8/uR0rB0/t0Fz2T9TtSLVW47frGqkeFYRIRMQqw2AZnhb+tMuJCDYt3GC1AoUekHYr3BSyCK9Li8kT50J6KMx73bPYWD4Uq6DF35zwBs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=VjYbmtGV; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="VjYbmtGV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D30A1F00893; Wed, 23 Sep 2026 22:32:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1790202772; bh=bldEngRTJyyg56zrJK599S6b6VVtxJa0mEwarvDBnDM=; h=Date:To:From:Subject; b=VjYbmtGVjHOIyuX1I27uqG4YMKnOb8YWT+iolnG+A8asbTllnmR86/+U7+crE7iW4 cubUT76Si95lgkUMLzcCzZfd3xYXsfSamaitBgJfmdRGEpigi32RPs8s+2isuVsKlV vKL+M9zGNtLOVTQj54Jz7IB84EugqVg+GF9bTlN0= Date: Wed, 23 Sep 2026 15:32:51 -0700 To: mm-commits@vger.kernel.org,kasong@tencent.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-huge_memory-clean-up-after-split-folio-freeing-in-__folio_split.patch added to mm-unstable branch Message-Id: <20260923223252.0D30A1F00893@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/huge_memory: clean up after-split folio freeing in __folio_split has been added to the -mm mm-unstable branch. Its filename is mm-huge_memory-clean-up-after-split-folio-freeing-in-__folio_split.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-huge_memory-clean-up-after-split-folio-freeing-in-__folio_split.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Kairui Song Subject: mm/huge_memory: clean up after-split folio freeing in __folio_split Date: Wed, 23 Sep 2026 23:32:46 +0200 Replace free_folio_and_swap_cache() with an explicit folio_free_swap() and folio_put() in the after-split loop. free_folio_and_swap_cache() must trylock it again and re-check folio_mapped() before freeing the swap cache entries. If the trylock loses a race, the entries are left behind even though the folio reference is dropped. The sub folios are still locked here, so just directly call folio_free_swap() under the lock if it's unmapped, then unlock and drop the reference. This makes the swap cache freeing deterministic and the reference drop explicit. Link: https://lore.kernel.org/20260923-swap-thp-cleanup-v6-15-ba1b4ba72c6f@tencent.com Signed-off-by: Kairui Song Signed-off-by: Andrew Morton Reviewed-by: Zi Yan Reviewed-by: Yeoreum Yun Reviewed-by: Kiryl Shutsemau (Meta) Acked-by: David Hildenbrand (Arm) Cc: Lorenzo Stoakes Cc: Baolin Wang Cc: Liam R. Howlett Cc: Nico Pache Cc: Ryan Roberts Cc: Dev Jain Cc: Lance Yang Cc: Usama Arif Cc: Vlastimil Babka Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Michal Hocko Cc: Chris Li Cc: Kemeng Shi Cc: Nhat Pham Cc: Baoquan He Cc: Barry Song Cc: Youngjun Park Cc: Shivam Kalra Cc: Kairui Song --- mm/huge_memory.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) --- a/mm/huge_memory.c~mm-huge_memory-clean-up-after-split-folio-freeing-in-__folio_split +++ a/mm/huge_memory.c @@ -4325,7 +4325,8 @@ static int __folio_split(struct folio *f struct list_head *list, enum split_type split_type) { struct folio *end_folio = folio_next(folio); - bool is_anon = folio_test_anon(folio); + const bool is_anon = folio_test_anon(folio); + const bool is_swapcache = folio_test_swapcache(folio); int old_order = folio_order(folio); struct folio *new_folio, *next; int ret; @@ -4365,14 +4366,16 @@ static int __folio_split(struct folio *f if (new_folio == page_folio(lock_at)) continue; - folio_unlock(new_folio); /* * 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 + * lru_lock, so we defer folio_put() on tail pages until * after the split completes. */ - free_folio_and_swap_cache(new_folio); + if (is_swapcache && !folio_mapped(new_folio)) + folio_free_swap(new_folio); + folio_unlock(new_folio); + folio_put(new_folio); } out: @@ -4399,7 +4402,7 @@ out: * isolated from LRU (if applicable) * * Upon return, the folio is not remapped, split folios are not added to LRU, - * free_folio_and_swap_cache() is not called, and new folios remain locked. + * folio_free_swap() is not called, and new folios remain locked. * * Return: 0 on success, -EAGAIN if the folio cannot be split (e.g., due to * insufficient reference count or extra pins). _ Patches currently in -mm which might be from kasong@tencent.com are mm-memcontrol-move-the-lru_zone_size-sanity-check-to-the-reader-side.patch mm-mglru-introduce-helpers-for-manipulating-gen-and-refs-flags.patch mm-migrate-copy-all-referenced-state-via-folio_migrate_lru_refs.patch mm-mglru-move-max_seq-read-into-walk_update_folio.patch mm-mglru-use-explicit-tier-range-in-read_ctrl_pos.patch mm-mglru-fix-potential-generation-folio-number-leak.patch mm-swap-fix-off-by-one-in-swap-cache-replace-sanity-check.patch mm-huge_memory-fix-rejection-of-swap-cache-folios-with-a-mapping.patch mm-huge_memory-invert-folio_ref_freeze-check-to-reduce-indentation.patch mm-huge_memory-split-the-routine-for-splitting-anon-and-file-folio.patch mm-huge_memory-rename-__split_unmapped_folio-to-__split_frozen_folio.patch mm-huge_memory-consolidate-irq-and-locking-for-folio-split.patch mm-huge_memory-move-eof-trimming-into-the-file-split-helper.patch mm-huge_memory-move-unmap-and-remap-into-the-split-helpers.patch mm-huge_memory-rename-remap_page-to-remap_anon_folio.patch mm-huge_memory-move-the-racy-refcount-check-into-unmap_folio.patch mm-huge_memory-move-filemap-management-into-the-file-split-helper.patch mm-huge_memory-move-anon_vma-handling-into-the-anon-split-helper.patch mm-huge_memory-move-memcg-switch-into-the-file-split-helper.patch mm-huge_memory-drop-the-unused-do_lru-argument-of-the-file-split-helper.patch mm-huge_memory-clean-up-after-split-folio-freeing-in-__folio_split.patch mm-huge_memory-count-only-swap-cache-refs-in-anon-folio-split.patch mm-huge_memory-drop-the-redundant-mapping-argument-of-__split_frozen_folio.patch