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 EEC942E62A4 for ; Tue, 15 Sep 2026 00:45:24 +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=1789433126; cv=none; b=BZuV8DeTwSbyPp+iw2u5uabZUnJqgWNpcm6jjI0jAukThlJL4W0i+B5zkHypJfByJBnER+XQjt++NlNKrK5GIiz6xBbMm/6Bp9gWpRS+0o7ZqokEis4Pj1ye4wWZbQrChRJXqtK8qEuMTIET4+cJkIBNHcvEayr+ykDpRa7PChI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789433126; c=relaxed/simple; bh=wx+bK7ovT8o+s3s7LdS4qjY9GYUPppfkqeRUOQiQtkI=; h=Date:To:From:Subject:Message-Id; b=Lo2TyVI2z7rT6JSpnCaayJu9p3ngGZJi1jLyyLK0fCKNFcQZwEpS24bwugfBssSjGfSZ2wmhCANp5Ncb4Kp3StUsiyFQ+ElBZhjCe1rCp/rCnGxskYoKnv6M0LNomJn+D7ktCrHr6y2BvEgGFtKlmeS8TdZmNyQRWdicJK/5foU= 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=mBebfd0M; 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="mBebfd0M" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5033D1F00893; Tue, 15 Sep 2026 00:45:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789433124; bh=kLjo8ez1SuZvy7vMCVwVCdvEUb+nonN+Cpsc6zcF8Xo=; h=Date:To:From:Subject; b=mBebfd0M1nMRe2UpZTo3Rg6a148wqljsa4PRQNiB9VZC3eMy9vt64FoJ4wrNYHbFX wkLcUuELzT2Z8FBc98vIflYNFR+8Fbx+ycFbHai5kEbnsZ9PwHBUMlVvt8dTBewkYx UcGyBewIC13P4SUm4VYg3ccfa+JRNc8Rza2dlNk0= Date: Mon, 14 Sep 2026 17:45:23 -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-new branch Message-Id: <20260915004524.5033D1F00893@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-new 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-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next 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: Tue, 15 Sep 2026 01:14:56 +0800 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/20260915-swap-thp-cleanup-v5-15-39878b37dfb0@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) Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Chris Li Cc: David Hildenbrand (Arm) Cc: Dev Jain Cc: Kemeng Shi Cc: Lance Yang Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Nhat Pham Cc: Ryan Roberts Cc: Suren Baghdasaryan Cc: Vlastimil Babka --- 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 @@ -4327,7 +4327,8 @@ 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; @@ -4367,14 +4368,16 @@ 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: @@ -4401,7 +4404,7 @@ 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