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 68D68469845 for ; Wed, 23 Sep 2026 22:32:54 +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=1790202775; cv=none; b=Y2IKv0WQkv2/vD2uP68IX2eyQ0TTN3aqKGL8UcIYyr1yz3TAKxA8ZTAyNwMcgQZd13SRSFxkPD8D4R1OJ4q0Fj75VSibjympdUDvhgDjjJJ2PBHoePU/WShIVTn7RJnMuYUjA5ojQfK1ZOeJ4DuKCrlO7/7TxI5cKRsRW/jBwUQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790202775; c=relaxed/simple; bh=fF9p8pcfSvWK+wsNiT3sXcxdpiVXd5sfZ7Ou8HvXAQ8=; h=Date:To:From:Subject:Message-Id; b=P4I2hlvtS6kQrPM0BjCgicHGDUg4w8QX+DqTUuKhQE0y8H0aueTu92LfvgbXKBIGYLiedW8FVoQ3vxgFCUOvXUqJVfUYNGiEwKT7b82w71J4ecs3nsh2gMqy9D5p8FfmbmZgMKGiPI4p91aSLYclGrz6hqLA7VtkdYwdb9lOlQ8= 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=t2JyoTfk; 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="t2JyoTfk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8DAC1F000FF; Wed, 23 Sep 2026 22:32:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1790202774; bh=aUkir04YoNgBeKr5kV6i2BIRlZbGf5LabVrhQ6dYpbE=; h=Date:To:From:Subject; b=t2JyoTfkAjykdJNln9HuENSg4fZQLmgP4wyqPB9mfwuh4fkbC4Wz5IgDza26ew4wr wHzVPOHklPaAit4P0z8uMftQBhiKzvYBn6PM2UVsasxW5tBPtxGg9T1VfUp7V1ZleP gtM0LR6x03Q6hEpSvUgW7rv/Ypc7ZAZruj7CkZPk= Date: Wed, 23 Sep 2026 15:32:53 -0700 To: mm-commits@vger.kernel.org,kasong@tencent.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-huge_memory-count-only-swap-cache-refs-in-anon-folio-split.patch added to mm-unstable branch Message-Id: <20260923223253.E8DAC1F000FF@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: count only swap cache refs in anon folio split has been added to the -mm mm-unstable branch. Its filename is mm-huge_memory-count-only-swap-cache-refs-in-anon-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-count-only-swap-cache-refs-in-anon-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: count only swap cache refs in anon folio split Date: Wed, 23 Sep 2026 23:32:47 +0200 Only __folio_freeze_split_anon() sees anon folios and swap cache folios now. The file split helper only handles page cache folios, which hold exactly folio_nr_pages() references. Rename folio_cache_ref_count() to folio_swapcache_ref_count() and drop the anon check so the helper counts what its name says. The file split helper now uses folio_nr_pages() directly. No feature change. Link: https://lore.kernel.org/20260923-swap-thp-cleanup-v6-16-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 | 35 +++++++++++++++-------------------- 1 file changed, 15 insertions(+), 20 deletions(-) --- a/mm/huge_memory.c~mm-huge_memory-count-only-swap-cache-refs-in-anon-folio-split +++ a/mm/huge_memory.c @@ -3997,10 +3997,10 @@ int folio_check_splittable(struct folio return 0; } -/* Number of folio references from the pagecache or the swapcache. */ -static unsigned int folio_cache_ref_count(const struct folio *folio) +/* Number of folio references from the swapcache. */ +static unsigned int folio_swapcache_ref_count(const struct folio *folio) { - if (folio_test_anon(folio) && !folio_test_swapcache(folio)) + if (!folio_test_swapcache(folio)) return 0; return folio_nr_pages(folio); } @@ -4067,7 +4067,7 @@ static int __folio_freeze_split_anon(str local_irq_disable(); - if (!folio_ref_freeze(folio, folio_cache_ref_count(folio) + 1)) { + if (!folio_ref_freeze(folio, folio_swapcache_ref_count(folio) + 1)) { ret = -EAGAIN; goto out_no_split; } @@ -4104,7 +4104,7 @@ static int __folio_freeze_split_anon(str next = folio_next(new_folio); zone_device_private_split_cb(folio, new_folio); folio_ref_unfreeze(new_folio, - folio_cache_ref_count(new_folio) + 1); + folio_swapcache_ref_count(new_folio) + 1); if (do_lru) lru_add_split_folio(folio, new_folio, lruvec, list); if (ci) @@ -4112,7 +4112,7 @@ static int __folio_freeze_split_anon(str } zone_device_private_split_cb(folio, NULL); - folio_ref_unfreeze(folio, folio_cache_ref_count(folio) + 1); + folio_ref_unfreeze(folio, folio_swapcache_ref_count(folio) + 1); if (do_lru) lruvec_unlock(lruvec); @@ -4138,6 +4138,7 @@ static int __folio_freeze_split_file(str unsigned int new_order, struct page *split_at, struct list_head *list, enum split_type split_type) { + const long old_nr_pages = folio_nr_pages(folio); struct address_space *mapping = folio->mapping; XA_STATE(xas, &mapping->i_pages, folio->index); struct folio *end_folio = folio_next(folio); @@ -4211,22 +4212,16 @@ static int __folio_freeze_split_file(str goto fail; } - if (!folio_ref_freeze(folio, folio_cache_ref_count(folio) + 1)) { + if (!folio_ref_freeze(folio, old_nr_pages + 1)) { ret = -EAGAIN; goto fail; } - if (folio_test_pmd_mappable(folio) && - new_order < HPAGE_PMD_ORDER) { - int nr = folio_nr_pages(folio); - - if (folio_test_swapbacked(folio)) { - lruvec_stat_mod_folio(folio, - NR_SHMEM_THPS, -nr); - } else { - lruvec_stat_mod_folio(folio, - NR_FILE_THPS, -nr); - } + if (folio_test_pmd_mappable(folio) && new_order < HPAGE_PMD_ORDER) { + if (folio_test_swapbacked(folio)) + lruvec_stat_mod_folio(folio, NR_SHMEM_THPS, -old_nr_pages); + else + lruvec_stat_mod_folio(folio, NR_FILE_THPS, -old_nr_pages); } /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ @@ -4250,7 +4245,7 @@ static int __folio_freeze_split_file(str next = folio_next(new_folio); folio_ref_unfreeze(new_folio, - folio_cache_ref_count(new_folio) + 1); + folio_nr_pages(new_folio) + 1); lru_add_split_folio(folio, new_folio, lruvec, list); @@ -4277,7 +4272,7 @@ static int __folio_freeze_split_file(str * Otherwise, a parallel folio_try_get() can grab @folio * and its caller can see stale page cache entries. */ - folio_ref_unfreeze(folio, folio_cache_ref_count(folio) + 1); + folio_ref_unfreeze(folio, folio_nr_pages(folio) + 1); lruvec_unlock(lruvec); fail: xas_unlock_irq(&xas); _ 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