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 D92637DA66 for ; Tue, 15 Sep 2026 00:45:26 +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=1789433128; cv=none; b=J8k26Alhhb0BhF2xE6hlQRxZbCuKaDcGvnVD5uVs/ZDJJ357qNHY4afOy29T4sltbBXuHEgeaKlgppp8nhtLuR/9hVZhbwNsfRVoq/pUFOkitkmpqMjAYdE6ZGl4kl4g8LAUz7FaSx7s2f5nwussPcSnZQUywTYnN5CNZooghRo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789433128; c=relaxed/simple; bh=8cDsmL0tJQcqmSwPmbkowuNGtahez3ulHbUo5it5RxM=; h=Date:To:From:Subject:Message-Id; b=ExxcMZWa+GZRg/rrZ2UFyZcFMlWYd/msVzQdPL2gYq2hdtcO7uBrlJw7NaS+8ESgUVCu1fq30pAk/mQAHQ3kZSpuGMlh5mDnrmb82BcsD6dxYvKZ5Ikntj8jrxhh90bzMSGFVyHDeNzsfIoHT4dm4RmrtUSh5cmyH2RVa83U/Bk= 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=FU2CNVNE; 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="FU2CNVNE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85B421F000FF; Tue, 15 Sep 2026 00:45:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789433126; bh=Mh3hi6V3YX3iKJUDi09801mHrSCw9CYrWPXIMrN6sZs=; h=Date:To:From:Subject; b=FU2CNVNERDbSe5/MwhGdiNY1NRqP3NujWnLz4iqJnvuQ73Wws2B62JKKUItaAtBYo bQElONEkgXx5SbDW+i6IAGhUlo28+Wzemrfr8H5pBWxkkSG7sumk4l4AigTZL3xsM2 jEPYC80HKSIFkcqh4f1uDgcjnDpjyqM5Bra1r6iM= Date: Mon, 14 Sep 2026 17:45:26 -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-new branch Message-Id: <20260915004526.85B421F000FF@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-new 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-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: count only swap cache refs in anon folio split Date: Tue, 15 Sep 2026 01:14:57 +0800 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/20260915-swap-thp-cleanup-v5-16-39878b37dfb0@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 | 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 @@ -3994,10 +3994,10 @@ 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); } @@ -4065,7 +4065,7 @@ 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; } @@ -4102,7 +4102,7 @@ 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) @@ -4110,7 +4110,7 @@ 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); @@ -4139,6 +4139,7 @@ static int __folio_freeze_split_file(str struct address_space *mapping = folio->mapping; XA_STATE(xas, &mapping->i_pages, folio->index); struct folio *end_folio = folio_next(folio); + long old_nr_pages = folio_nr_pages(folio); struct mem_cgroup *memcg, *old_memcg; struct folio *new_folio, *next; int nr_shmem_dropped = 0; @@ -4209,22 +4210,16 @@ 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 */ @@ -4248,7 +4243,7 @@ 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); @@ -4275,7 +4270,7 @@ 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: /* _ 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