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 CB7DA45D5FF for ; Wed, 23 Sep 2026 22:32:29 +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=1790202752; cv=none; b=d8Hl5nXn3B/+T0olI7+GnokYactbEJkBMG7R0aL0DNFfjnnYH3fgfMljt8ewOHget1KObHGT7wuS5aBl8ydlxzowBFQSbFzJWV4dfa/JMPk8U9xA87nr0+RGYbi55ChGAMKPeq6kVldLtIt6m1uzwldo9cHq1UftkuivCXMCXI8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790202752; c=relaxed/simple; bh=eHS12Aj72b1y7CSt3UCq1oYVwDV3GK5V6yuXB6QpY+Y=; h=Date:To:From:Subject:Message-Id; b=izmwjOaoYvHwk/bj6At5fJEcY6yXgJEMqRWIPIGpjhBbagV/gFTV3a7GDvldgULWMfdR4NAMhmK+xcZSYjsPDa+IZaRN8x6GvJLmWnibAOUzKvIWo5LWZyQl/qI3YWvqdGBAI2OT/lKx8nUkhw0QZZjTvKTWYfQ11ELEQx2rZtk= 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=XGmGdQNx; 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="XGmGdQNx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5C88B1F00893; Wed, 23 Sep 2026 22:32:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1790202748; bh=s+p2G4iDGFN6Mm0yOxWPRNiTd/DF3cuKCIWFjM5kfxk=; h=Date:To:From:Subject; b=XGmGdQNx+pDd3NoNwB7OR3aBT5mzFAd7YB3ee3cw6IuAZnySYm6jahuO/kIr1F9MP yp8IngIK1c7ZwftTeutqKxUIhdQQp6XUU/WKlaexVYI/Dd655GD9EunnI2yPkPZ4Cz 631VI1H8zVp9ibWjziLGy4lNv0RYdvg/edrcCZDE= Date: Wed, 23 Sep 2026 15:32:27 -0700 To: mm-commits@vger.kernel.org,kasong@tencent.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-huge_memory-invert-folio_ref_freeze-check-to-reduce-indentation.patch added to mm-unstable branch Message-Id: <20260923223228.5C88B1F00893@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: invert folio_ref_freeze() check to reduce indentation has been added to the -mm mm-unstable branch. Its filename is mm-huge_memory-invert-folio_ref_freeze-check-to-reduce-indentation.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-invert-folio_ref_freeze-check-to-reduce-indentation.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: invert folio_ref_freeze() check to reduce indentation Date: Wed, 23 Sep 2026 23:32:34 +0200 Invert the folio_ref_freeze() success check in __folio_freeze_and_split_unmapped() to return early on failure, which removes one level of indentation from the entire success path. This is a pure refactoring with no functional change. It prepares the function to be split into separate helpers for anonymous and file-backed folios in a later patch. Link: https://lore.kernel.org/20260923-swap-thp-cleanup-v6-3-ba1b4ba72c6f@tencent.com Signed-off-by: Kairui Song Signed-off-by: Andrew Morton Reviewed-by: Zi Yan Reviewed-by: Barry Song Acked-by: David Hildenbrand (Arm) Reviewed-by: Yeoreum Yun Reviewed-by: Kiryl Shutsemau (Meta) 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: Youngjun Park Cc: Shivam Kalra Cc: Kairui Song --- mm/huge_memory.c | 186 ++++++++++++++++++++++----------------------- 1 file changed, 92 insertions(+), 94 deletions(-) --- a/mm/huge_memory.c~mm-huge_memory-invert-folio_ref_freeze-check-to-reduce-indentation +++ a/mm/huge_memory.c @@ -4014,122 +4014,120 @@ static int __folio_freeze_and_split_unma pgoff_t end, int *nr_shmem_dropped) { struct folio *end_folio = folio_next(folio); + struct swap_cluster_info *ci = NULL; struct folio *new_folio, *next; + struct lruvec *lruvec; int ret = 0; VM_WARN_ON_ONCE(!mapping && end); - if (folio_ref_freeze(folio, folio_cache_ref_count(folio) + 1)) { - struct swap_cluster_info *ci = NULL; - struct lruvec *lruvec; - - /* Take off the deferred split queue while frozen and memcg set */ - folio_unqueue_deferred_split(folio); - - /* - * deferred_split_scan() takes the folio off the queue before it - * splits it, so the unqueue above finds an empty list and - * leaves PG_partially_mapped set. - * Clear it here: the flag does not survive the split. - */ - folio_reset_partially_mapped(folio); + if (!folio_ref_freeze(folio, folio_cache_ref_count(folio) + 1)) + return -EAGAIN; - if (mapping) { - int nr = folio_nr_pages(folio); + /* Take off the deferred split queue while frozen and memcg set */ + folio_unqueue_deferred_split(folio); - if (folio_test_pmd_mappable(folio) && - new_order < HPAGE_PMD_ORDER) { - if (folio_test_swapbacked(folio)) { - lruvec_stat_mod_folio(folio, - NR_SHMEM_THPS, -nr); - } else { - lruvec_stat_mod_folio(folio, - NR_FILE_THPS, -nr); - } + /* + * deferred_split_scan() takes the folio off the queue before it + * splits it, so the unqueue above finds an empty list and + * leaves PG_partially_mapped set. + * Clear it here: the flag does not survive the split. + */ + folio_reset_partially_mapped(folio); + + if (mapping) { + int nr = folio_nr_pages(folio); + + if (folio_test_pmd_mappable(folio) && + new_order < HPAGE_PMD_ORDER) { + 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_swapcache(folio)) - ci = swap_cluster_get_and_lock(folio); + if (folio_test_swapcache(folio)) + ci = swap_cluster_get_and_lock(folio); - /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ - if (do_lru) - lruvec = folio_lruvec_lock(folio); + /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ + if (do_lru) + lruvec = folio_lruvec_lock(folio); + + ret = __split_unmapped_folio(folio, new_order, split_at, xas, + mapping, split_type); + + /* + * Unfreeze after-split folios and put them back to the right + * list. @folio should be kept frozon until page cache + * entries are updated with all the other after-split folios + * to prevent others seeing stale page cache entries. + * As a result, new_folio starts from the next folio of + * @folio. + */ + for (new_folio = folio_next(folio); new_folio != end_folio; + new_folio = next) { + unsigned long nr_pages = folio_nr_pages(new_folio); - ret = __split_unmapped_folio(folio, new_order, split_at, xas, - mapping, split_type); + next = folio_next(new_folio); - /* - * Unfreeze after-split folios and put them back to the right - * list. @folio should be kept frozon until page cache - * entries are updated with all the other after-split folios - * to prevent others seeing stale page cache entries. - * As a result, new_folio starts from the next folio of - * @folio. - */ - for (new_folio = folio_next(folio); new_folio != end_folio; - new_folio = next) { - unsigned long nr_pages = folio_nr_pages(new_folio); - - 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); - - if (do_lru) - lru_add_split_folio(folio, new_folio, lruvec, list); - - /* - * Anonymous folio with swap cache. - * NOTE: shmem in swap cache is not supported yet. - */ - if (ci) { - __swap_cache_replace_folio(ci, folio, new_folio); - continue; - } + zone_device_private_split_cb(folio, new_folio); - /* Anonymous folio without swap cache */ - if (!mapping) - continue; - - /* Add the new folio to the page cache. */ - if (new_folio->index < end) { - __xa_store(&mapping->i_pages, new_folio->index, - new_folio, 0); - continue; - } + folio_ref_unfreeze(new_folio, + folio_cache_ref_count(new_folio) + 1); - VM_WARN_ON_ONCE(!nr_shmem_dropped); - /* Drop folio beyond EOF: ->index >= end */ - if (shmem_mapping(mapping) && nr_shmem_dropped) - *nr_shmem_dropped += nr_pages; - else if (folio_test_clear_dirty(new_folio)) - folio_account_cleaned( - new_folio, inode_to_wb(mapping->host)); - __filemap_remove_folio(new_folio, NULL); - folio_put_refs(new_folio, nr_pages); - } + if (do_lru) + lru_add_split_folio(folio, new_folio, lruvec, list); - zone_device_private_split_cb(folio, NULL); /* - * Unfreeze @folio only after all page cache entries, which - * used to point to it, have been updated with new folios. - * Otherwise, a parallel folio_try_get() can grab @folio - * and its caller can see stale page cache entries. + * Anonymous folio with swap cache. + * NOTE: shmem in swap cache is not supported yet. */ - folio_ref_unfreeze(folio, folio_cache_ref_count(folio) + 1); + if (ci) { + __swap_cache_replace_folio(ci, folio, new_folio); + continue; + } - if (do_lru) - lruvec_unlock(lruvec); + /* Anonymous folio without swap cache */ + if (!mapping) + continue; + + /* Add the new folio to the page cache. */ + if (new_folio->index < end) { + __xa_store(&mapping->i_pages, new_folio->index, + new_folio, 0); + continue; + } - if (ci) - swap_cluster_unlock(ci); - } else { - return -EAGAIN; + VM_WARN_ON_ONCE(!nr_shmem_dropped); + /* Drop folio beyond EOF: ->index >= end */ + if (shmem_mapping(mapping) && nr_shmem_dropped) + *nr_shmem_dropped += nr_pages; + else if (folio_test_clear_dirty(new_folio)) + folio_account_cleaned( + new_folio, inode_to_wb(mapping->host)); + __filemap_remove_folio(new_folio, NULL); + folio_put_refs(new_folio, nr_pages); } + zone_device_private_split_cb(folio, NULL); + /* + * Unfreeze @folio only after all page cache entries, which + * used to point to it, have been updated with new folios. + * 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); + + if (do_lru) + lruvec_unlock(lruvec); + + if (ci) + swap_cluster_unlock(ci); + return ret; } _ 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