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 22B4E2FC893 for ; Tue, 15 Sep 2026 00:45:10 +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=1789433114; cv=none; b=FEafWYev6nN9JVJA31l965VP5tsxCiX/bTv1O026rXQ5iZHNgjdDPMfP91Ixup7noHr9dSmZ/mjQ0fo/vvRgzNxGKoJVh7RszafXPoEr7rumJSdJyg9/81hbydkl66JXr3oOk4a6mNHy9CS8OQoxDX4PpNeR6m0snHJpr25wcHE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789433114; c=relaxed/simple; bh=Ts+NO0z50WNwBhsSlEmHArnEUcaxT/Q/9cgJ7g0QBf8=; h=Date:To:From:Subject:Message-Id; b=mUaGV7O8DWg4sKxdoOXwCz56mBu39JRpjyKtQQOHwF2MRhq17dDMgiQpsInuXSZZLTcUEQ/2+DUgZTHSuNObVSLAC0kINSXgiRcqARUfogWi0Q+VK072G5bi1gtkyGD5ZnL30JLvtl5lkHGagLQubQHD8sAxTKS0SDyzQHjYj2E= 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=nlRSZvID; 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="nlRSZvID" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A81801F000FF; Tue, 15 Sep 2026 00:45:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789433108; bh=eFnEmsPdTGBfTIe2+07t1DNRY8a2r8UbX5wZk74+WV0=; h=Date:To:From:Subject; b=nlRSZvIDizDBF/IOPTJhzXez7FKyOEfpf2V+mY1Hb8yA4vEa59XRa3Y9sbnCBgY4D sKGmjIXFxpWADFI/2duAt/LHlrc2Oit+5+AVE86Ejd+37ck8f/YTYy/pXigoqKIU4E 3LlJ/wKqHFJeyXn2bQaCELv28z9BoRq8G26qR000= Date: Mon, 14 Sep 2026 17:45:08 -0700 To: mm-commits@vger.kernel.org,kasong@tencent.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-huge_memory-move-unmap-and-remap-into-the-split-helpers.patch added to mm-new branch Message-Id: <20260915004508.A81801F000FF@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: move unmap and remap into the split helpers has been added to the -mm mm-new branch. Its filename is mm-huge_memory-move-unmap-and-remap-into-the-split-helpers.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-move-unmap-and-remap-into-the-split-helpers.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: move unmap and remap into the split helpers Date: Tue, 15 Sep 2026 01:14:49 +0800 To prepare for further cleanup, move the unmap/remap handling from __folio_split() into the split helpers. Only anon folios need to be remapped, so remap_page() is now only called for anon splits and the anon check in remap_page() is redundant and can be removed. Link: https://lore.kernel.org/20260915-swap-thp-cleanup-v5-8-39878b37dfb0@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 | 36 ++++++++++++++++++++++-------------- 1 file changed, 22 insertions(+), 14 deletions(-) --- a/mm/huge_memory.c~mm-huge_memory-move-unmap-and-remap-into-the-split-helpers +++ a/mm/huge_memory.c @@ -3641,9 +3641,6 @@ static void remap_page(struct folio *fol { int i = 0; - /* If unmap_folio() uses try_to_migrate() on file, remove this check */ - if (!folio_test_anon(folio)) - return; for (;;) { remove_migration_ptes(folio, folio, TTU_RMAP_LOCKED | flags); i += folio_nr_pages(folio); @@ -4017,15 +4014,23 @@ static int __folio_freeze_split_anon(str { struct folio *end_folio = folio_next(folio); struct swap_cluster_info *ci = NULL; + int old_order = folio_order(folio); struct folio *new_folio, *next; + enum ttu_flags ttu_flags = 0; struct lruvec *lruvec; + bool need_remap = false; int ret = 0; + if (folio_mapped(folio)) { + need_remap = true; + unmap_folio(folio); + } + local_irq_disable(); if (!folio_ref_freeze(folio, folio_cache_ref_count(folio) + 1)) { - local_irq_enable(); - return -EAGAIN; + ret = -EAGAIN; + goto out_no_split; } /* Take off the deferred split queue while frozen and memcg set */ @@ -4074,7 +4079,13 @@ static int __folio_freeze_split_anon(str lruvec_unlock(lruvec); if (ci) swap_cluster_unlock(ci); +out_no_split: local_irq_enable(); + if (need_remap) { + if (!ret && !folio_is_device_private(folio)) + ttu_flags = TTU_USE_SHARED_ZEROPAGE; + remap_page(folio, 1 << old_order, ttu_flags); + } return ret; } @@ -4106,6 +4117,8 @@ static int __folio_freeze_split_file(str if (shmem_mapping(mapping)) end = shmem_fallocend(mapping->host, end); + unmap_folio(folio); + xas_lock_irq(xas); /* @@ -4190,8 +4203,11 @@ static int __folio_freeze_split_file(str if (do_lru) lruvec_unlock(lruvec); - fail: + /* + * If we want to use try_to_migrate() on file in unmap_folio, + * remember to add remap_page() and adapt it. + */ xas_unlock_irq(xas); if (nr_shmem_dropped) shmem_uncharge(mapping->host, nr_shmem_dropped); @@ -4231,7 +4247,6 @@ static int __folio_split(struct folio *f struct anon_vma *anon_vma = NULL; int old_order = folio_order(folio); struct folio *new_folio, *next; - enum ttu_flags ttu_flags = 0; int ret; VM_WARN_ON_ONCE_FOLIO(!folio_test_locked(folio), folio); @@ -4319,8 +4334,6 @@ static int __folio_split(struct folio *f goto out_unlock; } - unmap_folio(folio); - if (is_anon) ret = __folio_freeze_split_anon(folio, new_order, split_at, true, list, split_type); @@ -4328,11 +4341,6 @@ static int __folio_split(struct folio *f ret = __folio_freeze_split_file(folio, new_order, split_at, &xas, mapping, true, list, split_type); - if (!ret && is_anon && !folio_is_device_private(folio)) - ttu_flags = TTU_USE_SHARED_ZEROPAGE; - - remap_page(folio, 1 << old_order, ttu_flags); - /* * Drop the mapping while the inode is still pinned. @folio stays * locked and present in the page cache until the loop below, so _ 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