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 D8E773403E1 for ; Wed, 23 Sep 2026 22:32:38 +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=1790202761; cv=none; b=rpMLhZ4MHn+0CQYN612sVwRNFFV6JgdFrpKy//P+VoqYBjac+mfMfkK28dxn/LdH7jaGgT9fMC55RE1uudcj5VYXRkuEZFDv+n8JSqS/VLBwc6s+/D8xoIdDz7hVqFUZMG6UPWRCpmn2m1ylOA6uow/SN+2PuaoiwoYucehdqAw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790202761; c=relaxed/simple; bh=NwiyLj5vfhXAdRKG6nC+UDC0JYgBRvgydJ/7CfOQeoI=; h=Date:To:From:Subject:Message-Id; b=gNQXszIbE1EFveTf0HKONhK4KTBNm+00upR5nnDc1Hv5iCZLTgNY4wzqKNBTeej4Cj3RLmaht1oqgOrlIpbUhnBgJ5GbyxK8hno6jmrynvlIaS2tW43hifreS5+EZxrm4WiMjTDPt4eeeoGwbA4pDX08h+QqKxcONy8VMLxOhi8= 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=vtE7xv3h; 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="vtE7xv3h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D1791F00893; Wed, 23 Sep 2026 22:32:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1790202758; bh=F1L9jFxIQZ1pJojyw57A5Z3VOPmYEhvGi73duKsaGY4=; h=Date:To:From:Subject; b=vtE7xv3hUVnzK/2M+W3HM4qfmIKYFTtYK9Kp7ykpvuFr2Yqt0bPsZVloY2GFSjBZo uZKsLfJwl0n2bSVy1qcPUSyFBtwayPcygxoEBE9dXBUSwj2+jeKWEPnYh+KqcYyCtl iRJrot96e3FHCImXAJWlqzNlGS5N67N2X2DYu6tY= Date: Wed, 23 Sep 2026 15:32:38 -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-unstable branch Message-Id: <20260923223238.6D1791F00893@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-unstable 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-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: move unmap and remap into the split helpers Date: Wed, 23 Sep 2026 23:32:39 +0200 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/20260923-swap-thp-cleanup-v6-8-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 | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-) --- a/mm/huge_memory.c~mm-huge_memory-move-unmap-and-remap-into-the-split-helpers +++ a/mm/huge_memory.c @@ -3640,9 +3640,6 @@ 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); @@ -4016,15 +4013,23 @@ static int __folio_freeze_split_anon(str { struct folio *end_folio = folio_next(folio); struct swap_cluster_info *ci = NULL; + const 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 */ @@ -4073,7 +4078,13 @@ 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; } @@ -4105,6 +4116,8 @@ static int __folio_freeze_split_file(str if (shmem_mapping(mapping)) end = shmem_fallocend(mapping->host, end); + unmap_folio(folio); + xas_lock_irq(xas); /* @@ -4189,7 +4202,6 @@ static int __folio_freeze_split_file(str if (do_lru) lruvec_unlock(lruvec); - fail: xas_unlock_irq(xas); if (nr_shmem_dropped) @@ -4230,7 +4242,6 @@ 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); @@ -4318,8 +4329,6 @@ 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); @@ -4327,11 +4336,6 @@ 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