From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794293108; b=l/FadmYFxXWCJa0z1gFd4VMBBtdXfCba81pC5sznqzaL8hpWbtAvwLWJ8GK02G+wxsav JwN+dWN/SDQFLV/iBssGH1pPJlntBBIjhhvYWWaZMFdS+c7U1GpZy6sBJpI75RPX7awhr iiK8we95mcpd7MUIipGKMh/KI0qREvRL61P0LOY6agNTnhlaYDvHJyPRBLbPpiEDY6ytV 17XKtYxeLVF8kDr11tacLgf6ca89UT7UOe1F9+AFd0B6v6M3RCmsjzOBXvU3nbxc9i85d vN4vPF+PM1AxjXBB1Rmq+FJ/sQ+5JGYKs/morXP9i+CckqeYlmurTO0ZWg3QBwCgtQA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794293108; h=Received:DKIM-Signature:Date:To:From:Subject:Message-Id; bh=1+EWMG1s4PtNLGMTM7gtsLhW6vrqjRkE1/MQE+IymZA=; b=Gg6jUWBS+o3wBfmZidfT0N6PCKRwKb9gc3ZiL49rG0UeO92wFTt/FPUMjb6L2hylzYjU EBKuTVsReoxbqgnLwEogxat8eeBXSZ2J6iMnm7482naVpZFTviSkbU/Hm+Notr2CI3sXk Db57UO79qK/9WFopnyEjzvxR9sJRBh9RONz2WVEzYtrUvuxjf2MEv03B5BF9VLtccKRWP tLdXqb2//WFCagAUzXzyla/xivR8TgTYJ/l/l1zWY/RP0iOEzszSJgls8OSCsQbV+Wdhn r+SldzOi9WscsjaDMANEsWpuBdyNWYa0QACL4VReHRZZKZgRV1aoipjzDQuHSUFo7cA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=0ss6A5T5; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 07FAE606CB02; Tue, 10 Nov 2026 06:45:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=0ss6A5T5 Received: by smtp.kernel.org (Postfix) with ESMTPSA id C32C61F008A3; Tue, 10 Nov 2026 06:45:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1794293107; bh=1+EWMG1s4PtNLGMTM7gtsLhW6vrqjRkE1/MQE+IymZA=; h=Date:To:From:Subject; b=0ss6A5T5OJa/842uN05Dof3gh2G0GChIP+yvamq8rOzY4lRAvoCJS4Lx+V8TPpgJA 7cy31gwUe+o82gawlNsVsXiHojKb2HG5eCaRg938aGGd1V9VVKQ95jlrQtknEWPPmW FXGzvIPya4Wai05kw44377yrtB/92kWwP6BBFwy4= Date: Mon, 09 Nov 2026 22:45:07 -0800 To: mm-commits@vger.kernel.org,ziy@nvidia.com,ying.huang@linux.alibaba.com, stable@vger.kernel.org,shivankg@amd.com,shakeel.butt@linux.dev, matthew.brost@intel.com,joshua.hahnjy@gmail.com,gourry@gourry.net, david@kernel.org,byungchul@sk.com,boris@bur.io,apopple@nvidia.com, chenridong@xiaomi.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-migrate-move-nr_kernel_file_pages-on-cross-node-migration.patch removed from -mm tree Message-Id: <20261110064507.C32C61F008A3@smtp.kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list The quilt patch titled Subject: mm/migrate: move NR_KERNEL_FILE_PAGES on cross-node migration has been removed from the -mm tree. Its filename was mm-migrate-move-nr_kernel_file_pages-on-cross-node-migration.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Ridong Chen Subject: mm/migrate: move NR_KERNEL_FILE_PAGES on cross-node migration Date: Tue, 27 Oct 2026 12:32:14 +0800 NR_KERNEL_FILE_PAGES counts page cache folios of mappings flagged AS_KERNEL_FILE (currently the btrfs btree inode). It is a per-node counter: filemap_add_folio() adds to folio_pgdat() of the new folio and filemap_unaccount_folio() subtracts from folio_pgdat() of the folio being removed. __folio_migrate_mapping() does not move it when such a folio is migrated to another node, so the source node keeps the count forever and the destination node underflows once the folio is freed. btree folios are migratable through btree_migrate_folio(), so demotion, DAMON-based migration (DAMOS_MIGRATE_{HOT,COLD}) or memory offlining all hit this. Reproducer, on a QEMU guest with two memory tiers (node0 is DRAM with all CPUs, node1 is a CPU-less slower node described via HMAT) and /sys/kernel/mm/numa/demotion_enabled set: 1. mount a btrfs and create 20000 empty files, so that btree folios are cached on node0; 2. echo 2G > /sys/devices/system/node/node0/reclaim, which demotes them to node1; 3. umount and drop caches. nr_kernel_file_pages in /sys/devices/system/node/nodeN/vmstat after each step: without this patch with this patch node0 node1 node0 node1 1. cached 1868 0 1868 0 2. demoted 1868 0 36 1832 3. dropped 1832 0 (*) 0 0 (*) the counter has underflowed to -1832; negative values read as 0. The global value in /proc/vmstat is 0 after step 3 in both cases. Move it together with the other node-keyed page cache counters. It is a node-only counter, so use the node accessor, matching how it is accounted elsewhere. Interrupts are disabled here, as for the zone counters below. This was pointed out by Shivank while reviewing the NR_FILE_THPS fix for the same function. Link: https://lore.kernel.org/20261027043214.2248986-1-ridong.chen@linux.dev Fixes: e3a9ac4e866e ("mm: add vmstat for kernel_file pages") Signed-off-by: Ridong Chen Signed-off-by: Andrew Morton Suggested-by: Shivank Garg Acked-by: David Hildenbrand (Arm) Reviewed-by: Shivank Garg Acked-by: Zi Yan Acked-by: Shakeel Butt Cc: Matthew Brost Cc: Joshua Hahn Cc: Byungchul Park Cc: Gregory Price Cc: Ying Huang Cc: Alistair Popple Cc: Boris Burkov Cc: --- mm/migrate.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/mm/migrate.c~mm-migrate-move-nr_kernel_file_pages-on-cross-node-migration +++ a/mm/migrate.c @@ -705,6 +705,12 @@ static int __folio_migrate_mapping(struc mod_lruvec_state(old_lruvec, NR_FILE_THPS, -nr); mod_lruvec_state(new_lruvec, NR_FILE_THPS, nr); } + if (test_bit(AS_KERNEL_FILE, &mapping->flags)) { + __mod_node_page_state(oldzone->zone_pgdat, + NR_KERNEL_FILE_PAGES, -nr); + __mod_node_page_state(newzone->zone_pgdat, + NR_KERNEL_FILE_PAGES, nr); + } #ifdef CONFIG_SWAP if (folio_test_swapcache(folio)) { mod_lruvec_state(old_lruvec, NR_SWAPCACHE, -nr); _ Patches currently in -mm which might be from chenridong@xiaomi.com are mm-memcontrol-drop-unused-vmscan-tracepoint-include.patch mm-vmscan-move-vmscan-tracepoints-to-a-local-header.patch mm-vmscan-move-struct-scan_control-to-a-dedicated-header.patch mm-vmscan-pass-scan_control-to-the-vmscan-tracepoints.patch mm-mglru-add-tracepoint-for-scan_folios.patch mm-mglru-add-lruvec_gen_size-helper.patch mm-mglru-add-tracepoint-for-aging.patch mailmap-add-entries-for-ridong-chen.patch