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 E20493F9F25; Mon, 17 Aug 2026 13:46:57 +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=1786974421; cv=none; b=j2IVQJ8+bUnw6mwGGDP/8YD22JaSafeJQo9amxsN5sQ0XCy937K1/Y1wq/sLPDNxCw+NgYLok/dtissM5veUbugZRV2l457ge4dCc/cAmXX0A+F9qW3YvtDg0SLkdmpHlDYhk+vI6v8ojVTnpyTov1FWcpQD2NSdOWIkONYOesc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786974421; c=relaxed/simple; bh=SsM6KBhOekdAGjaqyPvwOkVfel7cPNYMhs6/Vt1X62s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GLha/67vZywZ8394g+hJfNwHnbsLuSu3qCK69eKULhTYNodJBLjh31QjVb/SpHXgoK0HMKLg30DnvMhQx39fZskbbpSwaHpDn1Xl+sRwH0+G7fW9RHz3I1X+Q0IRvATGFMYPsjTgFLV+LeXqWRFfDiMAE8vBEAQ3S0A+h6ysniw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=JwnehFQY; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="JwnehFQY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7A3491F000E9; Mon, 17 Aug 2026 13:46:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786974417; bh=uE8O3KbgU+xzpk3Y482LuR5yEB2y3UiPvyhZ3rYOW0I=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JwnehFQYx8Pm5UCO2FcyYBQhOv+qQ2IB8AZ/GmkWzQ+8H5SkcvPrzF/CJD4PLpDJX 5KAhb/Ak25hK0jtmTSlHkDBdf3qUlehX0R9YhQDPQc+81aJZcDyLIoFb/K5NIRyf15 +mhmsVanxAzC9tytG4l9Fy1ytcEqBMyY9IuIbdK8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, SJ Park , Honggyu Kim , Hyeongtak Ji , Andrew Morton Subject: [PATCH 7.1 197/271] mm/damon: adjust isolated pages stat for DAMOS_MIGRATE_{HOT,COLD} Date: Mon, 17 Aug 2026 15:32:02 +0200 Message-ID: <20260817132544.927329465@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132536.752504388@linuxfoundation.org> References: <20260817132536.752504388@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: SJ Park commit 1ec0e6b6f7321feb769f50d2f094a0aa6c2eda63 upstream. Callers of migrate_pages() should adjust NR_MIGRATED_{ANON,FILE} for isolations and putback of the folios. That for migration succeeded folios is done by migrate_pages(), in migrate_folio_done(). That for MR_DEMOTION reason is an exception though. DAMOS_MIGRATE_{HOT,COLD} call migrate_pages() but mistakenly not doing the stat adjustment. As a result, use of DAMOS_MIGRATE_{HOT,COLD} could corrupt the stat. It could confuse too_many_isolated(), make compaction and reclaim to behave in unexpected ways. The stat corruption can be reproduced and confirmed using DAMON user-space tool [1] on NUMA systems, like below. $ numactl --hardware available: 2 nodes (0-1) [...] $ sudo ./damo start --damos_action migrate_hot 1 $ sudo cat /proc/sys/vm/stat_refresh $ sudo dmesg [...] [ 80.215554] vmstat_refresh: nr_isolated_anon -5578 [ 80.216842] vmstat_refresh: nr_isolated_file -34400 This issue was discovered [2] by Sashiko. Link: https://lore.kernel.org/20260728140404.94476-1-sj@kernel.org Link: https://github.com/damonitor/damo [1] Link: https://lore.kernel.org/20260726164356.87940-1-sj@kernel.org [2] Fixes: b51820ebea65 ("mm/damon/paddr: introduce DAMOS_MIGRATE_COLD action for demotion") Signed-off-by: SJ Park Cc: Honggyu Kim Cc: Hyeongtak Ji Cc: # 6.11.x Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/damon/ops-common.c | 4 ++++ mm/damon/paddr.c | 2 ++ mm/damon/vaddr.c | 3 ++- 3 files changed, 8 insertions(+), 1 deletion(-) --- a/mm/damon/ops-common.c +++ b/mm/damon/ops-common.c @@ -374,6 +374,8 @@ keep: while (!list_empty(folio_list)) { folio = lru_to_folio(folio_list); list_del(&folio->lru); + node_stat_sub_folio(folio, NR_ISOLATED_ANON + + folio_is_file_lru(folio)); folio_putback_lru(folio); } @@ -396,6 +398,8 @@ unsigned long damon_migrate_pages(struct struct folio *folio = lru_to_folio(folio_list); list_del(&folio->lru); + node_stat_sub_folio(folio, NR_ISOLATED_ANON + + folio_is_file_lru(folio)); folio_putback_lru(folio); } return nr_migrated; --- a/mm/damon/paddr.c +++ b/mm/damon/paddr.c @@ -277,6 +277,8 @@ static unsigned long damon_pa_migrate(st if (!folio_isolate_lru(folio)) goto put_folio; + node_stat_add_folio(folio, NR_ISOLATED_ANON + + folio_is_file_lru(folio)); list_add(&folio->lru, &folio_list); put_folio: addr += folio_size(folio); --- a/mm/damon/vaddr.c +++ b/mm/damon/vaddr.c @@ -627,7 +627,8 @@ static void damos_va_migrate_dests_add(s isolate: if (!folio_isolate_lru(folio)) return; - + node_stat_add_folio(folio, NR_ISOLATED_ANON + + folio_is_file_lru(folio)); list_add(&folio->lru, &migration_lists[i]); }