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 762B93A9629; Fri, 4 Sep 2026 05:40:22 +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=1788500423; cv=none; b=S1hfCpzHZctmNX2LZCr9Ft2KbygA9zQ577JKgouJxt/bpxLW4pyKwD48IvDiw4aA0WPgr249EiIQZS6e96x787/PqfS2mMHK202xiWpd4F2chLcO0/3RNETIMe85f7ZzFHl2jPCS/4XzB3g0IFrS34LFhYqLa39iaRnm4OuFoAE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788500423; c=relaxed/simple; bh=LCV5fpr3F/aWI2YqNUsEQFEz5p9KdjYmk2T6/2rAASs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PFDteM2CB0QSb6uLZxHg+An8+l+0H9d0kfQXMl7Vm9tj6l3VDKRAmyHXltzJS7VdD36XIoMw2ElkoDGbfYkQoM0gXfY67dg1I5XkTxv7PPj7sS75vyUbVww3bO7hl9pKUYXZgTsNZc0BELA02GoiNQRdLvVIoQXOYGW1TT/qkxs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Ecd3c+k4; 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="Ecd3c+k4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6426F1F00A3D; Fri, 4 Sep 2026 05:40:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788500422; bh=ksknkuZ9oZG1+KP9P1LM/SzX86hud4wEpiDZH49QXQw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Ecd3c+k4bgPukp2YyVRqitFaXRm+bqZ1G3oHWL78MW1M3bJtD7Vk3RDWZ+WNT+E4Z 1fZRWj4orx+7Ed/7e1NxlvXNQ7Xe99JabjoYi3oKAtJJAm52jDeWRvL6F746JN/6Se 2sMEZTo8vJf/KjL2hXACGQNfjhU/cRdJ3mgXUJZA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ridong Chen , Johannes Weiner , Barry Song , Qi Zheng , Song Hu , Shakeel Butt , Axel Rasmussen , Baoquan He , Chris Li , David Hildenbrand , Davidlohr Bueso , Kairui Song , Kemeng Shi , Lorenzo Stoakes , Michal Hocko , Muchun Song , Nhat Pham , Roman Gushchin , Wei Xu , Yuanchu Xie , Andrew Morton Subject: [PATCH 6.18 051/552] mm: vmscan: fix node reclaim ignoring swappiness parameter Date: Fri, 4 Sep 2026 06:53:28 +0200 Message-ID: <20260904045748.996266445@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045747.813364717@linuxfoundation.org> References: <20260904045747.813364717@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ridong Chen commit 8a905195850d383c0465ab5bdd3c91d94269b242 upstream. sc_swappiness() had two separate definitions depending on CONFIG_MEMCG. The !CONFIG_MEMCG variant simply returned vm_swappiness, ignoring the proactive_swappiness value passed through scan_control. This caused the swappiness parameter written to /sys/devices/system/node/nodeX/reclaim to have no effect when CONFIG_MEMCG is disabled. Fix this by consolidating sc_swappiness() into a single definition that checks sc->proactive_swappiness first, then falls back to mem_cgroup_swappiness() which already handles both CONFIG_MEMCG and !CONFIG_MEMCG. Before fix (swappiness=max ignored, mostly file pages reclaimed): # cat /proc/sys/vm/swappiness 60 # cat /proc/vmstat | grep pgsteal pgsteal_kswapd 0 pgsteal_direct 0 pgsteal_khugepaged 0 pgsteal_proactive 1840 pgsteal_anon 25 pgsteal_file 1815 # echo "64M swappiness=max" > /sys/devices/system/node/node0/reclaim # cat /proc/vmstat | grep pgsteal pgsteal_kswapd 0 pgsteal_direct 0 pgsteal_khugepaged 0 pgsteal_proactive 18013 pgsteal_anon 337 pgsteal_file 17676 After fix (swappiness=max honored, anon pages reclaimed as expected): # cat /proc/vmstat | grep pgsteal pgsteal_kswapd 0 pgsteal_direct 0 pgsteal_khugepaged 0 pgsteal_proactive 0 pgsteal_anon 0 pgsteal_file 0 # echo "64M swappiness=max" > /sys/devices/system/node/node0/reclaim # cat /proc/vmstat | grep pgsteal pgsteal_kswapd 0 pgsteal_direct 0 pgsteal_khugepaged 0 pgsteal_proactive 16283 pgsteal_anon 16283 pgsteal_file 0 Link: https://lore.kernel.org/20260723032434.2016749-3-ridong.chen@linux.dev Fixes: b980077899ea ("mm: introduce per-node proactive reclaim interface") Signed-off-by: Ridong Chen Acked-by: Johannes Weiner Reviewed-by: Barry Song Acked-by: Qi Zheng Tested-by: Song Hu Reviewed-by: Song Hu Acked-by: Shakeel Butt Cc: Axel Rasmussen Cc: Baoquan He Cc: Chris Li Cc: David Hildenbrand Cc: Davidlohr Bueso Cc: Kairui Song Cc: Kemeng Shi Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Muchun Song Cc: Nhat Pham Cc: Roman Gushchin Cc: Wei Xu Cc: Yuanchu Xie Cc: [6.17+] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/vmscan.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -201,6 +201,13 @@ struct scan_control { */ int vm_swappiness = 60; +static int sc_swappiness(struct scan_control *sc, struct mem_cgroup *memcg) +{ + if (sc->proactive && sc->proactive_swappiness) + return *sc->proactive_swappiness; + return mem_cgroup_swappiness(memcg); +} + #ifdef CONFIG_MEMCG /* Returns true for reclaim through cgroup limits or cgroup interfaces. */ @@ -241,13 +248,6 @@ static bool writeback_throttling_sane(st #endif return false; } - -static int sc_swappiness(struct scan_control *sc, struct mem_cgroup *memcg) -{ - if (sc->proactive && sc->proactive_swappiness) - return *sc->proactive_swappiness; - return mem_cgroup_swappiness(memcg); -} #else static bool cgroup_reclaim(struct scan_control *sc) { @@ -263,11 +263,6 @@ static bool writeback_throttling_sane(st { return true; } - -static int sc_swappiness(struct scan_control *sc, struct mem_cgroup *memcg) -{ - return READ_ONCE(vm_swappiness); -} #endif /* for_each_managed_zone_pgdat - helper macro to iterate over all managed zones in a pgdat up to