From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-181.mta0.migadu.com (out-181.mta0.migadu.com [91.218.175.181]) (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 7A5C6384CFF for ; Sat, 11 Jul 2026 09:12:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783761161; cv=none; b=EF8EiKy9WJb/yZ5G+h7G01q+GYxfH6PbjcTxpzBAxgvAZ00PxKwE7lI5Uxp4glp6kAfpuGO0CQ4qbYKNr56SAnXnqTb1ZLCl5KgHhQvwDNNUNN7rsgcWakO2Eu1DgmDQtoW9RDIoaI64cK280urQ4x7Zl4tIJvqjD0bbq1+ryh8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783761161; c=relaxed/simple; bh=2dzZnMMhKgkPZx/TuFfwfphvZUJfyHZWlcMPrdD4MzQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sOWfBVzI0TrEvuxHygzRAsZEj3GkVuVtEvkx5k9qkO7r7KEnn7mZ5x8TeUXOnB4EkwZoMVfz5EpXt5Dbc7tqCo4jcPwFvbMgHatkus40wC6ii9OCrJt40H5vQ4BFp13gj/Zc22yRKjcNw+00Y91VyLnkTBsPl8wXoBazTEMcmLk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=VrP+biTW; arc=none smtp.client-ip=91.218.175.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="VrP+biTW" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1783761157; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=txHSRzd4Tyll9+u/6ycOBWsZl1BLLa4J8x2YbM2XGjY=; b=VrP+biTWejQyufZrrsBWkZdS4Y44CAMVPA1t1uvFTYzGQyvivpH+acxA0fsBkOrv3yFNbW FwCVtuUgwOZrbyWhMHC7vjl3alqLcXGVBegb3WalKIIMUstbUpLhCpFJBQSYSRIJevONsD J8QqLiojiVVSfyKBPJ68zkmaZzViM9Q= From: Ridong Chen To: Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Chris Li , Kairui Song , David Hildenbrand , Barry Song , Yuanchu Xie Cc: linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, ridong.chen@linux.dev, Ridong Chen Subject: [PATCH 2/2] mm: vmscan: fix node reclaim ignoring swappiness parameter Date: Sat, 11 Jul 2026 17:11:57 +0800 Message-ID: <20260711091157.306070-3-ridong.chen@linux.dev> In-Reply-To: <20260711091157.306070-1-ridong.chen@linux.dev> References: <20260711091157.306070-1-ridong.chen@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT From: Ridong Chen 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 Fixes: 68cd9050d871 ("mm: add swappiness= arg to memory.reclaim") Signed-off-by: Ridong Chen --- mm/vmscan.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 35c3bb15ae96..5271bd023c1d 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -198,6 +198,13 @@ 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. */ @@ -239,12 +246,6 @@ static bool writeback_throttling_sane(struct scan_control *sc) 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) { @@ -261,10 +262,6 @@ static bool writeback_throttling_sane(struct scan_control *sc) return true; } -static int sc_swappiness(struct scan_control *sc, struct mem_cgroup *memcg) -{ - return READ_ONCE(vm_swappiness); -} #endif static void set_task_reclaim_state(struct task_struct *task, -- 2.43.0