From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-187.mta1.migadu.com (out-187.mta1.migadu.com [95.215.58.187]) (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 5117763B9 for ; Thu, 16 Jul 2026 03:26:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.187 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784172382; cv=none; b=BkJWEdjfR350bDbitIri+O4VYOv+/Tx4RsCrpWhnpSYvRMAvYPPGrdpWFadydvR9AMregQtK/puR7ngr8S/o/SlNt6F1ns0Zii68Rsf5k30i1Ep0HGiC9xbPFQnjRhtMhjevhO1AVg5klPIsg+Xjswaq604SktjmsserxPN0gSU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784172382; c=relaxed/simple; bh=WA917DKAKOwQI8iWYO+lgG3B+zDmXKZrt1gj1VohUHM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=OIGOjIoFXf5iwbtjQpH0IOayKM0FLpzbd3lUKoTBygTlqBOla9c/nTt6Xbanu8FZhiAVr77VK0LYXOTkRjOT/7MA+r8wSab8sMIsCjCdsCUPqdZ8M5dzHZIjNgJ4s10Ci2N+H31J7y0iWfiTFxOYX9dKZ5JHizeanIZv+IhVqfo= 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=Kzs63WiC; arc=none smtp.client-ip=95.215.58.187 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="Kzs63WiC" Message-ID: <688a39f3-4539-4916-80f7-67456a514169@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1784172378; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NnyjyDapX7AyGQm2q6tRWBOCLxlc24/i4a9N09iebLA=; b=Kzs63WiC192zhPydLmoGCNFB5idBm5wsZX6Yu30ywryMazQ5LAAcUpixyDemD8ow/Dz580 GT8Uhnk07l0TiaOF3IiOBWY8H1b6CE0TRhhwxhXUAY054weucbAwW1g7z7pz+3kkkokWnh pm3kdP5i5fgXXSZAJ/KYmvM3jEKx/qU= Date: Thu, 16 Jul 2026 11:25:58 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH v2 2/2] mm: vmscan: fix node reclaim ignoring swappiness parameter To: Ridong , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Andrew Morton , Chris Li , Kairui Song Cc: Muchun Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Youngjun Park , David Hildenbrand , Lorenzo Stoakes , Axel Rasmussen , Yuanchu Xie , Wei Xu , Davidlohr Bueso , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Ridong Chen , stable@vger.kernel.org References: <20260716031729.1064007-1-ridong.chen@linux.dev> <20260716031729.1064007-3-ridong.chen@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Qi Zheng In-Reply-To: <20260716031729.1064007-3-ridong.chen@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 7/16/26 11:17 AM, Ridong wrote: > 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 > > Cc: stable@vger.kernel.org # 6.17+ > Fixes: b980077899ea ("mm: introduce per-node proactive reclaim interface") > Signed-off-by: Ridong Chen > Acked-by: Johannes Weiner > Reviewed-by: Barry Song > --- > mm/vmscan.c | 19 +++++++------------ > 1 file changed, 7 insertions(+), 12 deletions(-) Thanks for fixing this! Acked-by: Qi Zheng