From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-186.mta1.migadu.com (out-186.mta1.migadu.com [95.215.58.186]) (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 359EF207DF7 for ; Tue, 14 Jul 2026 01:20:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.186 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783992017; cv=none; b=QMZGpQpT0NHZJkqTkC/p3GI1PqdPVP3TNIyZThG+IjyYOtcb3wTt7FNCoeyfTXguQQIxIF6wKWEfDbw5LzHWq4vy6L0NgZX0OEZA6+Kg95LXHQVBansbfn7LE6wsgii6qf9E9/xyu3Tsa502uv30OeHe+MjgacdiyYcWMdO2G3g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783992017; c=relaxed/simple; bh=PkJdQaEDMEfonIw8EEkQse6zdo9BDrmz2jybU6BcgoA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=p+06Lxfa4N1i45fpuNjOwGE109Gd+UKY+eGoaJCc1XInSM+xkqLHz8xOmn7nkfc5K2IrilXg8fezO/MEhjQ1srJKVznk+SSPJJTsI5rXftWqIahQlJSi951KdR7zHPIWFwm9DPiEHXgh25RaZdmQVTHWaRIiR2UuyPPHdDsf8Rs= 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=aLPVtxei; arc=none smtp.client-ip=95.215.58.186 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="aLPVtxei" Message-ID: <87dc4105-b98b-4541-bafe-c0adfbf58836@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1783992013; 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=ZctEu+mX1koEkj7iSspmtkQvsQ427myBTirKB+Ofv9Q=; b=aLPVtxeiDDTh4DfW/RDii/1ZK3BCZDRA8W8VefSwdDDRhy2veEza0ita+eFrzjWOY5Bk0U vLbN3hjYA6Wa1jSjTAKTmZn8V8wZFSNkQ3PzQuisAK1lml21UZjnDRdvQqr8v7DUdU0XZf mMwk10gxE/Gqd1uGn2LmMbIK2S+jeTg= Date: Tue, 14 Jul 2026 09:19:53 +0800 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH 1/2] memcg: move mem_cgroup_swappiness to memcontrol.h To: Barry Song Cc: Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Chris Li , Kairui Song , David Hildenbrand , Yuanchu Xie , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Ridong Chen References: <20260711091157.306070-1-ridong.chen@linux.dev> <20260711091157.306070-2-ridong.chen@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Ridong Chen In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 7/13/2026 11:08 PM, Barry Song wrote: > On Sat, Jul 11, 2026 at 5:12 PM Ridong Chen wrote: >> >> From: Ridong Chen >> >> The per-memcg swappiness knob is v1-only; v2 always uses global >> vm_swappiness and ignores the per-cgroup field. >> >> Guard memcg->swappiness with CONFIG_MEMCG_V1, and move the helper >> to memcontrol.h where it belongs. >> >> No functional change for v1; v2-only kernels drop the unused field. >> >> Signed-off-by: Ridong Chen >> Acked-by: Johannes Weiner > > Reviewed-by: Barry Song > > With some nits. > >> --- > [...] >> struct mem_cgroup_per_node *nodeinfo[]; >> @@ -365,6 +366,9 @@ enum objext_flags { >> >> #define OBJEXTS_FLAGS_MASK (__NR_OBJEXTS_FLAGS - 1) >> >> +/* Defined in mm/vmscan.c; used by mem_cgroup_swappiness(). */ >> +extern int vm_swappiness; > > This is a bit unusual. I'm not sure whether mm/swap.h would be > a more appropriate place for this. > Thank you for your reply. The vm_swappiness variable is not utilized within mm/swap.c. Furthermore, since memcontrol.h does not include swap.h, retaining the extern int vm_swappiness declaration in mm/swap.h will result in a compilation failure. -- Best regards Ridong