From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EBF10C44501 for ; Tue, 14 Jul 2026 07:43:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CA5036B0005; Tue, 14 Jul 2026 03:43:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C56866B0088; Tue, 14 Jul 2026 03:43:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B46E66B008A; Tue, 14 Jul 2026 03:43:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 898366B0005 for ; Tue, 14 Jul 2026 03:43:17 -0400 (EDT) Received: from smtpin06.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay07.hostedemail.com (Postfix) with ESMTP id F0AF61602C7 for ; Tue, 14 Jul 2026 07:43:16 +0000 (UTC) X-FDA: 84986591592.06.F4D56D3 Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) by imf18.hostedemail.com (Postfix) with ESMTP id D03AD1C0003 for ; Tue, 14 Jul 2026 07:43:14 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=hT0bmfKP; spf=pass (imf18.hostedemail.com: domain of ridong.chen@linux.dev designates 91.218.175.172 as permitted sender) smtp.mailfrom=ridong.chen@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1784014995; b=Gw+pFtoUGzvJFlVR7RH1xsh1hERcKc1jBn7R7MNYfwdm4La6ydqIfNNz+3hfilnidxA9Xa //6+X2522d/tpUrbWY/kDB+0VlIfbI5LPwHnNz2gmHsgZAHuO1PLRwqwTPlvc8h3iMoofJ bZZDltev1XnfZj/DEr4Xo2mR4pRt5Tg= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=hT0bmfKP; spf=pass (imf18.hostedemail.com: domain of ridong.chen@linux.dev designates 91.218.175.172 as permitted sender) smtp.mailfrom=ridong.chen@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1784014995; h=from:from:sender: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:dkim-signature; bh=f0I0BJ125x0ILzpKQzbAIfOkMzFcIP5uJz7O94Fnv8U=; b=FKTs7Md0rS+VK8zyDcq1qdEJA2YQuwndWIZh5JSy6hz4lrawVBie26zaXCP3tX6g7piEGF 5vrVqP4crLxmSCPhj8lf3DSO7G2pKs+wTIIkpr4VcqBVZMTBeWVqGfvwLm20I4n9dz3dgz +wZ3r8m2Uvxs2oJFZAak2EnU0wBdV7s= Message-ID: <0545ee70-b0a0-4a93-ac2c-3e84ff504e5a@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1784014992; 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=f0I0BJ125x0ILzpKQzbAIfOkMzFcIP5uJz7O94Fnv8U=; b=hT0bmfKPqQc9pDzFwsqCmtPPFoWQhN08bP7XCztt6T6O9I/sjqP6TCj1HVTvHABehMC/sC D5UK+iM2oYcDiV2UGmsSH4Db3ghqh9VfT3omemPDv4Yqjxh37MZa9Q3ToX9mJG0B4UETN7 atCNfg0O9qKFcAuPjlda6yCvqWeDXv4= Date: Tue, 14 Jul 2026 15:42:52 +0800 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> <87dc4105-b98b-4541-bafe-c0adfbf58836@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 X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: D03AD1C0003 X-Stat-Signature: rtjkkdfndyzq3114yq74hiqzf6khic4h X-HE-Tag: 1784014994-247182 X-HE-Meta: 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 gtGbGiKH 1VwlW+JSgy1zwTZudFAWErykM0YtYlttnxPmV+7xujQOzc3Z/M+G+WpZ8UsnZVqyb9y1SCmIYDbv08QbC6OLrI/S9UMMxwtuhe9M9D4/26j6guDTiftWcRHXfqX/VLsZ/kajweBqmo3qcMpYSl6/E11oYMLjw3XQh8dwEl9+DXevS0C7DtkPTieD/ws9IBgiXYOXHpn1s4yWHtvn45yfd+v7S5dZnLdV2RfbJWVttwELT/C4BzVeu3cJQ8Zliv56oOdmDLHS6jGUU/D7ErCF57m999uyT60YHhHGuEE2u1kJxLbeD7T3LQ22C8nLAmTqf6msP606hyXzRg5HcD/LFG4MJ1xgh3VlD9KTaM15QGouiGVIyMM8hovk9T1wjOpK7OyfrL5D5CT0Ab1rNBU3c7BYoCGH0PtZ19EgR Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 7/14/2026 9:48 AM, Barry Song wrote: > On Tue, Jul 14, 2026 at 9:43 AM Barry Song wrote: >> >> On Tue, Jul 14, 2026 at 9:20 AM Ridong Chen wrote: >>> >>> >>> >>> 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. >> >> If this is the case, it still seems better to keep >> extern int vm_swappiness in include/linux/swap.h. >> >> Then we don't need the comment: >> /* Defined in mm/vmscan.c; used by mem_cgroup_swappiness(). */ >> >> It also makes it clearer that vm_swappiness is an extern variable >> belonging to the swap module, rather than the memcontrol module. > > BTW, if mem_c_group_swappiness() and vm_swappiness are only used > within mm/, could all of these be moved to mm/swap.h and > mm/internal.h instead? > > We are making a big effort to move many unrelated things out of > include/linux/swap.h recently. Could you check? > > https://lore.kernel.org/linux-mm/20260708-ch-swap-series-plus-folio-lru-cleanup-v9-0-2bc72b4f8730@gmail.com/ Good suggestion. Moving them to mm/internal.h makes sense. Will update in the next version. -- Best regards Ridong