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 X-Spam-Level: X-Spam-Status: No, score=-12.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BFFFAC433DB for ; Wed, 17 Feb 2021 17:43:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F4A564D73 for ; Wed, 17 Feb 2021 17:43:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234678AbhBQRnh (ORCPT ); Wed, 17 Feb 2021 12:43:37 -0500 Received: from mx2.suse.de ([195.135.220.15]:42154 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234594AbhBQRn0 (ORCPT ); Wed, 17 Feb 2021 12:43:26 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1613583759; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=a6Rl/czINqek0rZKZZkZim1YkdyieBAQrw40eO7tWpo=; b=soFy8+R1BOZzWqypKMO/GP4dVw3MB+lo7eiyCGXhnG4ImOxT6IaKHEB11G9vIuv9sdAyA8 nw7VQtqcz8RaeT5LDfr2BPqVWi9/ddvB+QBzpoJOQmDYEVNzMUOjsvd/8KSUJszCzOWT0J wUDlYi6Sh9TDjry0L3TDFJVGZhBTqjI= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 2E6A9B7B8; Wed, 17 Feb 2021 17:42:39 +0000 (UTC) Date: Wed, 17 Feb 2021 18:42:32 +0100 From: Michal =?iso-8859-1?Q?Koutn=FD?= To: Johannes Weiner Cc: Andrew Morton , Tejun Heo , Michal Hocko , Roman Gushchin , Shakeel Butt , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH v3 4/8] cgroup: rstat: support cgroup1 Message-ID: <20210217174232.GA19239@blackbody.suse.cz> References: <20210209163304.77088-1-hannes@cmpxchg.org> <20210209163304.77088-5-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="YiEDa0DAkWCtVeE4" Content-Disposition: inline In-Reply-To: <20210209163304.77088-5-hannes@cmpxchg.org> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --YiEDa0DAkWCtVeE4 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello. On Tue, Feb 09, 2021 at 11:33:00AM -0500, Johannes Weiner wrote: > @@ -1971,10 +1978,14 @@ int cgroup_setup_root(struct cgroup_root *root, u= 16 ss_mask) > if (ret) > goto destroy_root; > =20 > - ret =3D rebind_subsystems(root, ss_mask); > + ret =3D cgroup_rstat_init(root_cgrp); Would it make sense to do cgroup_rstat_init() only if there's a subsys in ss_mask that makes use of rstat? (On legacy systems there could be individual hierarchy for each controller so the rstat space can be saved.) > @@ -5159,11 +5170,9 @@ static struct cgroup *cgroup_create(struct cgroup = *parent, const char *name, > if (ret) > goto out_free_cgrp; > =20 > - if (cgroup_on_dfl(parent)) { > - ret =3D cgroup_rstat_init(cgrp); > - if (ret) > - goto out_cancel_ref; > - } > + ret =3D cgroup_rstat_init(cgrp); And here do cgroup_rstat_init() only when parent has it. > @@ -285,8 +285,6 @@ void __init cgroup_rstat_boot(void) > =20 > for_each_possible_cpu(cpu) > raw_spin_lock_init(per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)); > - > - BUG_ON(cgroup_rstat_init(&cgrp_dfl_root.cgrp)); > } Regardless of the suggestion above, this removal obsoletes the comment cgroup_rstat_init: int cpu; =20 - /* the root cgrp has rstat_cpu preallocated */ if (!cgrp->rstat_cpu) { cgrp->rstat_cpu =3D alloc_percpu(struct cgroup_rstat_cpu); Regards, Michal --YiEDa0DAkWCtVeE4 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEEoQaUCWq8F2Id1tNia1+riC5qSgFAmAtVYQACgkQia1+riC5 qSgrug/8CSTeb3l4LFsYInnLNt+TFGvt5ZjsT2mDXjfBjDSY8Nxa0h9Epw58x19L CbDnD6Q0kLLnK4ZUw4CAM1UWpHqsLaNsRTWg7LhLkpt8YB4r7Mu2TWJFNbq+hvl8 ylFSNrEws0GLv+T7ymT5voKGZacN3TkS7krrEh/4eJfBKIfKVwyfbF984rLCmVk2 ZX7a/e6hc26KKLEEKgRl6bXHeMeQTHe0elonZh7o/U1ganJqzidcs/a4f/kDXy94 NxILYXpoO6A2P3AlzQsMpLxUItsW/8BWEGzwYx3XwXz2Yr5i7fr/5qK24egs4izQ o9BsDCE4mO+V7WEUxDQjG5LhQLFh4AmsGuk/NQeLZEPebTdkbBeA3FaWDzSd4SWw GWELqOFMduOse8dAofnWv0dAjSxUspJ2dyVSD9d2mAO4Zf1DohjdAtCR5BmFTS8E Jq0/DQk4bAY9dou2JzpA5CF8WSp/oKnPoZymFTW5om9bwm8yAsrhshzQ40d5DOD0 lwpswxSbv7cHE+qxyTU2/jEgjKfis9Fir+gS47OjHMQvBuZ4OLU4r7flg5IUo5X1 Vk8zvbDD9Y22pFVAzg5UXgRZZoHepbgJaGUW+E/A4+hy7iWpgX9M44f9Devyjyrt tL9oj/nw/RKkkdsCn3s4z2ZykQzhU0boLi2qzeHENef45VDHqyY= =LqMk -----END PGP SIGNATURE----- --YiEDa0DAkWCtVeE4--