From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH] cgroup: Show control files in cgroup2 root after mount Date: Tue, 18 Jul 2017 15:51:48 -0400 Message-ID: <20170718195148.GC3365493@devbig577.frc2.facebook.com> References: <1500406336-29512-1-git-send-email-longman@redhat.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=Oi6Lt84dX+4pkV4g1SXo4jVHX7wtRwDC/wuO4BZU198=; b=Lc084io9wrxRoWYNVFGEJZoIQPK6NknMql3xlPCeEe69R0Jvj1Uhjet9qaUbsfbQId kJlfWcQhK/lBoUJL/MsIlCrboVuydSngTOs/NHRqUkDx+KFiZ8o22tMRszDy/Fay+qD3 hpJTmEHPt4HcB6pEz//wwvQCUqPKSg9XlAwbu6CHZycGzsoN5oA4xyAJscs5LfXVxOH5 GnvZCMDlvfEpjAI/hp+ECfpD4+w7aOSHyiw2VWkn/BRzYm7McE5MIB+Mrg9gvAmYIYOG FGCHqOb1dsxlXzLXy7eUEfO5DYbiOag9SJt+k+QeFvNpnPtqXt/MHMiG++t2fbkmvDcc XR/g== Content-Disposition: inline In-Reply-To: <1500406336-29512-1-git-send-email-longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Waiman Long Cc: Li Zefan , Johannes Weiner , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Hello, Waiman. On Tue, Jul 18, 2017 at 03:32:16PM -0400, Waiman Long wrote: > It was found that when a cgroup2 filesystem was mounted, control > files other than the base cgroup.* ones were not shown in the root > directory. They were shown only after some controllers were activated > in the root's cgroup.subtree_control file. > > This was caused by a lack of the kernfs_activate() call which was fixed > by this patch. > > Signed-off-by: Waiman Long > --- > kernel/cgroup/cgroup.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c > index 89a23c6..fb1893b 100644 > --- a/kernel/cgroup/cgroup.c > +++ b/kernel/cgroup/cgroup.c > @@ -2024,8 +2024,10 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, > > dentry = cgroup_do_mount(&cgroup2_fs_type, flags, &cgrp_dfl_root, > CGROUP2_SUPER_MAGIC, ns); > - if (!IS_ERR(dentry)) > + if (!IS_ERR(dentry)) { > apply_cgroup_root_flags(root_flags); > + kernfs_activate(cgrp_dfl_root.cgrp.kn); > + } Heh, that's tricky. I'm not quite sure where the unactivated files are being added tho because that'd be where we should be activating. I *think* that they are already activated as part of cgroup_add_cftypes() but I am obviously qmissing something. I'll try to repro the issue and find where we're skipping the activation call. Thanks! -- tejun