From: Johannes Weiner <hannes@cmpxchg.org>
To: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Tejun Heo <tj@kernel.org>, Roman Gushchin <guro@fb.com>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH 4/7] cgroup: rstat: support cgroup1
Date: Thu, 4 Feb 2021 11:01:30 -0500 [thread overview]
Message-ID: <YBwaWkJgqPNF3I3w@cmpxchg.org> (raw)
In-Reply-To: <YBv5Dc1I9QpPH69n@dhcp22.suse.cz>
On Thu, Feb 04, 2021 at 02:39:25PM +0100, Michal Hocko wrote:
> On Tue 02-02-21 13:47:43, Johannes Weiner wrote:
> > Rstat currently only supports the default hierarchy in cgroup2. In
> > order to replace memcg's private stats infrastructure - used in both
> > cgroup1 and cgroup2 - with rstat, the latter needs to support cgroup1.
> >
> > The initialization and destruction callbacks for regular cgroups are
> > already in place. Remove the cgroup_on_dfl() guards to handle cgroup1.
> >
> > The initialization of the root cgroup is currently hardcoded to only
> > handle cgrp_dfl_root.cgrp. Move those callbacks to cgroup_setup_root()
> > and cgroup_destroy_root() to handle the default root as well as the
> > various cgroup1 roots we may set up during mounting.
> >
> > The linking of css to cgroups happens in code shared between cgroup1
> > and cgroup2 as well. Simply remove the cgroup_on_dfl() guard.
> >
> > Linkage of the root css to the root cgroup is a bit trickier: per
> > default, the root css of a subsystem controller belongs to the default
> > hierarchy (i.e. the cgroup2 root). When a controller is mounted in its
> > cgroup1 version, the root css is stolen and moved to the cgroup1 root;
> > on unmount, the css moves back to the default hierarchy. Annotate
> > rebind_subsystems() to move the root css linkage along between roots.
>
> I am not familiar with rstat API and from this patch it is not really
> clear to me how does it deal with memcg v1 use_hierarchy oddness.
That's gone, right?
static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
struct cftype *cft, u64 val)
{
if (val == 1)
return 0;
pr_warn_once("Non-hierarchical mode is deprecated. "
"Please report your usecase to linux-mm@kvack.org if you "
"depend on this functionality.\n");
return -EINVAL;
}
next prev parent reply other threads:[~2021-02-04 16:01 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-02 18:47 [PATCH 0/7]: mm: memcontrol: switch to rstat Johannes Weiner
2021-02-02 18:47 ` [PATCH 1/7] mm: memcontrol: fix cpuhotplug statistics flushing Johannes Weiner
2021-02-02 22:23 ` Shakeel Butt
2021-02-02 23:07 ` Roman Gushchin
2021-02-03 2:28 ` Roman Gushchin
2021-02-04 19:29 ` Johannes Weiner
2021-02-04 19:34 ` Roman Gushchin
2021-02-05 17:50 ` Johannes Weiner
2021-02-04 13:28 ` Michal Hocko
2021-02-02 18:47 ` [PATCH 2/7] mm: memcontrol: kill mem_cgroup_nodeinfo() Johannes Weiner
2021-02-02 22:24 ` Shakeel Butt
2021-02-02 23:13 ` Roman Gushchin
2021-02-04 13:29 ` Michal Hocko
2021-02-02 18:47 ` [PATCH 3/7] mm: memcontrol: privatize memcg_page_state query functions Johannes Weiner
2021-02-02 22:26 ` Shakeel Butt
2021-02-02 23:17 ` Roman Gushchin
2021-02-04 13:30 ` Michal Hocko
2021-02-02 18:47 ` [PATCH 4/7] cgroup: rstat: support cgroup1 Johannes Weiner
2021-02-03 1:16 ` Roman Gushchin
2021-02-04 13:39 ` Michal Hocko
2021-02-04 16:01 ` Johannes Weiner [this message]
2021-02-04 16:42 ` Michal Hocko
2021-02-02 18:47 ` [PATCH 5/7] cgroup: rstat: punt root-level optimization to individual controllers Johannes Weiner
2021-02-02 18:47 ` [PATCH 6/7] mm: memcontrol: switch to rstat Johannes Weiner
2021-02-03 1:47 ` Roman Gushchin
2021-02-04 16:26 ` Johannes Weiner
2021-02-04 18:45 ` Roman Gushchin
2021-02-04 20:05 ` Johannes Weiner
2021-02-04 14:19 ` Michal Hocko
2021-02-04 16:15 ` Johannes Weiner
2021-02-04 16:44 ` Michal Hocko
2021-02-04 20:28 ` Johannes Weiner
2021-02-05 15:05 ` Michal Hocko
2021-02-05 16:34 ` Johannes Weiner
2021-02-08 14:07 ` Michal Hocko
2021-02-02 18:47 ` [PATCH 7/7] mm: memcontrol: consolidate lruvec stat flushing Johannes Weiner
2021-02-03 2:25 ` Roman Gushchin
2021-02-04 21:44 ` Johannes Weiner
2021-02-04 21:47 ` Roman Gushchin
2021-02-05 15:17 ` Michal Hocko
2021-02-05 17:10 ` Johannes Weiner
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