The patch titled
Subject: cgroup: rstat: support cgroup1
has been added to the -mm tree. Its filename is
cgroup-rstat-support-cgroup1.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/cgroup-rstat-support-cgroup1.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/cgroup-rstat-support-cgroup1.patch
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------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: cgroup: rstat: support cgroup1
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.
Link: https://lkml.kernel.org/r/20210209163304.77088-5-hannes@xxxxxxxxxxx
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reviewed-by: Roman Gushchin <guro@xxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Reviewed-by: Michal Koutný <mkoutny@xxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/cgroup/cgroup.c | 34 +++++++++++++++++++++-------------
kernel/cgroup/rstat.c | 2 --
2 files changed, 21 insertions(+), 15 deletions(-)
--- a/kernel/cgroup/cgroup.c~cgroup-rstat-support-cgroup1
+++ a/kernel/cgroup/cgroup.c
@@ -1339,6 +1339,7 @@ static void cgroup_destroy_root(struct c
mutex_unlock(&cgroup_mutex);
+ cgroup_rstat_exit(cgrp);
kernfs_destroy_root(root->kf_root);
cgroup_free_root(root);
}
@@ -1751,6 +1752,12 @@ int rebind_subsystems(struct cgroup_root
&dcgrp->e_csets[ss->id]);
spin_unlock_irq(&css_set_lock);
+ if (ss->css_rstat_flush) {
+ list_del_rcu(&css->rstat_css_node);
+ list_add_rcu(&css->rstat_css_node,
+ &dcgrp->rstat_css_list);
+ }
+
/* default hierarchy doesn't enable controllers by default */
dst_root->subsys_mask |= 1 << ssid;
if (dst_root == &cgrp_dfl_root) {
@@ -1971,10 +1978,14 @@ int cgroup_setup_root(struct cgroup_root
if (ret)
goto destroy_root;
- ret = rebind_subsystems(root, ss_mask);
+ ret = cgroup_rstat_init(root_cgrp);
if (ret)
goto destroy_root;
+ ret = rebind_subsystems(root, ss_mask);
+ if (ret)
+ goto exit_stats;
+
ret = cgroup_bpf_inherit(root_cgrp);
WARN_ON_ONCE(ret);
@@ -2006,6 +2017,8 @@ int cgroup_setup_root(struct cgroup_root
ret = 0;
goto out;
+exit_stats:
+ cgroup_rstat_exit(root_cgrp);
destroy_root:
kernfs_destroy_root(root->kf_root);
root->kf_root = NULL;
@@ -4934,8 +4947,7 @@ static void css_free_rwork_fn(struct wor
cgroup_put(cgroup_parent(cgrp));
kernfs_put(cgrp->kn);
psi_cgroup_free(cgrp);
- if (cgroup_on_dfl(cgrp))
- cgroup_rstat_exit(cgrp);
+ cgroup_rstat_exit(cgrp);
kfree(cgrp);
} else {
/*
@@ -4976,8 +4988,7 @@ static void css_release_work_fn(struct w
/* cgroup release path */
TRACE_CGROUP_PATH(release, cgrp);
- if (cgroup_on_dfl(cgrp))
- cgroup_rstat_flush(cgrp);
+ cgroup_rstat_flush(cgrp);
spin_lock_irq(&css_set_lock);
for (tcgrp = cgroup_parent(cgrp); tcgrp;
@@ -5034,7 +5045,7 @@ static void init_and_link_css(struct cgr
css_get(css->parent);
}
- if (cgroup_on_dfl(cgrp) && ss->css_rstat_flush)
+ if (ss->css_rstat_flush)
list_add_rcu(&css->rstat_css_node, &cgrp->rstat_css_list);
BUG_ON(cgroup_css(cgrp, ss));
@@ -5159,11 +5170,9 @@ static struct cgroup *cgroup_create(stru
if (ret)
goto out_free_cgrp;
- if (cgroup_on_dfl(parent)) {
- ret = cgroup_rstat_init(cgrp);
- if (ret)
- goto out_cancel_ref;
- }
+ ret = cgroup_rstat_init(cgrp);
+ if (ret)
+ goto out_cancel_ref;
/* create the directory */
kn = kernfs_create_dir(parent->kn, name, mode, cgrp);
@@ -5250,8 +5259,7 @@ out_psi_free:
out_kernfs_remove:
kernfs_remove(cgrp->kn);
out_stat_exit:
- if (cgroup_on_dfl(parent))
- cgroup_rstat_exit(cgrp);
+ cgroup_rstat_exit(cgrp);
out_cancel_ref:
percpu_ref_exit(&cgrp->self.refcnt);
out_free_cgrp:
--- a/kernel/cgroup/rstat.c~cgroup-rstat-support-cgroup1
+++ a/kernel/cgroup/rstat.c
@@ -285,8 +285,6 @@ void __init cgroup_rstat_boot(void)
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));
}
/*
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
mm-page-writeback-simplify-memcg-handling-in-test_clear_page_writeback.patch
mm-memcontrol-fix-cpuhotplug-statistics-flushing.patch
mm-memcontrol-kill-mem_cgroup_nodeinfo.patch
mm-memcontrol-privatize-memcg_page_state-query-functions.patch
cgroup-rstat-support-cgroup1.patch
cgroup-rstat-punt-root-level-optimization-to-individual-controllers.patch
mm-memcontrol-switch-to-rstat.patch
mm-memcontrol-consolidate-lruvec-stat-flushing.patch
kselftests-cgroup-update-kmem-test-for-new-vmstat-implementation.patch
