From: Johannes Weiner hannes@cmpxchg.org
mainline inclusion from mainline-v5.13-rc1 commit a7df69b81aac5bdeb5c5aef9addd680ce22feebf category: feature bugzilla: 185803 https://gitee.com/openeuler/kernel/issues/I4JOG9?from=project-issue CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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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@cmpxchg.org Signed-off-by: Johannes Weiner hannes@cmpxchg.org Reviewed-by: Roman Gushchin guro@fb.com Reviewed-by: Shakeel Butt shakeelb@google.com Acked-by: Tejun Heo tj@kernel.org Reviewed-by: Michal Koutný mkoutny@suse.com Cc: Michal Hocko mhocko@suse.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Lu Jialin lujialin4@huawei.com Reviewed-by: Xiu Jianfeng xiujianfeng@huawei.com Reviewed-by: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- kernel/cgroup/cgroup.c | 34 +++++++++++++++++++++------------- kernel/cgroup/rstat.c | 2 -- 2 files changed, 21 insertions(+), 15 deletions(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index fafd2332457b..4158857414cc 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1342,6 +1342,7 @@ static void cgroup_destroy_root(struct cgroup_root *root)
mutex_unlock(&cgroup_mutex);
+ cgroup_rstat_exit(cgrp); kernfs_destroy_root(root->kf_root); cgroup_free_root(root); } @@ -1754,6 +1755,12 @@ int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask) &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) { @@ -1975,10 +1982,14 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask) 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);
@@ -2010,6 +2021,8 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask) ret = 0; goto out;
+exit_stats: + cgroup_rstat_exit(root_cgrp); destroy_root: kernfs_destroy_root(root->kf_root); root->kf_root = NULL; @@ -5032,8 +5045,7 @@ static void css_free_rwork_fn(struct work_struct *work) 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 { /* @@ -5074,8 +5086,7 @@ static void css_release_work_fn(struct work_struct *work) /* 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; @@ -5134,7 +5145,7 @@ static void init_and_link_css(struct cgroup_subsys_state *css, 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)); @@ -5268,11 +5279,9 @@ static struct cgroup *cgroup_create(struct cgroup *parent, const char *name, 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); @@ -5359,8 +5368,7 @@ static struct cgroup *cgroup_create(struct cgroup *parent, const char *name, 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: diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c index d51175cedfca..faa767a870ba 100644 --- a/kernel/cgroup/rstat.c +++ b/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)); }
/*