maillist inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5F6X6
CVE: NA

Reference: https://lore.kernel.org/all/20210916162451.709260-1-guro@fb.com/

-------------------

This patch adds 3 helpers useful for dealing with sched entities:
  u64 bpf_sched_entity_to_tgidpid(struct sched_entity *se);
  u64 bpf_sched_entity_to_cgrpid(struct sched_entity *se);
  long bpf_sched_entity_belongs_to_cgrp(struct sched_entity *se,
  	u64 cgrpid);

Sched entity is a basic structure used by the scheduler to represent
schedulable objects: tasks and cgroups (if CONFIG_FAIR_GROUP_SCHED
is enabled). It will be passed as an argument to many bpf hooks, so
scheduler bpf programs need a convenient way to deal with it.

bpf_sched_entity_to_tgidpid() and bpf_sched_entity_to_cgrpid() are
useful to identify a sched entity in userspace terms (pid, tgid and
cgroup id). bpf_sched_entity_belongs_to_cgrp() allows to check whether
a sched entity belongs to sub-tree of a cgroup. It allows to write
cgroup-specific scheduler policies even without enabling the cgroup
cpu controller.
Signed-off-by: NRoman Gushchin <guro@fb.com>
Signed-off-by: NChen Hui <judy.chenhui@huawei.com>
Signed-off-by: NRen Zhijie <renzhijie2@huawei.com>