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author | Tejun Heo <tj@kernel.org> | 2013-08-08 20:11:23 -0400 |
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committer | Tejun Heo <tj@kernel.org> | 2013-08-08 20:11:23 -0400 |
commit | 6387698699afd72d6304566fb6ccf84bffe07c56 (patch) | |
tree | 9440e96fa8e5adce62409a5b0e40984dfedaada3 /kernel/sched/cpuacct.c | |
parent | a7c6d554aa01236ac2a9f851ab0f75704f76dfa2 (diff) | |
download | linux-stable-6387698699afd72d6304566fb6ccf84bffe07c56.tar.gz linux-stable-6387698699afd72d6304566fb6ccf84bffe07c56.tar.bz2 linux-stable-6387698699afd72d6304566fb6ccf84bffe07c56.zip |
cgroup: add css_parent()
Currently, controllers have to explicitly follow the cgroup hierarchy
to find the parent of a given css. cgroup is moving towards using
cgroup_subsys_state as the main controller interface construct, so
let's provide a way to climb the hierarchy using just csses.
This patch implements css_parent() which, given a css, returns its
parent. The function is guarnateed to valid non-NULL parent css as
long as the target css is not at the top of the hierarchy.
freezer, cpuset, cpu, cpuacct, hugetlb, memory, net_cls and devices
are converted to use css_parent() instead of accessing cgroup->parent
directly.
* __parent_ca() is dropped from cpuacct and its usage is replaced with
parent_ca(). The only difference between the two was NULL test on
cgroup->parent which is now embedded in css_parent() making the
distinction moot. Note that eventually a css->parent field will be
added to css and the NULL check in css_parent() will go away.
This patch shouldn't cause any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'kernel/sched/cpuacct.c')
-rw-r--r-- | kernel/sched/cpuacct.c | 11 |
1 files changed, 2 insertions, 9 deletions
diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c index 8ccfa10cc89f..f6926a149a71 100644 --- a/kernel/sched/cpuacct.c +++ b/kernel/sched/cpuacct.c @@ -50,16 +50,9 @@ static inline struct cpuacct *task_ca(struct task_struct *tsk) return css_ca(task_css(tsk, cpuacct_subsys_id)); } -static inline struct cpuacct *__parent_ca(struct cpuacct *ca) -{ - return cgroup_ca(ca->css.cgroup->parent); -} - static inline struct cpuacct *parent_ca(struct cpuacct *ca) { - if (!ca->css.cgroup->parent) - return NULL; - return cgroup_ca(ca->css.cgroup->parent); + return css_ca(css_parent(&ca->css)); } static DEFINE_PER_CPU(u64, root_cpuacct_cpuusage); @@ -284,7 +277,7 @@ void cpuacct_account_field(struct task_struct *p, int index, u64 val) while (ca != &root_cpuacct) { kcpustat = this_cpu_ptr(ca->cpustat); kcpustat->cpustat[index] += val; - ca = __parent_ca(ca); + ca = parent_ca(ca); } rcu_read_unlock(); } |