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Code Issues Releases Wiki Activity

sched/cpuacct: Remove redundant RCU read lock 

The cpuacct_account_field() and it's cgroup v2 wrapper
cgroup_account_cputime_field() is only called from cputime
in task_group_account_field(), which is already in RCU read-side
critical section. So remove these redundant RCU read lock.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220220051426.5274-3-zhouchengming@bytedance.com
This commit is contained in:
Chengming Zhou 2022-02-20 13:14:26 +08:00 committed by Peter Zijlstra
parent dc6e0818bc
commit 3eba0505d0
2 changed files with 0 additions and 4 deletions
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2
include/linux/cgroup.h
View File

@ -804,11 +804,9 @@ static inline void cgroup_account_cputime_field(struct task_struct *task,
cpuacct_account_field(task, index, delta_exec);
rcu_read_lock();
cgrp = task_dfl_cgroup(task);
if (cgroup_parent(cgrp))
__cgroup_account_cputime_field(cgrp, index, delta_exec);
rcu_read_unlock();
}
#else /* CONFIG_CGROUPS */

2
kernel/sched/cpuacct.c
View File

@ -352,10 +352,8 @@ void cpuacct_account_field(struct task_struct *tsk, int index, u64 val)
{
struct cpuacct *ca;
rcu_read_lock();
for (ca = task_ca(tsk); ca != &root_cpuacct; ca = parent_ca(ca))
__this_cpu_add(ca->cpustat->cpustat[index], val);
rcu_read_unlock();
}
struct cgroup_subsys cpuacct_cgrp_subsys = {