The following commit has been merged into the sched/core branch of tip:
Commit-ID: 3eba0505d03a9c1eb30d40c2330c0880b22d1b3a
Gitweb: https://git.kernel.org/tip/3eba0505d03a9c1eb30d40c2330c0880b22d1b3a
Author: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
AuthorDate: Sun, 20 Feb 2022 13:14:26 +08:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Tue, 01 Mar 2022 16:18:38 +01:00
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@xxxxxxxxxx>
Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220220051426.5274-3-zhouchengming@xxxxxxxxxxxxx
---
include/linux/cgroup.h | 2 --
kernel/sched/cpuacct.c | 2 --
2 files changed, 4 deletions(-)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 9a109c6..1e356c2 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -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 */
diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index f79f884..d269ede 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -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 = {
|