diff options
| author | Chengming Zhou <[email protected]> | 2022-02-20 13:14:25 +0800 |
|---|---|---|
| committer | Peter Zijlstra <[email protected]> | 2022-03-01 16:18:38 +0100 |
| commit | dc6e0818bc9a0336d9accf3ea35d146d72aa7a18 (patch) | |
| tree | 81effaa3f69fa5c07bc23c9c0fb7899d149732af | |
| parent | 248cc9993d1cc12b8e9ed716cc3fc09f6c3517dd (diff) | |
sched/cpuacct: Optimize away RCU read lock
Since cpuacct_charge() is called from the scheduler update_curr(),
we must already have rq lock held, then the RCU read lock can
be optimized away.
And do the same thing in it's wrapper cgroup_account_cputime(),
but we can't use lockdep_assert_rq_held() there, which defined
in kernel/sched/sched.h.
Suggested-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Chengming Zhou <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
| -rw-r--r-- | include/linux/cgroup.h | 2 | ||||
| -rw-r--r-- | kernel/sched/cpuacct.c | 4 |
2 files changed, 1 insertions, 5 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 75c151413fda..9a109c6ac0e0 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -791,11 +791,9 @@ static inline void cgroup_account_cputime(struct task_struct *task, cpuacct_charge(task, delta_exec); - rcu_read_lock(); cgrp = task_dfl_cgroup(task); if (cgroup_parent(cgrp)) __cgroup_account_cputime(cgrp, delta_exec); - rcu_read_unlock(); } static inline void cgroup_account_cputime_field(struct task_struct *task, diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c index 307800586ac8..f79f88456d72 100644 --- a/kernel/sched/cpuacct.c +++ b/kernel/sched/cpuacct.c @@ -337,12 +337,10 @@ void cpuacct_charge(struct task_struct *tsk, u64 cputime) unsigned int cpu = task_cpu(tsk); struct cpuacct *ca; - rcu_read_lock(); + lockdep_assert_rq_held(cpu_rq(cpu)); for (ca = task_ca(tsk); ca; ca = parent_ca(ca)) *per_cpu_ptr(ca->cpuusage, cpu) += cputime; - - rcu_read_unlock(); } /* |