From: "tip-bot2 for Chengming Zhou" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Tejun Heo <tj@kernel.org>,
Chengming Zhou <zhouchengming@bytedance.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: sched/core] sched/cpuacct: Remove redundant RCU read lock
Date: Tue, 01 Mar 2022 15:24:41 -0000 [thread overview]
Message-ID: <164614828103.16921.3200748862262912069.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20220220051426.5274-3-zhouchengming@bytedance.com>
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@bytedance.com>
AuthorDate: Sun, 20 Feb 2022 13:14:26 +08:00
Committer: Peter Zijlstra <peterz@infradead.org>
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@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
---
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 = {
next prev parent reply other threads:[~2022-03-01 15:24 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-20 5:14 [PATCH v3 1/3] sched/cpuacct: fix charge percpu cpuusage Chengming Zhou
2022-02-20 5:14 ` [PATCH v3 2/3] sched/cpuacct: optimize away RCU read lock Chengming Zhou
2022-03-01 15:24 ` [tip: sched/core] sched/cpuacct: Optimize " tip-bot2 for Chengming Zhou
[not found] ` <CGME20220308232034eucas1p2b0f39cee0f462af6004ebdfbe5bacb9f@eucas1p2.samsung.com>
2022-03-08 23:20 ` [PATCH v3 2/3] sched/cpuacct: optimize " Marek Szyprowski
2022-03-08 23:32 ` Peter Zijlstra
2022-03-08 23:44 ` Paul E. McKenney
2022-03-09 0:21 ` Paul E. McKenney
2022-03-10 8:45 ` Peter Zijlstra
2022-03-10 15:01 ` Paul E. McKenney
2022-03-12 12:15 ` Peter Zijlstra
2022-03-12 17:44 ` Paul E. McKenney
2022-03-09 3:08 ` [External] " Chengming Zhou
2022-02-20 5:14 ` [PATCH v3 3/3] sched/cpuacct: remove redundant " Chengming Zhou
2022-03-01 15:24 ` tip-bot2 for Chengming Zhou [this message]
[not found] ` <CGME20220308233107eucas1p119a2f5a8d4f5b5eec38ea8dde92b3368@eucas1p1.samsung.com>
2022-03-08 23:31 ` Marek Szyprowski
2022-02-22 18:01 ` [PATCH v3 1/3] sched/cpuacct: fix charge percpu cpuusage Tejun Heo
2022-02-23 9:11 ` Peter Zijlstra
2022-03-01 15:24 ` [tip: sched/core] sched/cpuacct: Fix " tip-bot2 for Chengming Zhou
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