[SRU][Xenial][PATCH] sched/cpuacct: Simplify the cpuacct code
Gavin Guo
gavin.guo at canonical.com
Thu Jun 7 02:58:37 UTC 2018
From: Zhao Lei <zhaolei at cn.fujitsu.com>
BugLink: https://bugs.launchpad.net/bugs/1775326
- Use for() instead of while() loop in some functions
to make the code simpler.
- Use this_cpu_ptr() instead of per_cpu_ptr() to make the code
cleaner and a bit faster.
Suggested-by: Peter Zijlstra <peterz at infradead.org>
Signed-off-by: Zhao Lei <zhaolei at cn.fujitsu.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz at infradead.org>
Cc: Linus Torvalds <torvalds at linux-foundation.org>
Cc: Tejun Heo <htejun at gmail.com>
Cc: Thomas Gleixner <tglx at linutronix.de>
Link: http://lkml.kernel.org/r/d8a7ef9592f55224630cb26dea239f05b6398a4e.1458187654.git.zhaolei@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo at kernel.org>
(cherry picked from commit 73e6aafd9ea81498d31361f01db84a0118da2d1c)
Signed-off-by: Gavin Guo <gavin.guo at canonical.com>
---
kernel/sched/cpuacct.c | 28 +++++-----------------------
kernel/sched/cpuacct.h | 4 ++--
2 files changed, 7 insertions(+), 25 deletions(-)
diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index dd7cbb55bbf2..e14cfd0e8f20 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -235,23 +235,10 @@ static struct cftype files[] = {
void cpuacct_charge(struct task_struct *tsk, u64 cputime)
{
struct cpuacct *ca;
- int cpu;
-
- cpu = task_cpu(tsk);
rcu_read_lock();
-
- ca = task_ca(tsk);
-
- while (true) {
- u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
- *cpuusage += cputime;
-
- ca = parent_ca(ca);
- if (!ca)
- break;
- }
-
+ for (ca = task_ca(tsk); ca; ca = parent_ca(ca))
+ *this_cpu_ptr(ca->cpuusage) += cputime;
rcu_read_unlock();
}
@@ -260,18 +247,13 @@ void cpuacct_charge(struct task_struct *tsk, u64 cputime)
*
* Note: it's the caller that updates the account of the root cgroup.
*/
-void cpuacct_account_field(struct task_struct *p, int index, u64 val)
+void cpuacct_account_field(struct task_struct *tsk, int index, u64 val)
{
- struct kernel_cpustat *kcpustat;
struct cpuacct *ca;
rcu_read_lock();
- ca = task_ca(p);
- while (ca != &root_cpuacct) {
- kcpustat = this_cpu_ptr(ca->cpustat);
- kcpustat->cpustat[index] += val;
- ca = parent_ca(ca);
- }
+ for (ca = task_ca(tsk); ca != &root_cpuacct; ca = parent_ca(ca))
+ this_cpu_ptr(ca->cpustat)->cpustat[index] += val;
rcu_read_unlock();
}
diff --git a/kernel/sched/cpuacct.h b/kernel/sched/cpuacct.h
index ed605624a5e7..ba72807c73d4 100644
--- a/kernel/sched/cpuacct.h
+++ b/kernel/sched/cpuacct.h
@@ -1,7 +1,7 @@
#ifdef CONFIG_CGROUP_CPUACCT
extern void cpuacct_charge(struct task_struct *tsk, u64 cputime);
-extern void cpuacct_account_field(struct task_struct *p, int index, u64 val);
+extern void cpuacct_account_field(struct task_struct *tsk, int index, u64 val);
#else
@@ -10,7 +10,7 @@ static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime)
}
static inline void
-cpuacct_account_field(struct task_struct *p, int index, u64 val)
+cpuacct_account_field(struct task_struct *tsk, int index, u64 val)
{
}
--
2.7.4
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