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sched/cpuacct: Simplify the cpuacct code 

- 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@infradead.org>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/d8a7ef9592f55224630cb26dea239f05b6398a4e.1458187654.git.zhaolei@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Zhao Lei 2016-03-17 12:19:43 +08:00 committed by Ingo Molnar
parent 1a736b77a3
commit 73e6aafd9e
2 changed files with 7 additions and 25 deletions
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28
kernel/sched/cpuacct.c
View File

@ -238,23 +238,10 @@ 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();
}
@ -263,18 +250,13 @@ 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();
}

4
kernel/sched/cpuacct.h
View File

@ -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)
{
}