Commit 73e6aafd authored by Zhao Lei's avatar Zhao Lei Committed by Ingo Molnar
Browse files

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: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: default avatarPeter 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: default avatarIngo Molnar <mingo@kernel.org>
parent 1a736b77

kernel/sched/cpuacct.c

+5 −23
Original line number Diff line number Diff line
@@ -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();

}

kernel/sched/cpuacct.h

+2 −2
Original line number Diff line number Diff line 
#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)

{

}

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