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Commit 5ca3726a authored by Zhao Lei's avatar Zhao Lei Committed by Ingo Molnar
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sched/cpuacct: Show all possible CPUs in cpuacct output 



Current code show stats of online CPUs in cpuacct.statcpus,
show stats of present cpus in cpuacct.usage(_percpu), and using
present CPUs for setting cpuacct.usage.

It will cause inconsistent result when a CPU is online or offline
or hotpluged.

We should always use possible CPUs to avoid above problem.

Here are the contents of a cpuacct.usage_percpu sysfs file,
on a 4 CPU system with maxcpus=32:

Before the patch:
 # cat cpuacct.usage_percpu
 2456565 411435 1052897 832584

After the patch:
 # cat cpuacct.usage_percpu
 2456565 411435 1052897 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

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: Mike Galbraith <efault@gmx.de>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/a11d56cef12d0b4807f8be3a46bf9798c3014d59.1458635566.git.zhaolei@cn.fujitsu.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 283d7573

kernel/sched/cpuacct.c

+5 −5
Original line number Diff line number Diff line
@@ -138,7 +138,7 @@ static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft) 
	u64 totalcpuusage = 0;

	int i;



	for_each_present_cpu(i)

	for_each_possible_cpu(i)

		totalcpuusage += cpuacct_cpuusage_read(ca, i);



	return totalcpuusage;
@@ -159,7 +159,7 @@ static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft, 
		goto out;

	}



	for_each_present_cpu(i)

	for_each_possible_cpu(i)

		cpuacct_cpuusage_write(ca, i, 0);



out:
@@ -172,7 +172,7 @@ static int cpuacct_percpu_seq_show(struct seq_file *m, void *V) 
	u64 percpu;

	int i;



	for_each_present_cpu(i) {

	for_each_possible_cpu(i) {

		percpu = cpuacct_cpuusage_read(ca, i);

		seq_printf(m, "%llu ", (unsigned long long) percpu);

	}
@@ -191,7 +191,7 @@ static int cpuacct_stats_show(struct seq_file *sf, void *v) 
	int cpu;

	s64 val = 0;



	for_each_online_cpu(cpu) {

	for_each_possible_cpu(cpu) {

		struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);

		val += kcpustat->cpustat[CPUTIME_USER];

		val += kcpustat->cpustat[CPUTIME_NICE];
@@ -200,7 +200,7 @@ static int cpuacct_stats_show(struct seq_file *sf, void *v) 
	seq_printf(sf, "%s %lld\n", cpuacct_stat_desc[CPUACCT_STAT_USER], val);



	val = 0;

	for_each_online_cpu(cpu) {

	for_each_possible_cpu(cpu) {

		struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);

		val += kcpustat->cpustat[CPUTIME_SYSTEM];

		val += kcpustat->cpustat[CPUTIME_IRQ];