proc: stats: Use arch_idle_time for idle and iowait times if available (cb85a6ed) · Commits · 戴 / test

Git commit "proc: Consider NO_HZ when printing idle and iowait times" changes the code for /proc/stat to use get_cpu_idle_time_us and get_cpu_iowait_time_us if the system is running with nohz enabled. For architectures which define arch_idle_time (currently s390 only) this is a change for the worse. The result of arch_idle_time is supposed to be the exact sleep time of the target cpu and should be used instead of the value kept by the scheduler. Signed-off-by:

Martin Schwidefsky <schwidefsky@de.ibm.com> Reviewed-by:

Michal Hocko <mhocko@suse.cz> Reviewed-by:

Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/20120330122308.18720283@de.ibm.com Signed-off-by:

Thomas Gleixner <tglx@linutronix.de>

fs/proc/stat.c

+28 −6

Original line number	Diff line number	Diff line
		@@ -18,19 +18,39 @@
		#ifndef arch_irq_stat
		#define arch_irq_stat() 0
		#endif
		#ifndef arch_idle_time
		#define arch_idle_time(cpu) 0
		#endif

		#ifdef arch_idle_time

		static cputime64_t get_idle_time(int cpu)
		{
		cputime64_t idle;

		idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE];
		if (cpu_online(cpu) && !nr_iowait_cpu(cpu))
		idle += arch_idle_time(cpu);
		return idle;
		}

		static cputime64_t get_iowait_time(int cpu)
		{
		cputime64_t iowait;

		iowait = kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT];
		if (cpu_online(cpu) && nr_iowait_cpu(cpu))
		iowait += arch_idle_time(cpu);
		return iowait;
		}

		#else

		static u64 get_idle_time(int cpu)
		{
		u64 idle, idle_time = get_cpu_idle_time_us(cpu, NULL);

		if (idle_time == -1ULL) {
		if (idle_time == -1ULL)
		/* !NO_HZ so we can rely on cpustat.idle */
		idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE];
		idle += arch_idle_time(cpu);
		} else
		else
		idle = usecs_to_cputime64(idle_time);

		return idle;
		@@ -49,6 +69,8 @@ static u64 get_iowait_time(int cpu)
		return iowait;
		}

		#endif

		static int show_stat(struct seq_file p, void v)
		{
		int i, j;

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