Re: [PATCH 5/6] leds: Use all-in-one vtime aware kcpustat accessor

From: Ingo Molnar
Date: Thu Nov 21 2019 - 01:58:33 EST



* Frederic Weisbecker <frederic@xxxxxxxxxx> wrote:

> We can now safely read user kcpustat fields on nohz_full CPUs.
> Use the appropriate accessor.
>
> Reported-by: Yauheni Kaliuta <yauheni.kaliuta@xxxxxxxxxx>
> Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
> Cc: Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx>
> Cc: Pavel Machek <pavel@xxxxxx>
> Cc: Yauheni Kaliuta <yauheni.kaliuta@xxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Rik van Riel <riel@xxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> ---
> drivers/leds/trigger/ledtrig-activity.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/leds/trigger/ledtrig-activity.c b/drivers/leds/trigger/ledtrig-activity.c
> index ddfc5edd07c8..6901e3631c22 100644
> --- a/drivers/leds/trigger/ledtrig-activity.c
> +++ b/drivers/leds/trigger/ledtrig-activity.c
> @@ -57,11 +57,15 @@ static void led_activity_function(struct timer_list *t)
> curr_used = 0;
>
> for_each_possible_cpu(i) {
> - curr_used += kcpustat_cpu(i).cpustat[CPUTIME_USER]
> - + kcpustat_cpu(i).cpustat[CPUTIME_NICE]
> - + kcpustat_field(&kcpustat_cpu(i), CPUTIME_SYSTEM, i)
> - + kcpustat_cpu(i).cpustat[CPUTIME_SOFTIRQ]
> - + kcpustat_cpu(i).cpustat[CPUTIME_IRQ];
> + struct kernel_cpustat kcpustat;
> +
> + kcpustat_fetch_cpu(&kcpustat, i);
> +
> + curr_used += kcpustat.cpustat[CPUTIME_USER]
> + + kcpustat.cpustat[CPUTIME_NICE]
> + + kcpustat.cpustat[CPUTIME_SYSTEM]
> + + kcpustat.cpustat[CPUTIME_SOFTIRQ]
> + + kcpustat.cpustat[CPUTIME_IRQ];

Not the best tested series:

--- a/drivers/leds/trigger/ledtrig-activity.c
+++ b/drivers/leds/trigger/ledtrig-activity.c
@@ -59,7 +59,7 @@ static void led_activity_function(struct timer_list *t)
for_each_possible_cpu(i) {
struct kernel_cpustat kcpustat;

- kcpustat_fetch_cpu(&kcpustat, i);
+ kcpustat_cpu_fetch(&kcpustat, i);

curr_used += kcpustat.cpustat[CPUTIME_USER]
+ kcpustat.cpustat[CPUTIME_NICE]


:-)

Thanks,

Ingo