Re: [PATCH v2] mm: vmscan: fix the page state calculation in too_many_isolated

[Michal Hocko]

On Thu 29-01-15 11:32:43, Christoph Lameter wrote:
[...]
> Subject: vmstat: Reduce time interval to stat update on idle cpu
> 
> It was noted that the vm stat shepherd runs every 2 seconds and
> that the vmstat update is then scheduled 2 seconds in the future.
> 
> This yields an interval of double the time interval which is not
> desired.
> 
> Change the shepherd so that it does not delay the vmstat update
> on the other cpu. We stil have to use schedule_delayed_work since
> we are using a delayed_work_struct but we can set the delay to 0.
>
> 
> Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>

Acked-by: Michal Hocko <mhocko@xxxxxxx>

> 
> Index: linux/mm/vmstat.c
> ===================================================================
> --- linux.orig/mm/vmstat.c
> +++ linux/mm/vmstat.c
> @@ -1435,8 +1435,8 @@ static void vmstat_shepherd(struct work_
>  		if (need_update(cpu) &&
>  			cpumask_test_and_clear_cpu(cpu, cpu_stat_off))
> 
> -			schedule_delayed_work_on(cpu, &per_cpu(vmstat_work, cpu),
> -				__round_jiffies_relative(sysctl_stat_interval, cpu));
> +			schedule_delayed_work_on(cpu,
> +				&per_cpu(vmstat_work, cpu), 0);
> 
>  	put_online_cpus();
> 

-- 
Michal Hocko
SUSE Labs
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