Re: [patch 6/7] cpusets: per cpuset dirty ratios

Peter Zijlstra
2008-10-30T08:44:35Z

On Tue, 2008-10-28 at 09:08 -0700, David Rientjes wrote:

> +/*
> + * Determine the dirty ratios for the currently active cpuset
> + */
> +void cpuset_get_current_dirty_ratios(int *background, int *throttle)
> +{
> + mutex_lock(&callback_mutex);
> + task_lock(current);
> + *background = task_cs(current)->dirty_background_ratio;
> + *throttle = task_cs(current)->cpuset_dirty_ratio;
> + task_unlock(current);
> + mutex_unlock(&callback_mutex);
> +
> + if (*background == -1)
> + *background = dirty_background_ratio;
> + if (*throttle == -1)
> + *throttle = vm_dirty_ratio;
> +}

That's rather an awful lot of locking to read just two integers.