Re: [PATCH 0/8] Suspend block api (version 8)

Arve Hjønnevåg
2010-06-02T03:50:02Z

On Tue, Jun 1, 2010 at 7:05 AM, mark gross <640e9920@gmail.com> wrote:
> On Tue, Jun 01, 2010 at 09:07:37AM +0200, Florian Mickler wrote:
...
>> +static void update_target_val(int pm_qos_class, s32 val)
>> +{
>> +     s32 extreme_value;
>> +     s32 new_value;
>> +     extreme_value = atomic_read(&pm_qos_array[pm_qos_class]->target_value);
>> +     new_value = pm_qos_array[pm_qos_class]->comparitor(val,extreme_value);
>> +     if (extreme_value != new_value)
>> +             atomic_set(&pm_qos_array[pm_qos_class]->target_value,new_value);
>> +}
>> +
>
> Only works 1/2 the time, but I like the idea!
> It fails to get the righ answer when constraints are reduced.  But, this
> idea is a good improvement i'll roll into the next pm_qos update!
>

I think it would be a better idea to track your constraints with a
sorted data structure. That way you can to better than O(n) for both
directions. If you have a lot of constraints with the same value, it
may even be worthwhile to have a two stage structure where for
instance you use a rbtree for the unique values and list for identical
constraints.

--
Arve Hjønnevåg