/*
* Catch up with missed period expirations.
*
* until (c_{j} == c)
* x_{j} -= x_{j}/2;
* c_{j}++;
*/
static
void prop_norm_percpu(struct prop_global *pg, struct prop_local_percpu *pl)
{
unsigned long period = 1UL << (pg->shift - 1);
unsigned long period_mask = ~(period - 1);
unsigned long global_period;
unsigned long flags;
global_period = percpu_counter_read(&pg->events);
global_period &= period_mask;
/*
* Fast path - check if the local and global period count still match
* outside of the lock.
*/
if (pl->period == global_period)
return;
raw_spin_lock_irqsave(&pl->lock, flags);
prop_adjust_shift(&pl->shift, &pl->period, pg->shift);
/*
* For each missed period, we half the local counter.
* basically:
* pl->events >> (global_period - pl->period);
*/
period = (global_period - pl->period) >> (pg->shift - 1);
if (period < BITS_PER_LONG) {
s64 val = percpu_counter_read(&pl->events);
if (val < (nr_cpu_ids * PROP_BATCH))
val = percpu_counter_sum(&pl->events);
__percpu_counter_add(&pl->events, -val + (val >> period),
PROP_BATCH);
} else
static
void prop_norm_percpu(struct prop_global *pg, struct prop_local_percpu *pl)
{
unsigned long period = 1UL << (pg->shift - 1);
unsigned long period_mask = ~(period - 1);
unsigned long global_period;
unsigned long flags;
global_period = percpu_counter_read(&pg->events);
global_period &= period_mask;
/*
*/
if (pl->period == global_period)
return;
raw_spin_lock_irqsave(&pl->lock, flags);
prop_adjust_shift(&pl->shift, &pl->period, pg->shift);
/*
*/
period = (global_period - pl->period) >> (pg->shift - 1);
if (period < BITS_PER_LONG) {
s64 val = percpu_counter_read(&pl->events);
if (val < (nr_cpu_ids * PROP_BATCH))
val = percpu_counter_sum(&pl->events);
__percpu_counter_add(&pl->events, -val + (val >> period),
PROP_BATCH);
} else
/*
* Compare counter against given value.
* Return 1 if greater, 0 if equal and -1 if less
*/
int __percpu_counter_compare(struct percpu_counter *fbc, int64_t rhs,
int32_t batch)
{
int64_t count;
count = percpu_counter_read(fbc);
/* Check to see if rough count will be sufficient for comparison */
if (abs(count - rhs) > (batch * num_online_cpus())) {
if (count > rhs)
return 1;
else
return -1;
}
/* Need to use precise count */
count = percpu_counter_sum(fbc);
if (count > rhs)
return 1;
else if (count < rhs)
return -1;
else
return 0;
}