diff options
Diffstat (limited to 'lib/proportions.c')
| -rw-r--r-- | lib/proportions.c | 58 |
1 files changed, 43 insertions, 15 deletions
diff --git a/lib/proportions.c b/lib/proportions.c index 9508d9a7af3..05df84801b5 100644 --- a/lib/proportions.c +++ b/lib/proportions.c @@ -73,12 +73,6 @@ #include <linux/proportions.h> #include <linux/rcupdate.h> -/* - * Limit the time part in order to ensure there are some bits left for the - * cycle counter. - */ -#define PROP_MAX_SHIFT (3*BITS_PER_LONG/4) - int prop_descriptor_init(struct prop_descriptor *pd, int shift) { int err; @@ -89,11 +83,11 @@ int prop_descriptor_init(struct prop_descriptor *pd, int shift) pd->index = 0; pd->pg[0].shift = shift; mutex_init(&pd->mutex); - err = percpu_counter_init_irq(&pd->pg[0].events, 0); + err = percpu_counter_init(&pd->pg[0].events, 0); if (err) goto out; - err = percpu_counter_init_irq(&pd->pg[1].events, 0); + err = percpu_counter_init(&pd->pg[1].events, 0); if (err) percpu_counter_destroy(&pd->pg[0].events); @@ -153,6 +147,7 @@ out: * this is used to track the active references. */ static struct prop_global *prop_get_global(struct prop_descriptor *pd) +__acquires(RCU) { int index; @@ -166,6 +161,7 @@ static struct prop_global *prop_get_global(struct prop_descriptor *pd) } static void prop_put_global(struct prop_descriptor *pd, struct prop_global *pg) +__releases(RCU) { rcu_read_unlock(); } @@ -194,10 +190,10 @@ prop_adjust_shift(int *pl_shift, unsigned long *pl_period, int new_shift) int prop_local_init_percpu(struct prop_local_percpu *pl) { - spin_lock_init(&pl->lock); + raw_spin_lock_init(&pl->lock); pl->shift = 0; pl->period = 0; - return percpu_counter_init_irq(&pl->events, 0); + return percpu_counter_init(&pl->events, 0); } void prop_local_destroy_percpu(struct prop_local_percpu *pl) @@ -230,7 +226,7 @@ void prop_norm_percpu(struct prop_global *pg, struct prop_local_percpu *pl) if (pl->period == global_period) return; - spin_lock_irqsave(&pl->lock, flags); + raw_spin_lock_irqsave(&pl->lock, flags); prop_adjust_shift(&pl->shift, &pl->period, pg->shift); /* @@ -251,7 +247,7 @@ void prop_norm_percpu(struct prop_global *pg, struct prop_local_percpu *pl) percpu_counter_set(&pl->events, 0); pl->period = global_period; - spin_unlock_irqrestore(&pl->lock, flags); + raw_spin_unlock_irqrestore(&pl->lock, flags); } /* @@ -268,6 +264,38 @@ void __prop_inc_percpu(struct prop_descriptor *pd, struct prop_local_percpu *pl) } /* + * identical to __prop_inc_percpu, except that it limits this pl's fraction to + * @frac/PROP_FRAC_BASE by ignoring events when this limit has been exceeded. + */ +void __prop_inc_percpu_max(struct prop_descriptor *pd, + struct prop_local_percpu *pl, long frac) +{ + struct prop_global *pg = prop_get_global(pd); + + prop_norm_percpu(pg, pl); + + if (unlikely(frac != PROP_FRAC_BASE)) { + unsigned long period_2 = 1UL << (pg->shift - 1); + unsigned long counter_mask = period_2 - 1; + unsigned long global_count; + long numerator, denominator; + + numerator = percpu_counter_read_positive(&pl->events); + global_count = percpu_counter_read(&pg->events); + denominator = period_2 + (global_count & counter_mask); + + if (numerator > ((denominator * frac) >> PROP_FRAC_SHIFT)) + goto out_put; + } + + percpu_counter_add(&pl->events, 1); + percpu_counter_add(&pg->events, 1); + +out_put: + prop_put_global(pd, pg); +} + +/* * Obtain a fraction of this proportion * * p_{j} = x_{j} / (period/2 + t % period/2) @@ -296,7 +324,7 @@ void prop_fraction_percpu(struct prop_descriptor *pd, int prop_local_init_single(struct prop_local_single *pl) { - spin_lock_init(&pl->lock); + raw_spin_lock_init(&pl->lock); pl->shift = 0; pl->period = 0; pl->events = 0; @@ -328,7 +356,7 @@ void prop_norm_single(struct prop_global *pg, struct prop_local_single *pl) if (pl->period == global_period) return; - spin_lock_irqsave(&pl->lock, flags); + 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. @@ -339,7 +367,7 @@ void prop_norm_single(struct prop_global *pg, struct prop_local_single *pl) else pl->events = 0; pl->period = global_period; - spin_unlock_irqrestore(&pl->lock, flags); + raw_spin_unlock_irqrestore(&pl->lock, flags); } /* |