diff options
| -rw-r--r-- | include/linux/percpu_counter.h | 11 | ||||
| -rw-r--r-- | lib/percpu_counter.c | 27 |
2 files changed, 38 insertions, 0 deletions
diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h index c88d67b59394..8a7d510ffa9c 100644 --- a/include/linux/percpu_counter.h +++ b/include/linux/percpu_counter.h @@ -40,6 +40,7 @@ void percpu_counter_destroy(struct percpu_counter *fbc); void percpu_counter_set(struct percpu_counter *fbc, s64 amount); void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch); s64 __percpu_counter_sum(struct percpu_counter *fbc); +int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs); static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount) { @@ -98,6 +99,16 @@ static inline void percpu_counter_set(struct percpu_counter *fbc, s64 amount) fbc->count = amount; } +static inline int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs) +{ + if (fbc->count > rhs) + return 1; + else if (fbc->count < rhs) + return -1; + else + return 0; +} + static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount) { diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c index aeaa6d734447..ec9048e74f44 100644 --- a/lib/percpu_counter.c +++ b/lib/percpu_counter.c @@ -137,6 +137,33 @@ static int __cpuinit percpu_counter_hotcpu_callback(struct notifier_block *nb, return NOTIFY_OK; } +/* + * Compare counter against given value. + * Return 1 if greater, 0 if equal and -1 if less + */ +int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs) +{ + s64 count; + + count = percpu_counter_read(fbc); + /* Check to see if rough count will be sufficient for comparison */ + if (abs(count - rhs) > (percpu_counter_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; +} +EXPORT_SYMBOL(percpu_counter_compare); + static int __init percpu_counter_startup(void) { compute_batch_value(); |