Commit | Line | Data |
---|---|---|
3cbc5640 RT |
1 | /* |
2 | * Fast batching percpu counters. | |
3 | */ | |
4 | ||
5 | #include <linux/percpu_counter.h> | |
6 | #include <linux/module.h> | |
7 | ||
8 | void percpu_counter_mod(struct percpu_counter *fbc, long amount) | |
9 | { | |
10 | long count; | |
11 | long *pcount; | |
12 | int cpu = get_cpu(); | |
13 | ||
14 | pcount = per_cpu_ptr(fbc->counters, cpu); | |
15 | count = *pcount + amount; | |
16 | if (count >= FBC_BATCH || count <= -FBC_BATCH) { | |
17 | spin_lock(&fbc->lock); | |
18 | fbc->count += count; | |
19 | *pcount = 0; | |
20 | spin_unlock(&fbc->lock); | |
21 | } else { | |
22 | *pcount = count; | |
23 | } | |
24 | put_cpu(); | |
25 | } | |
26 | EXPORT_SYMBOL(percpu_counter_mod); | |
27 | ||
28 | /* | |
29 | * Add up all the per-cpu counts, return the result. This is a more accurate | |
30 | * but much slower version of percpu_counter_read_positive() | |
31 | */ | |
32 | long percpu_counter_sum(struct percpu_counter *fbc) | |
33 | { | |
34 | long ret; | |
35 | int cpu; | |
36 | ||
37 | spin_lock(&fbc->lock); | |
38 | ret = fbc->count; | |
39 | for_each_possible_cpu(cpu) { | |
40 | long *pcount = per_cpu_ptr(fbc->counters, cpu); | |
41 | ret += *pcount; | |
42 | } | |
43 | spin_unlock(&fbc->lock); | |
44 | return ret < 0 ? 0 : ret; | |
45 | } | |
46 | EXPORT_SYMBOL(percpu_counter_sum); |