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-rw-r--r--lib/Makefile1
-rw-r--r--lib/percpu_counter.c46
-rw-r--r--mm/swap.c42
3 files changed, 47 insertions, 42 deletions
diff --git a/lib/Makefile b/lib/Makefile
index b830c9a15541..79358ad1f113 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_TEXTSEARCH) += textsearch.o
46obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o 46obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o
47obj-$(CONFIG_TEXTSEARCH_BM) += ts_bm.o 47obj-$(CONFIG_TEXTSEARCH_BM) += ts_bm.o
48obj-$(CONFIG_TEXTSEARCH_FSM) += ts_fsm.o 48obj-$(CONFIG_TEXTSEARCH_FSM) += ts_fsm.o
49obj-$(CONFIG_SMP) += percpu_counter.o
49 50
50obj-$(CONFIG_SWIOTLB) += swiotlb.o 51obj-$(CONFIG_SWIOTLB) += swiotlb.o
51 52
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
new file mode 100644
index 000000000000..7a87003f8e8f
--- /dev/null
+++ b/lib/percpu_counter.c
@@ -0,0 +1,46 @@
1/*
2 * Fast batching percpu counters.
3 */
4
5#include <linux/percpu_counter.h>
6#include <linux/module.h>
7
8void 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}
26EXPORT_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 */
32long 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}
46EXPORT_SYMBOL(percpu_counter_sum);
diff --git a/mm/swap.c b/mm/swap.c
index 88895c249bc9..03ae2076f92f 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -480,48 +480,6 @@ static int cpu_swap_callback(struct notifier_block *nfb,
480#endif /* CONFIG_HOTPLUG_CPU */ 480#endif /* CONFIG_HOTPLUG_CPU */
481#endif /* CONFIG_SMP */ 481#endif /* CONFIG_SMP */
482 482
483#ifdef CONFIG_SMP
484void percpu_counter_mod(struct percpu_counter *fbc, long amount)
485{
486 long count;
487 long *pcount;
488 int cpu = get_cpu();
489
490 pcount = per_cpu_ptr(fbc->counters, cpu);
491 count = *pcount + amount;
492 if (count >= FBC_BATCH || count <= -FBC_BATCH) {
493 spin_lock(&fbc->lock);
494 fbc->count += count;
495 *pcount = 0;
496 spin_unlock(&fbc->lock);
497 } else {
498 *pcount = count;
499 }
500 put_cpu();
501}
502EXPORT_SYMBOL(percpu_counter_mod);
503
504/*
505 * Add up all the per-cpu counts, return the result. This is a more accurate
506 * but much slower version of percpu_counter_read_positive()
507 */
508long percpu_counter_sum(struct percpu_counter *fbc)
509{
510 long ret;
511 int cpu;
512
513 spin_lock(&fbc->lock);
514 ret = fbc->count;
515 for_each_possible_cpu(cpu) {
516 long *pcount = per_cpu_ptr(fbc->counters, cpu);
517 ret += *pcount;
518 }
519 spin_unlock(&fbc->lock);
520 return ret < 0 ? 0 : ret;
521}
522EXPORT_SYMBOL(percpu_counter_sum);
523#endif
524
525/* 483/*
526 * Perform any setup for the swap system 484 * Perform any setup for the swap system
527 */ 485 */