diff options
| -rw-r--r-- | include/linux/pcounter.h | 102 | ||||
| -rw-r--r-- | lib/Makefile | 1 | ||||
| -rw-r--r-- | lib/pcounter.c | 26 |
3 files changed, 129 insertions, 0 deletions
diff --git a/include/linux/pcounter.h b/include/linux/pcounter.h new file mode 100644 index 00000000000..620aaded4e9 --- /dev/null +++ b/include/linux/pcounter.h @@ -0,0 +1,102 @@ +#ifndef __LINUX_PCOUNTER_H +#define __LINUX_PCOUNTER_H + +struct pcounter { +#ifdef CONFIG_SMP + void (*add)(struct pcounter *self, int inc); + int (*getval)(const struct pcounter *self); + int *per_cpu_values; +#else + int val; +#endif +}; + +/* + * Special macros to let pcounters use a fast version of {getvalue|add} + * using a static percpu variable per pcounter instead of an allocated one, + * saving one dereference. + * This might be changed if/when dynamic percpu vars become fast. + */ +#ifdef CONFIG_SMP +#include <linux/cpumask.h> +#include <linux/percpu.h> + +#define DEFINE_PCOUNTER(NAME) \ +static DEFINE_PER_CPU(int, NAME##_pcounter_values); \ +static void NAME##_pcounter_add(struct pcounter *self, int inc) \ +{ \ + __get_cpu_var(NAME##_pcounter_values) += inc; \ +} \ + \ +static int NAME##_pcounter_getval(const struct pcounter *self) \ +{ \ + int res = 0, cpu; \ + \ + for_each_possible_cpu(cpu) \ + res += per_cpu(NAME##_pcounter_values, cpu); \ + return res; \ +} + +#define PCOUNTER_MEMBER_INITIALIZER(NAME, MEMBER) \ + MEMBER = { \ + .add = NAME##_pcounter_add, \ + .getval = NAME##_pcounter_getval, \ + } + +extern void pcounter_def_add(struct pcounter *self, int inc); +extern int pcounter_def_getval(const struct pcounter *self); + +static inline int pcounter_alloc(struct pcounter *self) +{ + int rc = 0; + if (self->add == NULL) { + self->per_cpu_values = alloc_percpu(int); + if (self->per_cpu_values != NULL) { + self->add = pcounter_def_add; + self->getval = pcounter_def_getval; + } else + rc = 1; + } + return rc; +} + +static inline void pcounter_free(struct pcounter *self) +{ + if (self->per_cpu_values != NULL) { + free_percpu(self->per_cpu_values); + self->per_cpu_values = NULL; + self->getval = NULL; + self->add = NULL; + } +} + +static inline void pcounter_add(struct pcounter *self, int inc) +{ + self->add(self, inc); +} + +static inline int pcounter_getval(const struct pcounter *self) +{ + return self->getval(self); +} + +#else /* CONFIG_SMP */ + +static inline void pcounter_add(struct pcounter *self, int inc) +{ + self->value += inc; +} + +static inline int pcounter_getval(const struct pcounter *self) +{ + return self->val; +} + +#define DEFINE_PCOUNTER(NAME) +#define PCOUNTER_MEMBER_INITIALIZER(NAME, MEMBER) +#define pcounter_alloc(self) 0 +#define pcounter_free(self) + +#endif /* CONFIG_SMP */ + +#endif /* __LINUX_PCOUNTER_H */ diff --git a/lib/Makefile b/lib/Makefile index 89841dc9d91..543f2502b60 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -61,6 +61,7 @@ obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o obj-$(CONFIG_TEXTSEARCH_BM) += ts_bm.o obj-$(CONFIG_TEXTSEARCH_FSM) += ts_fsm.o obj-$(CONFIG_SMP) += percpu_counter.o +obj-$(CONFIG_SMP) += pcounter.o obj-$(CONFIG_AUDIT_GENERIC) += audit.o obj-$(CONFIG_SWIOTLB) += swiotlb.o diff --git a/lib/pcounter.c b/lib/pcounter.c new file mode 100644 index 00000000000..93feea59825 --- /dev/null +++ b/lib/pcounter.c @@ -0,0 +1,26 @@ +/* + * Define default pcounter functions + * Note that often used pcounters use dedicated functions to get a speed increase. + * (see DEFINE_PCOUNTER/REF_PCOUNTER_MEMBER) + */ + +#include <linux/module.h> +#include <linux/pcounter.h> +#include <linux/smp.h> + +void pcounter_def_add(struct pcounter *self, int inc) +{ + per_cpu_ptr(self->per_cpu_values, smp_processor_id())[0] += inc; +} + +EXPORT_SYMBOL_GPL(pcounter_def_add); + +int pcounter_def_getval(const struct pcounter *self) +{ + int res = 0, cpu; + for_each_possible_cpu(cpu) + res += per_cpu_ptr(self->per_cpu_values, cpu)[0]; + return res; +} + +EXPORT_SYMBOL_GPL(pcounter_def_getval); |