linux-IllusionX/lib/pcounter.c
Eric Dumazet 571e768202 [LIB] pcounter : unline too big functions
Before pushing pcounter to Linus tree, I would like to make some adjustments.

Goal is to reduce kernel text size, by unlining too big functions.

When a pcounter is bound to a statically defined per_cpu variable,
we define two small helpers functions. (No more folding function
using the fat for_each_possible_cpu(cpu) ... )

static DEFINE_PER_CPU(int, NAME##_pcounter_values);
static void NAME##_pcounter_add(struct pcounter *self, int val)
{
       __get_cpu_var(NAME##_pcounter_values) += val;
}
static int NAME##_pcounter_getval(const struct pcounter *self, int cpu)
{
       return per_cpu(NAME##_pcounter_values, cpu);
}

Fast path is therefore unchanged, while folding/alloc/free is now unlined.

This saves 228 bytes on i386

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 15:00:35 -08:00

58 lines
1.2 KiB
C

/*
* 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>
#include <linux/cpumask.h>
static void pcounter_dyn_add(struct pcounter *self, int inc)
{
per_cpu_ptr(self->per_cpu_values, smp_processor_id())[0] += inc;
}
static int pcounter_dyn_getval(const struct pcounter *self, int cpu)
{
return per_cpu_ptr(self->per_cpu_values, cpu)[0];
}
int pcounter_getval(const struct pcounter *self)
{
int res = 0, cpu;
for_each_possible_cpu(cpu)
res += self->getval(self, cpu);
return res;
}
EXPORT_SYMBOL_GPL(pcounter_getval);
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_dyn_add;
self->getval = pcounter_dyn_getval;
} else
rc = 1;
}
return rc;
}
EXPORT_SYMBOL_GPL(pcounter_alloc);
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;
}
}
EXPORT_SYMBOL_GPL(pcounter_free);