forked from luck/tmp_suning_uos_patched
571e768202
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>
59 lines
1.2 KiB
C
59 lines
1.2 KiB
C
/*
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* Define default pcounter functions
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* Note that often used pcounters use dedicated functions to get a speed increase.
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* (see DEFINE_PCOUNTER/REF_PCOUNTER_MEMBER)
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*/
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#include <linux/module.h>
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#include <linux/pcounter.h>
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#include <linux/smp.h>
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#include <linux/cpumask.h>
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static void pcounter_dyn_add(struct pcounter *self, int inc)
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{
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per_cpu_ptr(self->per_cpu_values, smp_processor_id())[0] += inc;
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}
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static int pcounter_dyn_getval(const struct pcounter *self, int cpu)
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{
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return per_cpu_ptr(self->per_cpu_values, cpu)[0];
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}
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int pcounter_getval(const struct pcounter *self)
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{
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int res = 0, cpu;
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for_each_possible_cpu(cpu)
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res += self->getval(self, cpu);
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return res;
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}
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EXPORT_SYMBOL_GPL(pcounter_getval);
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int pcounter_alloc(struct pcounter *self)
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{
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int rc = 0;
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if (self->add == NULL) {
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self->per_cpu_values = alloc_percpu(int);
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if (self->per_cpu_values != NULL) {
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self->add = pcounter_dyn_add;
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self->getval = pcounter_dyn_getval;
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} else
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rc = 1;
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}
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return rc;
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}
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EXPORT_SYMBOL_GPL(pcounter_alloc);
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void pcounter_free(struct pcounter *self)
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{
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if (self->per_cpu_values != NULL) {
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free_percpu(self->per_cpu_values);
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self->per_cpu_values = NULL;
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self->getval = NULL;
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self->add = NULL;
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}
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}
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EXPORT_SYMBOL_GPL(pcounter_free);
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