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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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de4d1db369
This just generalises what was introduced by Eric Dumazet for the struct proto
inuse field in 286ab3d460:
[NET]: Define infrastructure to keep 'inuse' changes in an efficent SMP/NUMA way.
Please look at the comment in there to see the rationale.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
103 lines
2.4 KiB
C
103 lines
2.4 KiB
C
#ifndef __LINUX_PCOUNTER_H
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#define __LINUX_PCOUNTER_H
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struct pcounter {
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#ifdef CONFIG_SMP
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void (*add)(struct pcounter *self, int inc);
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int (*getval)(const struct pcounter *self);
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int *per_cpu_values;
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#else
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int val;
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#endif
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};
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/*
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* Special macros to let pcounters use a fast version of {getvalue|add}
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* using a static percpu variable per pcounter instead of an allocated one,
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* saving one dereference.
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* This might be changed if/when dynamic percpu vars become fast.
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*/
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#ifdef CONFIG_SMP
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#include <linux/cpumask.h>
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#include <linux/percpu.h>
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#define DEFINE_PCOUNTER(NAME) \
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static DEFINE_PER_CPU(int, NAME##_pcounter_values); \
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static void NAME##_pcounter_add(struct pcounter *self, int inc) \
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{ \
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__get_cpu_var(NAME##_pcounter_values) += inc; \
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} \
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\
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static int NAME##_pcounter_getval(const struct pcounter *self) \
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{ \
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int res = 0, cpu; \
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\
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for_each_possible_cpu(cpu) \
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res += per_cpu(NAME##_pcounter_values, cpu); \
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return res; \
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}
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#define PCOUNTER_MEMBER_INITIALIZER(NAME, MEMBER) \
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MEMBER = { \
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.add = NAME##_pcounter_add, \
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.getval = NAME##_pcounter_getval, \
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}
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extern void pcounter_def_add(struct pcounter *self, int inc);
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extern int pcounter_def_getval(const struct pcounter *self);
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static inline 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_def_add;
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self->getval = pcounter_def_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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static inline 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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static inline void pcounter_add(struct pcounter *self, int inc)
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{
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self->add(self, inc);
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}
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static inline int pcounter_getval(const struct pcounter *self)
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{
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return self->getval(self);
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}
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#else /* CONFIG_SMP */
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static inline void pcounter_add(struct pcounter *self, int inc)
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{
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self->value += inc;
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}
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static inline int pcounter_getval(const struct pcounter *self)
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{
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return self->val;
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}
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#define DEFINE_PCOUNTER(NAME)
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#define PCOUNTER_MEMBER_INITIALIZER(NAME, MEMBER)
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#define pcounter_alloc(self) 0
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#define pcounter_free(self)
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#endif /* CONFIG_SMP */
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#endif /* __LINUX_PCOUNTER_H */
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