1c1734090e
local_t is actually a win over atomic_t because it does not need lock prefixes. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
74 lines
1.9 KiB
C
74 lines
1.9 KiB
C
#ifndef _ARCH_X8664_LOCAL_H
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#define _ARCH_X8664_LOCAL_H
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#include <linux/percpu.h>
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typedef struct
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{
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volatile unsigned int counter;
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} local_t;
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#define LOCAL_INIT(i) { (i) }
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#define local_read(v) ((v)->counter)
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#define local_set(v,i) (((v)->counter) = (i))
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static __inline__ void local_inc(local_t *v)
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{
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__asm__ __volatile__(
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"incl %0"
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:"=m" (v->counter)
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:"m" (v->counter));
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}
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static __inline__ void local_dec(local_t *v)
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{
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__asm__ __volatile__(
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"decl %0"
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:"=m" (v->counter)
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:"m" (v->counter));
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}
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static __inline__ void local_add(unsigned long i, local_t *v)
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{
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__asm__ __volatile__(
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"addl %1,%0"
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:"=m" (v->counter)
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:"ir" (i), "m" (v->counter));
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}
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static __inline__ void local_sub(unsigned long i, local_t *v)
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{
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__asm__ __volatile__(
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"subl %1,%0"
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:"=m" (v->counter)
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:"ir" (i), "m" (v->counter));
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}
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/* On x86-64 these are better than the atomic variants on SMP kernels
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because they dont use a lock prefix. */
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#define __local_inc(l) local_inc(l)
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#define __local_dec(l) local_dec(l)
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#define __local_add(i,l) local_add((i),(l))
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#define __local_sub(i,l) local_sub((i),(l))
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/* Use these for per-cpu local_t variables: on some archs they are
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* much more efficient than these naive implementations. Note they take
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* a variable, not an address.
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*
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* This could be done better if we moved the per cpu data directly
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* after GS.
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*/
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#define cpu_local_read(v) local_read(&__get_cpu_var(v))
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#define cpu_local_set(v, i) local_set(&__get_cpu_var(v), (i))
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#define cpu_local_inc(v) local_inc(&__get_cpu_var(v))
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#define cpu_local_dec(v) local_dec(&__get_cpu_var(v))
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#define cpu_local_add(i, v) local_add((i), &__get_cpu_var(v))
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#define cpu_local_sub(i, v) local_sub((i), &__get_cpu_var(v))
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#define __cpu_local_inc(v) cpu_local_inc(v)
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#define __cpu_local_dec(v) cpu_local_dec(v)
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#define __cpu_local_add(i, v) cpu_local_add((i), (v))
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#define __cpu_local_sub(i, v) cpu_local_sub((i), (v))
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#endif /* _ARCH_I386_LOCAL_H */
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