ia64/linux-2.6.18-xen.hg

view include/asm-generic/local.h @ 782:9ab1c319531f

merge with linux-2.6.18-xen.hg
author Isaku Yamahata <yamahata@valinux.co.jp>
date Wed Jan 28 13:07:23 2009 +0900 (2009-01-28)
parents 831230e53067
children
line source
1 #ifndef _ASM_GENERIC_LOCAL_H
2 #define _ASM_GENERIC_LOCAL_H
4 #include <linux/percpu.h>
5 #include <linux/hardirq.h>
6 #include <asm/atomic.h>
7 #include <asm/types.h>
9 /*
10 * A signed long type for operations which are atomic for a single CPU.
11 * Usually used in combination with per-cpu variables.
12 *
13 * This is the default implementation, which uses atomic_long_t. Which is
14 * rather pointless. The whole point behind local_t is that some processors
15 * can perform atomic adds and subtracts in a manner which is atomic wrt IRQs
16 * running on this CPU. local_t allows exploitation of such capabilities.
17 */
19 /* Implement in terms of atomics. */
21 /* Don't use typedef: don't want them to be mixed with atomic_t's. */
22 typedef struct
23 {
24 atomic_long_t a;
25 } local_t;
27 #define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
29 #define local_read(l) atomic_long_read(&(l)->a)
30 #define local_set(l,i) atomic_long_set((&(l)->a),(i))
31 #define local_inc(l) atomic_long_inc(&(l)->a)
32 #define local_dec(l) atomic_long_dec(&(l)->a)
33 #define local_add(i,l) atomic_long_add((i),(&(l)->a))
34 #define local_sub(i,l) atomic_long_sub((i),(&(l)->a))
36 /* Non-atomic variants, ie. preemption disabled and won't be touched
37 * in interrupt, etc. Some archs can optimize this case well. */
38 #define __local_inc(l) local_set((l), local_read(l) + 1)
39 #define __local_dec(l) local_set((l), local_read(l) - 1)
40 #define __local_add(i,l) local_set((l), local_read(l) + (i))
41 #define __local_sub(i,l) local_set((l), local_read(l) - (i))
43 /* Use these for per-cpu local_t variables: on some archs they are
44 * much more efficient than these naive implementations. Note they take
45 * a variable (eg. mystruct.foo), not an address.
46 */
47 #define cpu_local_read(v) local_read(&__get_cpu_var(v))
48 #define cpu_local_set(v, i) local_set(&__get_cpu_var(v), (i))
49 #define cpu_local_inc(v) local_inc(&__get_cpu_var(v))
50 #define cpu_local_dec(v) local_dec(&__get_cpu_var(v))
51 #define cpu_local_add(i, v) local_add((i), &__get_cpu_var(v))
52 #define cpu_local_sub(i, v) local_sub((i), &__get_cpu_var(v))
54 /* Non-atomic increments, ie. preemption disabled and won't be touched
55 * in interrupt, etc. Some archs can optimize this case well.
56 */
57 #define __cpu_local_inc(v) __local_inc(&__get_cpu_var(v))
58 #define __cpu_local_dec(v) __local_dec(&__get_cpu_var(v))
59 #define __cpu_local_add(i, v) __local_add((i), &__get_cpu_var(v))
60 #define __cpu_local_sub(i, v) __local_sub((i), &__get_cpu_var(v))
62 #endif /* _ASM_GENERIC_LOCAL_H */