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author | Ingo Molnar <mingo@elte.hu> | 2009-04-14 11:32:23 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-04-14 11:32:30 +0200 |
commit | 05cfbd66d07c44865983c8b65ae9d0037d874206 (patch) | |
tree | 084b665cc97b47d1592fe76ea0a39a7753288a02 /include/linux/percpu.h | |
parent | 31c9a24ec82926fcae49483e53566d231e705057 (diff) | |
parent | ef631b0ca01655d24e9ca7e199262c4a46416a26 (diff) |
Merge branch 'core/urgent' into core/rcu
Merge reason: new patches to be queued up depend on:
ef631b0: rcu: Make hierarchical RCU less IPI-happy
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/percpu.h')
-rw-r--r-- | include/linux/percpu.h | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/include/linux/percpu.h b/include/linux/percpu.h index ee5615d6521..cfda2d5ad31 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -168,4 +168,56 @@ static inline void free_percpu(void *p) #define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \ __alignof__(type)) +/* + * Optional methods for optimized non-lvalue per-cpu variable access. + * + * @var can be a percpu variable or a field of it and its size should + * equal char, int or long. percpu_read() evaluates to a lvalue and + * all others to void. + * + * These operations are guaranteed to be atomic w.r.t. preemption. + * The generic versions use plain get/put_cpu_var(). Archs are + * encouraged to implement single-instruction alternatives which don't + * require preemption protection. + */ +#ifndef percpu_read +# define percpu_read(var) \ + ({ \ + typeof(per_cpu_var(var)) __tmp_var__; \ + __tmp_var__ = get_cpu_var(var); \ + put_cpu_var(var); \ + __tmp_var__; \ + }) +#endif + +#define __percpu_generic_to_op(var, val, op) \ +do { \ + get_cpu_var(var) op val; \ + put_cpu_var(var); \ +} while (0) + +#ifndef percpu_write +# define percpu_write(var, val) __percpu_generic_to_op(var, (val), =) +#endif + +#ifndef percpu_add +# define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=) +#endif + +#ifndef percpu_sub +# define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=) +#endif + +#ifndef percpu_and +# define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=) +#endif + +#ifndef percpu_or +# define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=) +#endif + +#ifndef percpu_xor +# define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=) +#endif + #endif /* __LINUX_PERCPU_H */ |