1 #ifndef __LINUX_PERCPU_H 2 #define __LINUX_PERCPU_H 3 #include <linux/spinlock.h> /* For preempt_disable() */ 4 #include <linux/slab.h> /* For kmalloc() */ 5 #include <linux/smp.h> 6 #include <linux/string.h> /* For memset() */ 7 #include <asm/percpu.h> 8 9 /* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */ 10 #ifndef PERCPU_ENOUGH_ROOM 11 #define PERCPU_ENOUGH_ROOM 32768 12 #endif 13 14 /* Must be an lvalue. */ 15 #define get_cpu_var(var) (*({ preempt_disable(); &__get_cpu_var(var); })) 16 #define put_cpu_var(var) preempt_enable() 17 18 #ifdef CONFIG_SMP 19 20 struct percpu_data { 21 void *ptrs[NR_CPUS]; 22 }; 23 24 /* 25 * Use this to get to a cpu's version of the per-cpu object allocated using 26 * alloc_percpu. Non-atomic access to the current CPU's version should 27 * probably be combined with get_cpu()/put_cpu(). 28 */ 29 #define per_cpu_ptr(ptr, cpu) \ 30 ({ \ 31 struct percpu_data *__p = (struct percpu_data *)~(unsigned long)(ptr); \ 32 (__typeof__(ptr))__p->ptrs[(cpu)]; \ 33 }) 34 35 extern void *__alloc_percpu(size_t size); 36 extern void free_percpu(const void *); 37 38 #else /* CONFIG_SMP */ 39 40 #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); }) 41 42 static inline void *__alloc_percpu(size_t size) 43 { 44 void *ret = kmalloc(size, GFP_KERNEL); 45 if (ret) 46 memset(ret, 0, size); 47 return ret; 48 } 49 static inline void free_percpu(const void *ptr) 50 { 51 kfree(ptr); 52 } 53 54 #endif /* CONFIG_SMP */ 55 56 /* Simple wrapper for the common case: zeros memory. */ 57 #define alloc_percpu(type) ((type *)(__alloc_percpu(sizeof(type)))) 58 59 #endif /* __LINUX_PERCPU_H */ 60
