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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/linux/percpu.h | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/linux/percpu.h')
-rw-r--r-- | include/linux/percpu.h | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/include/linux/percpu.h b/include/linux/percpu.h new file mode 100644 index 000000000000..5451eb1e781d --- /dev/null +++ b/include/linux/percpu.h @@ -0,0 +1,61 @@ +#ifndef __LINUX_PERCPU_H +#define __LINUX_PERCPU_H +#include <linux/spinlock.h> /* For preempt_disable() */ +#include <linux/slab.h> /* For kmalloc() */ +#include <linux/smp.h> +#include <linux/string.h> /* For memset() */ +#include <asm/percpu.h> + +/* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */ +#ifndef PERCPU_ENOUGH_ROOM +#define PERCPU_ENOUGH_ROOM 32768 +#endif + +/* Must be an lvalue. */ +#define get_cpu_var(var) (*({ preempt_disable(); &__get_cpu_var(var); })) +#define put_cpu_var(var) preempt_enable() + +#ifdef CONFIG_SMP + +struct percpu_data { + void *ptrs[NR_CPUS]; + void *blkp; +}; + +/* + * Use this to get to a cpu's version of the per-cpu object allocated using + * alloc_percpu. Non-atomic access to the current CPU's version should + * probably be combined with get_cpu()/put_cpu(). + */ +#define per_cpu_ptr(ptr, cpu) \ +({ \ + struct percpu_data *__p = (struct percpu_data *)~(unsigned long)(ptr); \ + (__typeof__(ptr))__p->ptrs[(cpu)]; \ +}) + +extern void *__alloc_percpu(size_t size, size_t align); +extern void free_percpu(const void *); + +#else /* CONFIG_SMP */ + +#define per_cpu_ptr(ptr, cpu) (ptr) + +static inline void *__alloc_percpu(size_t size, size_t align) +{ + void *ret = kmalloc(size, GFP_KERNEL); + if (ret) + memset(ret, 0, size); + return ret; +} +static inline void free_percpu(const void *ptr) +{ + kfree(ptr); +} + +#endif /* CONFIG_SMP */ + +/* Simple wrapper for the common case: zeros memory. */ +#define alloc_percpu(type) \ + ((type *)(__alloc_percpu(sizeof(type), __alignof__(type)))) + +#endif /* __LINUX_PERCPU_H */ |