From 7ff6f08295d90ab20d25200ef485ebb45b1b8d71 Mon Sep 17 00:00:00 2001 From: Martin Peschke Date: Mon, 25 Sep 2006 23:31:21 -0700 Subject: [PATCH] CPU hotplug compatible alloc_percpu() This patch splits alloc_percpu() up into two phases. Likewise for free_percpu(). This allows clients to limit initial allocations to online cpu's, and to populate or depopulate per-cpu data at run time as needed: struct my_struct *obj; /* initial allocation for online cpu's */ obj = percpu_alloc(sizeof(struct my_struct), GFP_KERNEL); ... /* populate per-cpu data for cpu coming online */ ptr = percpu_populate(obj, sizeof(struct my_struct), GFP_KERNEL, cpu); ... /* access per-cpu object */ ptr = percpu_ptr(obj, smp_processor_id()); ... /* depopulate per-cpu data for cpu going offline */ percpu_depopulate(obj, cpu); ... /* final removal */ percpu_free(obj); Signed-off-by: Martin Peschke Cc: Paul Jackson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/percpu.h | 79 ++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 60 insertions(+), 19 deletions(-) (limited to 'include/linux') diff --git a/include/linux/percpu.h b/include/linux/percpu.h index f926490a7d8..3835a9642f1 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -1,9 +1,12 @@ #ifndef __LINUX_PERCPU_H #define __LINUX_PERCPU_H + #include /* For preempt_disable() */ #include /* For kmalloc() */ #include #include /* For memset() */ +#include + #include /* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */ @@ -27,39 +30,77 @@ struct percpu_data { void *ptrs[NR_CPUS]; }; +#define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata) /* - * 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 + * Use this to get to a cpu's version of the per-cpu object dynamically + * allocated. 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)]; \ +#define percpu_ptr(ptr, cpu) \ +({ \ + struct percpu_data *__p = __percpu_disguise(ptr); \ + (__typeof__(ptr))__p->ptrs[(cpu)]; \ }) -extern void *__alloc_percpu(size_t size); -extern void free_percpu(const void *); +extern void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu); +extern void percpu_depopulate(void *__pdata, int cpu); +extern int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp, + cpumask_t *mask); +extern void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask); +extern void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask); +extern void percpu_free(void *__pdata); #else /* CONFIG_SMP */ -#define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); }) +#define percpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); }) + +static inline void percpu_depopulate(void *__pdata, int cpu) +{ +} + +static inline void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask) +{ +} -static inline void *__alloc_percpu(size_t size) +static inline void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, + int cpu) { - void *ret = kmalloc(size, GFP_KERNEL); - if (ret) - memset(ret, 0, size); - return ret; + return percpu_ptr(__pdata, cpu); } -static inline void free_percpu(const void *ptr) -{ - kfree(ptr); + +static inline int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp, + cpumask_t *mask) +{ + return 0; +} + +static inline void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask) +{ + return kzalloc(size, gfp); +} + +static inline void percpu_free(void *__pdata) +{ + kfree(__pdata); } #endif /* CONFIG_SMP */ -/* Simple wrapper for the common case: zeros memory. */ -#define alloc_percpu(type) ((type *)(__alloc_percpu(sizeof(type)))) +#define percpu_populate_mask(__pdata, size, gfp, mask) \ + __percpu_populate_mask((__pdata), (size), (gfp), &(mask)) +#define percpu_depopulate_mask(__pdata, mask) \ + __percpu_depopulate_mask((__pdata), &(mask)) +#define percpu_alloc_mask(size, gfp, mask) \ + __percpu_alloc_mask((size), (gfp), &(mask)) + +#define percpu_alloc(size, gfp) percpu_alloc_mask((size), (gfp), cpu_online_map) + +/* (legacy) interface for use without CPU hotplug handling */ + +#define __alloc_percpu(size) percpu_alloc_mask((size), GFP_KERNEL, \ + cpu_possible_map) +#define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type)) +#define free_percpu(ptr) percpu_free((ptr)) +#define per_cpu_ptr(ptr, cpu) percpu_ptr((ptr), (cpu)) #endif /* __LINUX_PERCPU_H */ -- cgit v1.2.3