diff options
| -rw-r--r-- | include/linux/percpu.h | 79 | ||||
| -rw-r--r-- | mm/slab.c | 166 |
2 files changed, 169 insertions, 76 deletions
diff --git a/include/linux/percpu.h b/include/linux/percpu.h index f926490a7d8b..3835a9642f13 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -1,9 +1,12 @@ #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 <linux/cpumask.h> + #include <asm/percpu.h> /* 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 */ diff --git a/mm/slab.c b/mm/slab.c index 5870bcbd33cf..00584dbbec03 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -3371,52 +3371,127 @@ EXPORT_SYMBOL(__kmalloc_track_caller); #ifdef CONFIG_SMP /** - * __alloc_percpu - allocate one copy of the object for every present - * cpu in the system, zeroing them. - * Objects should be dereferenced using the per_cpu_ptr macro only. + * percpu_depopulate - depopulate per-cpu data for given cpu + * @__pdata: per-cpu data to depopulate + * @cpu: depopulate per-cpu data for this cpu * - * @size: how many bytes of memory are required. + * Depopulating per-cpu data for a cpu going offline would be a typical + * use case. You need to register a cpu hotplug handler for that purpose. */ -void *__alloc_percpu(size_t size) +void percpu_depopulate(void *__pdata, int cpu) { - int i; - struct percpu_data *pdata = kmalloc(sizeof(*pdata), GFP_KERNEL); + struct percpu_data *pdata = __percpu_disguise(__pdata); + if (pdata->ptrs[cpu]) { + kfree(pdata->ptrs[cpu]); + pdata->ptrs[cpu] = NULL; + } +} +EXPORT_SYMBOL_GPL(percpu_depopulate); - if (!pdata) - return NULL; +/** + * percpu_depopulate_mask - depopulate per-cpu data for some cpu's + * @__pdata: per-cpu data to depopulate + * @mask: depopulate per-cpu data for cpu's selected through mask bits + */ +void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask) +{ + int cpu; + for_each_cpu_mask(cpu, *mask) + percpu_depopulate(__pdata, cpu); +} +EXPORT_SYMBOL_GPL(__percpu_depopulate_mask); - /* - * Cannot use for_each_online_cpu since a cpu may come online - * and we have no way of figuring out how to fix the array - * that we have allocated then.... - */ - for_each_possible_cpu(i) { - int node = cpu_to_node(i); +/** + * percpu_populate - populate per-cpu data for given cpu + * @__pdata: per-cpu data to populate further + * @size: size of per-cpu object + * @gfp: may sleep or not etc. + * @cpu: populate per-data for this cpu + * + * Populating per-cpu data for a cpu coming online would be a typical + * use case. You need to register a cpu hotplug handler for that purpose. + * Per-cpu object is populated with zeroed buffer. + */ +void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu) +{ + struct percpu_data *pdata = __percpu_disguise(__pdata); + int node = cpu_to_node(cpu); - if (node_online(node)) - pdata->ptrs[i] = kmalloc_node(size, GFP_KERNEL, node); - else - pdata->ptrs[i] = kmalloc(size, GFP_KERNEL); + BUG_ON(pdata->ptrs[cpu]); + if (node_online(node)) { + /* FIXME: kzalloc_node(size, gfp, node) */ + pdata->ptrs[cpu] = kmalloc_node(size, gfp, node); + if (pdata->ptrs[cpu]) + memset(pdata->ptrs[cpu], 0, size); + } else + pdata->ptrs[cpu] = kzalloc(size, gfp); + return pdata->ptrs[cpu]; +} +EXPORT_SYMBOL_GPL(percpu_populate); - if (!pdata->ptrs[i]) - goto unwind_oom; - memset(pdata->ptrs[i], 0, size); - } +/** + * percpu_populate_mask - populate per-cpu data for more cpu's + * @__pdata: per-cpu data to populate further + * @size: size of per-cpu object + * @gfp: may sleep or not etc. + * @mask: populate per-cpu data for cpu's selected through mask bits + * + * Per-cpu objects are populated with zeroed buffers. + */ +int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp, + cpumask_t *mask) +{ + cpumask_t populated = CPU_MASK_NONE; + int cpu; + + for_each_cpu_mask(cpu, *mask) + if (unlikely(!percpu_populate(__pdata, size, gfp, cpu))) { + __percpu_depopulate_mask(__pdata, &populated); + return -ENOMEM; + } else + cpu_set(cpu, populated); + return 0; +} +EXPORT_SYMBOL_GPL(__percpu_populate_mask); - /* Catch derefs w/o wrappers */ - return (void *)(~(unsigned long)pdata); +/** + * percpu_alloc_mask - initial setup of per-cpu data + * @size: size of per-cpu object + * @gfp: may sleep or not etc. + * @mask: populate per-data for cpu's selected through mask bits + * + * Populating per-cpu data for all online cpu's would be a typical use case, + * which is simplified by the percpu_alloc() wrapper. + * Per-cpu objects are populated with zeroed buffers. + */ +void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask) +{ + void *pdata = kzalloc(sizeof(struct percpu_data), gfp); + void *__pdata = __percpu_disguise(pdata); -unwind_oom: - while (--i >= 0) { - if (!cpu_possible(i)) - continue; - kfree(pdata->ptrs[i]); - } + if (unlikely(!pdata)) + return NULL; + if (likely(!__percpu_populate_mask(__pdata, size, gfp, mask))) + return __pdata; kfree(pdata); return NULL; } -EXPORT_SYMBOL(__alloc_percpu); -#endif +EXPORT_SYMBOL_GPL(__percpu_alloc_mask); + +/** + * percpu_free - final cleanup of per-cpu data + * @__pdata: object to clean up + * + * We simply clean up any per-cpu object left. No need for the client to + * track and specify through a bis mask which per-cpu objects are to free. + */ +void percpu_free(void *__pdata) +{ + __percpu_depopulate_mask(__pdata, &cpu_possible_map); + kfree(__percpu_disguise(__pdata)); +} +EXPORT_SYMBOL_GPL(percpu_free); +#endif /* CONFIG_SMP */ /** * kmem_cache_free - Deallocate an object @@ -3463,29 +3538,6 @@ void kfree(const void *objp) } EXPORT_SYMBOL(kfree); -#ifdef CONFIG_SMP -/** - * free_percpu - free previously allocated percpu memory - * @objp: pointer returned by alloc_percpu. - * - * Don't free memory not originally allocated by alloc_percpu() - * The complemented objp is to check for that. - */ -void free_percpu(const void *objp) -{ - int i; - struct percpu_data *p = (struct percpu_data *)(~(unsigned long)objp); - - /* - * We allocate for all cpus so we cannot use for online cpu here. - */ - for_each_possible_cpu(i) - kfree(p->ptrs[i]); - kfree(p); -} -EXPORT_SYMBOL(free_percpu); -#endif - unsigned int kmem_cache_size(struct kmem_cache *cachep) { return obj_size(cachep); |