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Code Issues Releases Wiki Activity

percpu: kill percpu_alloc() and friends 

Impact: kill unused functions

percpu_alloc() and its friends never saw much action.  It was supposed
to replace the cpu-mask unaware __alloc_percpu() but it never happened
and in fact __percpu_alloc_mask() itself never really grew proper
up/down handling interface either (no exported interface for
populate/depopulate).

percpu allocation is about to go through major reimplementation and
there's no reason to carry this unused interface around.  Replace it
with __alloc_percpu() and free_percpu().

Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tejun Heo 2009-02-20 16:29:08 +09:00
parent 313e458f81
commit f2a8205c4e
2 changed files with 50 additions and 47 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

65
include/linux/percpu.h
View File

@ -82,41 +82,10 @@ struct percpu_data {
#define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
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); })
static __always_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 */
#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, align) percpu_alloc_mask((size), GFP_KERNEL, \
cpu_possible_map)
#define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \
__alignof__(type))
#define free_percpu(ptr) percpu_free((ptr))
/*
* 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().
* 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) \
({ \
@ -124,4 +93,32 @@ static inline void percpu_free(void *__pdata)
(__typeof__(ptr))__p->ptrs[(cpu)]; \
})
extern void *__alloc_percpu(size_t size, size_t align);
extern void free_percpu(void *__pdata);
#else /* CONFIG_SMP */
#define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
static inline void *__alloc_percpu(size_t size, size_t align)
{
/*
* Can't easily make larger alignment work with kmalloc. WARN
* on it. Larger alignment should only be used for module
* percpu sections on SMP for which this path isn't used.
*/
WARN_ON_ONCE(align > __alignof__(unsigned long long));
return kzalloc(size, gfp);
}
static inline void free_percpu(void *p)
{
kfree(p);
}
#endif /* CONFIG_SMP */
#define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \
__alignof__(type))
#endif /* __LINUX_PERCPU_H */

32
mm/allocpercpu.c
View File

@ -99,45 +99,51 @@ static int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
__percpu_populate_mask((__pdata), (size), (gfp), &(mask))
/**
* percpu_alloc_mask - initial setup of per-cpu data
* alloc_percpu - 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
* @align: alignment
*
* 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.
* Allocate dynamic percpu area. Percpu objects are populated with
* zeroed buffers.
*/
void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
void *__alloc_percpu(size_t size, size_t align)
{
/*
* We allocate whole cache lines to avoid false sharing
*/
size_t sz = roundup(nr_cpu_ids * sizeof(void *), cache_line_size());
void *pdata = kzalloc(sz, gfp);
void *pdata = kzalloc(sz, GFP_KERNEL);
void *__pdata = __percpu_disguise(pdata);
/*
* Can't easily make larger alignment work with kmalloc. WARN
* on it. Larger alignment should only be used for module
* percpu sections on SMP for which this path isn't used.
*/
WARN_ON_ONCE(align > __alignof__(unsigned long long));
if (unlikely(!pdata))
return NULL;
if (likely(!__percpu_populate_mask(__pdata, size, gfp, mask)))
if (likely(!__percpu_populate_mask(__pdata, size, GFP_KERNEL,
&cpu_possible_map)))
return __pdata;
kfree(pdata);
return NULL;
}
EXPORT_SYMBOL_GPL(__percpu_alloc_mask);
EXPORT_SYMBOL_GPL(__alloc_percpu);
/**
* percpu_free - final cleanup of per-cpu data
* free_percpu - 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)
void free_percpu(void *__pdata)
{
if (unlikely(!__pdata))
return;
__percpu_depopulate_mask(__pdata, &cpu_possible_map);
kfree(__percpu_disguise(__pdata));
}
EXPORT_SYMBOL_GPL(percpu_free);
EXPORT_SYMBOL_GPL(free_percpu);