/* * linux/mm/allocpercpu.c * * Separated from slab.c August 11, 2006 Christoph Lameter */#include <linux/mm.h>#include <linux/module.h> #ifndef cache_line_size#define cache_line_size()	L1_CACHE_BYTES#endif /** * percpu_depopulate - depopulate per-cpu data for given cpu * @__pdata: per-cpu data to depopulate * @cpu: depopulate per-cpu data for this cpu * * 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. */static void percpu_depopulate(void *__pdata, int cpu){	struct percpu_data *pdata = __percpu_disguise(__pdata); 	kfree(pdata->ptrs[cpu]);	pdata->ptrs[cpu] = 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 */static void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask){	int cpu;	for_each_cpu_mask_nr(cpu, *mask)		percpu_depopulate(__pdata, cpu);} #define percpu_depopulate_mask(__pdata, mask) \	__percpu_depopulate_mask((__pdata), &(mask)) /** * 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. */static 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); 	/*	 * We should make sure each CPU gets private memory.	 */	size = roundup(size, cache_line_size()); 	BUG_ON(pdata->ptrs[cpu]);	if (node_online(node))		pdata->ptrs[cpu] = kmalloc_node(size, gfp|__GFP_ZERO, node);	else		pdata->ptrs[cpu] = kzalloc(size, gfp);	return pdata->ptrs[cpu];} /** * 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. */static int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,				  cpumask_t *mask){	cpumask_t populated;	int cpu; 	cpus_clear(populated);	for_each_cpu_mask_nr(cpu, *mask)		if (unlikely(!percpu_populate(__pdata, size, gfp, cpu))) {			__percpu_depopulate_mask(__pdata, &populated);			return -ENOMEM;		} else			cpu_set(cpu, populated);	return 0;} #define percpu_populate_mask(__pdata, size, gfp, mask) \	__percpu_populate_mask((__pdata), (size), (gfp), &(mask)) /** * 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){	/*	 * 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 = __percpu_disguise(pdata); 	if (unlikely(!pdata))		return NULL;	if (likely(!__percpu_populate_mask(__pdata, size, gfp, mask)))		return __pdata;	kfree(pdata);	return NULL;}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){	if (unlikely(!__pdata))		return;	__percpu_depopulate_mask(__pdata, &cpu_possible_map);	kfree(__percpu_disguise(__pdata));}EXPORT_SYMBOL_GPL(percpu_free);