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1/*
2 * linux/mm/allocpercpu.c
3 *
4 * Separated from slab.c August 11, 2006 Christoph Lameter
5 */
6#include <linux/mm.h>
7#include <linux/module.h>
8
9#ifndef cache_line_size
10#define cache_line_size() L1_CACHE_BYTES
11#endif
12
13/**
14 * percpu_depopulate - depopulate per-cpu data for given cpu
15 * @__pdata: per-cpu data to depopulate
16 * @cpu: depopulate per-cpu data for this cpu
17 *
18 * Depopulating per-cpu data for a cpu going offline would be a typical
19 * use case. You need to register a cpu hotplug handler for that purpose.
20 */
21void percpu_depopulate(void *__pdata, int cpu)
22{
23 struct percpu_data *pdata = __percpu_disguise(__pdata);
24
25 kfree(pdata->ptrs[cpu]);
26 pdata->ptrs[cpu] = NULL;
27}
28EXPORT_SYMBOL_GPL(percpu_depopulate);
29
30/**
31 * percpu_depopulate_mask - depopulate per-cpu data for some cpu's
32 * @__pdata: per-cpu data to depopulate
33 * @mask: depopulate per-cpu data for cpu's selected through mask bits
34 */
35void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask)
36{
37 int cpu;
38 for_each_cpu_mask(cpu, *mask)
39 percpu_depopulate(__pdata, cpu);
40}
41EXPORT_SYMBOL_GPL(__percpu_depopulate_mask);
42
43/**
44 * percpu_populate - populate per-cpu data for given cpu
45 * @__pdata: per-cpu data to populate further
46 * @size: size of per-cpu object
47 * @gfp: may sleep or not etc.
48 * @cpu: populate per-data for this cpu
49 *
50 * Populating per-cpu data for a cpu coming online would be a typical
51 * use case. You need to register a cpu hotplug handler for that purpose.
52 * Per-cpu object is populated with zeroed buffer.
53 */
54void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu)
55{
56 struct percpu_data *pdata = __percpu_disguise(__pdata);
57 int node = cpu_to_node(cpu);
58
59 /*
60 * We should make sure each CPU gets private memory.
61 */
62 size = roundup(size, cache_line_size());
63
64 BUG_ON(pdata->ptrs[cpu]);
65 if (node_online(node))
66 pdata->ptrs[cpu] = kmalloc_node(size, gfp|__GFP_ZERO, node);
67 else
68 pdata->ptrs[cpu] = kzalloc(size, gfp);
69 return pdata->ptrs[cpu];
70}
71EXPORT_SYMBOL_GPL(percpu_populate);
72
73/**
74 * percpu_populate_mask - populate per-cpu data for more cpu's
75 * @__pdata: per-cpu data to populate further
76 * @size: size of per-cpu object
77 * @gfp: may sleep or not etc.
78 * @mask: populate per-cpu data for cpu's selected through mask bits
79 *
80 * Per-cpu objects are populated with zeroed buffers.
81 */
82int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
83 cpumask_t *mask)
84{
85 cpumask_t populated;
86 int cpu;
87
88 cpus_clear(populated);
89 for_each_cpu_mask(cpu, *mask)
90 if (unlikely(!percpu_populate(__pdata, size, gfp, cpu))) {
91 __percpu_depopulate_mask(__pdata, &populated);
92 return -ENOMEM;
93 } else
94 cpu_set(cpu, populated);
95 return 0;
96}
97EXPORT_SYMBOL_GPL(__percpu_populate_mask);
98
99/**
100 * percpu_alloc_mask - initial setup of per-cpu data
101 * @size: size of per-cpu object
102 * @gfp: may sleep or not etc.
103 * @mask: populate per-data for cpu's selected through mask bits
104 *
105 * Populating per-cpu data for all online cpu's would be a typical use case,
106 * which is simplified by the percpu_alloc() wrapper.
107 * Per-cpu objects are populated with zeroed buffers.
108 */
109void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
110{
111 /*
112 * We allocate whole cache lines to avoid false sharing
113 */
114 size_t sz = roundup(nr_cpu_ids * sizeof(void *), cache_line_size());
115 void *pdata = kzalloc(sz, gfp);
116 void *__pdata = __percpu_disguise(pdata);
117
118 if (unlikely(!pdata))
119 return NULL;
120 if (likely(!__percpu_populate_mask(__pdata, size, gfp, mask)))
121 return __pdata;
122 kfree(pdata);
123 return NULL;
124}
125EXPORT_SYMBOL_GPL(__percpu_alloc_mask);
126
127/**
128 * percpu_free - final cleanup of per-cpu data
129 * @__pdata: object to clean up
130 *
131 * We simply clean up any per-cpu object left. No need for the client to
132 * track and specify through a bis mask which per-cpu objects are to free.
133 */
134void percpu_free(void *__pdata)
135{
136 if (unlikely(!__pdata))
137 return;
138 __percpu_depopulate_mask(__pdata, &cpu_possible_map);
139 kfree(__percpu_disguise(__pdata));
140}
141EXPORT_SYMBOL_GPL(percpu_free);