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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 */
21static void 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}
28
29/**
30 * percpu_depopulate_mask - depopulate per-cpu data for some cpu's
31 * @__pdata: per-cpu data to depopulate
32 * @mask: depopulate per-cpu data for cpu's selected through mask bits
33 */
34static void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask)
35{
36 int cpu;
37 for_each_cpu_mask_nr(cpu, *mask)
38 percpu_depopulate(__pdata, cpu);
39}
40
41#define percpu_depopulate_mask(__pdata, mask) \
42 __percpu_depopulate_mask((__pdata), &(mask))
43
44/**
45 * percpu_populate - populate per-cpu data for given cpu
46 * @__pdata: per-cpu data to populate further
47 * @size: size of per-cpu object
48 * @gfp: may sleep or not etc.
49 * @cpu: populate per-data for this cpu
50 *
51 * Populating per-cpu data for a cpu coming online would be a typical
52 * use case. You need to register a cpu hotplug handler for that purpose.
53 * Per-cpu object is populated with zeroed buffer.
54 */
55static void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu)
56{
57 struct percpu_data *pdata = __percpu_disguise(__pdata);
58 int node = cpu_to_node(cpu);
59
60 /*
61 * We should make sure each CPU gets private memory.
62 */
63 size = roundup(size, cache_line_size());
64
65 BUG_ON(pdata->ptrs[cpu]);
66 if (node_online(node))
67 pdata->ptrs[cpu] = kmalloc_node(size, gfp|__GFP_ZERO, node);
68 else
69 pdata->ptrs[cpu] = kzalloc(size, gfp);
70 return pdata->ptrs[cpu];
71}
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 */
82static int __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_nr(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}
97
98#define percpu_populate_mask(__pdata, size, gfp, mask) \
99 __percpu_populate_mask((__pdata), (size), (gfp), &(mask))
100
101/**
102 * percpu_alloc_mask - initial setup of per-cpu data
103 * @size: size of per-cpu object
104 * @gfp: may sleep or not etc.
105 * @mask: populate per-data for cpu's selected through mask bits
106 *
107 * Populating per-cpu data for all online cpu's would be a typical use case,
108 * which is simplified by the percpu_alloc() wrapper.
109 * Per-cpu objects are populated with zeroed buffers.
110 */
111void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
112{
113 /*
114 * We allocate whole cache lines to avoid false sharing
115 */
116 size_t sz = roundup(nr_cpu_ids * sizeof(void *), cache_line_size());
117 void *pdata = kzalloc(sz, gfp);
118 void *__pdata = __percpu_disguise(pdata);
119
120 if (unlikely(!pdata))
121 return NULL;
122 if (likely(!__percpu_populate_mask(__pdata, size, gfp, mask)))
123 return __pdata;
124 kfree(pdata);
125 return NULL;
126}
127EXPORT_SYMBOL_GPL(__percpu_alloc_mask);
128
129/**
130 * percpu_free - final cleanup of per-cpu data
131 * @__pdata: object to clean up
132 *
133 * We simply clean up any per-cpu object left. No need for the client to
134 * track and specify through a bis mask which per-cpu objects are to free.
135 */
136void percpu_free(void *__pdata)
137{
138 if (unlikely(!__pdata))
139 return;
140 __percpu_depopulate_mask(__pdata, &cpu_possible_map);
141 kfree(__percpu_disguise(__pdata));
142}
143EXPORT_SYMBOL_GPL(percpu_free);