summaryrefslogtreecommitdiffstats
path: root/mm/allocpercpu.c
blob: b0012e27fea8796da01cfb2172d1d5930c60d22f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
/*
 * linux/mm/allocpercpu.c
 *
 * Separated from slab.c August 11, 2006 Christoph Lameter <clameter@sgi.com>
 */
#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.
 */
void percpu_depopulate(void *__pdata, int cpu)
{
	struct percpu_data *pdata = __percpu_disguise(__pdata);

	kfree(pdata->ptrs[cpu]);
	pdata->ptrs[cpu] = NULL;
}
EXPORT_SYMBOL_GPL(percpu_depopulate);

/**
 * 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);

/**
 * 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);

	/*
	 * 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];
}
EXPORT_SYMBOL_GPL(percpu_populate);

/**
 * 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);

/**
 * 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);