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Christoph Lameterd00bcc92006-09-25 23:31:50 -07001/*
2 * linux/mm/allocpercpu.c
3 *
Christoph Lametercde53532008-07-04 09:59:22 -07004 * Separated from slab.c August 11, 2006 Christoph Lameter
Christoph Lameterd00bcc92006-09-25 23:31:50 -07005 */
6#include <linux/mm.h>
7#include <linux/module.h>
8
Eric Dumazetbe852792008-03-04 14:28:35 -08009#ifndef cache_line_size
10#define cache_line_size() L1_CACHE_BYTES
11#endif
12
Christoph Lameterd00bcc92006-09-25 23:31:50 -070013/**
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 */
Adrian Bunk9d8fddf2008-07-25 19:46:23 -070021static void percpu_depopulate(void *__pdata, int cpu)
Christoph Lameterd00bcc92006-09-25 23:31:50 -070022{
23 struct percpu_data *pdata = __percpu_disguise(__pdata);
Alan Sterna1205862006-12-06 20:32:37 -080024
25 kfree(pdata->ptrs[cpu]);
26 pdata->ptrs[cpu] = NULL;
Christoph Lameterd00bcc92006-09-25 23:31:50 -070027}
Christoph Lameterd00bcc92006-09-25 23:31:50 -070028
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 */
Adrian Bunk9d8fddf2008-07-25 19:46:23 -070034static void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask)
Christoph Lameterd00bcc92006-09-25 23:31:50 -070035{
36 int cpu;
Mike Travis6d6a4362008-05-12 21:21:13 +020037 for_each_cpu_mask_nr(cpu, *mask)
Christoph Lameterd00bcc92006-09-25 23:31:50 -070038 percpu_depopulate(__pdata, cpu);
39}
Adrian Bunk9d8fddf2008-07-25 19:46:23 -070040
41#define percpu_depopulate_mask(__pdata, mask) \
42 __percpu_depopulate_mask((__pdata), &(mask))
Christoph Lameterd00bcc92006-09-25 23:31:50 -070043
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 */
Adrian Bunk9d8fddf2008-07-25 19:46:23 -070055static void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu)
Christoph Lameterd00bcc92006-09-25 23:31:50 -070056{
57 struct percpu_data *pdata = __percpu_disguise(__pdata);
58 int node = cpu_to_node(cpu);
59
Eric Dumazetbe852792008-03-04 14:28:35 -080060 /*
61 * We should make sure each CPU gets private memory.
62 */
63 size = roundup(size, cache_line_size());
64
Christoph Lameterd00bcc92006-09-25 23:31:50 -070065 BUG_ON(pdata->ptrs[cpu]);
Christoph Lameter94f60302007-07-17 04:03:29 -070066 if (node_online(node))
67 pdata->ptrs[cpu] = kmalloc_node(size, gfp|__GFP_ZERO, node);
68 else
Christoph Lameterd00bcc92006-09-25 23:31:50 -070069 pdata->ptrs[cpu] = kzalloc(size, gfp);
70 return pdata->ptrs[cpu];
71}
Christoph Lameterd00bcc92006-09-25 23:31:50 -070072
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 */
Adrian Bunk9d8fddf2008-07-25 19:46:23 -070082static int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
83 cpumask_t *mask)
Christoph Lameterd00bcc92006-09-25 23:31:50 -070084{
Mike Travisd366f8c2008-04-04 18:11:12 -070085 cpumask_t populated;
Christoph Lameterd00bcc92006-09-25 23:31:50 -070086 int cpu;
87
Mike Travisd366f8c2008-04-04 18:11:12 -070088 cpus_clear(populated);
Mike Travis6d6a4362008-05-12 21:21:13 +020089 for_each_cpu_mask_nr(cpu, *mask)
Christoph Lameterd00bcc92006-09-25 23:31:50 -070090 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}
Adrian Bunk9d8fddf2008-07-25 19:46:23 -070097
98#define percpu_populate_mask(__pdata, size, gfp, mask) \
99 __percpu_populate_mask((__pdata), (size), (gfp), &(mask))
Christoph Lameterd00bcc92006-09-25 23:31:50 -0700100
101/**
Tejun Heof2a82052009-02-20 16:29:08 +0900102 * alloc_percpu - initial setup of per-cpu data
Christoph Lameterd00bcc92006-09-25 23:31:50 -0700103 * @size: size of per-cpu object
Tejun Heof2a82052009-02-20 16:29:08 +0900104 * @align: alignment
Christoph Lameterd00bcc92006-09-25 23:31:50 -0700105 *
Tejun Heof2a82052009-02-20 16:29:08 +0900106 * Allocate dynamic percpu area. Percpu objects are populated with
107 * zeroed buffers.
Christoph Lameterd00bcc92006-09-25 23:31:50 -0700108 */
Tejun Heof2a82052009-02-20 16:29:08 +0900109void *__alloc_percpu(size_t size, size_t align)
Christoph Lameterd00bcc92006-09-25 23:31:50 -0700110{
Eric Dumazetbe852792008-03-04 14:28:35 -0800111 /*
112 * We allocate whole cache lines to avoid false sharing
113 */
114 size_t sz = roundup(nr_cpu_ids * sizeof(void *), cache_line_size());
Tejun Heof2a82052009-02-20 16:29:08 +0900115 void *pdata = kzalloc(sz, GFP_KERNEL);
Christoph Lameterd00bcc92006-09-25 23:31:50 -0700116 void *__pdata = __percpu_disguise(pdata);
117
Tejun Heof2a82052009-02-20 16:29:08 +0900118 /*
119 * Can't easily make larger alignment work with kmalloc. WARN
120 * on it. Larger alignment should only be used for module
121 * percpu sections on SMP for which this path isn't used.
122 */
Tejun Heo60db5642009-03-11 14:36:54 +0900123 WARN_ON_ONCE(align > SMP_CACHE_BYTES);
Tejun Heof2a82052009-02-20 16:29:08 +0900124
Christoph Lameterd00bcc92006-09-25 23:31:50 -0700125 if (unlikely(!pdata))
126 return NULL;
Tejun Heof2a82052009-02-20 16:29:08 +0900127 if (likely(!__percpu_populate_mask(__pdata, size, GFP_KERNEL,
128 &cpu_possible_map)))
Christoph Lameterd00bcc92006-09-25 23:31:50 -0700129 return __pdata;
130 kfree(pdata);
131 return NULL;
132}
Tejun Heof2a82052009-02-20 16:29:08 +0900133EXPORT_SYMBOL_GPL(__alloc_percpu);
Christoph Lameterd00bcc92006-09-25 23:31:50 -0700134
135/**
Tejun Heof2a82052009-02-20 16:29:08 +0900136 * free_percpu - final cleanup of per-cpu data
Christoph Lameterd00bcc92006-09-25 23:31:50 -0700137 * @__pdata: object to clean up
138 *
139 * We simply clean up any per-cpu object left. No need for the client to
140 * track and specify through a bis mask which per-cpu objects are to free.
141 */
Tejun Heof2a82052009-02-20 16:29:08 +0900142void free_percpu(void *__pdata)
Christoph Lameterd00bcc92006-09-25 23:31:50 -0700143{
Alan Sterna1205862006-12-06 20:32:37 -0800144 if (unlikely(!__pdata))
145 return;
Rusty Russellaa85ea52009-03-30 22:05:15 -0600146 __percpu_depopulate_mask(__pdata, cpu_possible_mask);
Christoph Lameterd00bcc92006-09-25 23:31:50 -0700147 kfree(__percpu_disguise(__pdata));
148}
Tejun Heof2a82052009-02-20 16:29:08 +0900149EXPORT_SYMBOL_GPL(free_percpu);