Root/
1 | /* |
2 | * mm/percpu-km.c - kernel memory based chunk allocation |
3 | * |
4 | * Copyright (C) 2010 SUSE Linux Products GmbH |
5 | * Copyright (C) 2010 Tejun Heo <tj@kernel.org> |
6 | * |
7 | * This file is released under the GPLv2. |
8 | * |
9 | * Chunks are allocated as a contiguous kernel memory using gfp |
10 | * allocation. This is to be used on nommu architectures. |
11 | * |
12 | * To use percpu-km, |
13 | * |
14 | * - define CONFIG_NEED_PER_CPU_KM from the arch Kconfig. |
15 | * |
16 | * - CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK must not be defined. It's |
17 | * not compatible with PER_CPU_KM. EMBED_FIRST_CHUNK should work |
18 | * fine. |
19 | * |
20 | * - NUMA is not supported. When setting up the first chunk, |
21 | * @cpu_distance_fn should be NULL or report all CPUs to be nearer |
22 | * than or at LOCAL_DISTANCE. |
23 | * |
24 | * - It's best if the chunk size is power of two multiple of |
25 | * PAGE_SIZE. Because each chunk is allocated as a contiguous |
26 | * kernel memory block using alloc_pages(), memory will be wasted if |
27 | * chunk size is not aligned. percpu-km code will whine about it. |
28 | */ |
29 | |
30 | #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK |
31 | #error "contiguous percpu allocation is incompatible with paged first chunk" |
32 | #endif |
33 | |
34 | #include <linux/log2.h> |
35 | |
36 | static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size) |
37 | { |
38 | /* noop */ |
39 | return 0; |
40 | } |
41 | |
42 | static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size) |
43 | { |
44 | /* nada */ |
45 | } |
46 | |
47 | static struct pcpu_chunk *pcpu_create_chunk(void) |
48 | { |
49 | const int nr_pages = pcpu_group_sizes[0] >> PAGE_SHIFT; |
50 | struct pcpu_chunk *chunk; |
51 | struct page *pages; |
52 | int i; |
53 | |
54 | chunk = pcpu_alloc_chunk(); |
55 | if (!chunk) |
56 | return NULL; |
57 | |
58 | pages = alloc_pages(GFP_KERNEL, order_base_2(nr_pages)); |
59 | if (!pages) { |
60 | pcpu_free_chunk(chunk); |
61 | return NULL; |
62 | } |
63 | |
64 | for (i = 0; i < nr_pages; i++) |
65 | pcpu_set_page_chunk(nth_page(pages, i), chunk); |
66 | |
67 | chunk->data = pages; |
68 | chunk->base_addr = page_address(pages) - pcpu_group_offsets[0]; |
69 | return chunk; |
70 | } |
71 | |
72 | static void pcpu_destroy_chunk(struct pcpu_chunk *chunk) |
73 | { |
74 | const int nr_pages = pcpu_group_sizes[0] >> PAGE_SHIFT; |
75 | |
76 | if (chunk && chunk->data) |
77 | __free_pages(chunk->data, order_base_2(nr_pages)); |
78 | pcpu_free_chunk(chunk); |
79 | } |
80 | |
81 | static struct page *pcpu_addr_to_page(void *addr) |
82 | { |
83 | return virt_to_page(addr); |
84 | } |
85 | |
86 | static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai) |
87 | { |
88 | size_t nr_pages, alloc_pages; |
89 | |
90 | /* all units must be in a single group */ |
91 | if (ai->nr_groups != 1) { |
92 | printk(KERN_CRIT "percpu: can't handle more than one groups\n"); |
93 | return -EINVAL; |
94 | } |
95 | |
96 | nr_pages = (ai->groups[0].nr_units * ai->unit_size) >> PAGE_SHIFT; |
97 | alloc_pages = roundup_pow_of_two(nr_pages); |
98 | |
99 | if (alloc_pages > nr_pages) |
100 | printk(KERN_WARNING "percpu: wasting %zu pages per chunk\n", |
101 | alloc_pages - nr_pages); |
102 | |
103 | return 0; |
104 | } |
105 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9