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1 | /* | |
2 | * Quicklist support. | |
3 | * | |
4 | * Quicklists are light weight lists of pages that have a defined state | |
5 | * on alloc and free. Pages must be in the quicklist specific defined state | |
6 | * (zero by default) when the page is freed. It seems that the initial idea | |
7 | * for such lists first came from Dave Miller and then various other people | |
8 | * improved on it. | |
9 | * | |
10 | * Copyright (C) 2007 SGI, | |
11 | * Christoph Lameter <clameter@sgi.com> | |
12 | * Generalized, added support for multiple lists and | |
13 | * constructors / destructors. | |
14 | */ | |
15 | #include <linux/kernel.h> | |
16 | ||
17 | #include <linux/mm.h> | |
18 | #include <linux/mmzone.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/quicklist.h> | |
21 | ||
22 | DEFINE_PER_CPU(struct quicklist, quicklist)[CONFIG_NR_QUICK]; | |
23 | ||
24 | #define FRACTION_OF_NODE_MEM 16 | |
25 | ||
26 | static unsigned long max_pages(unsigned long min_pages) | |
27 | { | |
28 | unsigned long node_free_pages, max; | |
29 | int node = numa_node_id(); | |
30 | struct zone *zones = NODE_DATA(node)->node_zones; | |
31 | int num_cpus_on_node; | |
32 | const struct cpumask *cpumask_on_node = cpumask_of_node(node); | |
33 | ||
34 | node_free_pages = | |
35 | #ifdef CONFIG_ZONE_DMA | |
36 | zone_page_state(&zones[ZONE_DMA], NR_FREE_PAGES) + | |
37 | #endif | |
38 | #ifdef CONFIG_ZONE_DMA32 | |
39 | zone_page_state(&zones[ZONE_DMA32], NR_FREE_PAGES) + | |
40 | #endif | |
41 | zone_page_state(&zones[ZONE_NORMAL], NR_FREE_PAGES); | |
42 | ||
43 | max = node_free_pages / FRACTION_OF_NODE_MEM; | |
44 | ||
45 | num_cpus_on_node = cpus_weight_nr(*cpumask_on_node); | |
46 | max /= num_cpus_on_node; | |
47 | ||
48 | return max(max, min_pages); | |
49 | } | |
50 | ||
51 | static long min_pages_to_free(struct quicklist *q, | |
52 | unsigned long min_pages, long max_free) | |
53 | { | |
54 | long pages_to_free; | |
55 | ||
56 | pages_to_free = q->nr_pages - max_pages(min_pages); | |
57 | ||
58 | return min(pages_to_free, max_free); | |
59 | } | |
60 | ||
61 | /* | |
62 | * Trim down the number of pages in the quicklist | |
63 | */ | |
64 | void quicklist_trim(int nr, void (*dtor)(void *), | |
65 | unsigned long min_pages, unsigned long max_free) | |
66 | { | |
67 | long pages_to_free; | |
68 | struct quicklist *q; | |
69 | ||
70 | q = &get_cpu_var(quicklist)[nr]; | |
71 | if (q->nr_pages > min_pages) { | |
72 | pages_to_free = min_pages_to_free(q, min_pages, max_free); | |
73 | ||
74 | while (pages_to_free > 0) { | |
75 | /* | |
76 | * We pass a gfp_t of 0 to quicklist_alloc here | |
77 | * because we will never call into the page allocator. | |
78 | */ | |
79 | void *p = quicklist_alloc(nr, 0, NULL); | |
80 | ||
81 | if (dtor) | |
82 | dtor(p); | |
83 | free_page((unsigned long)p); | |
84 | pages_to_free--; | |
85 | } | |
86 | } | |
87 | put_cpu_var(quicklist); | |
88 | } | |
89 | ||
90 | unsigned long quicklist_total_size(void) | |
91 | { | |
92 | unsigned long count = 0; | |
93 | int cpu; | |
94 | struct quicklist *ql, *q; | |
95 | ||
96 | for_each_online_cpu(cpu) { | |
97 | ql = per_cpu(quicklist, cpu); | |
98 | for (q = ql; q < ql + CONFIG_NR_QUICK; q++) | |
99 | count += q->nr_pages; | |
100 | } | |
101 | return count; | |
102 | } | |
103 |