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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/gfp.h> |
18 | #include <linux/mm.h> |
19 | #include <linux/mmzone.h> |
20 | #include <linux/quicklist.h> |
21 | |
22 | DEFINE_PER_CPU(struct quicklist [CONFIG_NR_QUICK], quicklist); |
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 | |
33 | node_free_pages = |
34 | #ifdef CONFIG_ZONE_DMA |
35 | zone_page_state(&zones[ZONE_DMA], NR_FREE_PAGES) + |
36 | #endif |
37 | #ifdef CONFIG_ZONE_DMA32 |
38 | zone_page_state(&zones[ZONE_DMA32], NR_FREE_PAGES) + |
39 | #endif |
40 | zone_page_state(&zones[ZONE_NORMAL], NR_FREE_PAGES); |
41 | |
42 | max = node_free_pages / FRACTION_OF_NODE_MEM; |
43 | |
44 | num_cpus_on_node = cpumask_weight(cpumask_of_node(node)); |
45 | max /= num_cpus_on_node; |
46 | |
47 | return max(max, min_pages); |
48 | } |
49 | |
50 | static long min_pages_to_free(struct quicklist *q, |
51 | unsigned long min_pages, long max_free) |
52 | { |
53 | long pages_to_free; |
54 | |
55 | pages_to_free = q->nr_pages - max_pages(min_pages); |
56 | |
57 | return min(pages_to_free, max_free); |
58 | } |
59 | |
60 | /* |
61 | * Trim down the number of pages in the quicklist |
62 | */ |
63 | void quicklist_trim(int nr, void (*dtor)(void *), |
64 | unsigned long min_pages, unsigned long max_free) |
65 | { |
66 | long pages_to_free; |
67 | struct quicklist *q; |
68 | |
69 | q = &get_cpu_var(quicklist)[nr]; |
70 | if (q->nr_pages > min_pages) { |
71 | pages_to_free = min_pages_to_free(q, min_pages, max_free); |
72 | |
73 | while (pages_to_free > 0) { |
74 | /* |
75 | * We pass a gfp_t of 0 to quicklist_alloc here |
76 | * because we will never call into the page allocator. |
77 | */ |
78 | void *p = quicklist_alloc(nr, 0, NULL); |
79 | |
80 | if (dtor) |
81 | dtor(p); |
82 | free_page((unsigned long)p); |
83 | pages_to_free--; |
84 | } |
85 | } |
86 | put_cpu_var(quicklist); |
87 | } |
88 | |
89 | unsigned long quicklist_total_size(void) |
90 | { |
91 | unsigned long count = 0; |
92 | int cpu; |
93 | struct quicklist *ql, *q; |
94 | |
95 | for_each_online_cpu(cpu) { |
96 | ql = per_cpu(quicklist, cpu); |
97 | for (q = ql; q < ql + CONFIG_NR_QUICK; q++) |
98 | count += q->nr_pages; |
99 | } |
100 | return count; |
101 | } |
102 | |
103 |
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