1#ifndef LINUX_QUICKLIST_H
2#define LINUX_QUICKLIST_H
3/*
4 * Fast allocations and disposal of pages. Pages must be in the condition
5 * as needed after allocation when they are freed. Per cpu lists of pages
6 * are kept that only contain node local pages.
7 *
8 * (C) 2007, SGI. Christoph Lameter <clameter@sgi.com>
9 */
10#include <linux/kernel.h>
11#include <linux/gfp.h>
12#include <linux/percpu.h>
13
14#ifdef CONFIG_QUICKLIST
15
16struct quicklist {
17	void *page;
18	int nr_pages;
19};
20
21DECLARE_PER_CPU(struct quicklist, quicklist)[CONFIG_NR_QUICK];
22
23/*
24 * The two key functions quicklist_alloc and quicklist_free are inline so
25 * that they may be custom compiled for the platform.
26 * Specifying a NULL ctor can remove constructor support. Specifying
27 * a constant quicklist allows the determination of the exact address
28 * in the per cpu area.
29 *
30 * The fast patch in quicklist_alloc touched only a per cpu cacheline and
31 * the first cacheline of the page itself. There is minmal overhead involved.
32 */
33static inline void *quicklist_alloc(int nr, gfp_t flags, void (*ctor)(void *))
34{
35	struct quicklist *q;
36	void **p = NULL;
37
38	q =&get_cpu_var(quicklist)[nr];
39	p = q->page;
40	if (likely(p)) {
41		q->page = p[0];
42		p[0] = NULL;
43		q->nr_pages--;
44	}
45	put_cpu_var(quicklist);
46	if (likely(p))
47		return p;
48
49	p = (void *)__get_free_page(flags | __GFP_ZERO);
50	if (ctor && p)
51		ctor(p);
52	return p;
53}
54
55static inline void __quicklist_free(int nr, void (*dtor)(void *), void *p,
56	struct page *page)
57{
58	struct quicklist *q;
59
60	q = &get_cpu_var(quicklist)[nr];
61	*(void **)p = q->page;
62	q->page = p;
63	q->nr_pages++;
64	put_cpu_var(quicklist);
65}
66
67static inline void quicklist_free(int nr, void (*dtor)(void *), void *pp)
68{
69	__quicklist_free(nr, dtor, pp, virt_to_page(pp));
70}
71
72static inline void quicklist_free_page(int nr, void (*dtor)(void *),
73							struct page *page)
74{
75	__quicklist_free(nr, dtor, page_address(page), page);
76}
77
78void quicklist_trim(int nr, void (*dtor)(void *),
79	unsigned long min_pages, unsigned long max_free);
80
81unsigned long quicklist_total_size(void);
82
83#else
84
85static inline unsigned long quicklist_total_size(void)
86{
87	return 0;
88}
89
90#endif
91
92#endif /* LINUX_QUICKLIST_H */
93
94