1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef LINUX_QUICKLIST_H
3#define LINUX_QUICKLIST_H
4/*
5 * Fast allocations and disposal of pages. Pages must be in the condition
6 * as needed after allocation when they are freed. Per cpu lists of pages
7 * are kept that only contain node local pages.
8 *
9 * (C) 2007, SGI. Christoph Lameter <cl@linux.com>
10 */
11#include <linux/kernel.h>
12#include <linux/gfp.h>
13#include <linux/percpu.h>
14
15#ifdef CONFIG_QUICKLIST
16
17struct quicklist {
18 void *page;
19 int nr_pages;
20};
21
22DECLARE_PER_CPU(struct quicklist, quicklist)[CONFIG_NR_QUICK];
23
24/*
25 * The two key functions quicklist_alloc and quicklist_free are inline so
26 * that they may be custom compiled for the platform.
27 * Specifying a NULL ctor can remove constructor support. Specifying
28 * a constant quicklist allows the determination of the exact address
29 * in the per cpu area.
30 *
31 * The fast patch in quicklist_alloc touched only a per cpu cacheline and
32 * the first cacheline of the page itself. There is minmal overhead involved.
33 */
34static inline void *quicklist_alloc(int nr, gfp_t flags, void (*ctor)(void *))
35{
36 struct quicklist *q;
37 void **p = NULL;
38
39 q =&get_cpu_var(quicklist)[nr];
40 p = q->page;
41 if (likely(p)) {
42 q->page = p[0];
43 p[0] = NULL;
44 q->nr_pages--;
45 }
46 put_cpu_var(quicklist);
47 if (likely(p))
48 return p;
49
50 p = (void *)__get_free_page(flags | __GFP_ZERO);
51 if (ctor && p)
52 ctor(p);
53 return p;
54}
55
56static inline void __quicklist_free(int nr, void (*dtor)(void *), void *p,
57 struct page *page)
58{
59 struct quicklist *q;
60
61 q = &get_cpu_var(quicklist)[nr];
62 *(void **)p = q->page;
63 q->page = p;
64 q->nr_pages++;
65 put_cpu_var(quicklist);
66}
67
68static inline void quicklist_free(int nr, void (*dtor)(void *), void *pp)
69{
70 __quicklist_free(nr, dtor, pp, virt_to_page(pp));
71}
72
73static inline void quicklist_free_page(int nr, void (*dtor)(void *),
74 struct page *page)
75{
76 __quicklist_free(nr, dtor, page_address(page), page);
77}
78
79void quicklist_trim(int nr, void (*dtor)(void *),
80 unsigned long min_pages, unsigned long max_free);
81
82unsigned long quicklist_total_size(void);
83
84#else
85
86static inline unsigned long quicklist_total_size(void)
87{
88 return 0;
89}
90
91#endif
92
93#endif /* LINUX_QUICKLIST_H */
94
95