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
17 struct quicklist {
18 void *page;
19 int nr_pages;
20 };
21
22 DECLARE_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 */
quicklist_alloc(int nr,gfp_t flags,void (* ctor)(void *))34 static 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
__quicklist_free(int nr,void (* dtor)(void *),void * p,struct page * page)56 static 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
quicklist_free(int nr,void (* dtor)(void *),void * pp)68 static inline void quicklist_free(int nr, void (*dtor)(void *), void *pp)
69 {
70 __quicklist_free(nr, dtor, pp, virt_to_page(pp));
71 }
72
quicklist_free_page(int nr,void (* dtor)(void *),struct page * page)73 static 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
79 void quicklist_trim(int nr, void (*dtor)(void *),
80 unsigned long min_pages, unsigned long max_free);
81
82 unsigned long quicklist_total_size(void);
83
84 #else
85
quicklist_total_size(void)86 static inline unsigned long quicklist_total_size(void)
87 {
88 return 0;
89 }
90
91 #endif
92
93 #endif /* LINUX_QUICKLIST_H */
94
95