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