1 /* SPDX-License-Identifier: GPL-2.0 */
3 * include/linux/pagevec.h
5 * In many places it is efficient to batch an operation up against multiple
6 * pages. A pagevec is a multipage container which is used for that.
9 #ifndef _LINUX_PAGEVEC_H
10 #define _LINUX_PAGEVEC_H
12 #include <linux/xarray.h>
14 /* 15 pointers + header align the pagevec structure to a power of two */
15 #define PAGEVEC_SIZE 15
21 /* Layout must match folio_batch */
24 bool percpu_pvec_drained;
25 struct page *pages[PAGEVEC_SIZE];
28 void __pagevec_release(struct pagevec *pvec);
30 static inline void pagevec_init(struct pagevec *pvec)
33 pvec->percpu_pvec_drained = false;
36 static inline void pagevec_reinit(struct pagevec *pvec)
41 static inline unsigned pagevec_count(struct pagevec *pvec)
46 static inline unsigned pagevec_space(struct pagevec *pvec)
48 return PAGEVEC_SIZE - pvec->nr;
52 * Add a page to a pagevec. Returns the number of slots still available.
54 static inline unsigned pagevec_add(struct pagevec *pvec, struct page *page)
56 pvec->pages[pvec->nr++] = page;
57 return pagevec_space(pvec);
60 static inline void pagevec_release(struct pagevec *pvec)
62 if (pagevec_count(pvec))
63 __pagevec_release(pvec);
67 * struct folio_batch - A collection of folios.
69 * The folio_batch is used to amortise the cost of retrieving and
70 * operating on a set of folios. The order of folios in the batch may be
71 * significant (eg delete_from_page_cache_batch()). Some users of the
72 * folio_batch store "exceptional" entries in it which can be removed
73 * by calling folio_batch_remove_exceptionals().
77 bool percpu_pvec_drained;
78 struct folio *folios[PAGEVEC_SIZE];
81 /* Layout must match pagevec */
82 static_assert(sizeof(struct pagevec) == sizeof(struct folio_batch));
83 static_assert(offsetof(struct pagevec, pages) ==
84 offsetof(struct folio_batch, folios));
87 * folio_batch_init() - Initialise a batch of folios
88 * @fbatch: The folio batch.
90 * A freshly initialised folio_batch contains zero folios.
92 static inline void folio_batch_init(struct folio_batch *fbatch)
95 fbatch->percpu_pvec_drained = false;
98 static inline void folio_batch_reinit(struct folio_batch *fbatch)
103 static inline unsigned int folio_batch_count(struct folio_batch *fbatch)
108 static inline unsigned int fbatch_space(struct folio_batch *fbatch)
110 return PAGEVEC_SIZE - fbatch->nr;
114 * folio_batch_add() - Add a folio to a batch.
115 * @fbatch: The folio batch.
116 * @folio: The folio to add.
118 * The folio is added to the end of the batch.
119 * The batch must have previously been initialised using folio_batch_init().
121 * Return: The number of slots still available.
123 static inline unsigned folio_batch_add(struct folio_batch *fbatch,
126 fbatch->folios[fbatch->nr++] = folio;
127 return fbatch_space(fbatch);
130 static inline void folio_batch_release(struct folio_batch *fbatch)
132 pagevec_release((struct pagevec *)fbatch);
135 void folio_batch_remove_exceptionals(struct folio_batch *fbatch);
136 #endif /* _LINUX_PAGEVEC_H */