109 lines
2.7 KiB
C
109 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* include/linux/pagevec.h
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*
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* In many places it is efficient to batch an operation up against multiple
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* folios. A folio_batch is a container which is used for that.
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*/
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#ifndef _LINUX_PAGEVEC_H
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#define _LINUX_PAGEVEC_H
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#include <linux/types.h>
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#include <linux/rh_kabi.h>
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/* 31 pointers + header align the folio_batch structure to a power of two */
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#define PAGEVEC_SIZE 31
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struct folio;
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/**
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* struct folio_batch - A collection of folios.
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*
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* The folio_batch is used to amortise the cost of retrieving and
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* operating on a set of folios. The order of folios in the batch may be
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* significant (eg delete_from_page_cache_batch()). Some users of the
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* folio_batch store "exceptional" entries in it which can be removed
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* by calling folio_batch_remove_exceptionals().
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*/
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struct folio_batch {
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unsigned char nr;
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unsigned char i;
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bool percpu_pvec_drained;
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RH_KABI_RESERVE(1)
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RH_KABI_RESERVE(2)
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struct folio *folios[PAGEVEC_SIZE];
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};
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/**
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* folio_batch_init() - Initialise a batch of folios
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* @fbatch: The folio batch.
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*
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* A freshly initialised folio_batch contains zero folios.
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*/
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static inline void folio_batch_init(struct folio_batch *fbatch)
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{
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fbatch->nr = 0;
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fbatch->i = 0;
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fbatch->percpu_pvec_drained = false;
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}
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static inline void folio_batch_reinit(struct folio_batch *fbatch)
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{
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fbatch->nr = 0;
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fbatch->i = 0;
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}
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static inline unsigned int folio_batch_count(struct folio_batch *fbatch)
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{
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return fbatch->nr;
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}
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static inline unsigned int folio_batch_space(struct folio_batch *fbatch)
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{
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return PAGEVEC_SIZE - fbatch->nr;
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}
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/**
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* folio_batch_add() - Add a folio to a batch.
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* @fbatch: The folio batch.
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* @folio: The folio to add.
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*
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* The folio is added to the end of the batch.
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* The batch must have previously been initialised using folio_batch_init().
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*
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* Return: The number of slots still available.
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*/
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static inline unsigned folio_batch_add(struct folio_batch *fbatch,
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struct folio *folio)
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{
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fbatch->folios[fbatch->nr++] = folio;
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return folio_batch_space(fbatch);
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}
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/**
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* folio_batch_next - Return the next folio to process.
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* @fbatch: The folio batch being processed.
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*
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* Use this function to implement a queue of folios.
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*
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* Return: The next folio in the queue, or NULL if the queue is empty.
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*/
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static inline struct folio *folio_batch_next(struct folio_batch *fbatch)
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{
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if (fbatch->i == fbatch->nr)
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return NULL;
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return fbatch->folios[fbatch->i++];
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}
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void __folio_batch_release(struct folio_batch *pvec);
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static inline void folio_batch_release(struct folio_batch *fbatch)
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{
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if (folio_batch_count(fbatch))
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__folio_batch_release(fbatch);
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}
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void folio_batch_remove_exceptionals(struct folio_batch *fbatch);
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#endif /* _LINUX_PAGEVEC_H */
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