146500e960
We don't have to use an entire 'long' for the number of elements in the pagevec; we know it's a number between 0 and 14 (now 15). So we can store it in a char, and then the bool packs next to it and we still have two or six bytes of padding for more elements in the header. That gives us space to cram in an extra page. Link: http://lkml.kernel.org/r/20171206022521.GM26021@bombadil.infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
89 lines
2.3 KiB
C
89 lines
2.3 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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* pages. A pagevec is a multipage 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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/* 15 pointers + header align the pagevec structure to a power of two */
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#define PAGEVEC_SIZE 15
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struct page;
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struct address_space;
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struct pagevec {
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unsigned char nr;
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bool percpu_pvec_drained;
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struct page *pages[PAGEVEC_SIZE];
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};
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void __pagevec_release(struct pagevec *pvec);
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void __pagevec_lru_add(struct pagevec *pvec);
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unsigned pagevec_lookup_entries(struct pagevec *pvec,
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struct address_space *mapping,
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pgoff_t start, unsigned nr_entries,
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pgoff_t *indices);
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void pagevec_remove_exceptionals(struct pagevec *pvec);
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unsigned pagevec_lookup_range(struct pagevec *pvec,
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struct address_space *mapping,
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pgoff_t *start, pgoff_t end);
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static inline unsigned pagevec_lookup(struct pagevec *pvec,
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struct address_space *mapping,
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pgoff_t *start)
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{
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return pagevec_lookup_range(pvec, mapping, start, (pgoff_t)-1);
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}
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unsigned pagevec_lookup_range_tag(struct pagevec *pvec,
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struct address_space *mapping, pgoff_t *index, pgoff_t end,
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int tag);
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unsigned pagevec_lookup_range_nr_tag(struct pagevec *pvec,
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struct address_space *mapping, pgoff_t *index, pgoff_t end,
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int tag, unsigned max_pages);
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static inline unsigned pagevec_lookup_tag(struct pagevec *pvec,
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struct address_space *mapping, pgoff_t *index, int tag)
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{
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return pagevec_lookup_range_tag(pvec, mapping, index, (pgoff_t)-1, tag);
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}
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static inline void pagevec_init(struct pagevec *pvec)
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{
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pvec->nr = 0;
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pvec->percpu_pvec_drained = false;
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}
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static inline void pagevec_reinit(struct pagevec *pvec)
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{
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pvec->nr = 0;
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}
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static inline unsigned pagevec_count(struct pagevec *pvec)
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{
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return pvec->nr;
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}
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static inline unsigned pagevec_space(struct pagevec *pvec)
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{
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return PAGEVEC_SIZE - pvec->nr;
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}
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/*
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* Add a page to a pagevec. Returns the number of slots still available.
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*/
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static inline unsigned pagevec_add(struct pagevec *pvec, struct page *page)
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{
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pvec->pages[pvec->nr++] = page;
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return pagevec_space(pvec);
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}
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static inline void pagevec_release(struct pagevec *pvec)
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{
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if (pagevec_count(pvec))
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__pagevec_release(pvec);
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}
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#endif /* _LINUX_PAGEVEC_H */
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