From 72b045aecdd856b083521f2a963705b4c2e59680 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Wed, 15 Nov 2017 17:34:33 -0800 Subject: [PATCH] mm: implement find_get_pages_range_tag() Patch series "Ranged pagevec tagged lookup", v3. In this series I provide a ranged variant of pagevec_lookup_tag() and use it in places where it makes sense. This series removes some common code and it also has a potential for speeding up some operations similarly as for pagevec_lookup_range() (but for now I can think of only artificial cases where this happens). This patch (of 16): Implement a variant of find_get_pages_tag() that stops iterating at given index. Lots of users of this function (through pagevec_lookup()) actually want a range lookup and all of them are currently open-coding this. Also create corresponding pagevec_lookup_range_tag() function. Link: http://lkml.kernel.org/r/20171009151359.31984-2-jack@suse.cz Signed-off-by: Jan Kara Reviewed-by: Daniel Jordan Cc: Bob Peterson Cc: Chao Yu Cc: David Howells Cc: David Sterba Cc: Ilya Dryomov Cc: Jaegeuk Kim Cc: Ryusuke Konishi Cc: Steve French Cc: "Theodore Ts'o" Cc: "Yan, Zheng" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/pagemap.h | 12 ++++++++++-- include/linux/pagevec.h | 11 +++++++++-- mm/filemap.c | 33 ++++++++++++++++++++++++--------- mm/swap.c | 9 +++++---- 4 files changed, 48 insertions(+), 17 deletions(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index e08b5339023c..956d6a80e126 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -366,8 +366,16 @@ static inline unsigned find_get_pages(struct address_space *mapping, } unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start, unsigned int nr_pages, struct page **pages); -unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, - int tag, unsigned int nr_pages, struct page **pages); +unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index, + pgoff_t end, int tag, unsigned int nr_pages, + struct page **pages); +static inline unsigned find_get_pages_tag(struct address_space *mapping, + pgoff_t *index, int tag, unsigned int nr_pages, + struct page **pages) +{ + return find_get_pages_range_tag(mapping, index, (pgoff_t)-1, tag, + nr_pages, pages); +} unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start, int tag, unsigned int nr_entries, struct page **entries, pgoff_t *indices); diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h index 2636c0c0f279..afc718f586f8 100644 --- a/include/linux/pagevec.h +++ b/include/linux/pagevec.h @@ -38,9 +38,16 @@ static inline unsigned pagevec_lookup(struct pagevec *pvec, return pagevec_lookup_range(pvec, mapping, start, (pgoff_t)-1); } -unsigned pagevec_lookup_tag(struct pagevec *pvec, +unsigned pagevec_lookup_range_tag(struct pagevec *pvec, + struct address_space *mapping, pgoff_t *index, pgoff_t end, + int tag, unsigned nr_pages); +static inline unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping, pgoff_t *index, int tag, - unsigned nr_pages); + unsigned nr_pages) +{ + return pagevec_lookup_range_tag(pvec, mapping, index, (pgoff_t)-1, tag, + nr_pages); +} static inline void pagevec_init(struct pagevec *pvec, int cold) { diff --git a/mm/filemap.c b/mm/filemap.c index 594d73fef8b4..cf74d0dacc6a 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1754,9 +1754,10 @@ repeat: EXPORT_SYMBOL(find_get_pages_contig); /** - * find_get_pages_tag - find and return pages that match @tag + * find_get_pages_range_tag - find and return pages in given range matching @tag * @mapping: the address_space to search * @index: the starting page index + * @end: The final page index (inclusive) * @tag: the tag index * @nr_pages: the maximum number of pages * @pages: where the resulting pages are placed @@ -1764,8 +1765,9 @@ EXPORT_SYMBOL(find_get_pages_contig); * Like find_get_pages, except we only return pages which are tagged with * @tag. We update @index to index the next page for the traversal. */ -unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, - int tag, unsigned int nr_pages, struct page **pages) +unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index, + pgoff_t end, int tag, unsigned int nr_pages, + struct page **pages) { struct radix_tree_iter iter; void **slot; @@ -1778,6 +1780,9 @@ unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, *index, tag) { struct page *head, *page; + + if (iter.index > end) + break; repeat: page = radix_tree_deref_slot(slot); if (unlikely(!page)) @@ -1819,18 +1824,28 @@ repeat: } pages[ret] = page; - if (++ret == nr_pages) - break; + if (++ret == nr_pages) { + *index = pages[ret - 1]->index + 1; + goto out; + } } + /* + * We come here when we got at @end. We take care to not overflow the + * index @index as it confuses some of the callers. This breaks the + * iteration when there is page at index -1 but that is already broken + * anyway. + */ + if (end == (pgoff_t)-1) + *index = (pgoff_t)-1; + else + *index = end + 1; +out: rcu_read_unlock(); - if (ret) - *index = pages[ret - 1]->index + 1; - return ret; } -EXPORT_SYMBOL(find_get_pages_tag); +EXPORT_SYMBOL(find_get_pages_range_tag); /** * find_get_entries_tag - find and return entries that match @tag diff --git a/mm/swap.c b/mm/swap.c index a77d68f2c1b6..e1c74eb8a775 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -986,14 +986,15 @@ unsigned pagevec_lookup_range(struct pagevec *pvec, } EXPORT_SYMBOL(pagevec_lookup_range); -unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping, - pgoff_t *index, int tag, unsigned nr_pages) +unsigned pagevec_lookup_range_tag(struct pagevec *pvec, + struct address_space *mapping, pgoff_t *index, pgoff_t end, + int tag, unsigned nr_pages) { - pvec->nr = find_get_pages_tag(mapping, index, tag, + pvec->nr = find_get_pages_range_tag(mapping, index, end, tag, nr_pages, pvec->pages); return pagevec_count(pvec); } -EXPORT_SYMBOL(pagevec_lookup_tag); +EXPORT_SYMBOL(pagevec_lookup_range_tag); /* * Perform any setup for the swap system