From: Jan Kara <jack@xxxxxxx> Subject: 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@xxxxxxx Signed-off-by: Jan Kara <jack@xxxxxxx> Reviewed-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx> Cc: Bob Peterson <rpeterso@xxxxxxxxxx> Cc: Chao Yu <yuchao0@xxxxxxxxxx> Cc: David Howells <dhowells@xxxxxxxxxx> Cc: David Sterba <dsterba@xxxxxxxx> Cc: Ilya Dryomov <idryomov@xxxxxxxxx> Cc: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> Cc: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx> Cc: Steve French <sfrench@xxxxxxxxx> Cc: "Theodore Ts'o" <tytso@xxxxxxx> Cc: "Yan, Zheng" <zyan@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- 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 -puN include/linux/pagemap.h~mm-implement-find_get_pages_range_tag include/linux/pagemap.h --- a/include/linux/pagemap.h~mm-implement-find_get_pages_range_tag +++ a/include/linux/pagemap.h @@ -366,8 +366,16 @@ static inline unsigned find_get_pages(st } 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 -puN include/linux/pagevec.h~mm-implement-find_get_pages_range_tag include/linux/pagevec.h --- a/include/linux/pagevec.h~mm-implement-find_get_pages_range_tag +++ a/include/linux/pagevec.h @@ -38,9 +38,16 @@ static inline unsigned pagevec_lookup(st 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 -puN mm/filemap.c~mm-implement-find_get_pages_range_tag mm/filemap.c --- a/mm/filemap.c~mm-implement-find_get_pages_range_tag +++ a/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 addre 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 -puN mm/swap.c~mm-implement-find_get_pages_range_tag mm/swap.c --- a/mm/swap.c~mm-implement-find_get_pages_range_tag +++ a/mm/swap.c @@ -986,14 +986,15 @@ unsigned pagevec_lookup_range(struct pag } 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 _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
