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Commit 72b045ae authored by Jan Kara's avatar Jan Kara Committed by Linus Torvalds
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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: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarDaniel Jordan <daniel.m.jordan@oracle.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Steve French <sfrench@samba.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6b4c54e3

include/linux/pagemap.h

+10 −2
Original line number Diff line number Diff line
@@ -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);

include/linux/pagevec.h

+9 −2
Original line number Diff line number Diff line
@@ -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)

{

mm/filemap.c

+24 −9
Original line number Diff line number Diff line
@@ -1754,9 +1754,10 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, 
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 @@ unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, 
		}



		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

mm/swap.c

+5 −4
Original line number Diff line number Diff line
@@ -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