diff options
| author | Jan Kara <jack@suse.cz> | 2017-11-15 17:34:33 -0800 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2018-07-08 17:31:57 -0700 |
| commit | bf9510b162c4d0f19d4a7f834efe065b2e6b0659 (patch) | |
| tree | 7025ae2e017c51675a4aeb8d3fab996fbb8fcd34 /mm/filemap.c | |
| parent | 461247b21fde524b9022dcadb2a8e751ab520a55 (diff) | |
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 <jack@suse.cz>
Reviewed-by: Daniel 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/filemap.c')
| -rw-r--r-- | mm/filemap.c | 33 |
1 files changed, 24 insertions, 9 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 1bb007624b53..4d16907c0684 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1415,9 +1415,10 @@ 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 @@ -1425,8 +1426,9 @@ 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; @@ -1440,6 +1442,9 @@ restart: radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, *index, tag) { struct page *page; + + if (iter.index > end) + break; repeat: page = radix_tree_deref_slot(slot); if (unlikely(!page)) @@ -1478,18 +1483,28 @@ 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); /* * CD/DVDs are error prone. When a medium error occurs, the driver may fail |