diff options
| author | Matthew Wilcox (Oracle) | 2021-02-25 17:15:25 -0800 |
|---|---|---|
| committer | Linus Torvalds | 2021-02-26 09:40:58 -0800 |
| commit | c49f50d1983d53871ecc77b60c1fa69a2a5ca6d9 (patch) | |
| tree | 1259b083ab3052288b4b408f1d0e83bb803ce285 /mm | |
| parent | 6fbd6cf85a3be127454a1ad58525a3adcf8612ab (diff) | |
mm: make pagecache tagged lookups return only head pages
Patch series "Overhaul multi-page lookups for THP", v4.
This THP prep patchset changes several page cache iteration APIs to only
return head pages.
- It's only possible to tag head pages in the page cache, so only
return head pages, not all their subpages.
- Factor a lot of common code out of the various batch lookup routines
- Add mapping_seek_hole_data()
- Unify find_get_entries() and pagevec_lookup_entries()
- Make find_get_entries only return head pages, like find_get_entry().
These are only loosely connected, but they seem to make sense together as
a series.
This patch (of 14):
Pagecache tags are used for dirty page writeback. Since dirtiness is
tracked on a per-THP basis, we only want to return the head page rather
than each subpage of a tagged page. All the filesystems which use huge
pages today are in-memory, so there are no tagged huge pages today.
Link: https://lkml.kernel.org/r/20201112212641.27837-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/filemap.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 46a8b9e82434..57eae5163bce 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2062,7 +2062,7 @@ retry: EXPORT_SYMBOL(find_get_pages_contig); /** - * find_get_pages_range_tag - find and return pages in given range matching @tag + * find_get_pages_range_tag - Find and return head pages matching @tag. * @mapping: the address_space to search * @index: the starting page index * @end: The final page index (inclusive) @@ -2070,8 +2070,9 @@ EXPORT_SYMBOL(find_get_pages_contig); * @nr_pages: the maximum number of pages * @pages: where the resulting pages are placed * - * 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. + * Like find_get_pages(), except we only return head pages which are tagged + * with @tag. @index is updated to the index immediately after the last + * page we return, ready for the next iteration. * * Return: the number of pages which were found. */ @@ -2105,9 +2106,9 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index, if (unlikely(page != xas_reload(&xas))) goto put_page; - pages[ret] = find_subpage(page, xas.xa_index); + pages[ret] = page; if (++ret == nr_pages) { - *index = xas.xa_index + 1; + *index = page->index + thp_nr_pages(page); goto out; } continue; |