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.
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> Reviewed-by: Jan Kara <[email protected]> Reviewed-by: William Kucharski <[email protected]> --- mm/filemap.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 249cf489f5df..bb6f2ae5a68c 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2066,7 +2066,7 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, 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) @@ -2074,8 +2074,9 @@ 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. */ @@ -2109,9 +2110,9 @@ 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; -- 2.28.0
