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authorMatthew Wilcox (Oracle) <willy@infradead.org>2021-02-26 04:15:25 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-26 20:40:58 +0300
commitc49f50d1983d53871ecc77b60c1fa69a2a5ca6d9 (patch)
tree1259b083ab3052288b4b408f1d0e83bb803ce285 /mm/filemap.c
parent6fbd6cf85a3be127454a1ad58525a3adcf8612ab (diff)
downloadlinux-c49f50d1983d53871ecc77b60c1fa69a2a5ca6d9.tar.xz
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/filemap.c')
-rw-r--r--mm/filemap.c11
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;