| Message ID | 20201026041408.25230-2-willy@infradead.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Overhaul multi-page lookups for THP | expand |
On Mon, Oct 26, 2020 at 04:13:57AM +0000, Matthew Wilcox (Oracle) wrote: > 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) <willy@infradead.org> > Reviewed-by: Jan Kara <jack@suse.cz> > Reviewed-by: William Kucharski <william.kucharski@oracle.com> > --- > mm/filemap.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/mm/filemap.c b/mm/filemap.c > index d5e7c2029d16..edde5dc0d28f 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 +2074,8 @@ 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. We update @index to index the next page for the traversal. Nit: ^ next head page > * > * Return: the number of pages which were found. > */ > @@ -2109,9 +2109,9 @@ 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 > >
On Wed, Oct 28, 2020 at 09:50:56AM +0200, Mike Rapoport wrote: > > @@ -2074,8 +2074,8 @@ 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. We update @index to index the next page for the traversal. > > Nit: ^ next head page I don't love the sentence anyway. How about: * 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.
On Thu, Nov 12, 2020 at 05:41:50PM +0000, Matthew Wilcox wrote: > On Wed, Oct 28, 2020 at 09:50:56AM +0200, Mike Rapoport wrote: > > > @@ -2074,8 +2074,8 @@ 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. We update @index to index the next page for the traversal. > > > > Nit: ^ next head page > > I don't love the sentence anyway. How about: > > * 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. I like it.
diff --git a/mm/filemap.c b/mm/filemap.c index d5e7c2029d16..edde5dc0d28f 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 +2074,8 @@ 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. We update @index to index the next page for the traversal. * * Return: the number of pages which were found. */ @@ -2109,9 +2109,9 @@ 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;