Re: [PATCH v4 8/9] iomap: Create large folios in the buffered write path

["Darrick J. Wong" <djwong@kernel.org>]

On Mon, Jul 10, 2023 at 02:02:52PM +0100, Matthew Wilcox (Oracle) wrote:
> Use the size of the write as a hint for the size of the folio to create.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Very nice!!
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/gfs2/bmap.c         | 2 +-
>  fs/iomap/buffered-io.c | 6 ++++--
>  include/linux/iomap.h  | 2 +-
>  3 files changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
> index 8d611fbcf0bd..521d1e00a0ff 100644
> --- a/fs/gfs2/bmap.c
> +++ b/fs/gfs2/bmap.c
> @@ -971,7 +971,7 @@ gfs2_iomap_get_folio(struct iomap_iter *iter, loff_t pos, unsigned len)
>  	if (status)
>  		return ERR_PTR(status);
>  
> -	folio = iomap_get_folio(iter, pos);
> +	folio = iomap_get_folio(iter, pos, len);
>  	if (IS_ERR(folio))
>  		gfs2_trans_end(sdp);
>  	return folio;
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 5e9380cc3e83..2d3e90f4d16e 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -461,16 +461,18 @@ EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate);
>   * iomap_get_folio - get a folio reference for writing
>   * @iter: iteration structure
>   * @pos: start offset of write
> + * @len: Suggested size of folio to create.
>   *
>   * Returns a locked reference to the folio at @pos, or an error pointer if the
>   * folio could not be obtained.
>   */
> -struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos)
> +struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len)
>  {
>  	fgf_t fgp = FGP_WRITEBEGIN | FGP_NOFS;
>  
>  	if (iter->flags & IOMAP_NOWAIT)
>  		fgp |= FGP_NOWAIT;
> +	fgp |= fgf_set_order(len);
>  
>  	return __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT,
>  			fgp, mapping_gfp_mask(iter->inode->i_mapping));
> @@ -597,7 +599,7 @@ static struct folio *__iomap_get_folio(struct iomap_iter *iter, loff_t pos,
>  	if (folio_ops && folio_ops->get_folio)
>  		return folio_ops->get_folio(iter, pos, len);
>  	else
> -		return iomap_get_folio(iter, pos);
> +		return iomap_get_folio(iter, pos, len);
>  }
>  
>  static void __iomap_put_folio(struct iomap_iter *iter, loff_t pos, size_t ret,
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index e2b836c2e119..80facb9c9e5b 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -261,7 +261,7 @@ int iomap_file_buffered_write_punch_delalloc(struct inode *inode,
>  int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops);
>  void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
>  bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count);
> -struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos);
> +struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len);
>  bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags);
>  void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len);
>  int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
> -- 
> 2.39.2
>