From: Bean Huo <[email protected]> Current generic_file_buffered_read() will break up the larger batches of pages and read data in single page length in case of ra->ra_pages == 0. This patch is to allow it to pass the batches of pages down to the device if the supported maximum IO size >= the requested size.
Signed-off-by: Bean Huo <[email protected]> --- mm/filemap.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 1aaea26556cc..0deec1897817 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2062,6 +2062,7 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb, struct file *filp = iocb->ki_filp; struct address_space *mapping = filp->f_mapping; struct inode *inode = mapping->host; + struct backing_dev_info *bdi = inode_to_bdi(mapping->host); struct file_ra_state *ra = &filp->f_ra; loff_t *ppos = &iocb->ki_pos; pgoff_t index; @@ -2098,9 +2099,14 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb, if (!page) { if (iocb->ki_flags & IOCB_NOIO) goto would_block; - page_cache_sync_readahead(mapping, - ra, filp, - index, last_index - index); + + if (!ra->ra_pages && bdi->io_pages >= last_index - index) + __do_page_cache_readahead(mapping, filp, index, + last_index - index, 0); + else + page_cache_sync_readahead(mapping, ra, filp, + index, + last_index - index); page = find_get_page(mapping, index); if (unlikely(page == NULL)) goto no_cached_page; -- 2.17.1
