On 4/26/25 02:08, Joanne Koong wrote:
> Add support for folios larger than one page size for readahead.
>
> Signed-off-by: Joanne Koong <joannelkoong@xxxxxxxxx>
> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/fuse/file.c | 36 +++++++++++++++++++++++++++---------
> 1 file changed, 27 insertions(+), 9 deletions(-)
>
> diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> index 1d38486fae50..9a31f2a516b9 100644
> --- a/fs/fuse/file.c
> +++ b/fs/fuse/file.c
> @@ -876,14 +876,13 @@ static void fuse_readpages_end(struct fuse_mount *fm, struct fuse_args *args,
> fuse_io_free(ia);
> }
>
> -static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file)
> +static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file,
> + unsigned int count)
> {
> struct fuse_file *ff = file->private_data;
> struct fuse_mount *fm = ff->fm;
> struct fuse_args_pages *ap = &ia->ap;
> loff_t pos = folio_pos(ap->folios[0]);
> - /* Currently, all folios in FUSE are one page */
> - size_t count = ap->num_folios << PAGE_SHIFT;
> ssize_t res;
> int err;
>
> @@ -918,6 +917,7 @@ static void fuse_readahead(struct readahead_control *rac)
> struct inode *inode = rac->mapping->host;
> struct fuse_conn *fc = get_fuse_conn(inode);
> unsigned int max_pages, nr_pages;
> + struct folio *folio = NULL;
>
> if (fuse_is_bad(inode))
> return;
> @@ -939,8 +939,8 @@ static void fuse_readahead(struct readahead_control *rac)
> while (nr_pages) {
> struct fuse_io_args *ia;
> struct fuse_args_pages *ap;
> - struct folio *folio;
> unsigned cur_pages = min(max_pages, nr_pages);
> + unsigned int pages = 0;
>
> if (fc->num_background >= fc->congestion_threshold &&
> rac->ra->async_size >= readahead_count(rac))
> @@ -952,10 +952,12 @@ static void fuse_readahead(struct readahead_control *rac)
>
> ia = fuse_io_alloc(NULL, cur_pages);
> if (!ia)
> - return;
> + break;
> ap = &ia->ap;
>
> - while (ap->num_folios < cur_pages) {
> + while (pages < cur_pages) {
> + unsigned int folio_pages;
> +
> /*
> * This returns a folio with a ref held on it.
> * The ref needs to be held until the request is
> @@ -963,13 +965,29 @@ static void fuse_readahead(struct readahead_control *rac)
> * fuse_try_move_page()) drops the ref after it's
> * replaced in the page cache.
> */
> - folio = __readahead_folio(rac);
> + if (!folio)
> + folio = __readahead_folio(rac);
> +
> + folio_pages = folio_nr_pages(folio);
> + if (folio_pages > cur_pages - pages)
> + break;
> +
Hmm, so let's assume this would be a 2MB folio, but fc->max_pages is
limited to 1MB - we not do read-ahead anymore?
Thanks,
Bernd
> ap->folios[ap->num_folios] = folio;
> ap->descs[ap->num_folios].length = folio_size(folio);
> ap->num_folios++;
> + pages += folio_pages;
> + folio = NULL;
> + }
> + if (!pages) {
> + fuse_io_free(ia);
> + break;
> }
> - fuse_send_readpages(ia, rac->file);
> - nr_pages -= cur_pages;
> + fuse_send_readpages(ia, rac->file, pages << PAGE_SHIFT);
> + nr_pages -= pages;
> + }
> + if (folio) {
> + folio_end_read(folio, false);
> + folio_put(folio);
> }
> }
>
