Re: [PATCH 04/12] xfs: refactor the ioend merging code

Darrick J. Wong
2019-10-15T17:56:33Z

On Tue, Oct 15, 2019 at 05:43:37PM +0200, Christoph Hellwig wrote:
> Introduce two nicely abstracted helper, which can be moved to the
> iomap code later. Also use list_pop_entry and list_first_entry_or_null
> to simplify the code a bit.

No we don't use these.... ^^^^^^^^^^^^^^

Everything else looks ok.

--D

> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/xfs/xfs_aops.c | 73 +++++++++++++++++++++++++++--------------------
> 1 file changed, 42 insertions(+), 31 deletions(-)
>
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index 91899de2be09..c29ef69d1e51 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -116,6 +116,22 @@ xfs_destroy_ioend(
> }
> }
>
> +static void
> +xfs_destroy_ioends(
> + struct xfs_ioend *ioend,
> + int error)
> +{
> + struct list_head tmp;
> +
> + list_replace_init(&ioend->io_list, &tmp);
> + xfs_destroy_ioend(ioend, error);
> + while ((ioend = list_first_entry_or_null(&tmp, struct xfs_ioend,
> + io_list))) {
> + list_del_init(&ioend->io_list);
> + xfs_destroy_ioend(ioend, error);
> + }
> +}
> +
> /*
> * Fast and loose check if this write could update the on-disk inode size.
> */
> @@ -230,7 +246,6 @@ STATIC void
> xfs_end_ioend(
> struct xfs_ioend *ioend)
> {
> - struct list_head ioend_list;
> struct xfs_inode *ip = XFS_I(ioend->io_inode);
> xfs_off_t offset = ioend->io_offset;
> size_t size = ioend->io_size;
> @@ -275,16 +290,7 @@ xfs_end_ioend(
> done:
> if (ioend->io_append_trans)
> error = xfs_setfilesize_ioend(ioend, error);
> - list_replace_init(&ioend->io_list, &ioend_list);
> - xfs_destroy_ioend(ioend, error);
> -
> - while (!list_empty(&ioend_list)) {
> - ioend = list_first_entry(&ioend_list, struct xfs_ioend,
> - io_list);
> - list_del_init(&ioend->io_list);
> - xfs_destroy_ioend(ioend, error);
> - }
> -
> + xfs_destroy_ioends(ioend, error);
> memalloc_nofs_restore(nofs_flag);
> }
>
> @@ -333,17 +339,18 @@ xfs_ioend_try_merge(
> struct xfs_ioend *ioend,
> struct list_head *more_ioends)
> {
> - struct xfs_ioend *next_ioend;
> + struct xfs_ioend *next;
> +
> + INIT_LIST_HEAD(&ioend->io_list);
>
> - while (!list_empty(more_ioends)) {
> - next_ioend = list_first_entry(more_ioends, struct xfs_ioend,
> - io_list);
> - if (!xfs_ioend_can_merge(ioend, next_ioend))
> + while ((next = list_first_entry_or_null(more_ioends, struct xfs_ioend,
> + io_list))) {
> + if (!xfs_ioend_can_merge(ioend, next))
> break;
> - list_move_tail(&next_ioend->io_list, &ioend->io_list);
> - ioend->io_size += next_ioend->io_size;
> - if (next_ioend->io_append_trans)
> - xfs_ioend_merge_append_transactions(ioend, next_ioend);
> + list_move_tail(&next->io_list, &ioend->io_list);
> + ioend->io_size += next->io_size;
> + if (next->io_append_trans)
> + xfs_ioend_merge_append_transactions(ioend, next);
> }
> }
>
> @@ -366,29 +373,33 @@ xfs_ioend_compare(
> return 0;
> }
>
> +static void
> +xfs_sort_ioends(
> + struct list_head *ioend_list)
> +{
> + list_sort(NULL, ioend_list, xfs_ioend_compare);
> +}
> +
> /* Finish all pending io completions. */
> void
> xfs_end_io(
> struct work_struct *work)
> {
> - struct xfs_inode *ip;
> + struct xfs_inode *ip =
> + container_of(work, struct xfs_inode, i_ioend_work);
> struct xfs_ioend *ioend;
> - struct list_head completion_list;
> + struct list_head tmp;
> unsigned long flags;
>
> - ip = container_of(work, struct xfs_inode, i_ioend_work);
> -
> spin_lock_irqsave(&ip->i_ioend_lock, flags);
> - list_replace_init(&ip->i_ioend_list, &completion_list);
> + list_replace_init(&ip->i_ioend_list, &tmp);
> spin_unlock_irqrestore(&ip->i_ioend_lock, flags);
>
> - list_sort(NULL, &completion_list, xfs_ioend_compare);
> -
> - while (!list_empty(&completion_list)) {
> - ioend = list_first_entry(&completion_list, struct xfs_ioend,
> - io_list);
> + xfs_sort_ioends(&tmp);
> + while ((ioend = list_first_entry_or_null(&tmp, struct xfs_ioend,
> + io_list))) {
> list_del_init(&ioend->io_list);
> - xfs_ioend_try_merge(ioend, &completion_list);
> + xfs_ioend_try_merge(ioend, &tmp);
> xfs_end_ioend(ioend);
> }
> }
> --
> 2.20.1
>