On Thu, Nov 15, 2018 at 04:53:01PM +0800, Ming Lei wrote:
> This patch pulls the trigger for multi-page bvecs.
>
> Now any request queue which supports queue cluster will see multi-page
> bvecs.
>
> Cc: Dave Chinner <dchin...@redhat.com>
> Cc: Kent Overstreet <kent.overstr...@gmail.com>
> Cc: Mike Snitzer <snit...@redhat.com>
> Cc: dm-devel@redhat.com
> Cc: Alexander Viro <v...@zeniv.linux.org.uk>
> Cc: linux-fsde...@vger.kernel.org
> Cc: Shaohua Li <s...@kernel.org>
> Cc: linux-r...@vger.kernel.org
> Cc: linux-er...@lists.ozlabs.org
> Cc: David Sterba <dste...@suse.com>
> Cc: linux-bt...@vger.kernel.org
> Cc: Darrick J. Wong <darrick.w...@oracle.com>
> Cc: linux-...@vger.kernel.org
> Cc: Gao Xiang <gaoxian...@huawei.com>
> Cc: Christoph Hellwig <h...@lst.de>
> Cc: Theodore Ts'o <ty...@mit.edu>
> Cc: linux-e...@vger.kernel.org
> Cc: Coly Li <col...@suse.de>
> Cc: linux-bca...@vger.kernel.org
> Cc: Boaz Harrosh <o...@electrozaur.com>
> Cc: Bob Peterson <rpete...@redhat.com>
> Cc: cluster-de...@redhat.com
> Signed-off-by: Ming Lei <ming....@redhat.com>
> ---
> block/bio.c | 24 ++++++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/block/bio.c b/block/bio.c
> index 6486722d4d4b..ed6df6f8e63d 100644
> --- a/block/bio.c
> +++ b/block/bio.c
This comment above __bio_try_merge_page() doesn't make sense after this
change:
This is a
a useful optimisation for file systems with a block size smaller than the
page size.
Can you please get rid of it in this patch?
> @@ -767,12 +767,24 @@ bool __bio_try_merge_page(struct bio *bio, struct page
> *page,
>
> if (bio->bi_vcnt > 0) {
> struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
> -
> - if (page == bv->bv_page && off == bv->bv_offset + bv->bv_len) {
> - bv->bv_len += len;
> - bio->bi_iter.bi_size += len;
> - return true;
> - }
> + struct request_queue *q = NULL;
> +
> + if (page == bv->bv_page && off == (bv->bv_offset + bv->bv_len)
> + && (off + len) <= PAGE_SIZE)
> + goto merge;
The parentheses around (bv->bv_offset + bv->bv_len) and (off + len) are
unnecessary noise.
What's the point of the new (off + len) <= PAGE_SIZE check?
> +
> + if (bio->bi_disk)
> + q = bio->bi_disk->queue;
> +
> + /* disable multi-page bvec too if cluster isn't enabled */
> + if (!q || !blk_queue_cluster(q) ||
> + ((page_to_phys(bv->bv_page) + bv->bv_offset + bv->bv_len) !=
> + (page_to_phys(page) + off)))
More unnecessary parentheses here.
> + return false;
> + merge:
> + bv->bv_len += len;
> + bio->bi_iter.bi_size += len;
> + return true;
> }
> return false;
> }
> --
> 2.9.5
>
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