On Mon, Mar 18, 2019 at 3:10 PM Ilya Dryomov <idryomov@xxxxxxxxx> wrote:
>
> Now that we have alloc_size that controls our discard behavior, it
> doesn't make sense to have these set to object (set) size. alloc_size
> defaults to 64k, but because discard_granularity is likely 4M, only
> ranges that are equal to or bigger than 4M can be considered during
> fstrim. A smaller io_min is also more likely to be met, resulting in
> fewer deferred writes on bluestore OSDs.
>
> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
> ---
> drivers/block/rbd.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index a32d5b54d59e..e037f1ab2fde 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -834,7 +834,7 @@ static int parse_rbd_opts_token(char *c, void *private)
> pctx->opts->queue_depth = intval;
> break;
> case Opt_alloc_size:
> - if (intval < 1) {
> + if (intval < SECTOR_SIZE) {
> pr_err("alloc_size out of range\n");
> return -EINVAL;
> }
> @@ -4204,12 +4204,12 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
> q->limits.max_sectors = queue_max_hw_sectors(q);
> blk_queue_max_segments(q, USHRT_MAX);
> blk_queue_max_segment_size(q, UINT_MAX);
> - blk_queue_io_min(q, objset_bytes);
> - blk_queue_io_opt(q, objset_bytes);
> + blk_queue_io_min(q, rbd_dev->opts->alloc_size);
> + blk_queue_io_opt(q, rbd_dev->opts->alloc_size);
>
> if (rbd_dev->opts->trim) {
> blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
> - q->limits.discard_granularity = objset_bytes;
> + q->limits.discard_granularity = rbd_dev->opts->alloc_size;
> blk_queue_max_discard_sectors(q, objset_bytes >> SECTOR_SHIFT);
> blk_queue_max_write_zeroes_sectors(q, objset_bytes >> SECTOR_SHIFT);
> }
> --
> 2.19.2
>
Reviewed-by: Jason Dillaman <dillaman@xxxxxxxxxx>
--
Jason
