On 09/29/2017 07:09 PM, weiping zhang wrote:
> add an option that disable io scheduler for null block device.
>
> Signed-off-by: weiping zhang <[email protected]>
> ---
> drivers/block/null_blk.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
> index bd92286..3c63863 100644
> --- a/drivers/block/null_blk.c
> +++ b/drivers/block/null_blk.c
> @@ -154,6 +154,10 @@ enum {
> NULL_Q_MQ = 2,
> };
>
> +static int g_no_sched;
> +module_param_named(no_sched, g_no_sched, int, S_IRUGO);
> +MODULE_PARM_DESC(no_sched, "No io scheduler");
> +
> static int g_submit_queues = 1;
> module_param_named(submit_queues, g_submit_queues, int, S_IRUGO);
> MODULE_PARM_DESC(submit_queues, "Number of submission queues");
> @@ -1753,7 +1757,7 @@ static int null_init_tag_set(struct nullb *nullb,
> struct blk_mq_tag_set *set)
> g_hw_queue_depth;
> set->numa_node = nullb ? nullb->dev->home_node : g_home_node;
> set->cmd_size = sizeof(struct nullb_cmd);
> - set->flags = BLK_MQ_F_SHOULD_MERGE;
> + set->flags = g_no_sched ? BLK_MQ_F_NO_SCHED : BLK_MQ_F_SHOULD_MERGE;
This should be:
set->flags = BLK_MQ_F_SHOULD_MERGE;
if (g_no_sched)
set->flags |= BLK_MQ_F_NO_SCHED;
--
Jens Axboe
