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From: Ming Lei <ming.lei@redhat.com>
To: Damien Le Moal <damien.lemoal@wdc.com>
Cc: linux-block@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
	linux-scsi@vger.kernel.org,
	"Martin K . Petersen" <martin.petersen@oracle.com>
Subject: Re: [PATCH v3 1/7] block: Cleanup elevator_init_mq() use
Date: Wed, 4 Sep 2019 17:02:04 +0800	[thread overview]
Message-ID: <20190904090202.GD7578@ming.t460p> (raw)
In-Reply-To: <20190904084247.23338-2-damien.lemoal@wdc.com>

On Wed, Sep 04, 2019 at 05:42:41PM +0900, Damien Le Moal wrote:
> Instead of checking a queue tag_set BLK_MQ_F_NO_SCHED flag before
> calling elevator_init_mq() to make sure that the queue supports IO
> scheduling, use the elevator.c function elv_support_iosched() in
> elevator_init_mq(). This does not introduce any functional change but
> ensure that elevator_init_mq() does the right thing based on the queue
> settings.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
>  block/blk-mq.c   |  8 +++-----
>  block/elevator.c | 23 +++++++++++++----------
>  2 files changed, 16 insertions(+), 15 deletions(-)
> 
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index b622029b19ea..13923630e00a 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -2904,11 +2904,9 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
>  	blk_mq_add_queue_tag_set(set, q);
>  	blk_mq_map_swqueue(q);
>  
> -	if (!(set->flags & BLK_MQ_F_NO_SCHED)) {
> -		ret = elevator_init_mq(q);
> -		if (ret)
> -			goto err_tag_set;
> -	}
> +	ret = elevator_init_mq(q);
> +	if (ret)
> +		goto err_tag_set;
>  
>  	return q;
>  
> diff --git a/block/elevator.c b/block/elevator.c
> index 86100de88883..4721834815bb 100644
> --- a/block/elevator.c
> +++ b/block/elevator.c
> @@ -619,16 +619,26 @@ int elevator_switch_mq(struct request_queue *q,
>  	return ret;
>  }
>  
> +static inline bool elv_support_iosched(struct request_queue *q)
> +{
> +	if (q->tag_set && (q->tag_set->flags & BLK_MQ_F_NO_SCHED))
> +		return false;
> +	return true;
> +}
> +
>  /*
> - * For blk-mq devices, we default to using mq-deadline, if available, for single
> - * queue devices.  If deadline isn't available OR we have multiple queues,
> - * default to "none".
> + * For blk-mq devices supporting IO scheduling, we default to using mq-deadline,
> + * if available, for single queue devices. If deadline isn't available OR we
> + * have multiple queues, default to "none".
>   */
>  int elevator_init_mq(struct request_queue *q)
>  {
>  	struct elevator_type *e;
>  	int err = 0;
>  
> +	if (!elv_support_iosched(q))
> +		return 0;
> +
>  	if (q->nr_hw_queues != 1)
>  		return 0;
>  
> @@ -706,13 +716,6 @@ static int __elevator_change(struct request_queue *q, const char *name)
>  	return elevator_switch(q, e);
>  }
>  
> -static inline bool elv_support_iosched(struct request_queue *q)
> -{
> -	if (q->tag_set && (q->tag_set->flags & BLK_MQ_F_NO_SCHED))
> -		return false;
> -	return true;
> -}
> -
>  ssize_t elv_iosched_store(struct request_queue *q, const char *name,
>  			  size_t count)
>  {
> -- 
> 2.21.0
> 

Reviewed-by: Ming Lei <ming.lei@redhat.com>

-- 
Ming

  reply	other threads:[~2019-09-04  9:02 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-04  8:42 [PATCH v3 0/7] Elevator cleanups and improvements Damien Le Moal
2019-09-04  8:42 ` [PATCH v3 1/7] block: Cleanup elevator_init_mq() use Damien Le Moal
2019-09-04  9:02   ` Ming Lei [this message]
2019-09-04  8:42 ` [PATCH v3 2/7] block: Change elevator_init_mq() to always succeed Damien Le Moal
2019-09-04  9:05   ` Ming Lei
2019-09-04  8:42 ` [PATCH v3 3/7] block: Introduce elevator features Damien Le Moal
2019-09-04  8:42 ` [PATCH v3 4/7] block: Improve default elevator selection Damien Le Moal
2019-09-04  8:51   ` Johannes Thumshirn
2019-09-04  8:42 ` [PATCH v3 5/7] block: Delay default elevator initialization Damien Le Moal
2019-09-04  8:56   ` Johannes Thumshirn
2019-09-04  9:02     ` Damien Le Moal
2019-09-04 12:56       ` Jens Axboe
2019-09-05  4:30         ` Damien Le Moal
2019-09-04  9:29   ` Ming Lei
2019-09-04  8:42 ` [PATCH v3 6/7] block: Set ELEVATOR_F_ZBD_SEQ_WRITE for nullblk zoned disks Damien Le Moal
2019-09-04  8:52   ` Johannes Thumshirn
2019-09-04  8:42 ` [PATCH v3 7/7] sd: Set ELEVATOR_F_ZBD_SEQ_WRITE for ZBC disks Damien Le Moal
2019-09-04  8:52   ` Johannes Thumshirn

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