On 08/15/2018 07:32 PM, Ming Lei wrote:
> On Wed, Aug 15, 2018 at 3:25 PM, Jianchao Wang
> <jianchao.w.wang@xxxxxxxxxx> wrote:
>> Kyber depends on the mapping between cpu and nr_hw_queues. When
>> update nr_hw_queues, elevator_type->ops.mq.init_hctx will be
>> invoked before the mapping is adapted correctly, this would cause
>> terrible result. A simply way to fix this is switch the io scheduler
>> to none before update the nr_hw_queues, and then get it back after
>> update nr_hw_queues. To achieve this, we add a new member elv_type
>> in request_queue to save the original elevator and adapt and export
>> elevator_switch_mq.
>>
>> Signed-off-by: Jianchao Wang <jianchao.w.wang@xxxxxxxxxx>
>> ---
>> block/blk-mq.c | 37 +++++++++++++++++++++++++++++--------
>> block/blk.h | 2 ++
>> block/elevator.c | 20 ++++++++++++--------
>> include/linux/blkdev.h | 3 +++
>> 4 files changed, 46 insertions(+), 16 deletions(-)
>>
>> diff --git a/block/blk-mq.c b/block/blk-mq.c
>> index 5efd789..89904cc 100644
>> --- a/block/blk-mq.c
>> +++ b/block/blk-mq.c
>> @@ -112,6 +112,7 @@ void blk_mq_in_flight(struct request_queue *q, struct hd_struct *part,
>> struct mq_inflight mi = { .part = part, .inflight = inflight, };
>>
>> inflight[0] = inflight[1] = 0;
>> +
>
> Not necessary to do that.
Yes, I will discard this.
>
>> blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
>> }
>>
>> @@ -2147,8 +2148,6 @@ static void blk_mq_exit_hctx(struct request_queue *q,
>> if (set->ops->exit_request)
>> set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx);
>>
>> - blk_mq_sched_exit_hctx(q, hctx, hctx_idx);
>> -
>> if (set->ops->exit_hctx)
>> set->ops->exit_hctx(hctx, hctx_idx);
>>
>> @@ -2216,12 +2215,9 @@ static int blk_mq_init_hctx(struct request_queue *q,
>> set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
>> goto free_bitmap;
>>
>> - if (blk_mq_sched_init_hctx(q, hctx, hctx_idx))
>> - goto exit_hctx;
>> -
>> hctx->fq = blk_alloc_flush_queue(q, hctx->numa_node, set->cmd_size);
>> if (!hctx->fq)
>> - goto sched_exit_hctx;
>> + goto exit_hctx;
>>
>> if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx, node))
>> goto free_fq;
>> @@ -2235,8 +2231,6 @@ static int blk_mq_init_hctx(struct request_queue *q,
>>
>> free_fq:
>> kfree(hctx->fq);
>> - sched_exit_hctx:
>> - blk_mq_sched_exit_hctx(q, hctx, hctx_idx);
>
> Seems both blk_mq_sched_init_hctx() and blk_mq_sched_exit_hctx() may be
> removed now.
Yes, I will remove them in V2.
Thanks
Jianchao
