Re: [PATCH] blk-mq: count the hctx as active before allocate tag

[jianchao.wang]

On 08/08/2018 05:24 PM, Ming Lei wrote:
> On Wed, Aug 8, 2018 at 4:22 PM, Jianchao Wang
> <jianchao.w.wang@xxxxxxxxxx> wrote:
>> Currently, we count the hctx as active after allocate tag
>> successfully. The other shared-tags users could exhaust the tags
>> and starve a non-active and waiting-tag hctx. Count the hctx as
>> active before try to allocate tag to fix this.
> 
> This patch looks fine.
> 
>>
>> Signed-off-by: Jianchao Wang <jianchao.w.wang@xxxxxxxxxx>
>> ---
>>  block/blk-mq.c | 6 +++++-
>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/block/blk-mq.c b/block/blk-mq.c
>> index ae44e85..acd40eb 100644
>> --- a/block/blk-mq.c
>> +++ b/block/blk-mq.c
>> @@ -369,6 +369,8 @@ static struct request *blk_mq_get_request(struct request_queue *q,
>>                         e->type->ops.mq.limit_depth(op, data);
>>         }
>>
>> +       blk_mq_tag_busy(data.hctx);
>> +
> 
> blk_mq_tag_busy is only required for driver tag.
> 

Yes, I will change it and post the V2.

Thanks
Jianchao