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From: Sagi Grimberg <sagi@grimberg.me>
To: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>
Cc: linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
	linux-rdma@vger.kernel.org, Keith Busch <keith.busch@intel.com>
Subject: Re: [PATCH RFC 4/4] nvme-multipath: disable polling for underlying namespace request queue
Date: Tue, 11 Dec 2018 23:19:22 -0800	[thread overview]
Message-ID: <d0d76a09-7ec9-2018-d4ce-7a08d4ab4002@grimberg.me> (raw)
In-Reply-To: <20181212071140.GD28461@lst.de>


> [adding Jens]
> 
>> --- a/drivers/nvme/host/core.c
>> +++ b/drivers/nvme/host/core.c
>> @@ -1547,6 +1547,8 @@ static void __nvme_revalidate_disk(struct gendisk *disk, struct nvme_id_ns *id)
>>   	if (ns->head->disk) {
>>   		nvme_update_disk_info(ns->head->disk, ns, id);
>>   		blk_queue_stack_limits(ns->head->disk->queue, ns->queue);
>> +		/* XXX: multipath device does not support polling for now... */
>> +		blk_queue_flag_clear(QUEUE_FLAG_POLL, ns->queue);
> 
> I'd drop the XXX.  But I think we actually have a block layer problem
> here.  Currently stacking devices will just pass through REQ_HIPRI,
> despite none of them supporting any polling for it.

Yea... forgot there are other stack devices...

> So we need to make sure in the block layer or I/O submitter that
> REQ_HIPRI is only set if QUEUE_FLAG_POLL is supported.  I think it would
> also help if we rename it to REQ_POLL to make this more obvious.

It used to check for it, but was changed to look at nr_maps instead...
So I think this is a regression...

  reply	other threads:[~2018-12-12  7:19 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-11 23:36 [PATCH RFC 0/4] restore polling to nvme-rdma Sagi Grimberg
2018-12-11 23:36 ` [PATCH RFC 1/4] nvme-fabrics: allow user to pass in nr_poll_queues Sagi Grimberg
2018-12-11 23:36 ` [PATCH RFC 2/4] rdma: introduce ib_change_cq_ctx Sagi Grimberg
2018-12-11 23:36 ` [PATCH RFC 3/4] nvme-rdma: implement polling queue map Sagi Grimberg
2018-12-11 23:36 ` [PATCH RFC 4/4] nvme-multipath: disable polling for underlying namespace request queue Sagi Grimberg
2018-12-12  7:11   ` Christoph Hellwig
2018-12-12  7:19     ` Sagi Grimberg [this message]
2018-12-12  7:21       ` Christoph Hellwig
2018-12-12  7:29         ` Sagi Grimberg
2018-12-12  7:37           ` Christoph Hellwig
2018-12-11 23:36 ` [PATCH RFC nvme-cli 5/4] fabrics: pass in number of polling queues Sagi Grimberg
2018-12-12  0:27   ` Sagi Grimberg
2018-12-12  7:07 ` [PATCH RFC 0/4] restore polling to nvme-rdma Christoph Hellwig
2018-12-12  7:16   ` Sagi Grimberg
2018-12-12  8:09     ` Christoph Hellwig
2018-12-12  8:53       ` Sagi Grimberg
2018-12-12 14:05         ` Christoph Hellwig
2018-12-12 18:23           ` Sagi Grimberg
2018-12-12 16:37 ` Steve Wise
2018-12-12 18:05   ` Sagi Grimberg
2018-12-12 18:10     ` Steve Wise

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