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From: Ming Lei <ming.lei@redhat.com>
To: Daniel Wagner <dwagner@suse.de>
Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
	Hannes Reinecke <hare@suse.de>, Sagi Grimberg <sagi@grimberg.me>,
	Keith Busch <kbusch@kernel.org>, Wen Xiong <wenxiong@us.ibm.com>,
	Himanshu Madhani <himanshu.madhani@oracle.com>,
	James Smart <jsmart2021@gmail.com>
Subject: Re: [PATCH v7 3/3] nvme-fc: Remove freeze/unfreeze around update_nr_hw_queues
Date: Wed, 15 Sep 2021 08:08:43 +0800	[thread overview]
Message-ID: <YUE5i77P7JF2zjpT@T590> (raw)
In-Reply-To: <20210914092008.40370-4-dwagner@suse.de>

On Tue, Sep 14, 2021 at 11:20:08AM +0200, Daniel Wagner wrote:
> From: James Smart <jsmart2021@gmail.com>
> 
> Remove the freeze/unfreeze around changes to the number of hardware
> queues. Study and retest has indicated there are no ios that can be
> active at this point so there is nothing to freeze.
> 
> nvme-fc is draining the queues in the shutdown and error recovery path
> in __nvme_fc_abort_outstanding_ios.
> 
> This patch primarily reverts 88e837ed0f1f "nvme-fc: wait for queues to
> freeze before calling update_hr_hw_queues". It's not an exact revert as
> it leaves the adjusting of hw queues only if the count changes.
> 
> Signed-off-by: James Smart <jsmart2021@gmail.com>
> [dwagner: added explanation why no IO is pending]
> Signed-off-by: Daniel Wagner <dwagner@suse.de>
> ---
>  drivers/nvme/host/fc.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
> index 6ebe68396712..aa14ad963d91 100644
> --- a/drivers/nvme/host/fc.c
> +++ b/drivers/nvme/host/fc.c
> @@ -2957,9 +2957,7 @@ nvme_fc_recreate_io_queues(struct nvme_fc_ctrl *ctrl)
>  		dev_info(ctrl->ctrl.device,
>  			"reconnect: revising io queue count from %d to %d\n",
>  			prior_ioq_cnt, nr_io_queues);
> -		nvme_wait_freeze(&ctrl->ctrl);
>  		blk_mq_update_nr_hw_queues(&ctrl->tag_set, nr_io_queues);
> -		nvme_unfreeze(&ctrl->ctrl);
>  	}

Both connect queue and ns queues are added to this tag_set, so blk_mq_update_nr_hw_queues()
will freeze them all before updating nr_hw_queues.

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

-- 
Ming


_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

WARNING: multiple messages have this Message-ID (diff)
From: Ming Lei <ming.lei@redhat.com>
To: Daniel Wagner <dwagner@suse.de>
Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
	Hannes Reinecke <hare@suse.de>, Sagi Grimberg <sagi@grimberg.me>,
	Keith Busch <kbusch@kernel.org>, Wen Xiong <wenxiong@us.ibm.com>,
	Himanshu Madhani <himanshu.madhani@oracle.com>,
	James Smart <jsmart2021@gmail.com>
Subject: Re: [PATCH v7 3/3] nvme-fc: Remove freeze/unfreeze around update_nr_hw_queues
Date: Wed, 15 Sep 2021 08:08:43 +0800	[thread overview]
Message-ID: <YUE5i77P7JF2zjpT@T590> (raw)
In-Reply-To: <20210914092008.40370-4-dwagner@suse.de>

On Tue, Sep 14, 2021 at 11:20:08AM +0200, Daniel Wagner wrote:
> From: James Smart <jsmart2021@gmail.com>
> 
> Remove the freeze/unfreeze around changes to the number of hardware
> queues. Study and retest has indicated there are no ios that can be
> active at this point so there is nothing to freeze.
> 
> nvme-fc is draining the queues in the shutdown and error recovery path
> in __nvme_fc_abort_outstanding_ios.
> 
> This patch primarily reverts 88e837ed0f1f "nvme-fc: wait for queues to
> freeze before calling update_hr_hw_queues". It's not an exact revert as
> it leaves the adjusting of hw queues only if the count changes.
> 
> Signed-off-by: James Smart <jsmart2021@gmail.com>
> [dwagner: added explanation why no IO is pending]
> Signed-off-by: Daniel Wagner <dwagner@suse.de>
> ---
>  drivers/nvme/host/fc.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
> index 6ebe68396712..aa14ad963d91 100644
> --- a/drivers/nvme/host/fc.c
> +++ b/drivers/nvme/host/fc.c
> @@ -2957,9 +2957,7 @@ nvme_fc_recreate_io_queues(struct nvme_fc_ctrl *ctrl)
>  		dev_info(ctrl->ctrl.device,
>  			"reconnect: revising io queue count from %d to %d\n",
>  			prior_ioq_cnt, nr_io_queues);
> -		nvme_wait_freeze(&ctrl->ctrl);
>  		blk_mq_update_nr_hw_queues(&ctrl->tag_set, nr_io_queues);
> -		nvme_unfreeze(&ctrl->ctrl);
>  	}

Both connect queue and ns queues are added to this tag_set, so blk_mq_update_nr_hw_queues()
will freeze them all before updating nr_hw_queues.

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

-- 
Ming


  parent reply	other threads:[~2021-09-15  0:09 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-14  9:20 [PATCH v7 0/3] Handle update hardware queues and queue freeze more carefully Daniel Wagner
2021-09-14  9:20 ` Daniel Wagner
2021-09-14  9:20 ` [PATCH v7 1/3] nvme-fc: Update hardware queues before using them Daniel Wagner
2021-09-14  9:20   ` Daniel Wagner
2021-09-14 13:52   ` Himanshu Madhani
2021-09-14 13:52     ` Himanshu Madhani
2021-09-14  9:20 ` [PATCH v7 2/3] nvme-fc: avoid race between time out and tear down Daniel Wagner
2021-09-14  9:20   ` Daniel Wagner
2021-09-14 13:54   ` Himanshu Madhani
2021-09-14 13:54     ` Himanshu Madhani
2021-09-14  9:20 ` [PATCH v7 3/3] nvme-fc: Remove freeze/unfreeze around update_nr_hw_queues Daniel Wagner
2021-09-14  9:20   ` Daniel Wagner
2021-09-14 10:58   ` Hannes Reinecke
2021-09-14 10:58     ` Hannes Reinecke
2021-09-14 13:55   ` Himanshu Madhani
2021-09-14 13:55     ` Himanshu Madhani
2021-09-15  0:08   ` Ming Lei [this message]
2021-09-15  0:08     ` Ming Lei
2021-09-21  7:04 ` [PATCH v7 0/3] Handle update hardware queues and queue freeze more carefully Christoph Hellwig
2021-09-21  7:04   ` Christoph Hellwig

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