From: Chao Leng <lengchao@huawei.com>
To: Sagi Grimberg <sagi@grimberg.me>,
<linux-nvme@lists.infradead.org>, Christoph Hellwig <hch@lst.de>,
Keith Busch <kbusch@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH rfc v2 3/4] nvme-core: reduce io failover time
Date: Sat, 25 Jul 2020 16:51:52 +0800 [thread overview]
Message-ID: <2442ebd7-12ff-3a8b-902f-2dd5d000ce02@huawei.com> (raw)
In-Reply-To: <20200724230604.34625-4-sagi@grimberg.me>
On 2020/7/25 7:06, Sagi Grimberg wrote:
> From: Chao Leng <lengchao@huawei.com>
>
> We test nvme over roce fail over with multipath when 1000 namespaces
> configured, io pause more than 10 seconds. The reason: nvme_stop_queues
> will quiesce all queues for each namespace when io timeout cause path
> error. Quiesce queue wait all ongoing dispatches finished through
> synchronize_rcu, need more than 10 milliseconds for each wait,
> thus io pause more than 10 seconds.
>
> To reduce io pause time, nvme_stop_queues use
> blk_mq_quiesce_queue_nowait to quiesce the queue, nvme_stop_queues wait
> all ongoing dispatches completed after all queues has been quiesced.
>
> Signed-off-by: Chao Leng <lengchao@huawei.com>
> Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
> ---
> drivers/nvme/host/core.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 2ae8caa4e25f..e3fae68f7de6 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -4548,8 +4548,13 @@ void nvme_stop_queues(struct nvme_ctrl *ctrl)
>
> down_read(&ctrl->namespaces_rwsem);
> list_for_each_entry(ns, &ctrl->namespaces, list)
> - blk_mq_quiesce_queue(ns->queue);
> + blk_mq_quiesce_queue_nowait(ns->queue);
> up_read(&ctrl->namespaces_rwsem);
> + /*
> + * BLK_MQ_F_BLOCKING drivers should never call us
> + */
> + WARN_ON_ONCE(ctrl->tagset.flags & BLK_MQ_F_BLOCKING);
There is a little compile bug, ctrl->tagset is a pointer. it should:
WARN_ON_ONCE(ctrl->tagset->flags & BLK_MQ_F_BLOCKING);
> + synchronize_rcu();
> }
> EXPORT_SYMBOL_GPL(nvme_stop_queues);
>
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next prev parent reply other threads:[~2020-07-25 8:52 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-24 23:06 [PATCH rfc v2 0/4] improve quiesce time for large amount of namespaces Sagi Grimberg
2020-07-24 23:06 ` [PATCH rfc v2 1/4] blk-mq: add async quiesce interface for blocking hw queues Sagi Grimberg
2020-07-25 7:03 ` Chao Leng
2020-07-25 17:35 ` Sagi Grimberg
2020-07-24 23:06 ` [PATCH rfc v2 2/4] nvme: improve quiesce for blocking queues Sagi Grimberg
2020-07-24 23:06 ` [PATCH rfc v2 3/4] nvme-core: reduce io failover time Sagi Grimberg
2020-07-24 23:15 ` Sagi Grimberg
2020-07-25 8:51 ` Chao Leng [this message]
2020-07-24 23:06 ` [PATCH for-testing v2 4/4] nvme-rdma: use blocking quiesce interface Sagi Grimberg
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