From: Sagi Grimberg <sagi@grimberg.me>
To: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>,
Ming Lei <ming.lei@redhat.com>,
Damien Le Moal <Damien.LeMoal@wdc.com>,
Keith Busch <kbusch@kernel.org>,
"Wunderlich, Mark" <mark.wunderlich@intel.com>,
"Vasudevan, Anil" <anil.vasudevan@intel.com>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-nvme@lists.infradead.org
Subject: Re: [PATCH 15/15] nvme-multipath: enable polled I/O
Date: Wed, 12 May 2021 15:10:58 -0700 [thread overview]
Message-ID: <2ae11b40-1d03-af08-aade-022fc1f0a743@grimberg.me> (raw)
In-Reply-To: <20210512131545.495160-16-hch@lst.de>
> Set the poll queue flag to enable polling, given that the multipath
> node just dispatches the bios to a lower queue.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> drivers/nvme/host/multipath.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index 516fe977606d..e95b93655d06 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -446,6 +446,15 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
> goto out;
> blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
> blk_queue_flag_set(QUEUE_FLAG_NOWAIT, q);
> + /*
> + * This assumes all controllers that refer to a namespace either
> + * support poll queues or not. That is not a strict guarantee,
> + * but if the assumption is wrong the effect is only suboptimal
> + * performance but not correctness problem.
> + */
> + if (ctrl->tagset->nr_maps > HCTX_TYPE_POLL &&
> + ctrl->tagset->map[HCTX_TYPE_POLL].nr_queues)
> + blk_queue_flag_set(QUEUE_FLAG_POLL, q);
If one controller does not support polling and the other does, won't
the block layer fail to map a queue for REQ_POLLED requests?
Maybe clear in the else case here?
WARNING: multiple messages have this Message-ID (diff)
From: Sagi Grimberg <sagi@grimberg.me>
To: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>,
Ming Lei <ming.lei@redhat.com>,
Damien Le Moal <Damien.LeMoal@wdc.com>,
Keith Busch <kbusch@kernel.org>,
"Wunderlich, Mark" <mark.wunderlich@intel.com>,
"Vasudevan, Anil" <anil.vasudevan@intel.com>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-nvme@lists.infradead.org
Subject: Re: [PATCH 15/15] nvme-multipath: enable polled I/O
Date: Wed, 12 May 2021 15:10:58 -0700 [thread overview]
Message-ID: <2ae11b40-1d03-af08-aade-022fc1f0a743@grimberg.me> (raw)
In-Reply-To: <20210512131545.495160-16-hch@lst.de>
> Set the poll queue flag to enable polling, given that the multipath
> node just dispatches the bios to a lower queue.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> drivers/nvme/host/multipath.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index 516fe977606d..e95b93655d06 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -446,6 +446,15 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
> goto out;
> blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
> blk_queue_flag_set(QUEUE_FLAG_NOWAIT, q);
> + /*
> + * This assumes all controllers that refer to a namespace either
> + * support poll queues or not. That is not a strict guarantee,
> + * but if the assumption is wrong the effect is only suboptimal
> + * performance but not correctness problem.
> + */
> + if (ctrl->tagset->nr_maps > HCTX_TYPE_POLL &&
> + ctrl->tagset->map[HCTX_TYPE_POLL].nr_queues)
> + blk_queue_flag_set(QUEUE_FLAG_POLL, q);
If one controller does not support polling and the other does, won't
the block layer fail to map a queue for REQ_POLLED requests?
Maybe clear in the else case here?
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next prev parent reply other threads:[~2021-05-12 22:58 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-12 13:15 switch block layer polling to a bio based model v3 Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 13:15 ` [PATCH 01/15] direct-io: remove blk_poll support Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 13:15 ` [PATCH 02/15] block: don't try to poll multi-bio I/Os in __blkdev_direct_IO Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 20:54 ` Sagi Grimberg
2021-05-12 20:54 ` Sagi Grimberg
2021-05-16 18:01 ` Kanchan Joshi
2021-05-16 18:01 ` Kanchan Joshi
2021-05-12 13:15 ` [PATCH 03/15] iomap: don't try to poll multi-bio I/Os in __iomap_dio_rw Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 21:32 ` Darrick J. Wong
2021-05-12 21:32 ` Darrick J. Wong
2021-05-12 13:15 ` [PATCH 04/15] blk-mq: factor out a blk_qc_to_hctx helper Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 20:58 ` Sagi Grimberg
2021-05-12 20:58 ` Sagi Grimberg
2021-05-12 13:15 ` [PATCH 05/15] blk-mq: factor out a "classic" poll helper Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 20:59 ` Sagi Grimberg
2021-05-12 20:59 ` Sagi Grimberg
2021-05-12 13:15 ` [PATCH 06/15] blk-mq: remove blk_qc_t_to_tag and blk_qc_t_is_internal Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 21:42 ` Sagi Grimberg
2021-05-12 21:42 ` Sagi Grimberg
2021-05-12 13:15 ` [PATCH 07/15] blk-mq: remove blk_qc_t_valid Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 21:43 ` Sagi Grimberg
2021-05-12 21:43 ` Sagi Grimberg
2021-05-12 13:15 ` [PATCH 08/15] io_uring: don't sleep when polling for I/O Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 21:55 ` Sagi Grimberg
2021-05-12 21:55 ` Sagi Grimberg
2021-05-19 13:02 ` Christoph Hellwig
2021-05-19 13:02 ` Christoph Hellwig
2021-05-12 13:15 ` [PATCH 09/15] block: rename REQ_HIPRI to REQ_POLLED Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 21:56 ` Sagi Grimberg
2021-05-12 21:56 ` Sagi Grimberg
2021-05-12 22:43 ` Chaitanya Kulkarni
2021-05-12 22:43 ` Chaitanya Kulkarni
2021-05-12 13:15 ` [PATCH 10/15] block: use SLAB_TYPESAFE_BY_RCU for the bio slab Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 13:15 ` [PATCH 11/15] block: define 'struct bvec_iter' as packed Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 21:58 ` Sagi Grimberg
2021-05-12 21:58 ` Sagi Grimberg
2021-05-12 13:15 ` [PATCH 12/15] block: switch polling to be bio based Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 22:03 ` Sagi Grimberg
2021-05-12 22:03 ` Sagi Grimberg
2021-05-12 22:12 ` Keith Busch
2021-05-12 22:12 ` Keith Busch
2021-05-14 2:50 ` Keith Busch
2021-05-14 2:50 ` Keith Busch
2021-05-14 16:26 ` Keith Busch
2021-05-14 16:26 ` Keith Busch
2021-05-14 16:28 ` Christoph Hellwig
2021-05-14 16:28 ` Christoph Hellwig
2021-05-13 1:26 ` Ming Lei
2021-05-13 1:26 ` Ming Lei
2021-05-13 1:23 ` Ming Lei
2021-05-13 1:23 ` Ming Lei
2021-05-12 13:15 ` [PATCH 13/15] block: don't allow writing to the poll queue attribute Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 22:04 ` Sagi Grimberg
2021-05-12 22:04 ` Sagi Grimberg
2021-05-12 13:15 ` [PATCH 14/15] nvme-multipath: set QUEUE_FLAG_NOWAIT Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 13:15 ` [PATCH 15/15] nvme-multipath: enable polled I/O Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig
2021-05-12 22:10 ` Sagi Grimberg [this message]
2021-05-12 22:10 ` Sagi Grimberg
2021-05-12 22:16 ` Keith Busch
2021-05-12 22:16 ` Keith Busch
2021-05-13 23:33 ` switch block layer polling to a bio based model v3 Wunderlich, Mark
2021-05-13 23:33 ` Wunderlich, Mark
-- strict thread matches above, loose matches on Subject: below --
2021-04-27 16:16 switch block layer polling to a bio based model v2 Christoph Hellwig
2021-04-27 16:16 ` [PATCH 15/15] nvme-multipath: enable polled I/O Christoph Hellwig
2021-04-28 2:36 ` Ming Lei
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