All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ming Lei <ming.lei@redhat.com>
To: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
	Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
	Daniel Wagner <dwagner@suse.de>, Wen Xiong <wenxiong@us.ibm.com>,
	John Garry <john.garry@huawei.com>
Subject: Re: [PATCH 2/2] nvme: pass BLK_MQ_F_NOT_USE_MANAGED_IRQ for fc/rdma/tcp/loop
Date: Wed, 30 Jun 2021 16:47:44 +0800	[thread overview]
Message-ID: <YNwvsNcTBu6yGW1o@T590> (raw)
In-Reply-To: <46fdb02d-8d71-d465-072d-5e8d6ec3601f@suse.de>

On Wed, Jun 30, 2021 at 10:15:46AM +0200, Hannes Reinecke wrote:
> On 6/29/21 9:49 AM, Ming Lei wrote:
> > All the 4 host drivers don't use managed irq for completing request, so
> > it is correct to pass the flag to blk-mq.
> > 
> > Secondly with this flag, blk-mq will help us dispatch connect request
> > allocated via blk_mq_alloc_request_hctx() to driver even though all
> > CPU in the specified hctx's cpumask are offline.
> > 
> How is this supposed to work?
> To my understanding, only cpus in the hctx cpumask are eligible to send I/O.
> So if all of these CPUs are offline, who exactly is submitting I/O?
> More to the point, which CPU will be submitting the connect request?

Please see __blk_mq_delay_run_hw_queue(), which will pass WORK_CPU_UNBOUND 
to kblockd_mod_delayed_work_on() for this situation.


Thanks,
Ming


WARNING: multiple messages have this Message-ID (diff)
From: Ming Lei <ming.lei@redhat.com>
To: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
	Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
	Daniel Wagner <dwagner@suse.de>, Wen Xiong <wenxiong@us.ibm.com>,
	John Garry <john.garry@huawei.com>
Subject: Re: [PATCH 2/2] nvme: pass BLK_MQ_F_NOT_USE_MANAGED_IRQ for fc/rdma/tcp/loop
Date: Wed, 30 Jun 2021 16:47:44 +0800	[thread overview]
Message-ID: <YNwvsNcTBu6yGW1o@T590> (raw)
In-Reply-To: <46fdb02d-8d71-d465-072d-5e8d6ec3601f@suse.de>

On Wed, Jun 30, 2021 at 10:15:46AM +0200, Hannes Reinecke wrote:
> On 6/29/21 9:49 AM, Ming Lei wrote:
> > All the 4 host drivers don't use managed irq for completing request, so
> > it is correct to pass the flag to blk-mq.
> > 
> > Secondly with this flag, blk-mq will help us dispatch connect request
> > allocated via blk_mq_alloc_request_hctx() to driver even though all
> > CPU in the specified hctx's cpumask are offline.
> > 
> How is this supposed to work?
> To my understanding, only cpus in the hctx cpumask are eligible to send I/O.
> So if all of these CPUs are offline, who exactly is submitting I/O?
> More to the point, which CPU will be submitting the connect request?

Please see __blk_mq_delay_run_hw_queue(), which will pass WORK_CPU_UNBOUND 
to kblockd_mod_delayed_work_on() for this situation.


Thanks,
Ming


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

  reply	other threads:[~2021-06-30  8:48 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-29  7:49 [PATCH 0/2] blk-mq: fix blk_mq_alloc_request_hctx Ming Lei
2021-06-29  7:49 ` Ming Lei
2021-06-29  7:49 ` [PATCH 1/2] blk-mq: not deactivate hctx if the device doesn't use managed irq Ming Lei
2021-06-29  7:49   ` Ming Lei
2021-06-29 12:39   ` Hannes Reinecke
2021-06-29 12:39     ` Hannes Reinecke
2021-06-29 14:17     ` Ming Lei
2021-06-29 14:17       ` Ming Lei
2021-06-29 15:49   ` John Garry
2021-06-29 15:49     ` John Garry
2021-06-30  0:32     ` Ming Lei
2021-06-30  0:32       ` Ming Lei
2021-06-30  9:25       ` John Garry
2021-06-30  9:25         ` John Garry
2021-07-01  9:52       ` Christoph Hellwig
2021-07-01  9:52         ` Christoph Hellwig
2021-06-29 23:30   ` Damien Le Moal
2021-06-29 23:30     ` Damien Le Moal
2021-06-30 18:58     ` Sagi Grimberg
2021-06-30 18:58       ` Sagi Grimberg
2021-06-30 21:57       ` Damien Le Moal
2021-06-30 21:57         ` Damien Le Moal
2021-07-01 14:20         ` Keith Busch
2021-07-01 14:20           ` Keith Busch
2021-06-29  7:49 ` [PATCH 2/2] nvme: pass BLK_MQ_F_NOT_USE_MANAGED_IRQ for fc/rdma/tcp/loop Ming Lei
2021-06-29  7:49   ` Ming Lei
2021-06-30  8:15   ` Hannes Reinecke
2021-06-30  8:15     ` Hannes Reinecke
2021-06-30  8:47     ` Ming Lei [this message]
2021-06-30  8:47       ` Ming Lei
2021-06-30  8:18 ` [PATCH 0/2] blk-mq: fix blk_mq_alloc_request_hctx Hannes Reinecke
2021-06-30  8:18   ` Hannes Reinecke
2021-06-30  8:42   ` Ming Lei
2021-06-30  8:42     ` Ming Lei
2021-06-30  9:43     ` Hannes Reinecke
2021-06-30  9:43       ` Hannes Reinecke
2021-06-30  9:53       ` Ming Lei
2021-06-30  9:53         ` Ming Lei
2021-06-30 18:59         ` Sagi Grimberg
2021-06-30 18:59           ` Sagi Grimberg
2021-06-30 19:46           ` Hannes Reinecke
2021-06-30 19:46             ` Hannes Reinecke
2021-06-30 23:59             ` Ming Lei
2021-06-30 23:59               ` Ming Lei
2021-07-01  8:00               ` Hannes Reinecke
2021-07-01  8:00                 ` Hannes Reinecke
2021-07-01  9:13                 ` Ming Lei
2021-07-01  9:13                   ` Ming Lei
2021-07-02  9:47             ` Daniel Wagner
2021-07-02  9:47               ` Daniel Wagner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YNwvsNcTBu6yGW1o@T590 \
    --to=ming.lei@redhat.com \
    --cc=axboe@kernel.dk \
    --cc=dwagner@suse.de \
    --cc=hare@suse.de \
    --cc=hch@lst.de \
    --cc=john.garry@huawei.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-nvme@lists.infradead.org \
    --cc=sagi@grimberg.me \
    --cc=wenxiong@us.ibm.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.