From: Christoph Hellwig <hch@lst.de>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
Keith Busch <kbusch@kernel.org>, Chao Leng <lengchao@huawei.com>,
Ming Lei <ming.lei@redhat.com>,
linux-nvme@lists.infradead.org, linux-block@vger.kernel.org
Subject: Re: [PATCH 6/8] nvme: move the NS_DEAD flag to the controller
Date: Fri, 21 Oct 2022 15:28:15 +0200 [thread overview]
Message-ID: <20221021132815.GE22327@lst.de> (raw)
In-Reply-To: <ac33021a-b7a1-37cf-b156-df021ac4de43@grimberg.me>
On Thu, Oct 20, 2022 at 04:30:21PM +0300, Sagi Grimberg wrote:
>> -
>> + if (!test_and_set_bit(NVME_CTRL_NS_DEAD, &ctrl->flags)) {
>> + list_for_each_entry(ns, &ctrl->namespaces, list)
>> + nvme_set_queue_dying(ns);
>> + }
>
> Looking at it now, I'm not sure I understand the need for this flag. It
> seems to make nvme_kill_queues reentrant safe, but the admin queue
> unquiesce can still end up unbalanced under reentrance?
>
> How is this not broken today (or ever since quiesce/unquiesce started
> accounting)? Maybe I lost some context on the exact subtlety of how
> nvme-pci uses this interface...
Yes, this also looks weird and I had a TODO list entry for myself
to look into what is going on here. The whole interaction
with nvme_remove_namespaces is pretty weird to start with, and then
the code in PCIe is even more weird. But to feel confident to
touch this I'd need real hot removal testing, for which I don't
have a good rig right now.
next prev parent reply other threads:[~2022-10-21 13:28 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-20 10:56 per-tagset SRCU struct and quiesce Christoph Hellwig
2022-10-20 10:56 ` [PATCH 1/8] block: set the disk capacity to 0 in blk_mark_disk_dead Christoph Hellwig
2022-10-20 13:16 ` Sagi Grimberg
2022-10-21 1:09 ` Ming Lei
2022-10-21 13:11 ` Christoph Hellwig
2022-10-21 1:53 ` Chao Leng
2022-10-21 6:49 ` Hannes Reinecke
2022-10-21 13:13 ` Christoph Hellwig
2022-10-21 21:12 ` Bart Van Assche
2022-10-20 10:56 ` [PATCH 2/8] blk-mq: skip non-mq queues in blk_mq_quiesce_queue Christoph Hellwig
2022-10-20 13:16 ` Sagi Grimberg
2022-10-21 1:13 ` Ming Lei
2022-10-21 13:19 ` Christoph Hellwig
2022-10-21 15:08 ` Ming Lei
2022-10-21 2:47 ` Chao Leng
2022-10-21 3:16 ` Chao Leng
2022-10-21 6:49 ` Hannes Reinecke
2022-10-20 10:56 ` [PATCH 3/8] blk-mq: move the srcu_struct used for quiescing to the tagset Christoph Hellwig
2022-10-20 13:23 ` Sagi Grimberg
2022-10-20 17:26 ` Keith Busch
2022-10-21 13:20 ` Christoph Hellwig
2022-10-21 1:41 ` Ming Lei
2022-10-21 2:49 ` Chao Leng
2022-10-21 6:50 ` Hannes Reinecke
2022-10-21 7:16 ` Chao Leng
2022-10-21 13:22 ` Christoph Hellwig
2022-10-20 10:56 ` [PATCH 4/8] blk-mq: pass a tagset to blk_mq_wait_quiesce_done Christoph Hellwig
2022-10-20 13:23 ` Sagi Grimberg
2022-10-21 1:46 ` Ming Lei
2022-10-21 13:23 ` Christoph Hellwig
2022-10-21 2:49 ` Chao Leng
2022-10-21 6:50 ` Hannes Reinecke
2022-10-21 21:18 ` Bart Van Assche
2022-10-20 10:56 ` [PATCH 5/8] blk-mq: add tagset quiesce interface Christoph Hellwig
2022-10-20 13:24 ` Sagi Grimberg
2022-10-21 1:53 ` Ming Lei
2022-10-21 2:49 ` Chao Leng
2022-10-21 6:51 ` Hannes Reinecke
2022-10-21 21:22 ` Bart Van Assche
2022-10-24 1:57 ` Chao Leng
2022-10-24 13:35 ` Bart Van Assche
2022-10-25 1:38 ` Chao Leng
2022-10-20 10:56 ` [PATCH 6/8] nvme: move the NS_DEAD flag to the controller Christoph Hellwig
2022-10-20 13:30 ` Sagi Grimberg
2022-10-21 13:28 ` Christoph Hellwig [this message]
2022-10-24 8:43 ` Sagi Grimberg
2022-10-24 8:50 ` Sagi Grimberg
2022-10-21 2:49 ` Chao Leng
2022-10-21 6:51 ` Hannes Reinecke
2022-10-20 10:56 ` [PATCH 7/8] nvme: remove nvme_set_queue_dying Christoph Hellwig
2022-10-20 13:10 ` Sagi Grimberg
2022-10-21 13:29 ` Christoph Hellwig
2022-10-24 8:48 ` Sagi Grimberg
2022-10-21 2:50 ` Chao Leng
2022-10-21 6:52 ` Hannes Reinecke
2022-10-20 10:56 ` [PATCH 8/8] nvme: use blk_mq_[un]quiesce_tagset Christoph Hellwig
2022-10-20 13:35 ` Sagi Grimberg
2022-10-21 2:50 ` Chao Leng
2022-10-21 6:52 ` Hannes Reinecke
2022-10-20 13:16 ` per-tagset SRCU struct and quiesce Sagi Grimberg
2022-10-21 18:06 ` Keith Busch
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=20221021132815.GE22327@lst.de \
--to=hch@lst.de \
--cc=axboe@kernel.dk \
--cc=kbusch@kernel.org \
--cc=lengchao@huawei.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-nvme@lists.infradead.org \
--cc=ming.lei@redhat.com \
--cc=sagi@grimberg.me \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox