From: John Garry <john.garry@huawei.com>
To: Ming Lei <ming.lei@redhat.com>
Cc: <axboe@kernel.dk>, <linux-block@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <hch@lst.de>, <hare@suse.de>,
<ppvk@codeaurora.org>, <bvanassche@acm.org>,
<kashyap.desai@broadcom.com>
Subject: Re: [RFC PATCH] blk-mq: Clean up references when freeing rqs
Date: Wed, 9 Dec 2020 09:55:30 +0000 [thread overview]
Message-ID: <13327a68-6f86-96da-0c5f-5fa0be326d6f@huawei.com> (raw)
In-Reply-To: <20201209010102.GA1217988@T590>
On 09/12/2020 01:01, Ming Lei wrote:
> blk_mq_queue_tag_busy_iter() can be run on another request queue just
> between one driver tag is allocated and updating the request map, so one
> extra request reference still can be grabbed.
>
> So looks only holding one queue's usage_counter doesn't help this issue, since
> bt_for_each() always iterates on driver tags wide.
>
>> But I didn't see such a guard for blk_mq_tagset_busy_iter().
> IMO there isn't real difference between the two iteration.
ok, I see. Let me try to recreate that one, which will prob again
require artificial delays added.
Apart from this, my concern is that we come with for a solution, but
it's a complicated solution and may not be accepted as this issue is not
seen as a problem in practice.
Thanks,
John
next prev parent reply other threads:[~2020-12-09 9:56 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 13:02 John Garry
2020-12-02 3:31 ` Ming Lei
2020-12-02 11:18 ` John Garry
2020-12-03 0:55 ` Ming Lei
2020-12-03 9:26 ` John Garry
2020-12-08 11:36 ` John Garry
2020-12-08 17:36 ` John Garry
2020-12-09 1:01 ` Ming Lei
2020-12-09 9:55 ` John Garry [this message]
2020-12-10 2:07 ` Ming Lei
2020-12-10 10:44 ` John Garry
2020-12-10 12:22 ` John Garry
2020-12-11 0:21 ` Ming Lei
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=13327a68-6f86-96da-0c5f-5fa0be326d6f@huawei.com \
--to=john.garry@huawei.com \
--cc=axboe@kernel.dk \
--cc=bvanassche@acm.org \
--cc=hare@suse.de \
--cc=hch@lst.de \
--cc=kashyap.desai@broadcom.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=ming.lei@redhat.com \
--cc=ppvk@codeaurora.org \
/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
all inboxes | Powered by JetHome®