From: Hillf Danton <hdanton@sina.com>
To: "Ionut Nechita (Wind River)" <ionut.nechita@windriver.com>
Cc: axboe@kernel.dk, torvalds@linux-foundation.org,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
bigeasy@linutronix.de
Subject: Re: [PATCH v3 1/1] block/blk-mq: use atomic_t for quiesce_depth to avoid lock contention on RT
Date: Thu, 12 Feb 2026 21:26:43 +0800 [thread overview]
Message-ID: <20260212132644.2998-1-hdanton@sina.com> (raw)
In-Reply-To: <20260212071418.7622-1-ionut.nechita@windriver.com>
On Thu, 12 Feb 2026 09:14:18 +0200 Ionut Nechita (Wind River) wrote:
>
> PREEMPT_RT has been merged into mainline since v6.12. There is no
> separate RT tree for this kind of fix anymore. The spinlock in question
https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/
> converts to rt_mutex under PREEMPT_RT, which is now a mainline
> configuration option, so the contention issue is a mainline problem.
>
CONFIG_PREEMPT_RT can not be found in your patch.
> Beyond the RT aspect, replacing the spinlock with atomic_t in the hot
> path is arguably a simplification that benefits all configurations -
> it removes locking overhead and eliminates the two-variable
> synchronization (quiesce_depth + QUEUE_FLAG_QUIESCED) in favor of a
> single atomic counter.
>
Then it was not wise to add the spinlock, yes?
next prev parent reply other threads:[~2026-02-12 13:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-11 20:39 [PATCH v3 1/1] block/blk-mq: use atomic_t for quiesce_depth to avoid lock contention on RT Ionut Nechita (Wind River)
2026-02-11 23:59 ` Hillf Danton
2026-02-12 7:14 ` Ionut Nechita (Wind River)
2026-02-12 13:26 ` Hillf Danton [this message]
2026-02-12 14:09 ` Jens Axboe
2026-02-12 14:48 ` Sebastian Andrzej Siewior
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=20260212132644.2998-1-hdanton@sina.com \
--to=hdanton@sina.com \
--cc=axboe@kernel.dk \
--cc=bigeasy@linutronix.de \
--cc=ionut.nechita@windriver.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=torvalds@linux-foundation.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