From: Tejun Heo <tj@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: axboe@kernel.dk, josef@toxicpanda.com,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] blkcg: Drop unnecessary RCU read [un]locks from blkg_conf_prep/finish()
Date: Tue, 10 Jan 2023 08:24:08 -1000 [thread overview]
Message-ID: <Y72tSI0eQky7Tr42@slm.duckdns.org> (raw)
In-Reply-To: <20230110064900.GA10277@lst.de>
Hello,
On Tue, Jan 10, 2023 at 07:49:00AM +0100, Christoph Hellwig wrote:
> On Mon, Jan 09, 2023 at 10:48:55AM -1000, Tejun Heo wrote:
> > Now that all RCU flavors have been combined, holding a spin lock, disabling
> > irq, disabling preemption all imply RCU read lock.
>
> Can you write it like this in the commit log, please?
Sure, will do.
> > I can drop the changes but this actually bothers me. The annotation has been
> > broken for a *long* time and nobody noticed. Furthermore, I can't remember a
> > time when __acquires/__releases notation caught anything that lockdep
> > couldn't trivially and can't even think of a way how it could. AFAICS, these
> > annotations don't contribute anything other than preservation of themselves.
> > I don't see why we would want to keep them.
>
> People have noticed it. It just hasn't been a priority as there are
> lots of even more problematic things.
That doesn't really shed a positive light on them, does it? I'll drop this
part but can you think of actual reasons to keep these around other than to
keep sparse happy? I'm genuninely curious and have asked several people.
Nobody had a good answer.
Thanks.
--
tejun
next prev parent reply other threads:[~2023-01-10 18:29 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-05 21:24 [PATCHSET v2 block/for-next] blkcg: Improve blkg config helpers and make iolatency init lazy Tejun Heo
2023-01-05 21:24 ` [PATCH 1/4] blkcg: Drop unnecessary RCU read [un]locks from blkg_conf_prep/finish() Tejun Heo
2023-01-08 17:02 ` Christoph Hellwig
2023-01-09 20:48 ` Tejun Heo
2023-01-10 6:49 ` Christoph Hellwig
2023-01-10 18:24 ` Tejun Heo [this message]
2023-01-05 21:24 ` [PATCH 2/4] blkcg: Restructure blkg_conf_prep() and friends Tejun Heo
2023-01-10 7:09 ` Christoph Hellwig
2023-01-10 18:33 ` Tejun Heo
2023-01-05 21:24 ` [PATCH 3/4] blk-iolatency: s/blkcg_rq_qos/iolat_rq_qos/ Tejun Heo
2023-01-10 7:09 ` Christoph Hellwig
2023-01-05 21:24 ` [PATCH 4/4] blk-iolatency: Make initialization lazy Tejun Heo
2023-01-10 7:10 ` Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2023-04-13 0:06 [PATCHSET v4 block/for-next] blkcg: Improve blkg config helpers and make iolatency init lazy Tejun Heo
2023-04-13 0:06 ` [PATCH 1/4] blkcg: Drop unnecessary RCU read [un]locks from blkg_conf_prep/finish() Tejun Heo
2023-04-13 4:59 ` Christoph Hellwig
2023-01-10 22:27 [PATCHSET v3 block/for-next] blkcg: Improve blkg config helpers and make iolatency init lazy Tejun Heo
2023-01-10 22:27 ` [PATCH 1/4] blkcg: Drop unnecessary RCU read [un]locks from blkg_conf_prep/finish() Tejun Heo
2023-01-05 0:20 [PATCHSET block/for-next] blkcg: Improve blkg config helpers and make iolatency init lazy Tejun Heo
2023-01-05 0:20 ` [PATCH 1/4] blkcg: Drop unnecessary RCU read [un]locks from blkg_conf_prep/finish() Tejun Heo
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