From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
"Luis Claudio R. Goncalves" <lgoncalv@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Boqun Feng <boqun.feng@gmail.com>, Ingo Molnar <mingo@redhat.com>,
John Ogness <john.ogness@linutronix.de>,
Mel Gorman <mgorman@techsingularity.net>,
Michal Hocko <mhocko@suse.com>,
Peter Zijlstra <peterz@infradead.org>,
Petr Mladek <pmladek@suse.com>,
Thomas Gleixner <tglx@linutronix.de>,
Waiman Long <longman@redhat.com>, Will Deacon <will@kernel.org>
Subject: Re: [PATCH v2 1/2] seqlock: Do the lockdep annotation before locking in do_write_seqcount_begin_nested()
Date: Mon, 26 Jun 2023 10:12:54 +0200 [thread overview]
Message-ID: <20230626081254.XmorFrhs@linutronix.de> (raw)
In-Reply-To: <d9b7c170-ed0d-5d37-e099-20d233115943@I-love.SAKURA.ne.jp>
On 2023-06-24 15:54:12 [+0900], Tetsuo Handa wrote:
> Why not to do the same on the end side?
>
> static inline void do_write_seqcount_end(seqcount_t *s)
> {
> - seqcount_release(&s->dep_map, _RET_IP_);
> do_raw_write_seqcount_end(s);
> + seqcount_release(&s->dep_map, _RET_IP_);
> }
I don't have a compelling argument for doing it. It is probably better
to release the lock from lockdep's point of view and then really release
it (so it can't be acquired before it is released).
Looking at other locking primitives (spin_lock_unlock(),
mutex_unlock(),…) that is what they do in the unlock path: lockdep
annotation followed by the actual operation. Therefore I would keep the
current ordering to remain in-sync with the other primitives.
Sebastian
next prev parent reply other threads:[~2023-06-26 8:13 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-23 17:12 [PATCH v2 0/2] seqlock,mm: lockdep annotation + write_seqlock_irqsave() Sebastian Andrzej Siewior
2023-06-23 17:12 ` [PATCH v2 1/2] seqlock: Do the lockdep annotation before locking in do_write_seqcount_begin_nested() Sebastian Andrzej Siewior
2023-06-24 6:54 ` Tetsuo Handa
2023-06-26 8:12 ` Sebastian Andrzej Siewior [this message]
2023-06-26 9:25 ` Tetsuo Handa
2023-06-26 10:48 ` Peter Zijlstra
2023-06-26 11:26 ` Tetsuo Handa
2023-06-26 11:35 ` Michal Hocko
2023-06-26 12:27 ` Tetsuo Handa
2023-06-26 13:16 ` Michal Hocko
2023-06-26 12:46 ` Sebastian Andrzej Siewior
2023-06-26 13:13 ` Sebastian Andrzej Siewior
2023-06-26 14:44 ` Petr Mladek
2023-06-28 12:14 ` Tetsuo Handa
2023-07-27 15:10 ` Sebastian Andrzej Siewior
2023-07-29 5:31 ` Tetsuo Handa
2023-07-29 11:05 ` Tetsuo Handa
2023-07-31 14:25 ` Michal Hocko
2023-08-03 13:18 ` Tetsuo Handa
2023-08-03 14:49 ` Michal Hocko
2023-08-04 13:27 ` Tetsuo Handa
2023-08-07 8:20 ` Michal Hocko
2023-06-26 12:56 ` Mel Gorman
2023-06-23 17:12 ` [PATCH v2 2/2] mm/page_alloc: Use write_seqlock_irqsave() instead write_seqlock() + local_irq_save() Sebastian Andrzej Siewior
2023-06-23 18:17 ` Michal Hocko
2023-06-23 20:15 ` [PATCH v3 " Sebastian Andrzej Siewior
2023-06-26 7:56 ` David Hildenbrand
2023-06-26 13:14 ` Mel Gorman
2023-06-28 13:56 ` Michal Hocko
2023-06-25 2:27 ` [PATCH v2 0/2] seqlock,mm: lockdep annotation + write_seqlock_irqsave() Tetsuo Handa
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