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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>,
	Andrea Parri <andrea.parri@amarulasolutions.com>,
	Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org,
	Andrea Parri <parri.andrea@gmail.com>,
	Alan Stern <stern@rowland.harvard.edu>,
	Will Deacon <will.deacon@arm.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	Nicholas Piggin <npiggin@gmail.com>,
	Jade Alglave <j.alglave@ucl.ac.uk>,
	Luc Maranget <luc.maranget@inria.fr>,
	Akira Yokosawa <akiyks@gmail.com>
Subject: Re: [PATCH v2 1/3] locking: Document the semantics of spin_is_locked()
Date: Tue, 3 Apr 2018 09:11:34 -0700	[thread overview]
Message-ID: <20180403161134.GA31898@linux.vnet.ibm.com> (raw)
In-Reply-To: <20180403150356.GJ3948@linux.vnet.ibm.com>

On Tue, Apr 03, 2018 at 08:03:56AM -0700, Paul E. McKenney wrote:
> On Tue, Apr 03, 2018 at 04:43:00PM +0200, Peter Zijlstra wrote:
> > On Tue, Apr 03, 2018 at 07:17:18AM -0700, Paul E. McKenney wrote:
> > > Suggestions for a fix?  Clearly great care is required when using it
> > > in things like WARN_ON()...
> > 
> > Yeah, don't use it there, use lockdep_assert_held().
> 
> Good point, -ETOOEARLY.  ;-)
> 
> > As I stated before in this thread, ideally we'd make *_is_locked() go
> > away entirely.
> 
> After being reminded of the issues on UP systems, I now have much more
> sympathy for that view...

And so the main remaining use case is debug prints on !PROVE_LOCKING
builds.  Which need some thought about the UP case.

Or am I missing something here?

							Thanx, Paul

  reply	other threads:[~2018-04-03 16:11 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-01 16:41 [PATCH v3 0/3] Changes, clean-ups and documentation for spin_is_locked() Andrea Parri
2018-04-01 16:41 ` [PATCH v2 1/3] locking: Document the semantics of spin_is_locked() Andrea Parri
2018-04-02 14:03   ` Alan Stern
2018-04-02 19:35     ` Paul E. McKenney
2018-04-03 12:49   ` David Howells
2018-04-03 13:35     ` Andrea Parri
2018-04-03 13:52       ` David Howells
2018-04-03 14:07         ` Andrea Parri
2018-04-03 15:23           ` David Howells
2018-04-03 19:31             ` Andrea Parri
2018-04-03 20:04               ` Alan Stern
2018-04-03 21:43                 ` David Howells
2018-04-03 21:47                   ` Randy Dunlap
2018-04-04 21:22                     ` David Howells
2018-04-04 12:47                   ` Andrea Parri
2018-04-03 14:17         ` Paul E. McKenney
2018-04-03 14:43           ` Peter Zijlstra
2018-04-03 15:03             ` Paul E. McKenney
2018-04-03 16:11               ` Paul E. McKenney [this message]
2018-04-05  7:47     ` Christoph Hellwig
2018-04-05  8:56       ` Andrea Parri
2018-04-06 19:47   ` [PATCH v4 " Andrea Parri
2018-04-06 21:00     ` Paul E. McKenney
2018-04-06 21:01     ` Randy Dunlap
2018-04-06 21:07       ` Paul E. McKenney
2018-04-06 21:08         ` Randy Dunlap
2018-04-06 21:58           ` Andrea Parri
2018-04-08 21:14             ` Paul E. McKenney
2018-04-08 21:32               ` Randy Dunlap
2018-04-08 22:00                 ` Paul E. McKenney
2018-04-01 16:41 ` [PATCH v3 2/3] arm64: Remove smp_mb() from arch_spin_is_locked() Andrea Parri
2018-04-01 16:41 ` [PATCH v3 3/3] locking: Clean up comment and #ifndef for {,queued_}spin_is_locked() Andrea Parri
2018-04-01 18:24 ` [PATCH v3 0/3] Changes, clean-ups and documentation for spin_is_locked() Paul E. McKenney

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