From: Alan Stern <stern@rowland.harvard.edu>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-arch@vger.kernel.org>, <parri.andrea@gmail.com>,
<j.alglave@ucl.ac.uk>, <luc.maranget@inria.fr>,
<boqun.feng@gmail.com>, <will.deacon@arm.com>,
<peterz@infradead.org>, <npiggin@gmail.com>,
<dhowells@redhat.com>, <elena.reshetova@intel.com>,
<mhocko@suse.com>, <akiyks@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [GIT PULL tools] Linux kernel memory model
Date: Sat, 3 Feb 2018 17:10:06 -0500 (EST) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1802031708380.29515-100000@netrider.rowland.org> (raw)
In-Reply-To: <20180203084809.GE3617@linux.vnet.ibm.com>
On Sat, 3 Feb 2018, Paul E. McKenney wrote:
> Please see below for an initial patch to this effect. This activity
> proved to be more productive than expected for these tests, which certainly
> supports our assertion that locking needs more testing...
>
> MP+polocks.litmus
> MP+porevlocks.litmus
>
> These are allowed by the current model, which surprised me a bit,
> given that even powerpc would forbid them. Is the rationale
> that a lock-savvy compiler could pull accesses into the lock's
> critical section and then reorder those accesses? Or does this
> constitute a bug in our model of locking?
>
> (And these were allowed when I wrote recipes.txt, embarrassingly
> enough...)
>
> Z6.0+pooncelock+poonceLock+pombonce.litmus
>
> This was forbidden when I wrote recipes.txt, but now is allowed.
> The header comment for smp_mb__after_spinlock() makes it pretty
> clear that it must be forbidden. So this one is a bug in our
> model of locking.
I just tried testing these under the most recent version of herd, and
all three were forbidden.
Alan
next prev parent reply other threads:[~2018-02-03 22:10 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-25 9:34 [GIT PULL tools] Linux kernel memory model Paul E. McKenney
2018-01-29 6:57 ` Ingo Molnar
2018-01-29 9:54 ` Paul E. McKenney
2018-01-31 9:00 ` Ingo Molnar
2018-01-31 10:08 ` Peter Zijlstra
2018-01-31 23:53 ` Paul E. McKenney
2018-02-01 1:17 ` Paul E. McKenney
2018-02-01 6:57 ` Ingo Molnar
2018-02-01 23:14 ` Paul E. McKenney
2018-02-02 4:46 ` Boqun Feng
2018-02-02 5:40 ` Paul E. McKenney
2018-02-03 8:48 ` Paul E. McKenney
2018-02-03 22:10 ` Alan Stern [this message]
2018-02-04 9:16 ` Paul E. McKenney
2018-02-04 10:17 ` Paul E. McKenney
2018-02-04 16:29 ` Andrea Parri
2018-02-05 5:00 ` Paul E. McKenney
2018-02-04 16:37 ` Alan Stern
2018-02-05 7:19 ` Paul E. McKenney
2018-02-08 18:41 ` Patrick Bellasi
2018-02-08 20:02 ` Peter Zijlstra
2018-02-09 9:11 ` Andrea Parri
2018-02-09 11:29 ` Paul E. McKenney
2018-02-09 12:41 ` Andrea Parri
2018-02-09 12:56 ` Paul E. McKenney
2018-02-09 11:33 ` Paul E. McKenney
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