From: Andrea Parri <andrea.parri@amarulasolutions.com>
To: Will Deacon <will.deacon@arm.com>
Cc: Alan Stern <stern@rowland.harvard.edu>,
Andrea Parri <parri.andrea@gmail.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
mingo@kernel.org, peterz@infradead.org, boqun.feng@gmail.com,
npiggin@gmail.com, dhowells@redhat.com, j.alglave@ucl.ac.uk,
luc.maranget@inria.fr, akiyks@gmail.com
Subject: Re: [PATCH RFC LKMM 1/7] tools/memory-model: Add extra ordering for locks and remove it for ordinary release/acquire
Date: Fri, 31 Aug 2018 20:28:46 +0200 [thread overview]
Message-ID: <20180831182845.GA4673@andrea> (raw)
In-Reply-To: <20180831160640.GG30626@arm.com>
> > Yes, it's true that implementing locks with atomic_cmpxchg_acquire
> > should be correct on all existing architectures. And Paul has invited
> > a patch to modify the LKMM accordingly. If you feel that such a change
> > would be a useful enhancement to the LKMM's applicability, please write
> > it.
>
> Yes, please! That would be the "RmW" discussion which Andrea partially
> quoted earlier on, so getting that going independently from this patch
> sounds like a great idea to me.
That was indeed one of the proposal we discussed. As you recalled, that
proposal only covered RmWs load-acquire (and ordinary store-release); in
particular, I realized that comments such as:
"The atomic_cond_read_acquire() call above has provided the
necessary acquire semantics required for locking."
[from kernel/locking/qspinlock.c]
(for example) would still _not have "generic validity" _if we added the
above po-unlock-rf-lock-po term... (which, again, makes me somehow uncon-
fortable); Would to have _all_ the acquire be admissible for you?
Andrea
>
> Cheers,
>
> Will
next prev parent reply other threads:[~2018-08-31 18:28 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-29 21:10 [PATCH RFC memory-model 0/7] Memory-model changes Paul E. McKenney
2018-08-29 21:10 ` [PATCH RFC LKMM 1/7] tools/memory-model: Add extra ordering for locks and remove it for ordinary release/acquire Paul E. McKenney
2018-08-30 12:50 ` Andrea Parri
2018-08-30 21:31 ` Alan Stern
2018-08-30 21:31 ` Alan Stern
2018-08-31 9:17 ` Andrea Parri
2018-08-31 14:52 ` Alan Stern
2018-08-31 14:52 ` Alan Stern
2018-08-31 16:06 ` Will Deacon
2018-08-31 18:28 ` Andrea Parri [this message]
2018-09-03 9:01 ` Andrea Parri
2018-09-03 17:04 ` Will Deacon
2018-09-04 8:11 ` Andrea Parri
2018-09-04 19:09 ` Alan Stern
2018-09-04 19:09 ` Alan Stern
2018-09-05 7:21 ` Andrea Parri
2018-09-05 14:33 ` Akira Yokosawa
2018-09-05 14:53 ` Paul E. McKenney
2018-09-05 15:00 ` Andrea Parri
2018-09-05 15:04 ` Akira Yokosawa
2018-09-05 15:24 ` Andrea Parri
2018-09-03 17:52 ` Alan Stern
2018-09-03 17:52 ` Alan Stern
2018-09-03 18:28 ` Andrea Parri
2018-09-06 1:25 ` Alan Stern
2018-09-06 1:25 ` Alan Stern
2018-09-06 9:36 ` Andrea Parri
2018-09-07 16:00 ` Alan Stern
2018-09-07 16:00 ` Alan Stern
2018-09-07 16:09 ` Will Deacon
2018-09-07 16:39 ` Daniel Lustig
2018-09-07 16:39 ` Daniel Lustig
2018-09-07 17:38 ` Alan Stern
2018-09-07 17:38 ` Alan Stern
2018-09-08 0:04 ` Daniel Lustig
2018-09-08 0:04 ` Daniel Lustig
2018-09-08 9:58 ` Andrea Parri
2018-09-11 19:31 ` Alan Stern
2018-09-11 19:31 ` Alan Stern
2018-09-11 20:03 ` Paul E. McKenney
2018-09-12 14:24 ` Alan Stern
2018-09-12 14:24 ` Alan Stern
2018-09-13 17:07 ` Alan Stern
2018-09-13 17:07 ` Alan Stern
2018-09-14 14:37 ` Andrea Parri
2018-09-14 16:29 ` Alan Stern
2018-09-14 16:29 ` Alan Stern
2018-09-14 19:44 ` Andrea Parri
2018-09-14 21:08 ` [PATCH v5] " Alan Stern
2018-09-14 21:08 ` Alan Stern
2018-09-15 3:56 ` Paul E. McKenney
2018-09-03 17:05 ` [PATCH RFC LKMM 1/7] " Will Deacon
2018-08-31 17:55 ` Andrea Parri
2018-08-29 21:10 ` [PATCH RFC LKMM 2/7] doc: Replace smp_cond_acquire() with smp_cond_load_acquire() Paul E. McKenney
2018-09-14 16:59 ` Will Deacon
2018-09-14 18:20 ` Paul E. McKenney
2018-08-29 21:10 ` [PATCH RFC LKMM 3/7] EXP tools/memory-model: Add more LKMM limitations Paul E. McKenney
2018-08-30 9:17 ` Andrea Parri
2018-08-30 22:18 ` Paul E. McKenney
2018-08-31 9:43 ` Andrea Parri
2018-09-06 18:34 ` Paul E. McKenney
2018-08-29 21:10 ` [PATCH RFC LKMM 4/7] tools/memory-model: Fix a README typo Paul E. McKenney
2018-08-29 21:10 ` [PATCH RFC LKMM 5/7] EXP tools/memory-model: Add scripts to check github litmus tests Paul E. McKenney
2018-08-29 21:10 ` [PATCH RFC LKMM 6/7] EXP tools/memory-model: Make scripts take "-j" abbreviation for "--jobs" Paul E. McKenney
2018-08-29 21:10 ` [PATCH RFC LKMM 7/7] EXP tools/memory-model: Add .cfg and .cat files for s390 Paul E. McKenney
2018-08-31 16:06 ` Will Deacon
2018-09-01 17:08 ` Paul E. McKenney
2018-09-14 16:36 ` [PATCH RFC memory-model 0/7] Memory-model changes Paul E. McKenney
2018-09-14 17:19 ` Alan Stern
2018-09-14 17:19 ` Alan Stern
2018-09-14 18:29 ` Paul E. McKenney
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