From: Andrea Parri <andrea.parri@amarulasolutions.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Andrea Parri <parri.andrea@gmail.com>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
mingo@kernel.org, stern@rowland.harvard.edu, will.deacon@arm.com,
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 3/7] EXP tools/memory-model: Add more LKMM limitations
Date: Fri, 31 Aug 2018 11:43:42 +0200 [thread overview]
Message-ID: <20180831094341.GA4634@andrea> (raw)
Message-ID: <20180831094342.7YoOtV90egwojagfMUPsEOyCJ2jaygDC72ga3MxRUZw@z> (raw)
In-Reply-To: <20180830221814.GQ4225@linux.vnet.ibm.com>
> > > + b. The "unless" RMW operations are not currently modeled:
> > > + atomic_long_add_unless(), atomic_add_unless(),
> > > + atomic_inc_unless_negative(), and
> > > + atomic_dec_unless_positive(). These can be emulated
> > > + in litmus tests, for example, by using atomic_cmpxchg().
> >
> > There is a prototype atomic_add_unless(): with current herd7,
> >
> > $ cat atomic_add_unless.litmus
> > C atomic_add_unless
> >
> > {}
> >
> > P0(atomic_t *u, atomic_t *v)
> > {
> > int r0;
> > int r1;
> >
> > r0 = atomic_add_unless(u, 1, 2);
> > r1 = atomic_read(v);
> > }
> >
> > P1(atomic_t *u, atomic_t *v)
> > {
> > int r0;
> > int r1;
> >
> > r0 = atomic_add_unless(v, 1, 2);
> > r1 = atomic_read(u);
> > }
> >
> > exists (0:r1=0 /\ 1:r1=0)
> >
> > $ herd7 -conf linux-kernel.cfg atomic_add_unless.litmus
> > Test atomic_add_unless Allowed
> > States 3
> > 0:r1=0; 1:r1=1;
> > 0:r1=1; 1:r1=0;
> > 0:r1=1; 1:r1=1;
> > No
> > Witnesses
> > Positive: 0 Negative: 3
> > Condition exists (0:r1=0 /\ 1:r1=0)
> > Observation atomic_add_unless Never 0 3
> > Time atomic_add_unless 0.00
> > Hash=fa37a2359831690299e4cc394e45d966
> >
> > The last commit in the herdtools7 repo. related to this implementation
> > (AFAICT) is:
> >
> > 9523c340917b6a ("herd/linux: make atomic_add_unless a primitive, so as to yield more precise dependencies for the returned boolean.")
> >
> > but I can only vaguely remember those dependencies issues now :/ ...;
> > maybe we can now solve these issues? or should we change herd7 to re-
> > turn a warning? (Notice that this primitive is currently not exported
> > to the linux-kernel.def file.)
>
> Cool! It would be good to add this to the .def file once the underlying
> herd7 machinery is ready. And then I would update the documentation
> accordingly. Or happily accept a patch updating the documentation,
> as the case might be. ;-)
Fair enough, ;-) Please feel free to add:
Reviewed-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Andrea
next prev parent reply other threads:[~2018-08-31 13:50 UTC|newest]
Thread overview: 112+ 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 ` 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
2018-08-29 21:10 ` Paul E. McKenney
2018-08-30 12:50 ` Andrea Parri
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 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 16:06 ` Will Deacon
2018-08-31 18:28 ` Andrea Parri
2018-08-31 18:28 ` Andrea Parri
2018-09-03 9:01 ` Andrea Parri
2018-09-03 9:01 ` Andrea Parri
2018-09-03 17:04 ` Will Deacon
2018-09-03 17:04 ` Will Deacon
2018-09-04 8:11 ` Andrea Parri
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 7:21 ` Andrea Parri
2018-09-05 14:33 ` Akira Yokosawa
2018-09-05 14:33 ` Akira Yokosawa
2018-09-05 14:53 ` Paul E. McKenney
2018-09-05 14:53 ` Paul E. McKenney
2018-09-05 15:00 ` Andrea Parri
2018-09-05 15:00 ` Andrea Parri
2018-09-05 15:04 ` Akira Yokosawa
2018-09-05 15:04 ` Akira Yokosawa
2018-09-05 15:24 ` Andrea Parri
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
2018-09-03 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
2018-09-06 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 16:09 ` 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
2018-09-08 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
2018-09-11 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 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 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
2018-09-15 3:56 ` Paul E. McKenney
2018-09-03 17:05 ` [PATCH RFC LKMM 1/7] " Will Deacon
2018-09-03 17:05 ` Will Deacon
2018-08-31 17:55 ` Andrea Parri
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
2018-08-29 21:10 ` Paul E. McKenney
2018-09-14 16:59 ` Will Deacon
2018-09-14 16:59 ` Will Deacon
2018-09-14 18:20 ` Paul E. McKenney
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
2018-08-29 21:10 ` Paul E. McKenney
2018-08-30 9:17 ` Andrea Parri
2018-08-30 9:17 ` Andrea Parri
2018-08-30 22:18 ` Paul E. McKenney
2018-08-30 22:18 ` Paul E. McKenney
2018-08-31 9:43 ` Andrea Parri [this message]
2018-08-31 9:43 ` Andrea Parri
2018-09-06 18:34 ` Paul E. McKenney
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 ` 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 ` 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 ` 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
2018-08-29 21:10 ` Paul E. McKenney
2018-08-31 16:06 ` Will Deacon
2018-08-31 16:06 ` Will Deacon
2018-09-01 17:08 ` Paul E. McKenney
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 16:36 ` 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
2018-09-14 18:29 ` Paul E. McKenney
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