From: Andrea Parri <parri.andrea@gmail.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: "Paul E. McKenney" <paulmck@kernel.org>,
Jonas Oberhauser <jonas.oberhauser@huawei.com>,
will@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, dlustig@nvidia.com,
joel@joelfernandes.org, urezki@gmail.com,
quic_neeraju@quicinc.com, frederic@kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] tools/memory-model: Make ppo a subrelation of po
Date: Mon, 27 Feb 2023 20:40:00 +0100 [thread overview]
Message-ID: <Y/0HEESX2wDWtPS1@andrea> (raw)
In-Reply-To: <Y/rEH2r9i0BtfxEW@rowland.harvard.edu>
> The LKMM doesn't believe that a control or data dependency orders a
> plain write after a marked read. Hence in this test it thinks that P1's
> store to u0 can happen before the load of x1. I don't remember why we
> did it this way -- probably we just wanted to minimize the restrictions
> on when plain accesses can execute. (I do remember the reason for
> making address dependencies induce order; it was so RCU would work.)
>
> The patch below will change what the LKMM believes. It eliminates the
> positive outcome of the litmus test and the data race. Should it be
> adopted into the memory model?
(Unpopular opinion I know,) it should drop dependencies ordering, not
add/promote it.
Andrea
next prev parent reply other threads:[~2023-02-27 19:40 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-24 13:52 [PATCH v3] tools/memory-model: Make ppo a subrelation of po Jonas Oberhauser
2023-02-24 15:32 ` Alan Stern
2023-02-24 18:37 ` Paul E. McKenney
2023-02-26 1:01 ` Paul E. McKenney
2023-02-26 2:29 ` Alan Stern
2023-02-26 3:03 ` Paul E. McKenney
2023-02-26 18:49 ` Paul E. McKenney
2023-02-26 3:09 ` Boqun Feng
2023-02-26 3:30 ` Alan Stern
2023-02-26 11:17 ` Jonas Oberhauser
2023-02-26 16:51 ` Alan Stern
2023-02-26 18:45 ` Paul E. McKenney
2023-02-26 19:32 ` Alan Stern
2023-02-27 14:03 ` Jonas Oberhauser
2023-02-27 16:16 ` Alan Stern
2023-02-27 16:50 ` Jonas Oberhauser
2023-02-27 18:41 ` Alan Stern
2023-02-27 19:40 ` Andrea Parri [this message]
2023-02-27 20:13 ` Jonas Oberhauser
2023-02-27 22:21 ` Paul E. McKenney
2023-02-28 8:49 ` Jonas Oberhauser
2023-02-28 15:40 ` Paul E. McKenney
2023-03-01 10:52 ` Jonas Oberhauser
2023-03-02 1:42 ` Paul E. McKenney
2023-02-26 2:58 ` Paul E. McKenney
2023-02-26 16:23 ` Joel Fernandes
2023-02-27 14:39 ` Jonas Oberhauser
2023-02-27 17:57 ` Joel Fernandes
2023-02-27 20:24 ` Jonas Oberhauser
2023-02-27 19:35 ` Andrea Parri
2023-02-28 22:01 ` Paul E. McKenney
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