From: Valentin Schneider <valentin.schneider@arm.com>
To: Joel Fernandes <joel@joelfernandes.org>,
Thomas Gleixner <tglx@linutronix.de>
Cc: Alan Stern <stern@rowland.harvard.edu>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
rostedt <rostedt@goodmis.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
paulmck <paulmck@linux.ibm.com>,
Boqun Feng <boqun.feng@gmail.com>,
Will Deacon <will.deacon@arm.com>,
David Howells <dhowells@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 1/1] Fix: trace sched switch start/stop racy updates
Date: Fri, 16 Aug 2019 23:27:46 +0100 [thread overview]
Message-ID: <3c0cb8a2-eba2-7bea-8523-b948253a6804@arm.com> (raw)
In-Reply-To: <20190816205740.GF10481@google.com>
On 16/08/2019 21:57, Joel Fernandes wrote:
>> Can we finally put a foot down and tell compiler and standard committee
>> people to stop this insanity?
>
> Sure, or could the compilers provide flags which prevent such optimization
> similar to -O* flags?
>
How would you differentiate optimizations you want from those you don't with
just a flag? There's a reason we use volatile casts instead of declaring
everything volatile: we actually *want* those optimizations. It just so
happens that we don't want them *in some places*, and we have tools to tag
them as such.
The alternative is having a compiler that can magically correlate e.g. locked
writes with lock-free reads and properly handle them, but I don't think
there's a foolproof way of doing that.
> thanks,
>
> - Joel
>
next prev parent reply other threads:[~2019-08-16 22:27 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-18 10:29 WARNING in tracepoint_probe_register_prio (3) syzbot
2019-08-16 0:11 ` syzbot
2019-08-16 14:26 ` [PATCH 1/1] Fix: trace sched switch start/stop racy updates Mathieu Desnoyers
2019-08-16 16:25 ` Steven Rostedt
2019-08-16 16:48 ` Valentin Schneider
2019-08-16 17:04 ` Steven Rostedt
2019-08-16 17:41 ` Mathieu Desnoyers
2019-08-16 19:18 ` Steven Rostedt
2019-08-16 19:19 ` Alan Stern
2019-08-16 20:44 ` Joel Fernandes
2019-08-16 20:49 ` Thomas Gleixner
2019-08-16 20:57 ` Joel Fernandes
2019-08-16 22:27 ` Valentin Schneider [this message]
2019-08-16 22:57 ` Linus Torvalds
2019-08-17 1:41 ` Mathieu Desnoyers
2019-08-17 4:52 ` Paul E. McKenney
2019-08-17 8:28 ` Linus Torvalds
2019-08-17 8:44 ` Linus Torvalds
2019-08-17 15:02 ` Mathieu Desnoyers
2019-08-17 20:03 ` Valentin Schneider
2019-08-17 23:00 ` Paul E. McKenney
2019-08-19 10:34 ` Valentin Schneider
2019-08-17 22:28 ` Paul E. McKenney
2019-08-20 14:01 ` Peter Zijlstra
2019-08-20 20:31 ` Paul E. McKenney
2019-08-20 20:39 ` Peter Zijlstra
2019-08-20 20:52 ` Paul E. McKenney
2019-08-16 21:04 ` Linus Torvalds
2019-08-17 1:36 ` Mathieu Desnoyers
2019-08-17 2:13 ` Steven Rostedt
2019-08-17 14:40 ` Mathieu Desnoyers
2019-08-17 15:26 ` Steven Rostedt
2019-08-17 15:55 ` Mathieu Desnoyers
2019-08-17 16:40 ` Steven Rostedt
2019-08-17 22:06 ` Paul E. McKenney
2019-08-17 8:08 ` Linus Torvalds
2019-08-20 13:56 ` Peter Zijlstra
2019-08-20 20:29 ` Paul E. McKenney
2019-08-21 10:32 ` Will Deacon
2019-08-21 13:23 ` Paul E. McKenney
2019-08-21 13:32 ` Will Deacon
2019-08-21 13:56 ` Paul E. McKenney
2019-08-21 16:22 ` Will Deacon
2019-08-21 15:33 ` Peter Zijlstra
2019-08-21 15:48 ` Mathieu Desnoyers
2019-08-21 16:14 ` Paul E. McKenney
2019-08-21 19:03 ` Joel Fernandes
2019-09-09 6:21 ` Herbert Xu
2019-08-16 20:49 ` Steven Rostedt
2019-08-16 20:59 ` Joel Fernandes
2019-08-17 1:25 ` Mathieu Desnoyers
2019-08-18 9:15 ` stable markup was " Pavel Machek
2019-08-16 17:19 ` Mathieu Desnoyers
2019-08-16 19:15 ` Steven Rostedt
2019-08-17 14:27 ` Mathieu Desnoyers
2019-08-17 15:42 ` Steven Rostedt
2019-08-17 15:53 ` Mathieu Desnoyers
2019-08-17 16:43 ` Steven Rostedt
2019-08-16 12:32 ` WARNING in tracepoint_probe_register_prio (3) syzbot
2019-08-16 12:41 ` Sebastian Andrzej Siewior
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