From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, rostedt@goodmis.org,
dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com,
oleg@redhat.com
Subject: Re: [PATCH tip/core/rcu 4/5] sys_membarrier: Add expedited option
Date: Thu, 27 Jul 2017 05:56:59 -0700 [thread overview]
Message-ID: <20170727125659.GO3730@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170727101426.gvbympkitoqyvfxj@hirez.programming.kicks-ass.net>
On Thu, Jul 27, 2017 at 12:14:26PM +0200, Peter Zijlstra wrote:
> On Tue, Jul 25, 2017 at 12:36:12PM -0700, Paul E. McKenney wrote:
> > This horse is already out, so trying to shut the gate won't be effective.
>
> So I'm not convinced it is. The mprotect() hack isn't portable as we've
> established and on x86 where it does work, it doesn't (much) perturb
> tasks not related to our process because we keep a tight mm_cpumask().
Wrong. People are using it today, portable or not. If we want them
to stop using it, we need to give them an alternative. Period.
> And if there are other (unpriv.) means of spraying IPIs around, we
> should most certainly look at fixing those, not just shrug and make
> matters worse.
We need to keep an open mind for a bit. If there was a trivial
solution, we would have implemented it back in 2010.
Thanx, Paul
next prev parent reply other threads:[~2017-07-27 12:57 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-24 21:57 [PATCH tip/core/rcu 0/5] Related non-RCU updates Paul E. McKenney
2017-07-24 21:58 ` [PATCH tip/core/rcu 1/5] module: Fix pr_fmt() bug for header use of printk Paul E. McKenney
2017-07-24 21:58 ` [PATCH tip/core/rcu 2/5] init_task: Remove redundant INIT_TASK_RCU_TREE_PREEMPT() macro Paul E. McKenney
2017-07-24 21:58 ` [PATCH tip/core/rcu 3/5] EXPERIMENTAL sched: Allow migrating kthreads into online but inactive CPUs Paul E. McKenney
2017-07-24 21:58 ` [PATCH tip/core/rcu 4/5] sys_membarrier: Add expedited option Paul E. McKenney
2017-07-25 4:27 ` Boqun Feng
2017-07-25 16:24 ` Paul E. McKenney
2017-07-25 13:21 ` Mathieu Desnoyers
2017-07-25 16:48 ` Paul E. McKenney
2017-07-25 16:33 ` Peter Zijlstra
2017-07-25 16:49 ` Paul E. McKenney
2017-07-25 16:59 ` Peter Zijlstra
2017-07-25 17:17 ` Paul E. McKenney
2017-07-25 18:53 ` Peter Zijlstra
2017-07-25 19:36 ` Paul E. McKenney
2017-07-25 20:24 ` Peter Zijlstra
2017-07-25 21:19 ` Paul E. McKenney
2017-07-25 21:55 ` Peter Zijlstra
2017-07-25 22:39 ` Mathieu Desnoyers
2017-07-25 22:50 ` Mathieu Desnoyers
2017-07-26 0:01 ` Paul E. McKenney
2017-07-26 7:46 ` Peter Zijlstra
2017-07-26 15:42 ` Paul E. McKenney
2017-07-26 18:01 ` Mathieu Desnoyers
2017-07-26 18:30 ` Paul E. McKenney
2017-07-26 20:37 ` Mathieu Desnoyers
2017-07-26 21:11 ` Paul E. McKenney
2017-07-27 1:45 ` Paul E. McKenney
2017-07-27 12:39 ` Mathieu Desnoyers
2017-07-27 14:44 ` Paul E. McKenney
2017-07-27 10:24 ` Peter Zijlstra
2017-07-27 14:52 ` Paul E. McKenney
2017-07-27 8:53 ` Peter Zijlstra
2017-07-27 10:09 ` Peter Zijlstra
2017-07-27 10:22 ` Will Deacon
2017-07-27 13:14 ` Paul E. McKenney
2017-07-25 23:59 ` Paul E. McKenney
2017-07-26 7:41 ` Peter Zijlstra
2017-07-26 15:41 ` Paul E. McKenney
2017-07-27 8:30 ` Peter Zijlstra
2017-07-27 13:08 ` Paul E. McKenney
2017-07-27 13:49 ` Peter Zijlstra
2017-07-27 14:32 ` Paul E. McKenney
2017-07-27 14:36 ` Peter Zijlstra
2017-07-27 14:46 ` Paul E. McKenney
2017-07-27 13:55 ` Boqun Feng
2017-07-27 14:16 ` Paul E. McKenney
2017-07-27 14:29 ` Boqun Feng
2017-07-27 14:36 ` Paul E. McKenney
2017-07-27 14:41 ` Will Deacon
2017-07-27 14:47 ` Boqun Feng
2017-07-27 14:55 ` Paul E. McKenney
2017-07-27 13:56 ` Peter Zijlstra
2017-07-27 15:19 ` Peter Zijlstra
2017-07-26 9:36 ` Will Deacon
2017-07-26 15:46 ` Paul E. McKenney
2017-07-27 10:14 ` Peter Zijlstra
2017-07-27 12:56 ` Paul E. McKenney [this message]
2017-07-27 13:37 ` Peter Zijlstra
2017-07-27 14:33 ` Paul E. McKenney
2017-07-24 21:58 ` [PATCH tip/core/rcu 5/5] EXP: sched/cputime: Fix using smp_processor_id() in preemptible Paul E. McKenney
2017-07-24 22:01 ` Wanpeng Li
2017-07-24 22:29 ` Paul E. McKenney
2017-07-31 22:51 ` [PATCH tip/core/rcu 0/5] Related non-RCU updates Paul E. McKenney
2017-07-31 22:53 ` [PATCH v2 tip/core/rcu 1/4] module: Fix pr_fmt() bug for header use of printk Paul E. McKenney
2017-07-31 22:53 ` [PATCH v2 tip/core/rcu 2/4] init_task: Remove redundant INIT_TASK_RCU_TREE_PREEMPT() macro Paul E. McKenney
2017-07-31 22:53 ` [PATCH v2 tip/core/rcu 3/4] sched: Allow migrating kthreads into online but inactive CPUs Paul E. McKenney
2017-07-31 22:53 ` [PATCH v2 tip/core/rcu 4/4] membarrier: Expedited private command Paul E. McKenney
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