From: Will Deacon <will.deacon@arm.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
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: Wed, 26 Jul 2017 10:36:46 +0100 [thread overview]
Message-ID: <20170726093645.GA2115@arm.com> (raw)
In-Reply-To: <20170725211926.GA3730@linux.vnet.ibm.com>
On Tue, Jul 25, 2017 at 02:19:26PM -0700, Paul E. McKenney wrote:
> Some architectures are less precise than others in tracking which
> CPUs are running a given process due to ASIDs, though this is
> thought to be a non-problem:
>
> https://marc.info/?l=linux-arch&m=126716090413065&w=2
> https://marc.info/?l=linux-arch&m=126716262815202&w=2
>
> Thoughts?
On arm64, we *never* touch mm_cpumask, so it will always be empty. The only
thing we could potentially use it for is non-broadcast TLB invalidation if
the mm was only active on a single CPU, but when I implemented that we
pretty much never hit that case. I was hoping fork()+exec() would trigger it
(e.g. scripts), but the scheduler treats both of those as rebalancing points
so the temporary ASID before the exec always has two CPUs set in its mask.
Will
next prev parent reply other threads:[~2017-07-26 9:36 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 [this message]
2017-07-26 15:46 ` Paul E. McKenney
2017-07-27 10:14 ` Peter Zijlstra
2017-07-27 12:56 ` Paul E. McKenney
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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