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From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: paulmck <paulmck@kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>,
	rcu <rcu@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	kernel-team <kernel-team@fb.com>, Ingo Molnar <mingo@kernel.org>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	dipankar <dipankar@in.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Josh Triplett <josh@joshtriplett.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	rostedt <rostedt@goodmis.org>,
	David Howells <dhowells@redhat.com>,
	Eric Dumazet <edumazet@google.com>, fweisbec <fweisbec@gmail.com>,
	Oleg Nesterov <oleg@redhat.com>,
	"Joel Fernandes, Google" <joel@joelfernandes.org>
Subject: Re: [PATCH RFC tip/core/rcu 0/16] Prototype RCU usable from idle, exception, offline
Date: Sun, 15 Mar 2020 13:45:05 -0400 (EDT)	[thread overview]
Message-ID: <2062731308.28584.1584294305768.JavaMail.zimbra@efficios.com> (raw)
In-Reply-To: <20200313154243.GU3199@paulmck-ThinkPad-P72>

----- On Mar 13, 2020, at 11:42 AM, paulmck paulmck@kernel.org wrote:

> On Fri, Mar 13, 2020 at 03:41:46PM +0100, Frederic Weisbecker wrote:
>> On Thu, Mar 12, 2020 at 11:16:18AM -0700, Paul E. McKenney wrote:
>> > Hello!
>> > 
>> > This series provides two variants of Tasks RCU, a rude variant inspired
>> > by Steven Rostedt's use of schedule_on_each_cpu(), and a tracing variant
>> > requested by the BPF folks and perhaps also of use for other tracing
>> > use cases.
>> > 
>> > The tracing variant has explicit read-side markers to permit finite grace
>> > periods even given in-kernel loops in PREEMPT=n builds It also protects
>> > code in the idle loop, on exception entry/exit paths, and on the various
>> > CPU-hotplug online/offline code paths, thus having protection properties
>> > similar to SRCU.  However, unlike SRCU, this variant avoids expensive
>> > instructions in the read-side primitives, thus having read-side overhead
>> > similar to that of preemptible RCU.
>> > 
>> > There are of course downsides.  The grace-period code can send IPIs to
>> > CPUs, even when those CPUs are in the idle loop or in nohz_full userspace.
>> > It is necessary to scan the full tasklist, much as for Tasks RCU.  There
>> > is a single callback queue guarded by a single lock, again, much as for
>> > Tasks RCU.  If needed, these downsides can be at least partially remedied
>> 
>> So what we trade to fix the issues we are having with tracing against extended
>> grace periods, we lose in CPU isolation. That worries me a bit as tracing can
>> be thoroughly used with nohz_full and CPU isolation.
> 
> First, disturbing nohz_full CPUs can be avoided by the sysadm simply
> refusing to remove tracepoints while sensitive applications are running
> on nohz_full CPUs.

I doubt this approach will survive real-life.

> 
> Second, for non-CPU-bound real-time programs with mostly-idle CPUs,
> I should be able to decrease the likelihood of sending IPIs pretty much
> to zero.
> 
> Or am I missing something here?

I would recommend considering the following alternative for this tracing-rcu
flavor:

- For all CPUs which are not nohz_full:
  - Implement fast RCU read-side which only requires compiler barriers,
  - Use IPIs to each of those CPUs when doing a grace period.

- For all nohz_full CPUS:
  - Dynamically detect CPUs which are nohz_full,
  - Implement slower RCU read-side with memory barriers,
  - No need to issue any IPI to those CPUs when doing the grace period.

This should cover all use-cases: staying fast for the common case, without
disturbing RT workloads.

Thoughts ?

Thanks,

Mathieu




-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

  reply	other threads:[~2020-03-15 17:45 UTC|newest]

Thread overview: 171+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-12 18:16 [PATCH RFC tip/core/rcu 0/16] Prototype RCU usable from idle, exception, offline Paul E. McKenney
2020-03-12 18:16 ` [PATCH RFC tip/core/rcu 01/16] sched/core: Add function to sample state of non-running function paulmck
2020-03-12 18:16 ` [PATCH RFC tip/core/rcu 02/16] rcu: Add per-task state to RCU CPU stall warnings paulmck
2020-03-12 18:16 ` [PATCH RFC tip/core/rcu 03/16] rcutorture: Add flag to produce non-busy-wait task stalls paulmck
2020-03-12 18:16 ` [PATCH RFC tip/core/rcu 04/16] rcu-tasks: Move Tasks RCU to its own file paulmck
2020-03-12 18:16 ` [PATCH RFC tip/core/rcu 05/16] rcu-tasks: Create struct to hold state information paulmck
2020-03-12 18:16 ` [PATCH RFC tip/core/rcu 06/16] rcu: Reinstate synchronize_rcu_mult() paulmck
2020-03-12 18:16 ` [PATCH RFC tip/core/rcu 07/16] rcutorture: Add a test for synchronize_rcu_mult() paulmck
2020-03-12 18:16 ` [PATCH RFC tip/core/rcu 08/16] rcu-tasks: Refactor RCU-tasks to allow variants to be added paulmck
2020-03-12 18:16 ` [PATCH RFC tip/core/rcu 09/16] rcu-tasks: Add an RCU-tasks rude variant paulmck
2020-03-16 19:47   ` Joel Fernandes
2020-03-16 20:17     ` Joel Fernandes
2020-03-16 20:32       ` Paul E. McKenney
2020-03-16 21:32         ` Steven Rostedt
2020-03-16 21:45           ` Joel Fernandes
2020-03-16 22:03             ` Steven Rostedt
2020-03-16 22:11               ` Paul E. McKenney
2020-05-10  9:59               ` Lai Jiangshan
2020-05-10 15:49                 ` Paul E. McKenney
2020-05-11  0:06                   ` Lai Jiangshan
2020-05-11  2:44                     ` Paul E. McKenney
2020-05-11  0:44                 ` Masami Hiramatsu
2020-05-11 16:07                 ` Steven Rostedt
2020-05-11 19:48                 ` Steven Rostedt
2020-03-16 20:29     ` Paul E. McKenney
2020-03-12 18:16 ` [PATCH RFC tip/core/rcu 10/16] rcutorture: Add torture tests for RCU Tasks Rude paulmck
2020-03-12 18:16 ` [PATCH RFC tip/core/rcu 11/16] rcu-tasks: Use unique names for RCU-Tasks kthreads and messages paulmck
2020-03-12 18:16 ` [PATCH RFC tip/core/rcu 12/16] rcu-tasks: Further refactor RCU-tasks to allow adding more variants paulmck
2020-03-12 18:16 ` [PATCH RFC tip/core/rcu 13/16] rcu-tasks: Code movement to allow more Tasks RCU variants paulmck
2020-03-12 18:17 ` [PATCH RFC tip/core/rcu 14/16] rcu: Add an RCU Tasks Trace to simplify protection of tracing hooks paulmck
2020-03-12 18:17 ` [PATCH RFC tip/core/rcu 15/16] rcutorture: Add torture tests for RCU Tasks Trace paulmck
2020-03-12 18:17 ` [PATCH RFC tip/core/rcu 16/16] rcu-tasks: Add stall warnings " paulmck
2020-03-13 14:41 ` [PATCH RFC tip/core/rcu 0/16] Prototype RCU usable from idle, exception, offline Frederic Weisbecker
2020-03-13 15:42   ` Paul E. McKenney
2020-03-15 17:45     ` Mathieu Desnoyers [this message]
2020-03-15 17:59       ` Paul E. McKenney
2020-03-16 18:36         ` Steven Rostedt
2020-03-16 18:52           ` Paul E. McKenney
2020-03-16 14:45     ` Frederic Weisbecker
2020-03-16 15:39       ` Paul E. McKenney
2020-03-19  0:10 ` [PATCH RFC v2 tip/core/rcu 0/22] " Paul E. McKenney
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 01/22] sched/core: Add function to sample state of locked-down task paulmck
2020-03-19 17:22     ` Steven Rostedt
2020-03-19 17:35       ` Paul E. McKenney
2020-03-20  2:49         ` Paul E. McKenney
2020-03-20  3:09           ` Steven Rostedt
2020-03-20 16:27             ` Paul E. McKenney
2020-03-24  0:06           ` Joel Fernandes
2020-03-24  0:15             ` Joel Fernandes
2020-03-24 16:26               ` Paul E. McKenney
2020-03-24 15:48             ` Paul E. McKenney
2020-03-24 16:52               ` Joel Fernandes
2020-03-24 17:20                 ` Paul E. McKenney
2020-03-24 18:19                   ` Joel Fernandes
2020-03-25  0:58                     ` Paul E. McKenney
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 02/22] rcu: Add per-task state to RCU CPU stall warnings paulmck
2020-03-19 17:27     ` Steven Rostedt
2020-03-19 17:41       ` Paul E. McKenney
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 03/22] rcutorture: Add flag to produce non-busy-wait task stalls paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 04/22] rcu-tasks: Move Tasks RCU to its own file paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 05/22] rcu-tasks: Create struct to hold state information paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 06/22] rcu: Reinstate synchronize_rcu_mult() paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 07/22] rcutorture: Add a test for synchronize_rcu_mult() paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 08/22] rcu-tasks: Refactor RCU-tasks to allow variants to be added paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 09/22] rcu-tasks: Add an RCU-tasks rude variant paulmck
2020-03-19 19:04     ` Steven Rostedt
2020-03-19 23:58       ` Paul E. McKenney
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 10/22] rcutorture: Add torture tests for RCU Tasks Rude paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 11/22] rcu-tasks: Use unique names for RCU-Tasks kthreads and messages paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 12/22] rcu-tasks: Further refactor RCU-tasks to allow adding more variants paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 13/22] rcu-tasks: Code movement to allow more Tasks RCU variants paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 14/22] rcu-tasks: Add an RCU Tasks Trace to simplify protection of tracing hooks paulmck
2020-03-19  1:37     ` Joel Fernandes
2020-03-19  1:58       ` Joel Fernandes
2020-03-19  3:40         ` Paul E. McKenney
2020-03-19 19:42     ` Steven Rostedt
2020-03-20  0:28       ` Paul E. McKenney
2020-03-20  0:48         ` Steven Rostedt
2020-03-20  2:41           ` Paul E. McKenney
2020-03-28 14:06             ` Joel Fernandes
2020-03-28 15:34               ` Paul E. McKenney
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 15/22] rcutorture: Add torture tests for RCU Tasks Trace paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 16/22] rcu-tasks: Add stall warnings " paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 17/22] rcu-tasks: Move #ifdef into tasks.h paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 18/22] rcu-tasks: Add RCU tasks to rcutorture writer stall output paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 19/22] rcu-tasks: Make rcutorture writer stall output include GP state paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 20/22] rcu-tasks: Make RCU Tasks Trace make use of RCU scheduler hooks paulmck
2020-03-19  0:10   ` [PATCH RFC v2 tip/core/rcu 21/22] rcu-tasks: Add a grace-period start time for throttling and debug paulmck
2020-03-19  0:11   ` [PATCH RFC v2 tip/core/rcu 22/22] rcu-tasks: Provide boot parameter to delay IPIs until late in grace period paulmck
2020-03-19 11:31   ` [PATCH RFC v2 tip/core/rcu 0/22] Prototype RCU usable from idle, exception, offline Mathieu Desnoyers
2020-03-19 13:13     ` Paul E. McKenney
     [not found]   ` <20200319104614.11444-1-hdanton@sina.com>
2020-03-19 12:38     ` [PATCH RFC v2 tip/core/rcu 03/22] rcutorture: Add flag to produce non-busy-wait task stalls Paul E. McKenney
     [not found]     ` <20200319133947.12172-1-hdanton@sina.com>
2020-03-19 15:22       ` Paul E. McKenney
     [not found]       ` <20200320040329.9840-1-hdanton@sina.com>
2020-03-20 16:11         ` Paul E. McKenney
     [not found]   ` <20200320071228.9740-1-hdanton@sina.com>
2020-03-20 19:14     ` [PATCH RFC v2 tip/core/rcu 04/22] rcu-tasks: Move Tasks RCU to its own file Paul E. McKenney
2020-03-27 22:23   ` [PATCH RFC v3 tip/core/rcu 0/34] Prototype RCU usable from idle, exception, offline Paul E. McKenney
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 01/34] sched/core: Add function to sample state of locked-down task paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 02/34] rcu: Add per-task state to RCU CPU stall warnings paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 03/34] rcutorture: Add flag to produce non-busy-wait task stalls paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 04/34] rcu-tasks: Move Tasks RCU to its own file paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 05/34] rcu-tasks: Create struct to hold state information paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 06/34] rcu: Reinstate synchronize_rcu_mult() paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 07/34] rcutorture: Add a test for synchronize_rcu_mult() paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 08/34] rcu-tasks: Refactor RCU-tasks to allow variants to be added paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 09/34] rcu-tasks: Add an RCU-tasks rude variant paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 10/34] rcutorture: Add torture tests for RCU Tasks Rude paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 11/34] rcu-tasks: Use unique names for RCU-Tasks kthreads and messages paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 12/34] rcu-tasks: Further refactor RCU-tasks to allow adding more variants paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 13/34] rcu-tasks: Code movement to allow more Tasks RCU variants paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 14/34] rcu-tasks: Add an RCU Tasks Trace to simplify protection of tracing hooks paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 15/34] rcutorture: Add torture tests for RCU Tasks Trace paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 16/34] rcu-tasks: Add stall warnings " paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 17/34] rcu-tasks: Move #ifdef into tasks.h paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 18/34] rcu-tasks: Add RCU tasks to rcutorture writer stall output paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 19/34] rcu-tasks: Make rcutorture writer stall output include GP state paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 20/34] rcu-tasks: Make RCU Tasks Trace make use of RCU scheduler hooks paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 21/34] rcu-tasks: Add a grace-period start time for throttling and debug paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 22/34] rcu-tasks: Provide boot parameter to delay IPIs until late in grace period paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 23/34] rcu-tasks: Split ->trc_reader_need_end paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 24/34] rcu-tasks: Add grace-period and IPI counts to statistics paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 25/34] rcu-tasks: Add Kconfig option to mediate smp_mb() vs. IPI paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 26/34] rcu-tasks: Avoid IPIing userspace/idle tasks if kernel is so built paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 27/34] rcu-tasks: Allow rcu_read_unlock_trace() under scheduler locks paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 28/34] rcu-tasks: Disable CPU hotplug across RCU tasks trace scans paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 29/34] rcu-tasks: Handle the running-offline idle-task special case paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 30/34] rcu-tasks: Make RCU tasks trace also wait for idle tasks paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 31/34] rcu-tasks: Add rcu_dynticks_zero_in_eqs() effectiveness statistics paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 32/34] rcu-tasks: Add count for idle tasks on offline CPUs paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 33/34] rcutorture: Add TRACE02 scenario enabling RCU Tasks Trace IPIs paulmck
2020-03-27 22:24     ` [PATCH v3 tip/core/rcu 34/34] rcu-tasks: Add IPI failure count to statistics paulmck
2020-04-15 18:18     ` [PATCH v4 tip/core/rcu 0/38] Prototype RCU usable from idle, exception, offline Paul E. McKenney
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 01/38] rcu: Add comments marking transitions between RCU watching and not paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 02/38] rcu-tasks: Use context-switch hook for PREEMPT=y kernels paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 03/38] sched/core: Add function to sample state of locked-down task paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 04/38] rcu: Add per-task state to RCU CPU stall warnings paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 05/38] rcu-tasks: Move Tasks RCU to its own file paulmck
2020-05-10  7:42         ` Lai Jiangshan
2020-05-10 15:39           ` Paul E. McKenney
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 06/38] rcu-tasks: Create struct to hold state information paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 07/38] rcu: Reinstate synchronize_rcu_mult() paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 08/38] rcutorture: Add a test for synchronize_rcu_mult() paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 09/38] rcu-tasks: Refactor RCU-tasks to allow variants to be added paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 10/38] rcu-tasks: Add an RCU-tasks rude variant paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 11/38] rcutorture: Add torture tests for RCU Tasks Rude paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 12/38] rcu-tasks: Use unique names for RCU-Tasks kthreads and messages paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 13/38] rcu-tasks: Further refactor RCU-tasks to allow adding more variants paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 14/38] rcu-tasks: Code movement to allow more Tasks RCU variants paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 15/38] rcu-tasks: Add an RCU Tasks Trace to simplify protection of tracing hooks paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 16/38] rcutorture: Add torture tests for RCU Tasks Trace paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 17/38] rcu-tasks: Add stall warnings " paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 18/38] rcu-tasks: Move #ifdef into tasks.h paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 19/38] rcu-tasks: Add RCU tasks to rcutorture writer stall output paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 20/38] rcu-tasks: Make rcutorture writer stall output include GP state paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 21/38] rcu-tasks: Make RCU Tasks Trace make use of RCU scheduler hooks paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 22/38] rcu-tasks: Add a grace-period start time for throttling and debug paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 23/38] rcu-tasks: Provide boot parameter to delay IPIs until late in grace period paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 24/38] rcu-tasks: Split ->trc_reader_need_end paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 25/38] rcu-tasks: Add grace-period and IPI counts to statistics paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 26/38] rcu-tasks: Add Kconfig option to mediate smp_mb() vs. IPI paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 27/38] rcu-tasks: Avoid IPIing userspace/idle tasks if kernel is so built paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 28/38] rcu-tasks: Allow rcu_read_unlock_trace() under scheduler locks paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 29/38] rcu-tasks: Disable CPU hotplug across RCU tasks trace scans paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 30/38] rcu-tasks: Handle the running-offline idle-task special case paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 31/38] rcu-tasks: Make RCU tasks trace also wait for idle tasks paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 32/38] rcu-tasks: Add rcu_dynticks_zero_in_eqs() effectiveness statistics paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 33/38] rcu-tasks: Add count for idle tasks on offline CPUs paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 34/38] rcutorture: Add TRACE02 scenario enabling RCU Tasks Trace IPIs paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 35/38] rcu-tasks: Add IPI failure count to statistics paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 36/38] rcu-tasks: Allow standalone use of TASKS_{TRACE_,}RCU paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 37/38] ftrace: Use synchronize_rcu_tasks_rude() instead of ftrace_sync() paulmck
2020-04-15 18:19       ` [PATCH v4 tip/core/rcu 38/38] rcu: Don't acquire lock in NMI handler in rcu_nmi_enter_common() paulmck

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