From: "Paul E. McKenney" <paulmck@kernel.org> To: Steven Rostedt <rostedt@goodmis.org> Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, Alexei Starovoitov <alexei.starovoitov@gmail.com>, Andrii Nakryiko <andriin@fb.com> Subject: Re: [PATCH RFC v2 tip/core/rcu 14/22] rcu-tasks: Add an RCU Tasks Trace to simplify protection of tracing hooks Date: Thu, 19 Mar 2020 17:28:13 -0700 Message-ID: <20200320002813.GL3199@paulmck-ThinkPad-P72> (raw) In-Reply-To: <20200319154239.6d67877d@gandalf.local.home> On Thu, Mar 19, 2020 at 03:42:39PM -0400, Steven Rostedt wrote: > On Wed, 18 Mar 2020 17:10:52 -0700 > paulmck@kernel.org wrote: > > > From: "Paul E. McKenney" <paulmck@kernel.org> > > > > Because RCU does not watch exception early-entry/late-exit, idle-loop, > > or CPU-hotplug execution, protection of tracing and BPF operations is > > needlessly complicated. This commit therefore adds a variant of > > Tasks RCU that: > > > > o Has explicit read-side markers to allow finite grace periods in > > the face of in-kernel loops for PREEMPT=n builds. These markers > > are rcu_read_lock_trace() and rcu_read_unlock_trace(). > > > > o Protects code in the idle loop, exception entry/exit, and > > CPU-hotplug code paths. In this respect, RCU-tasks trace is > > similar to SRCU, but with lighter-weight readers. > > > > o Avoids expensive read-side instruction, having overhead similar > > to that of Preemptible RCU. > > > > There are of course downsides: > > > > o The grace-period code can send IPIs to CPUs, even when those CPUs > > are in the idle loop or in nohz_full userspace. This will be > > addressed by later commits. > > > > o It is necessary to scan the full tasklist, much as for Tasks RCU. > > > > o There is a single callback queue guarded by a single lock, > > again, much as for Tasks RCU. However, those early use cases > > that request multiple grace periods in quick succession are > > expected to do so from a single task, which makes the single > > lock almost irrelevant. If needed, multiple callback queues > > can be provided using any number of schemes. > > > > Perhaps most important, this variant of RCU does not affect the vanilla > > flavors, rcu_preempt and rcu_sched. The fact that RCU Tasks Trace > > readers can operate from idle, offline, and exception entry/exit in no > > way enables rcu_preempt and rcu_sched readers to do so. > > > > This effort benefited greatly from off-list discussions of BPF > > requirements with Alexei Starovoitov and Andrii Nakryiko. At least > > some of the on-list discussions are captured in the Link: tags below. > > In addition, KCSAN was quite helpful in finding some early bugs. > > If we have this, do we still need to have RCU Tasks Rude flavor? I have no idea. It is not a drop-in replacement for RCU Tasks Rude because preempt_disable() acts as a reader for Rude but not for Trace, which needs explicit rcu_read_lock_trace() and rcu_read_unlock_trace() markers. But it might well be that all of the schedule_on_each_cpu(ftrace_sync) users could be adapted to use RCU Tasks Trace instead. I would have to defer to you. ;-) > > Link: https://lore.kernel.org/lkml/20200219150744.428764577@infradead.org/ > > Link: https://lore.kernel.org/lkml/87mu8p797b.fsf@nanos.tec.linutronix.de/ > > Link: https://lore.kernel.org/lkml/20200225221305.605144982@linutronix.de/ > > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > > Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> > > Cc: Andrii Nakryiko <andriin@fb.com> > > --- > > include/linux/rcupdate_trace.h | 84 ++++++++++ > > include/linux/sched.h | 8 + > > init/init_task.c | 4 + > > kernel/fork.c | 4 + > > kernel/rcu/Kconfig | 12 +- > > kernel/rcu/tasks.h | 359 ++++++++++++++++++++++++++++++++++++++++- > > 6 files changed, 462 insertions(+), 9 deletions(-) > > create mode 100644 include/linux/rcupdate_trace.h > > > > > > diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig > > index 0d43ec1..187226b 100644 > > --- a/kernel/rcu/Kconfig > > +++ b/kernel/rcu/Kconfig > > @@ -71,7 +71,7 @@ config TREE_SRCU > > This option selects the full-fledged version of SRCU. > > > > config TASKS_RCU_GENERIC > > - def_bool TASKS_RCU || TASKS_RUDE_RCU > > + def_bool TASKS_RCU || TASKS_RUDE_RCU || TASKS_TRACE_RCU > > select SRCU > > help > > This option enables generic infrastructure code supporting > > @@ -94,6 +94,16 @@ config TASKS_RUDE_RCU > > switches on all online CPUs, including idle ones, so use > > with caution. Not for manual selection. > > > > +config TASKS_TRACE_RCU > > + def_bool 0 > > + default n > > Again, no need for "default n" > > > + help > > + This option enables a task-based RCU implementation that uses > > + explicit rcu_read_lock_trace() read-side markers, and allows > > + these readers to appear in the idle loop as well as on the CPU > > + hotplug code paths. It can force IPIs on online CPUs, including > > + idle ones, so use with caution. Not for manual selection. > > And no real need for "Not for manual selection". Both removed, thank you! > > + > > config RCU_STALL_COMMON > > def_bool TREE_RCU > > help > > > > > @@ -480,10 +489,10 @@ core_initcall(rcu_spawn_tasks_kthread); > > // > > // "Rude" variant of Tasks RCU, inspired by Steve Rostedt's trick of > > // passing an empty function to schedule_on_each_cpu(). This approach > > -// provides an asynchronous call_rcu_rude() API and batching of concurrent > > -// calls to the synchronous synchronize_rcu_rude() API. This sends IPIs > > -// far and wide and induces otherwise unnecessary context switches on all > > -// online CPUs, whether online or not. > > +// provides an asynchronous call_rcu_tasks_rude() API and batching > > +// of concurrent calls to the synchronous synchronize_rcu_rude() API. > > +// This sends IPIs far and wide and induces otherwise unnecessary context > > +// switches on all online CPUs, whether online or not. > > This looks out of place for this patch. Perhaps you fixed this code and > applied it to the wrong patch? Indeed I did, good catch! Huh. I guess the easiest fix is to back out this change, rebase, then apply it to the earlier commit in a second rebase. I guess git -might- figure it out in one pass. ;-) > > // Empty function to allow workqueues to force a context switch. > > static void rcu_tasks_be_rude(struct work_struct *work) > > @@ -569,3 +578,337 @@ static int __init rcu_spawn_tasks_rude_kthread(void) > > core_initcall(rcu_spawn_tasks_rude_kthread); > > > > #endif /* #ifdef CONFIG_TASKS_RUDE_RCU */ > > + > > +//////////////////////////////////////////////////////////////////////// > > +// > > +// Tracing variant of Tasks RCU. This variant is designed to be used > > +// to protect tracing hooks, including those of BPF. This variant > > +// therefore: > > +// > > +// 1. Has explicit read-side markers to allow finite grace periods > > +// in the face of in-kernel loops for PREEMPT=n builds. > > +// > > +// 2. Protects code in the idle loop, exception entry/exit, and > > +// CPU-hotplug code paths, similar to the capabilities of SRCU. > > +// > > +// 3. Avoids expensive read-side instruction, having 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. > > +// > > +// Perhaps most important, this variant of RCU does not affect the vanilla > > +// flavors, rcu_preempt and rcu_sched. The fact that RCU Tasks Trace > > +// readers can operate from idle, offline, and exception entry/exit in no > > +// way allows rcu_preempt and rcu_sched readers to also do so. > > + > > +// The lockdep state must be outside of #ifdef to be useful. > > +#ifdef CONFIG_DEBUG_LOCK_ALLOC > > +static struct lock_class_key rcu_lock_trace_key; > > +struct lockdep_map rcu_trace_lock_map = > > + STATIC_LOCKDEP_MAP_INIT("rcu_read_lock_trace", &rcu_lock_trace_key); > > +EXPORT_SYMBOL_GPL(rcu_trace_lock_map); > > +#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ > > + > > +#ifdef CONFIG_TASKS_TRACE_RCU > > + > > +atomic_t trc_n_readers_need_end; // Number of waited-for readers. > > +DECLARE_WAIT_QUEUE_HEAD(trc_wait); // List of holdout tasks. > > + > > +// Record outstanding IPIs to each CPU. No point in sending two... > > +static DEFINE_PER_CPU(bool, trc_ipi_to_cpu); > > + > > +/* If we are the last reader, wake up the grace-period kthread. */ > > +void rcu_read_unlock_trace_special(struct task_struct *t) > > +{ > > + WRITE_ONCE(t->trc_reader_need_end, false); > > + if (atomic_dec_and_test(&trc_n_readers_need_end)) > > + wake_up(&trc_wait); > > Hmm, this can't be called in places that hold the rq->lock can it? Good point. If interrupts are disabled, it will need to use some other mechanism. One approach is irqwork. Another is a timer. Suggestions? Thanx, Paul > -- Steve > > > +} > > +EXPORT_SYMBOL_GPL(rcu_read_unlock_trace_special); > > + > > +/* Add a task to the holdout list, if it is not already on the list. */ > > +static void trc_add_holdout(struct task_struct *t, struct list_head *bhp) > > +{ > > + if (list_empty(&t->trc_holdout_list)) { > > + get_task_struct(t); > > + list_add(&t->trc_holdout_list, bhp); > > + } > > +} > > +ndif /* #else #ifdef CONFIG_TASKS_TRACE_RCU */ >
next prev parent reply index 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 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 [this message] 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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