From: "Paul E. McKenney" <paulmck@kernel.org> To: Joel Fernandes <joel@joelfernandes.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, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com Subject: Re: [PATCH RFC tip/core/rcu 09/16] rcu-tasks: Add an RCU-tasks rude variant Date: Mon, 16 Mar 2020 13:29:41 -0700 Message-ID: <20200316202941.GA3199@paulmck-ThinkPad-P72> (raw) In-Reply-To: <20200316194754.GA172196@google.com> On Mon, Mar 16, 2020 at 03:47:54PM -0400, Joel Fernandes wrote: > On Thu, Mar 12, 2020 at 11:16:55AM -0700, paulmck@kernel.org wrote: > > From: "Paul E. McKenney" <paulmck@kernel.org> > > > > This commit adds a "rude" variant of RCU-tasks that has as quiescent > > states schedule(), cond_resched_tasks_rcu_qs(), userspace execution, > > and (in theory, anyway) cond_resched(). Updates make use of IPIs and > > force an IPI and a context switch on each online CPU. This variant > > is useful in some situations in tracing. > > Would it be possible to better clarify that the "rude version" works only > from preempt-disabled regions? Is that also true for the "non-rude" version? The rude version's read-side critical sections are preempt-disabled regions. The prior non-rude version's critical sections are not limited to preempt-disabled regions, but instead extend between voluntary context switches, as described in the header comment for synchronize_rcu_tasks(). > Also it would be good to clarify better in cover letter, how these new > flavors relate to the existing Tasks-RCU implementation. The cover letter did that for the tracing variant (shown below), but I can add this information for the rude variant on the next round. 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. > In the existing one, a quiescent state is a task updating its context switch > counters such that it went to sleep at least once, implying there is no > chance it is on an about to be destroyed trampoline. Yes, voluntary context switch. > However, here we are trying to determine if a task state is no longer on an > RQ (which I gleaned from the first patch). Sounds very similar, would the > context switch counters not help in that determination as well? If it is Ok, > it would be good to describe in cover letter about what is exactly is a > quiescent state and what exactly is a reader section in the cover letter, for > both non-rude and rude version. Thanks! No, for both of the new variants, a task can be in a quiescent state while still being on a runqueue. The rude variant can be preempted and the tracing variant can be outside of its explicitly marked read-side critical sections. The existing non-rude version's quiescent states are already listed in the docbook header comment for synchronize_rcu_tasks(). Thanx, Paul > thanks, > > - Joel > > > > > > > Suggested-by: Steven Rostedt <rostedt@goodmis.org> > > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > > --- > > include/linux/rcupdate.h | 3 ++ > > kernel/rcu/Kconfig | 12 +++++- > > kernel/rcu/tasks.h | 99 ++++++++++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 113 insertions(+), 1 deletion(-) > > > > diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h > > index 5523145..2be97a8 100644 > > --- a/include/linux/rcupdate.h > > +++ b/include/linux/rcupdate.h > > @@ -37,6 +37,7 @@ > > /* Exported common interfaces */ > > void call_rcu(struct rcu_head *head, rcu_callback_t func); > > void rcu_barrier_tasks(void); > > +void rcu_barrier_tasks_rude(void); > > void synchronize_rcu(void); > > > > #ifdef CONFIG_PREEMPT_RCU > > @@ -138,6 +139,8 @@ static inline void rcu_init_nohz(void) { } > > #define rcu_note_voluntary_context_switch(t) rcu_tasks_qs(t) > > void call_rcu_tasks(struct rcu_head *head, rcu_callback_t func); > > void synchronize_rcu_tasks(void); > > +void call_rcu_tasks_rude(struct rcu_head *head, rcu_callback_t func); > > +void synchronize_rcu_tasks_rude(void); > > void exit_tasks_rcu_start(void); > > void exit_tasks_rcu_finish(void); > > #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */ > > diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig > > index 38475d0..0d43ec1 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 > > + def_bool TASKS_RCU || TASKS_RUDE_RCU > > select SRCU > > help > > This option enables generic infrastructure code supporting > > @@ -84,6 +84,16 @@ config TASKS_RCU > > only voluntary context switch (not preemption!), idle, and > > user-mode execution as quiescent states. Not for manual selection. > > > > +config TASKS_RUDE_RCU > > + def_bool 0 > > + default n > > + help > > + This option enables a task-based RCU implementation that uses > > + only context switch (including preemption) and user-mode > > + execution as quiescent states. It forces IPIs and context > > + switches on all online CPUs, including idle ones, so use > > + with caution. Not for manual selection. > > + > > config RCU_STALL_COMMON > > def_bool TREE_RCU > > help > > diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h > > index d77921e..1d25c50 100644 > > --- a/kernel/rcu/tasks.h > > +++ b/kernel/rcu/tasks.h > > @@ -180,6 +180,9 @@ static void __init rcu_tasks_bootup_oddness(void) > > else > > pr_info("\tTasks RCU enabled.\n"); > > #endif /* #ifdef CONFIG_TASKS_RCU */ > > +#ifdef CONFIG_TASKS_RUDE_RCU > > + pr_info("\tRude variant of Tasks RCU enabled.\n"); > > +#endif /* #ifdef CONFIG_TASKS_RUDE_RCU */ > > } > > > > #endif /* #ifndef CONFIG_TINY_RCU */ > > @@ -410,3 +413,99 @@ static int __init rcu_spawn_tasks_kthread(void) > > core_initcall(rcu_spawn_tasks_kthread); > > > > #endif /* #ifdef CONFIG_TASKS_RCU */ > > + > > +#ifdef CONFIG_TASKS_RUDE_RCU > > + > > +//////////////////////////////////////////////////////////////////////// > > +// > > +// "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. > > + > > +// Empty function to allow workqueues to force a context switch. > > +static void rcu_tasks_be_rude(struct work_struct *work) > > +{ > > +} > > + > > +// Wait for one rude RCU-tasks grace period. > > +static void rcu_tasks_rude_wait_gp(struct rcu_tasks *rtp) > > +{ > > + schedule_on_each_cpu(rcu_tasks_be_rude); > > +} > > +EXPORT_SYMBOL_GPL(rcu_tasks_rude_wait_gp); > > + > > +void call_rcu_tasks_rude(struct rcu_head *rhp, rcu_callback_t func); > > +DEFINE_RCU_TASKS(rcu_tasks_rude, rcu_tasks_rude_wait_gp, call_rcu_tasks_rude); > > + > > +/** > > + * call_rcu_tasks_rude() - Queue a callback rude task-based grace period > > + * @rhp: structure to be used for queueing the RCU updates. > > + * @func: actual callback function to be invoked after the grace period > > + * > > + * The callback function will be invoked some time after a full grace > > + * period elapses, in other words after all currently executing RCU > > + * read-side critical sections have completed. call_rcu_tasks_rude() > > + * assumes that the read-side critical sections end at context switch, > > + * cond_resched_rcu_qs(), or transition to usermode execution. As such, > > + * there are no read-side primitives analogous to rcu_read_lock() and > > + * rcu_read_unlock() because this primitive is intended to determine > > + * that all tasks have passed through a safe state, not so much for > > + * data-strcuture synchronization. > > + * > > + * See the description of call_rcu() for more detailed information on > > + * memory ordering guarantees. > > + */ > > +void call_rcu_tasks_rude(struct rcu_head *rhp, rcu_callback_t func) > > +{ > > + call_rcu_tasks_generic(rhp, func, &rcu_tasks_rude); > > +} > > +EXPORT_SYMBOL_GPL(call_rcu_tasks_rude); > > + > > +/** > > + * synchronize_rcu_tasks_rude - wait for a rude rcu-tasks grace period > > + * > > + * Control will return to the caller some time after a rude rcu-tasks > > + * grace period has elapsed, in other words after all currently > > + * executing rcu-tasks read-side critical sections have elapsed. These > > + * read-side critical sections are delimited by calls to schedule(), > > + * cond_resched_tasks_rcu_qs(), userspace execution, and (in theory, > > + * anyway) cond_resched(). > > + * > > + * This is a very specialized primitive, intended only for a few uses in > > + * tracing and other situations requiring manipulation of function preambles > > + * and profiling hooks. The synchronize_rcu_tasks_rude() function is not > > + * (yet) intended for heavy use from multiple CPUs. > > + * > > + * See the description of synchronize_rcu() for more detailed information > > + * on memory ordering guarantees. > > + */ > > +void synchronize_rcu_tasks_rude(void) > > +{ > > + synchronize_rcu_tasks_generic(&rcu_tasks_rude); > > +} > > +EXPORT_SYMBOL_GPL(synchronize_rcu_tasks_rude); > > + > > +/** > > + * rcu_barrier_tasks_rude - Wait for in-flight call_rcu_tasks_rude() callbacks. > > + * > > + * Although the current implementation is guaranteed to wait, it is not > > + * obligated to, for example, if there are no pending callbacks. > > + */ > > +void rcu_barrier_tasks_rude(void) > > +{ > > + /* There is only one callback queue, so this is easy. ;-) */ > > + synchronize_rcu_tasks_rude(); > > +} > > +EXPORT_SYMBOL_GPL(rcu_barrier_tasks_rude); > > + > > +static int __init rcu_spawn_tasks_rude_kthread(void) > > +{ > > + rcu_spawn_tasks_kthread_generic(&rcu_tasks_rude); > > + return 0; > > +} > > +core_initcall(rcu_spawn_tasks_rude_kthread); > > + > > +#endif /* #ifdef CONFIG_TASKS_RUDE_RCU */ > > -- > > 2.9.5 > >
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 [this message] 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 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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