From: paulmck@kernel.org To: rcu@vger.kernel.org Cc: 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, joel@joelfernandes.org, "Paul E. McKenney" <paulmck@kernel.org> Subject: [PATCH v4 tip/core/rcu 27/38] rcu-tasks: Avoid IPIing userspace/idle tasks if kernel is so built Date: Wed, 15 Apr 2020 11:19:30 -0700 Message-ID: <20200415181941.11653-27-paulmck@kernel.org> (raw) In-Reply-To: <20200415181856.GA11037@paulmck-ThinkPad-P72> From: "Paul E. McKenney" <paulmck@kernel.org> Systems running CPU-bound real-time task do not want IPIs sent to CPUs executing nohz_full userspace tasks. Battery-powered systems don't want IPIs sent to idle CPUs in low-power mode. Unfortunately, RCU tasks trace can and will send such IPIs in some cases. Both of these situations occur only when the target CPU is in RCU dyntick-idle mode, in other words, when RCU is not watching the target CPU. This suggests that CPUs in dyntick-idle mode should use memory barriers in outermost invocations of rcu_read_lock_trace() and rcu_read_unlock_trace(), which would allow the RCU tasks trace grace period to directly read out the target CPU's read-side state. One challenge is that RCU tasks trace is not targeting a specific CPU, but rather a task. And that task could switch from one CPU to another at any time. This commit therefore uses try_invoke_on_locked_down_task() and checks for task_curr() in trc_inspect_reader_notrunning(). When this condition holds, the target task is running and cannot move. If CONFIG_TASKS_TRACE_RCU_READ_MB=y, the new rcu_dynticks_zero_in_eqs() function can be used to check if the specified integer (in this case, t->trc_reader_nesting) is zero while the target CPU remains in that same dyntick-idle sojourn. If so, the target task is in a quiescent state. If not, trc_read_check_handler() must indicate failure so that the grace-period kthread can take appropriate action or retry after an appropriate delay, as the case may be. With this change, given CONFIG_TASKS_TRACE_RCU_READ_MB=y, if a given CPU remains idle or a given task continues executing in nohz_full mode, the RCU tasks trace grace-period kthread will detect this without the need to send an IPI. Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> --- kernel/rcu/rcu.h | 2 ++ kernel/rcu/tasks.h | 36 ++++++++++++++++++++++++++---------- kernel/rcu/tree.c | 24 ++++++++++++++++++++++++ kernel/rcu/tree.h | 2 ++ kernel/rcu/tree_plugin.h | 18 ++++++++++++++++++ 5 files changed, 72 insertions(+), 10 deletions(-) diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index e1089fd..296f926 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -501,6 +501,7 @@ void srcutorture_get_gp_data(enum rcutorture_type test_type, #endif #ifdef CONFIG_TINY_RCU +static inline bool rcu_dynticks_zero_in_eqs(int cpu, int *vp) { return false; } static inline unsigned long rcu_get_gp_seq(void) { return 0; } static inline unsigned long rcu_exp_batches_completed(void) { return 0; } static inline unsigned long @@ -510,6 +511,7 @@ static inline void show_rcu_gp_kthreads(void) { } static inline int rcu_get_gp_kthreads_prio(void) { return 0; } static inline void rcu_fwd_progress_check(unsigned long j) { } #else /* #ifdef CONFIG_TINY_RCU */ +bool rcu_dynticks_zero_in_eqs(int cpu, int *vp); unsigned long rcu_get_gp_seq(void); unsigned long rcu_exp_batches_completed(void); unsigned long srcu_batches_completed(struct srcu_struct *sp); diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 64a5b97..3eed886 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -806,22 +806,38 @@ static void trc_read_check_handler(void *t_in) /* Callback function for scheduler to check locked-down task. */ static bool trc_inspect_reader(struct task_struct *t, void *arg) { - if (task_curr(t)) - return false; // It is running, so decline to inspect it. + int cpu = task_cpu(t); + bool in_qs = false; + + if (task_curr(t)) { + // If no chance of heavyweight readers, do it the hard way. + if (!IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB)) + return false; + + // If heavyweight readers are enabled on the remote task, + // we can inspect its state despite its currently running. + // However, we cannot safely change its state. + if (!rcu_dynticks_zero_in_eqs(cpu, &t->trc_reader_nesting)) + return false; // No quiescent state, do it the hard way. + in_qs = true; + } else { + in_qs = likely(!t->trc_reader_nesting); + } // Mark as checked. Because this is called from the grace-period // kthread, also remove the task from the holdout list. t->trc_reader_checked = true; trc_del_holdout(t); - // If the task is in a read-side critical section, set up its - // its state so that it will awaken the grace-period kthread upon - // exit from that critical section. - if (unlikely(t->trc_reader_nesting)) { - atomic_inc(&trc_n_readers_need_end); // One more to wait on. - WARN_ON_ONCE(t->trc_reader_special.b.need_qs); - WRITE_ONCE(t->trc_reader_special.b.need_qs, true); - } + if (in_qs) + return true; // Already in quiescent state, done!!! + + // The task is in a read-side critical section, so set up its + // state so that it will awaken the grace-period kthread upon exit + // from that critical section. + atomic_inc(&trc_n_readers_need_end); // One more to wait on. + WARN_ON_ONCE(t->trc_reader_special.b.need_qs); + WRITE_ONCE(t->trc_reader_special.b.need_qs, true); return true; } diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index e54a8a1..7dd7a17 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -252,6 +252,7 @@ static void rcu_dynticks_eqs_enter(void) * critical sections, and we also must force ordering with the * next idle sojourn. */ + rcu_dynticks_task_trace_enter(); // Before ->dynticks update! seq = atomic_add_return(RCU_DYNTICK_CTRL_CTR, &rdp->dynticks); // RCU is no longer watching. Better be in extended quiescent state! WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && @@ -278,6 +279,7 @@ static void rcu_dynticks_eqs_exit(void) */ seq = atomic_add_return(RCU_DYNTICK_CTRL_CTR, &rdp->dynticks); // RCU is now watching. Better not be in an extended quiescent state! + rcu_dynticks_task_trace_exit(); // After ->dynticks update! WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !(seq & RCU_DYNTICK_CTRL_CTR)); if (seq & RCU_DYNTICK_CTRL_MASK) { @@ -350,6 +352,28 @@ static bool rcu_dynticks_in_eqs_since(struct rcu_data *rdp, int snap) } /* + * Return true if the referenced integer is zero while the specified + * CPU remains within a single extended quiescent state. + */ +bool rcu_dynticks_zero_in_eqs(int cpu, int *vp) +{ + struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); + int snap; + + // If not quiescent, force back to earlier extended quiescent state. + snap = atomic_read(&rdp->dynticks) & ~(RCU_DYNTICK_CTRL_MASK | + RCU_DYNTICK_CTRL_CTR); + + smp_rmb(); // Order ->dynticks and *vp reads. + if (READ_ONCE(*vp)) + return false; // Non-zero, so report failure; + smp_rmb(); // Order *vp read and ->dynticks re-read. + + // If still in the same extended quiescent state, we are good! + return snap == (atomic_read(&rdp->dynticks) & ~RCU_DYNTICK_CTRL_MASK); +} + +/* * Set the special (bottom) bit of the specified CPU so that it * will take special action (such as flushing its TLB) on the * next exit from an extended quiescent state. Returns true if diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 9dc2ec0..29ba799 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -454,6 +454,8 @@ static void rcu_bind_gp_kthread(void); static bool rcu_nohz_full_cpu(void); static void rcu_dynticks_task_enter(void); static void rcu_dynticks_task_exit(void); +static void rcu_dynticks_task_trace_enter(void); +static void rcu_dynticks_task_trace_exit(void); /* Forward declarations for tree_stall.h */ static void record_gp_stall_check_time(void); diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 37e0281..4cef7e3 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2552,3 +2552,21 @@ static void rcu_dynticks_task_exit(void) WRITE_ONCE(current->rcu_tasks_idle_cpu, -1); #endif /* #if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL) */ } + +/* Turn on heavyweight RCU tasks trace readers on idle/user entry. */ +static void rcu_dynticks_task_trace_enter(void) +{ +#ifdef CONFIG_TASKS_RCU_TRACE + if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB)) + current->trc_reader_special.b.need_mb = true; +#endif /* #ifdef CONFIG_TASKS_RCU_TRACE */ +} + +/* Turn off heavyweight RCU tasks trace readers on idle/user exit. */ +static void rcu_dynticks_task_trace_exit(void) +{ +#ifdef CONFIG_TASKS_RCU_TRACE + if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB)) + current->trc_reader_special.b.need_mb = false; +#endif /* #ifdef CONFIG_TASKS_RCU_TRACE */ +} -- 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 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 ` paulmck [this message] 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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