Commit 35dc0352 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'rcu.2022.03.13a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu 

Pull RCU updates from Paul McKenney:

 - Fix idle detection (Neeraj Upadhyay) and missing access marking
   detected by KCSAN.

 - Reduce coupling between rcu_barrier() and CPU-hotplug operations, so
   that rcu_barrier() no longer needs to do cpus_read_lock(). This may
   also someday allow system boot to bring CPUs online concurrently.

 - Enable more aggressive movement to per-CPU queueing when reacting to
   excessive lock contention due to workloads placing heavy update-side
   stress on RCU tasks.

 - Improvements to RCU priority boosting, including changes from Neeraj
   Upadhyay, Zqiang, and Alison Chaiken.

 - Various fixes improving test robustness and debug information.

 - Add tests for SRCU size transitions, further compress torture.sh
   build products, and improve debug output.

 - Miscellaneous fixes.

* tag 'rcu.2022.03.13a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (49 commits)
  rcu: Replace cpumask_weight with cpumask_empty where appropriate
  rcu: Remove __read_mostly annotations from rcu_scheduler_active externs
  rcu: Uninline multi-use function: finish_rcuwait()
  rcu: Mark writes to the rcu_segcblist structure's ->flags field
  kasan: Record work creation stack trace with interrupts enabled
  rcu: Inline __call_rcu() into call_rcu()
  rcu: Add mutex for rcu boost kthread spawning and affinity setting
  rcu: Fix description of kvfree_rcu()
  MAINTAINERS:  Add Frederic and Neeraj to their RCU files
  rcutorture: Provide non-power-of-two Tasks RCU scenarios
  rcutorture: Test SRCU size transitions
  torture: Make torture.sh help message match reality
  rcu-tasks: Set ->percpu_enqueue_shift to zero upon contention
  rcu-tasks: Use order_base_2() instead of ilog2()
  rcu: Create and use an rcu_rdp_cpu_online()
  rcu: Make rcu_barrier() no longer block CPU-hotplug operations
  rcu: Rework rcu_barrier() and callback-migration logic
  rcu: Refactor rcu_barrier() empty-list handling
  rcu: Kill rnp->ofl_seq and use only rcu_state.ofl_lock for exclusion
  torture: Change KVM environment variable to RCUTORTURE
  ...
parents a04b1bf5 d5578190

Documentation/admin-guide/kernel-parameters.txt

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@@ -4504,6 +4504,8 @@ 
			(the least-favored priority).  Otherwise, when

			RCU_BOOST is not set, valid values are 0-99 and

			the default is zero (non-realtime operation).

			When RCU_NOCB_CPU is set, also adjust the

			priority of NOCB callback kthreads.



	rcutree.rcu_nocb_gp_stride= [KNL]

			Set the number of NOCB callback kthreads in

MAINTAINERS

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@@ -16324,6 +16324,8 @@ F: tools/testing/selftests/resctrl/ 








READ-COPY UPDATE (RCU)









M:	"Paul E. McKenney" <paulmck@kernel.org>









M:	Frederic Weisbecker <frederic@kernel.org> (kernel/rcu/tree_nocb.h)









M:	Neeraj Upadhyay <quic_neeraju@quicinc.com> (kernel/rcu/tasks.h)









M:	Josh Triplett <josh@joshtriplett.org>









R:	Steven Rostedt <rostedt@goodmis.org>









R:	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
































include/linux/rcupdate.h



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−2






























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@@ -84,7 +84,7 @@ static inline int rcu_preempt_depth(void)

















/* Internal to kernel */









void rcu_init(void);









extern int rcu_scheduler_active __read_mostly;









extern int rcu_scheduler_active;









void rcu_sched_clock_irq(int user);









void rcu_report_dead(unsigned int cpu);









void rcutree_migrate_callbacks(int cpu);








@@ -924,7 +924,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)







 *









 *     kvfree_rcu(ptr);









 *









 * where @ptr is a pointer to kvfree().









 * where @ptr is the pointer to be freed by kvfree().









 *









 * Please note, head-less way of freeing is permitted to









 * use from a context that has to follow might_sleep()
































include/linux/rcutree.h



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@@ -62,7 +62,7 @@ static inline void rcu_irq_exit_check_preempt(void) { }







void exit_rcu(void);



















void rcu_scheduler_starting(void);









extern int rcu_scheduler_active __read_mostly;









extern int rcu_scheduler_active;









void rcu_end_inkernel_boot(void);









bool rcu_inkernel_boot_has_ended(void);









bool rcu_is_watching(void);
































include/linux/rcuwait.h



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@@ -47,11 +47,7 @@ static inline void prepare_to_rcuwait(struct rcuwait *w)







	rcu_assign_pointer(w->task, current);









}



















static inline void finish_rcuwait(struct rcuwait *w)









{









        rcu_assign_pointer(w->task, NULL);









	__set_current_state(TASK_RUNNING);









}









extern void finish_rcuwait(struct rcuwait *w);



















#define rcuwait_wait_event(w, condition, state)				\









({									\