include/linux/rcupdate.h

122  * RCU_NONIDLE - Indicate idle-loop code that needs RCU readers
123  * @a: Code that RCU needs to pay attention to.
125  * RCU read-side critical sections are forbidden in the inner idle loop,
126  * that is, between the rcu_idle_enter() and the rcu_idle_exit() -- RCU
131  * will tell RCU that it needs to pay attention, invoke its argument
133  * and then tell RCU to go back to ignoring this CPU.  It is permissible
147  * Note a quasi-voluntary context switch for RCU-tasks's benefit.
203  * cond_resched_tasks_rcu_qs - Report potential quiescent states to RCU
206  * report potential quiescent states to RCU-tasks even if the cond_resched()
225 #error "Unknown RCU implementation specified to kernel configuration"
323 			 "Illegal context switch in RCU read-side critical section");  in rcu_preempt_sleep_check()
333 				 "Illegal context switch in RCU-bh read-side critical section"); \
335 				 "Illegal context switch in RCU-sched read-side critical section"); \
349  * multiple pointers markings to match different RCU implementations
388  * RCU_INITIALIZER() - statically initialize an RCU-protected global variable
394  * rcu_assign_pointer() - assign to RCU-protected pointer
398  * Assigns the specified value to the specified RCU-protected
399  * pointer, ensuring that any concurrent RCU readers will see
406  * will be dereferenced by RCU read-side code.
436  * rcu_replace_pointer() - replace an RCU pointer, returning its old value
437  * @rcu_ptr: RCU pointer, whose old value is returned
441  * Perform a replacement, where @rcu_ptr is an RCU-annotated
454  * rcu_access_pointer() - fetch RCU pointer with no dereferencing
457  * Return the value of the specified RCU-protected pointer, but omit the
458  * lockdep checks for being in an RCU read-side critical section.  This is
460  * not dereferenced, for example, when testing an RCU-protected pointer
467  * is the case in the context of the RCU callback that is freeing up
483  * An implicit check for being in an RCU read-side critical section
504  * which pointers are protected by RCU and checks that the pointer is
515  * This is the RCU-bh counterpart to rcu_dereference_check().
525  * This is the RCU-sched counterpart to rcu_dereference_check().
532  * The tracing infrastructure traces RCU (we want that), but unfortunately
533  * some of the RCU checks causes tracing to lock up the system.
541  * rcu_dereference_protected() - fetch RCU pointer when updates prevented
545  * Return the value of the specified RCU-protected pointer, but omit
561  * rcu_dereference() - fetch RCU-protected pointer for dereferencing
569  * rcu_dereference_bh() - fetch an RCU-bh-protected pointer for dereferencing
577  * rcu_dereference_sched() - fetch RCU-sched-protected pointer for dereferencing
585  * rcu_pointer_handoff() - Hand off a pointer from RCU to other mechanism
589  * is handed off from RCU to some other synchronization mechanism, for
607  * rcu_read_lock() - mark the beginning of an RCU read-side critical section
610  * are within RCU read-side critical sections, then the
613  * on one CPU while other CPUs are within RCU read-side critical
614  * sections, invocation of the corresponding RCU callback is deferred
617  * Note, however, that RCU callbacks are permitted to run concurrently
618  * with new RCU read-side critical sections.  One way that this can happen
619  * is via the following sequence of events: (1) CPU 0 enters an RCU
621  * an RCU callback, (3) CPU 0 exits the RCU read-side critical section,
622  * (4) CPU 2 enters a RCU read-side critical section, (5) the RCU
623  * callback is invoked.  This is legal, because the RCU read-side critical
625  * therefore might be referencing something that the corresponding RCU
627  * RCU callback is invoked.
629  * RCU read-side critical sections may be nested.  Any deferred actions
630  * will be deferred until the outermost RCU read-side critical section
634  * following this rule: don't put anything in an rcu_read_lock() RCU
638  * In non-preemptible RCU implementations (pure TREE_RCU and TINY_RCU),
639  * it is illegal to block while in an RCU read-side critical section.
640  * In preemptible RCU implementations (PREEMPT_RCU) in CONFIG_PREEMPTION
641  * kernel builds, RCU read-side critical sections may be preempted,
642  * but explicit blocking is illegal.  Finally, in preemptible RCU
643  * implementations in real-time (with -rt patchset) kernel builds, RCU
650 	__acquire(RCU);  in rcu_read_lock()
658  * way for writers to lock out RCU readers.  This is a feature, not
659  * a bug -- this property is what provides RCU's performance benefits.
662  * used as well.  RCU does not care how the writers keep out of each
667  * rcu_read_unlock() - marks the end of an RCU read-side critical section.
677  * That said, RCU readers are never priority boosted unless they were
679  * that preemption never happens within any RCU read-side critical
687  * that that preemption never happens within any RCU read-side critical
703 	__release(RCU);  in rcu_read_unlock()
709  * rcu_read_lock_bh() - mark the beginning of an RCU-bh critical section
713  * an RCU read-side critical section.
730  * rcu_read_unlock_bh() - marks the end of a softirq-only RCU critical section
744  * rcu_read_lock_sched() - mark the beginning of a RCU-sched critical section
772  * rcu_read_unlock_sched() - marks the end of a RCU-classic critical section
793  * RCU_INIT_POINTER() - initialize an RCU protected pointer
797  * Initialize an RCU-protected pointer in special cases where readers
803  *	RCU readers from concurrently accessing this pointer *or*
816  * will look OK in crash dumps, but any concurrent RCU readers might
820  * If you are creating an RCU-protected linked structure that is accessed
821  * by a single external-to-structure RCU-protected pointer, then you may
822  * use RCU_INIT_POINTER() to initialize the internal RCU-protected
837  * RCU_POINTER_INITIALIZER() - statically initialize an RCU protected pointer
841  * GCC-style initialization for an RCU-protected pointer in a structure field.
866  * Many rcu callbacks functions just call kfree() on the base structure.
974  * in an RCU read-side critical section that includes a read-side fetch