1 /* SPDX-License-Identifier: GPL-2.0+ */ << 2 /* 1 /* 3 * Read-Copy Update mechanism for mutual exclu 2 * Read-Copy Update mechanism for mutual exclusion (tree-based version) 4 * 3 * >> 4 * This program is free software; you can redistribute it and/or modify >> 5 * it under the terms of the GNU General Public License as published by >> 6 * the Free Software Foundation; either version 2 of the License, or >> 7 * (at your option) any later version. >> 8 * >> 9 * This program is distributed in the hope that it will be useful, >> 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of >> 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >> 12 * GNU General Public License for more details. >> 13 * >> 14 * You should have received a copy of the GNU General Public License >> 15 * along with this program; if not, write to the Free Software >> 16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. >> 17 * 5 * Copyright IBM Corporation, 2008 18 * Copyright IBM Corporation, 2008 6 * 19 * 7 * Author: Dipankar Sarma <dipankar@in.ibm.com 20 * Author: Dipankar Sarma <dipankar@in.ibm.com> 8 * Paul E. McKenney <paulmck@linux.ibm !! 21 * Paul E. McKenney <paulmck@linux.vnet.ibm.com> Hierarchical algorithm 9 * 22 * 10 * Based on the original work by Paul McKenney !! 23 * Based on the original work by Paul McKenney <paulmck@us.ibm.com> 11 * and inputs from Rusty Russell, Andrea Arcan 24 * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen. 12 * 25 * 13 * For detailed explanation of Read-Copy Updat 26 * For detailed explanation of Read-Copy Update mechanism see - 14 * Documentation/RCU 27 * Documentation/RCU 15 */ 28 */ 16 29 17 #ifndef __LINUX_RCUTREE_H 30 #ifndef __LINUX_RCUTREE_H 18 #define __LINUX_RCUTREE_H 31 #define __LINUX_RCUTREE_H 19 32 20 void rcu_softirq_qs(void); !! 33 extern void rcu_init(void); 21 void rcu_note_context_switch(bool preempt); !! 34 extern void rcu_note_context_switch(int cpu); 22 int rcu_needs_cpu(void); !! 35 extern int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies); 23 void rcu_cpu_stall_reset(void); !! 36 extern void rcu_cpu_stall_reset(void); 24 void rcu_request_urgent_qs_task(struct task_st << 25 37 26 /* 38 /* 27 * Note a virtualization-based context switch. 39 * Note a virtualization-based context switch. This is simply a 28 * wrapper around rcu_note_context_switch(), w 40 * wrapper around rcu_note_context_switch(), which allows TINY_RCU 29 * to save a few bytes. The caller must have d !! 41 * to save a few bytes. 30 */ 42 */ 31 static inline void rcu_virt_note_context_switc !! 43 static inline void rcu_virt_note_context_switch(int cpu) 32 { 44 { 33 rcu_note_context_switch(false); !! 45 rcu_note_context_switch(cpu); 34 } 46 } 35 47 36 void synchronize_rcu_expedited(void); !! 48 extern void synchronize_rcu_bh(void); 37 void kvfree_call_rcu(struct rcu_head *head, vo !! 49 extern void synchronize_sched_expedited(void); >> 50 extern void synchronize_rcu_expedited(void); 38 51 39 void rcu_barrier(void); !! 52 void kfree_call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); 40 void rcu_momentary_dyntick_idle(void); << 41 void kfree_rcu_scheduler_running(void); << 42 bool rcu_gp_might_be_stalled(void); << 43 << 44 struct rcu_gp_oldstate { << 45 unsigned long rgos_norm; << 46 unsigned long rgos_exp; << 47 }; << 48 << 49 // Maximum number of rcu_gp_oldstate values co << 50 // not-yet-completed RCU grace periods. << 51 #define NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE 4 << 52 53 53 /** 54 /** 54 * same_state_synchronize_rcu_full - Are two o !! 55 * synchronize_rcu_bh_expedited - Brute-force RCU-bh grace period 55 * @rgosp1: First old-state value. !! 56 * 56 * @rgosp2: Second old-state value. !! 57 * Wait for an RCU-bh grace period to elapse, but use a "big hammer" 57 * !! 58 * approach to force the grace period to end quickly. This consumes 58 * The two old-state values must have been obt !! 59 * significant time on all CPUs and is unfriendly to real-time workloads, 59 * get_state_synchronize_rcu_full(), start_pol !! 60 * so is thus not recommended for any sort of common-case code. In fact, 60 * or get_completed_synchronize_rcu_full(). R !! 61 * if you are using synchronize_rcu_bh_expedited() in a loop, please 61 * values are identical and @false otherwise. !! 62 * restructure your code to batch your updates, and then use a single 62 * whose lifetimes are tracked by old-state va !! 63 * synchronize_rcu_bh() instead. 63 * to a list header, allowing those structures !! 64 * 64 * !! 65 * Note that it is illegal to call this function while holding any lock 65 * Note that equality is judged on a bitwise b !! 66 * that is acquired by a CPU-hotplug notifier. And yes, it is also illegal 66 * @rcu_gp_oldstate structure with an already- !! 67 * to call this function from a CPU-hotplug notifier. Failing to observe 67 * will compare not-equal to a structure with !! 68 * these restriction will result in deadlock. 68 * in the other field. After all, the @rcu_gp << 69 * so how did such a situation come to pass in << 70 */ 69 */ 71 static inline bool same_state_synchronize_rcu_ !! 70 static inline void synchronize_rcu_bh_expedited(void) 72 << 73 { 71 { 74 return rgosp1->rgos_norm == rgosp2->rg !! 72 synchronize_sched_expedited(); 75 } 73 } 76 74 77 unsigned long start_poll_synchronize_rcu_exped !! 75 extern void rcu_barrier(void); 78 void start_poll_synchronize_rcu_expedited_full !! 76 extern void rcu_barrier_bh(void); 79 void cond_synchronize_rcu_expedited(unsigned l !! 77 extern void rcu_barrier_sched(void); 80 void cond_synchronize_rcu_expedited_full(struc !! 78 81 unsigned long get_state_synchronize_rcu(void); !! 79 extern unsigned long rcutorture_testseq; 82 void get_state_synchronize_rcu_full(struct rcu !! 80 extern unsigned long rcutorture_vernum; 83 unsigned long start_poll_synchronize_rcu(void) !! 81 extern long rcu_batches_completed(void); 84 void start_poll_synchronize_rcu_full(struct rc !! 82 extern long rcu_batches_completed_bh(void); 85 bool poll_state_synchronize_rcu(unsigned long !! 83 extern long rcu_batches_completed_sched(void); 86 bool poll_state_synchronize_rcu_full(struct rc !! 84 87 void cond_synchronize_rcu(unsigned long oldsta !! 85 extern void rcu_force_quiescent_state(void); 88 void cond_synchronize_rcu_full(struct rcu_gp_o !! 86 extern void rcu_bh_force_quiescent_state(void); 89 !! 87 extern void rcu_sched_force_quiescent_state(void); 90 #ifdef CONFIG_PROVE_RCU << 91 void rcu_irq_exit_check_preempt(void); << 92 #else << 93 static inline void rcu_irq_exit_check_preempt( << 94 #endif << 95 << 96 struct task_struct; << 97 void rcu_preempt_deferred_qs(struct task_struc << 98 << 99 void exit_rcu(void); << 100 << 101 void rcu_scheduler_starting(void); << 102 extern int rcu_scheduler_active; << 103 void rcu_end_inkernel_boot(void); << 104 bool rcu_inkernel_boot_has_ended(void); << 105 bool rcu_is_watching(void); << 106 #ifndef CONFIG_PREEMPTION << 107 void rcu_all_qs(void); << 108 #endif << 109 << 110 /* RCUtree hotplug events */ << 111 int rcutree_prepare_cpu(unsigned int cpu); << 112 int rcutree_online_cpu(unsigned int cpu); << 113 void rcutree_report_cpu_starting(unsigned int << 114 << 115 #ifdef CONFIG_HOTPLUG_CPU << 116 int rcutree_dead_cpu(unsigned int cpu); << 117 int rcutree_dying_cpu(unsigned int cpu); << 118 int rcutree_offline_cpu(unsigned int cpu); << 119 #else << 120 #define rcutree_dead_cpu NULL << 121 #define rcutree_dying_cpu NULL << 122 #define rcutree_offline_cpu NULL << 123 #endif << 124 << 125 void rcutree_migrate_callbacks(int cpu); << 126 88 127 /* Called from hotplug and also arm64 early se !! 89 extern void rcu_scheduler_starting(void); 128 void rcutree_report_cpu_dead(void); !! 90 extern int rcu_scheduler_active __read_mostly; 129 91 130 #endif /* __LINUX_RCUTREE_H */ 92 #endif /* __LINUX_RCUTREE_H */ 131 93
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