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, you can access it online at
>> 16 * http://www.gnu.org/licenses/gpl-2.0.html.
>> 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); <<
21 void rcu_note_context_switch(bool preempt); 33 void rcu_note_context_switch(bool preempt);
22 int rcu_needs_cpu(void); !! 34 int rcu_needs_cpu(u64 basem, u64 *nextevt);
23 void rcu_cpu_stall_reset(void); 35 void rcu_cpu_stall_reset(void);
24 void rcu_request_urgent_qs_task(struct task_st <<
25 36
26 /* 37 /*
27 * Note a virtualization-based context switch. 38 * Note a virtualization-based context switch. This is simply a
28 * wrapper around rcu_note_context_switch(), w 39 * wrapper around rcu_note_context_switch(), which allows TINY_RCU
29 * to save a few bytes. The caller must have d 40 * to save a few bytes. The caller must have disabled interrupts.
30 */ 41 */
31 static inline void rcu_virt_note_context_switc !! 42 static inline void rcu_virt_note_context_switch(int cpu)
32 { 43 {
33 rcu_note_context_switch(false); 44 rcu_note_context_switch(false);
34 } 45 }
35 46
>> 47 void synchronize_rcu_bh(void);
>> 48 void synchronize_sched_expedited(void);
36 void synchronize_rcu_expedited(void); 49 void synchronize_rcu_expedited(void);
37 void kvfree_call_rcu(struct rcu_head *head, vo <<
38 50
39 void rcu_barrier(void); !! 51 void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func);
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 52
53 /** 53 /**
54 * same_state_synchronize_rcu_full - Are two o !! 54 * synchronize_rcu_bh_expedited - Brute-force RCU-bh grace period
55 * @rgosp1: First old-state value. !! 55 *
56 * @rgosp2: Second old-state value. !! 56 * Wait for an RCU-bh grace period to elapse, but use a "big hammer"
57 * !! 57 * approach to force the grace period to end quickly. This consumes
58 * The two old-state values must have been obt !! 58 * significant time on all CPUs and is unfriendly to real-time workloads,
59 * get_state_synchronize_rcu_full(), start_pol !! 59 * so is thus not recommended for any sort of common-case code. In fact,
60 * or get_completed_synchronize_rcu_full(). R !! 60 * if you are using synchronize_rcu_bh_expedited() in a loop, please
61 * values are identical and @false otherwise. !! 61 * restructure your code to batch your updates, and then use a single
62 * whose lifetimes are tracked by old-state va !! 62 * synchronize_rcu_bh() instead.
63 * to a list header, allowing those structures !! 63 *
64 * !! 64 * Note that it is illegal to call this function while holding any lock
65 * Note that equality is judged on a bitwise b !! 65 * that is acquired by a CPU-hotplug notifier. And yes, it is also illegal
66 * @rcu_gp_oldstate structure with an already- !! 66 * to call this function from a CPU-hotplug notifier. Failing to observe
67 * will compare not-equal to a structure with !! 67 * 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 */ 68 */
71 static inline bool same_state_synchronize_rcu_ !! 69 static inline void synchronize_rcu_bh_expedited(void)
72 <<
73 { 70 {
74 return rgosp1->rgos_norm == rgosp2->rg !! 71 synchronize_sched_expedited();
75 } 72 }
76 73
77 unsigned long start_poll_synchronize_rcu_exped !! 74 void rcu_barrier(void);
78 void start_poll_synchronize_rcu_expedited_full !! 75 void rcu_barrier_bh(void);
79 void cond_synchronize_rcu_expedited(unsigned l !! 76 void rcu_barrier_sched(void);
80 void cond_synchronize_rcu_expedited_full(struc !! 77 bool rcu_eqs_special_set(int cpu);
81 unsigned long get_state_synchronize_rcu(void); 78 unsigned long get_state_synchronize_rcu(void);
82 void get_state_synchronize_rcu_full(struct rcu <<
83 unsigned long start_poll_synchronize_rcu(void) <<
84 void start_poll_synchronize_rcu_full(struct rc <<
85 bool poll_state_synchronize_rcu(unsigned long <<
86 bool poll_state_synchronize_rcu_full(struct rc <<
87 void cond_synchronize_rcu(unsigned long oldsta 79 void cond_synchronize_rcu(unsigned long oldstate);
88 void cond_synchronize_rcu_full(struct rcu_gp_o !! 80 unsigned long get_state_synchronize_sched(void);
89 !! 81 void cond_synchronize_sched(unsigned long oldstate);
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 82
96 struct task_struct; !! 83 void rcu_idle_enter(void);
97 void rcu_preempt_deferred_qs(struct task_struc !! 84 void rcu_idle_exit(void);
>> 85 void rcu_irq_enter(void);
>> 86 void rcu_irq_exit(void);
>> 87 void rcu_irq_enter_irqson(void);
>> 88 void rcu_irq_exit_irqson(void);
98 89
99 void exit_rcu(void); 90 void exit_rcu(void);
100 91
101 void rcu_scheduler_starting(void); 92 void rcu_scheduler_starting(void);
102 extern int rcu_scheduler_active; !! 93 extern int rcu_scheduler_active __read_mostly;
103 void rcu_end_inkernel_boot(void); 94 void rcu_end_inkernel_boot(void);
104 bool rcu_inkernel_boot_has_ended(void); <<
105 bool rcu_is_watching(void); 95 bool rcu_is_watching(void);
106 #ifndef CONFIG_PREEMPTION <<
107 void rcu_all_qs(void); 96 void rcu_all_qs(void);
108 #endif <<
109 97
110 /* RCUtree hotplug events */ 98 /* RCUtree hotplug events */
111 int rcutree_prepare_cpu(unsigned int cpu); 99 int rcutree_prepare_cpu(unsigned int cpu);
112 int rcutree_online_cpu(unsigned int cpu); 100 int rcutree_online_cpu(unsigned int cpu);
113 void rcutree_report_cpu_starting(unsigned int !! 101 int rcutree_offline_cpu(unsigned int cpu);
114 <<
115 #ifdef CONFIG_HOTPLUG_CPU <<
116 int rcutree_dead_cpu(unsigned int cpu); 102 int rcutree_dead_cpu(unsigned int cpu);
117 int rcutree_dying_cpu(unsigned int cpu); 103 int rcutree_dying_cpu(unsigned int cpu);
118 int rcutree_offline_cpu(unsigned int cpu); !! 104 void rcu_cpu_starting(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 <<
127 /* Called from hotplug and also arm64 early se <<
128 void rcutree_report_cpu_dead(void); <<
129 105
130 #endif /* __LINUX_RCUTREE_H */ 106 #endif /* __LINUX_RCUTREE_H */
131 107
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