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 struct notifier_block;
21 void rcu_note_context_switch(bool preempt); <<
22 int rcu_needs_cpu(void); <<
23 void rcu_cpu_stall_reset(void); <<
24 void rcu_request_urgent_qs_task(struct task_st <<
25 34
26 /* !! 35 extern void rcu_sched_qs(int cpu);
27 * Note a virtualization-based context switch. !! 36 extern void rcu_bh_qs(int cpu);
28 * wrapper around rcu_note_context_switch(), w !! 37 extern int rcu_cpu_notify(struct notifier_block *self,
29 * to save a few bytes. The caller must have d !! 38 unsigned long action, void *hcpu);
30 */ !! 39 extern int rcu_needs_cpu(int cpu);
31 static inline void rcu_virt_note_context_switc !! 40 extern int rcu_expedited_torture_stats(char *page);
>> 41
>> 42 #ifdef CONFIG_TREE_PREEMPT_RCU
>> 43
>> 44 extern void __rcu_read_lock(void);
>> 45 extern void __rcu_read_unlock(void);
>> 46 extern void exit_rcu(void);
>> 47
>> 48 #else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
>> 49
>> 50 static inline void __rcu_read_lock(void)
32 { 51 {
33 rcu_note_context_switch(false); !! 52 preempt_disable();
34 } 53 }
35 54
36 void synchronize_rcu_expedited(void); !! 55 static inline void __rcu_read_unlock(void)
37 void kvfree_call_rcu(struct rcu_head *head, vo !! 56 {
38 void kvfree_rcu_barrier(void); !! 57 preempt_enable();
39 !! 58 }
40 void rcu_barrier(void); !! 59
41 void rcu_momentary_eqs(void); !! 60 #define __synchronize_sched() synchronize_rcu()
42 void kfree_rcu_scheduler_running(void); !! 61
43 bool rcu_gp_might_be_stalled(void); !! 62 static inline void exit_rcu(void)
44 !! 63 {
45 struct rcu_gp_oldstate { !! 64 }
46 unsigned long rgos_norm; !! 65
47 unsigned long rgos_exp; !! 66 #endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
48 }; !! 67
49 !! 68 static inline void __rcu_read_lock_bh(void)
50 // Maximum number of rcu_gp_oldstate values co !! 69 {
51 // not-yet-completed RCU grace periods. !! 70 local_bh_disable();
52 #define NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE 4 !! 71 }
53 !! 72 static inline void __rcu_read_unlock_bh(void)
54 /** !! 73 {
55 * same_state_synchronize_rcu_full - Are two o !! 74 local_bh_enable();
56 * @rgosp1: First old-state value. !! 75 }
57 * @rgosp2: Second old-state value. !! 76
58 * !! 77 extern void call_rcu_sched(struct rcu_head *head,
59 * The two old-state values must have been obt !! 78 void (*func)(struct rcu_head *rcu));
60 * get_state_synchronize_rcu_full(), start_pol !! 79 extern void synchronize_rcu_expedited(void);
61 * or get_completed_synchronize_rcu_full(). R !! 80
62 * values are identical and @false otherwise. !! 81 static inline void synchronize_rcu_bh_expedited(void)
63 * whose lifetimes are tracked by old-state va <<
64 * to a list header, allowing those structures <<
65 * <<
66 * Note that equality is judged on a bitwise b <<
67 * @rcu_gp_oldstate structure with an already- <<
68 * will compare not-equal to a structure with <<
69 * in the other field. After all, the @rcu_gp <<
70 * so how did such a situation come to pass in <<
71 */ <<
72 static inline bool same_state_synchronize_rcu_ <<
73 <<
74 { 82 {
75 return rgosp1->rgos_norm == rgosp2->rg !! 83 synchronize_sched_expedited();
76 } 84 }
77 85
78 unsigned long start_poll_synchronize_rcu_exped !! 86 extern void __rcu_init(void);
79 void start_poll_synchronize_rcu_expedited_full !! 87 extern void rcu_check_callbacks(int cpu, int user);
80 void cond_synchronize_rcu_expedited(unsigned l <<
81 void cond_synchronize_rcu_expedited_full(struc <<
82 unsigned long get_state_synchronize_rcu(void); <<
83 void get_state_synchronize_rcu_full(struct rcu <<
84 unsigned long start_poll_synchronize_rcu(void) <<
85 void start_poll_synchronize_rcu_full(struct rc <<
86 bool poll_state_synchronize_rcu(unsigned long <<
87 bool poll_state_synchronize_rcu_full(struct rc <<
88 void cond_synchronize_rcu(unsigned long oldsta <<
89 void cond_synchronize_rcu_full(struct rcu_gp_o <<
90 <<
91 #ifdef CONFIG_PROVE_RCU <<
92 void rcu_irq_exit_check_preempt(void); <<
93 #else <<
94 static inline void rcu_irq_exit_check_preempt( <<
95 #endif <<
96 <<
97 struct task_struct; <<
98 void rcu_preempt_deferred_qs(struct task_struc <<
99 <<
100 void exit_rcu(void); <<
101 <<
102 void rcu_scheduler_starting(void); <<
103 extern int rcu_scheduler_active; <<
104 void rcu_end_inkernel_boot(void); <<
105 bool rcu_inkernel_boot_has_ended(void); <<
106 bool rcu_is_watching(void); <<
107 #ifndef CONFIG_PREEMPTION <<
108 void rcu_all_qs(void); <<
109 #endif <<
110 <<
111 /* RCUtree hotplug events */ <<
112 int rcutree_prepare_cpu(unsigned int cpu); <<
113 int rcutree_online_cpu(unsigned int cpu); <<
114 void rcutree_report_cpu_starting(unsigned int <<
115 <<
116 #ifdef CONFIG_HOTPLUG_CPU <<
117 int rcutree_dead_cpu(unsigned int cpu); <<
118 int rcutree_dying_cpu(unsigned int cpu); <<
119 int rcutree_offline_cpu(unsigned int cpu); <<
120 #else <<
121 #define rcutree_dead_cpu NULL <<
122 #define rcutree_dying_cpu NULL <<
123 #define rcutree_offline_cpu NULL <<
124 #endif <<
125 88
126 void rcutree_migrate_callbacks(int cpu); !! 89 extern long rcu_batches_completed(void);
>> 90 extern long rcu_batches_completed_bh(void);
>> 91 extern long rcu_batches_completed_sched(void);
>> 92
>> 93 #ifdef CONFIG_NO_HZ
>> 94 void rcu_enter_nohz(void);
>> 95 void rcu_exit_nohz(void);
>> 96 #else /* CONFIG_NO_HZ */
>> 97 static inline void rcu_enter_nohz(void)
>> 98 {
>> 99 }
>> 100 static inline void rcu_exit_nohz(void)
>> 101 {
>> 102 }
>> 103 #endif /* CONFIG_NO_HZ */
127 104
128 /* Called from hotplug and also arm64 early se !! 105 /* A context switch is a grace period for RCU-sched and RCU-bh. */
129 void rcutree_report_cpu_dead(void); !! 106 static inline int rcu_blocking_is_gp(void)
>> 107 {
>> 108 return num_online_cpus() == 1;
>> 109 }
130 110
131 #endif /* __LINUX_RCUTREE_H */ 111 #endif /* __LINUX_RCUTREE_H */
132 112
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