1 /* SPDX-License-Identifier: GPL-2.0+ */ 1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /* 2 /*
3 * Read-Copy Update mechanism for mutual exclu 3 * Read-Copy Update mechanism for mutual exclusion (tree-based version)
4 * 4 *
5 * Copyright IBM Corporation, 2008 5 * Copyright IBM Corporation, 2008
6 * 6 *
7 * Author: Dipankar Sarma <dipankar@in.ibm.com 7 * Author: Dipankar Sarma <dipankar@in.ibm.com>
8 * Paul E. McKenney <paulmck@linux.ibm 8 * Paul E. McKenney <paulmck@linux.ibm.com> Hierarchical algorithm
9 * 9 *
10 * Based on the original work by Paul McKenney 10 * Based on the original work by Paul McKenney <paulmck@linux.ibm.com>
11 * and inputs from Rusty Russell, Andrea Arcan 11 * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
12 * 12 *
13 * For detailed explanation of Read-Copy Updat 13 * For detailed explanation of Read-Copy Update mechanism see -
14 * Documentation/RCU 14 * Documentation/RCU
15 */ 15 */
16 16
17 #ifndef __LINUX_RCUTREE_H 17 #ifndef __LINUX_RCUTREE_H
18 #define __LINUX_RCUTREE_H 18 #define __LINUX_RCUTREE_H
19 19
20 void rcu_softirq_qs(void); 20 void rcu_softirq_qs(void);
21 void rcu_note_context_switch(bool preempt); 21 void rcu_note_context_switch(bool preempt);
22 int rcu_needs_cpu(void); 22 int rcu_needs_cpu(void);
23 void rcu_cpu_stall_reset(void); 23 void rcu_cpu_stall_reset(void);
24 void rcu_request_urgent_qs_task(struct task_st 24 void rcu_request_urgent_qs_task(struct task_struct *t);
25 25
26 /* 26 /*
27 * Note a virtualization-based context switch. 27 * Note a virtualization-based context switch. This is simply a
28 * wrapper around rcu_note_context_switch(), w 28 * wrapper around rcu_note_context_switch(), which allows TINY_RCU
29 * to save a few bytes. The caller must have d 29 * to save a few bytes. The caller must have disabled interrupts.
30 */ 30 */
31 static inline void rcu_virt_note_context_switc 31 static inline void rcu_virt_note_context_switch(void)
32 { 32 {
33 rcu_note_context_switch(false); 33 rcu_note_context_switch(false);
34 } 34 }
35 35
36 void synchronize_rcu_expedited(void); 36 void synchronize_rcu_expedited(void);
37 void kvfree_call_rcu(struct rcu_head *head, vo 37 void kvfree_call_rcu(struct rcu_head *head, void *ptr);
38 void kvfree_rcu_barrier(void); 38 void kvfree_rcu_barrier(void);
39 39
40 void rcu_barrier(void); 40 void rcu_barrier(void);
41 void rcu_momentary_eqs(void); 41 void rcu_momentary_eqs(void);
42 void kfree_rcu_scheduler_running(void); 42 void kfree_rcu_scheduler_running(void);
43 bool rcu_gp_might_be_stalled(void); 43 bool rcu_gp_might_be_stalled(void);
44 44
45 struct rcu_gp_oldstate { 45 struct rcu_gp_oldstate {
46 unsigned long rgos_norm; 46 unsigned long rgos_norm;
47 unsigned long rgos_exp; 47 unsigned long rgos_exp;
48 }; 48 };
49 49
50 // Maximum number of rcu_gp_oldstate values co 50 // Maximum number of rcu_gp_oldstate values corresponding to
51 // not-yet-completed RCU grace periods. 51 // not-yet-completed RCU grace periods.
52 #define NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE 4 52 #define NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE 4
53 53
54 /** 54 /**
55 * same_state_synchronize_rcu_full - Are two o 55 * same_state_synchronize_rcu_full - Are two old-state values identical?
56 * @rgosp1: First old-state value. 56 * @rgosp1: First old-state value.
57 * @rgosp2: Second old-state value. 57 * @rgosp2: Second old-state value.
58 * 58 *
59 * The two old-state values must have been obt 59 * The two old-state values must have been obtained from either
60 * get_state_synchronize_rcu_full(), start_pol 60 * get_state_synchronize_rcu_full(), start_poll_synchronize_rcu_full(),
61 * or get_completed_synchronize_rcu_full(). R 61 * or get_completed_synchronize_rcu_full(). Returns @true if the two
62 * values are identical and @false otherwise. 62 * values are identical and @false otherwise. This allows structures
63 * whose lifetimes are tracked by old-state va 63 * whose lifetimes are tracked by old-state values to push these values
64 * to a list header, allowing those structures 64 * to a list header, allowing those structures to be slightly smaller.
65 * 65 *
66 * Note that equality is judged on a bitwise b 66 * Note that equality is judged on a bitwise basis, so that an
67 * @rcu_gp_oldstate structure with an already- 67 * @rcu_gp_oldstate structure with an already-completed state in one field
68 * will compare not-equal to a structure with 68 * will compare not-equal to a structure with an already-completed state
69 * in the other field. After all, the @rcu_gp 69 * in the other field. After all, the @rcu_gp_oldstate structure is opaque
70 * so how did such a situation come to pass in 70 * so how did such a situation come to pass in the first place?
71 */ 71 */
72 static inline bool same_state_synchronize_rcu_ 72 static inline bool same_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp1,
73 73 struct rcu_gp_oldstate *rgosp2)
74 { 74 {
75 return rgosp1->rgos_norm == rgosp2->rg 75 return rgosp1->rgos_norm == rgosp2->rgos_norm && rgosp1->rgos_exp == rgosp2->rgos_exp;
76 } 76 }
77 77
78 unsigned long start_poll_synchronize_rcu_exped 78 unsigned long start_poll_synchronize_rcu_expedited(void);
79 void start_poll_synchronize_rcu_expedited_full 79 void start_poll_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp);
80 void cond_synchronize_rcu_expedited(unsigned l 80 void cond_synchronize_rcu_expedited(unsigned long oldstate);
81 void cond_synchronize_rcu_expedited_full(struc 81 void cond_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp);
82 unsigned long get_state_synchronize_rcu(void); 82 unsigned long get_state_synchronize_rcu(void);
83 void get_state_synchronize_rcu_full(struct rcu 83 void get_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
84 unsigned long start_poll_synchronize_rcu(void) 84 unsigned long start_poll_synchronize_rcu(void);
85 void start_poll_synchronize_rcu_full(struct rc 85 void start_poll_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
86 bool poll_state_synchronize_rcu(unsigned long 86 bool poll_state_synchronize_rcu(unsigned long oldstate);
87 bool poll_state_synchronize_rcu_full(struct rc 87 bool poll_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
88 void cond_synchronize_rcu(unsigned long oldsta 88 void cond_synchronize_rcu(unsigned long oldstate);
89 void cond_synchronize_rcu_full(struct rcu_gp_o 89 void cond_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
90 90
91 #ifdef CONFIG_PROVE_RCU 91 #ifdef CONFIG_PROVE_RCU
92 void rcu_irq_exit_check_preempt(void); 92 void rcu_irq_exit_check_preempt(void);
93 #else 93 #else
94 static inline void rcu_irq_exit_check_preempt( 94 static inline void rcu_irq_exit_check_preempt(void) { }
95 #endif 95 #endif
96 96
97 struct task_struct; 97 struct task_struct;
98 void rcu_preempt_deferred_qs(struct task_struc 98 void rcu_preempt_deferred_qs(struct task_struct *t);
99 99
100 void exit_rcu(void); 100 void exit_rcu(void);
101 101
102 void rcu_scheduler_starting(void); 102 void rcu_scheduler_starting(void);
103 extern int rcu_scheduler_active; 103 extern int rcu_scheduler_active;
104 void rcu_end_inkernel_boot(void); 104 void rcu_end_inkernel_boot(void);
105 bool rcu_inkernel_boot_has_ended(void); 105 bool rcu_inkernel_boot_has_ended(void);
106 bool rcu_is_watching(void); 106 bool rcu_is_watching(void);
107 #ifndef CONFIG_PREEMPTION 107 #ifndef CONFIG_PREEMPTION
108 void rcu_all_qs(void); 108 void rcu_all_qs(void);
109 #endif 109 #endif
110 110
111 /* RCUtree hotplug events */ 111 /* RCUtree hotplug events */
112 int rcutree_prepare_cpu(unsigned int cpu); 112 int rcutree_prepare_cpu(unsigned int cpu);
113 int rcutree_online_cpu(unsigned int cpu); 113 int rcutree_online_cpu(unsigned int cpu);
114 void rcutree_report_cpu_starting(unsigned int 114 void rcutree_report_cpu_starting(unsigned int cpu);
115 115
116 #ifdef CONFIG_HOTPLUG_CPU 116 #ifdef CONFIG_HOTPLUG_CPU
117 int rcutree_dead_cpu(unsigned int cpu); 117 int rcutree_dead_cpu(unsigned int cpu);
118 int rcutree_dying_cpu(unsigned int cpu); 118 int rcutree_dying_cpu(unsigned int cpu);
119 int rcutree_offline_cpu(unsigned int cpu); 119 int rcutree_offline_cpu(unsigned int cpu);
120 #else 120 #else
121 #define rcutree_dead_cpu NULL 121 #define rcutree_dead_cpu NULL
122 #define rcutree_dying_cpu NULL 122 #define rcutree_dying_cpu NULL
123 #define rcutree_offline_cpu NULL 123 #define rcutree_offline_cpu NULL
124 #endif 124 #endif
125 125
126 void rcutree_migrate_callbacks(int cpu); 126 void rcutree_migrate_callbacks(int cpu);
127 127
128 /* Called from hotplug and also arm64 early se 128 /* Called from hotplug and also arm64 early secondary boot failure */
129 void rcutree_report_cpu_dead(void); 129 void rcutree_report_cpu_dead(void);
130 130
131 #endif /* __LINUX_RCUTREE_H */ 131 #endif /* __LINUX_RCUTREE_H */
132 132
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