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29c00b4a PM |
1 | /* |
2 | * Read-Copy Update definitions shared among RCU implementations. | |
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 | |
87de1cfd PM |
15 | * along with this program; if not, you can access it online at |
16 | * http://www.gnu.org/licenses/gpl-2.0.html. | |
29c00b4a PM |
17 | * |
18 | * Copyright IBM Corporation, 2011 | |
19 | * | |
20 | * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com> | |
21 | */ | |
22 | ||
23 | #ifndef __LINUX_RCU_H | |
24 | #define __LINUX_RCU_H | |
25 | ||
5cb5c6e1 | 26 | #include <trace/events/rcu.h> |
e99033c5 PM |
27 | #ifdef CONFIG_RCU_TRACE |
28 | #define RCU_TRACE(stmt) stmt | |
29 | #else /* #ifdef CONFIG_RCU_TRACE */ | |
30 | #define RCU_TRACE(stmt) | |
31 | #endif /* #else #ifdef CONFIG_RCU_TRACE */ | |
32 | ||
4145fa7f PM |
33 | /* |
34 | * Process-level increment to ->dynticks_nesting field. This allows for | |
35 | * architectures that use half-interrupts and half-exceptions from | |
36 | * process context. | |
29e37d81 PM |
37 | * |
38 | * DYNTICK_TASK_NEST_MASK defines a field of width DYNTICK_TASK_NEST_WIDTH | |
39 | * that counts the number of process-based reasons why RCU cannot | |
40 | * consider the corresponding CPU to be idle, and DYNTICK_TASK_NEST_VALUE | |
41 | * is the value used to increment or decrement this field. | |
42 | * | |
43 | * The rest of the bits could in principle be used to count interrupts, | |
44 | * but this would mean that a negative-one value in the interrupt | |
45 | * field could incorrectly zero out the DYNTICK_TASK_NEST_MASK field. | |
46 | * We therefore provide a two-bit guard field defined by DYNTICK_TASK_MASK | |
47 | * that is set to DYNTICK_TASK_FLAG upon initial exit from idle. | |
48 | * The DYNTICK_TASK_EXIT_IDLE value is thus the combined value used upon | |
49 | * initial exit from idle. | |
4145fa7f | 50 | */ |
29e37d81 PM |
51 | #define DYNTICK_TASK_NEST_WIDTH 7 |
52 | #define DYNTICK_TASK_NEST_VALUE ((LLONG_MAX >> DYNTICK_TASK_NEST_WIDTH) + 1) | |
53 | #define DYNTICK_TASK_NEST_MASK (LLONG_MAX - DYNTICK_TASK_NEST_VALUE + 1) | |
54 | #define DYNTICK_TASK_FLAG ((DYNTICK_TASK_NEST_VALUE / 8) * 2) | |
55 | #define DYNTICK_TASK_MASK ((DYNTICK_TASK_NEST_VALUE / 8) * 3) | |
56 | #define DYNTICK_TASK_EXIT_IDLE (DYNTICK_TASK_NEST_VALUE + \ | |
57 | DYNTICK_TASK_FLAG) | |
4145fa7f | 58 | |
29c00b4a PM |
59 | /* |
60 | * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally | |
61 | * by call_rcu() and rcu callback execution, and are therefore not part of the | |
62 | * RCU API. Leaving in rcupdate.h because they are used by all RCU flavors. | |
63 | */ | |
64 | ||
65 | #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD | |
66 | # define STATE_RCU_HEAD_READY 0 | |
67 | # define STATE_RCU_HEAD_QUEUED 1 | |
68 | ||
69 | extern struct debug_obj_descr rcuhead_debug_descr; | |
70 | ||
ae150184 | 71 | static inline int debug_rcu_head_queue(struct rcu_head *head) |
29c00b4a | 72 | { |
ae150184 PM |
73 | int r1; |
74 | ||
75 | r1 = debug_object_activate(head, &rcuhead_debug_descr); | |
29c00b4a PM |
76 | debug_object_active_state(head, &rcuhead_debug_descr, |
77 | STATE_RCU_HEAD_READY, | |
78 | STATE_RCU_HEAD_QUEUED); | |
ae150184 | 79 | return r1; |
29c00b4a PM |
80 | } |
81 | ||
82 | static inline void debug_rcu_head_unqueue(struct rcu_head *head) | |
83 | { | |
84 | debug_object_active_state(head, &rcuhead_debug_descr, | |
85 | STATE_RCU_HEAD_QUEUED, | |
86 | STATE_RCU_HEAD_READY); | |
87 | debug_object_deactivate(head, &rcuhead_debug_descr); | |
88 | } | |
89 | #else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */ | |
ae150184 | 90 | static inline int debug_rcu_head_queue(struct rcu_head *head) |
29c00b4a | 91 | { |
ae150184 | 92 | return 0; |
29c00b4a PM |
93 | } |
94 | ||
95 | static inline void debug_rcu_head_unqueue(struct rcu_head *head) | |
96 | { | |
97 | } | |
98 | #endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */ | |
99 | ||
bd73a7f5 | 100 | void kfree(const void *); |
29c00b4a | 101 | |
e66c33d5 | 102 | static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head) |
29c00b4a PM |
103 | { |
104 | unsigned long offset = (unsigned long)head->func; | |
105 | ||
24ef659a | 106 | rcu_lock_acquire(&rcu_callback_map); |
29c00b4a | 107 | if (__is_kfree_rcu_offset(offset)) { |
d4c08f2a | 108 | RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset)); |
29c00b4a | 109 | kfree((void *)head - offset); |
24ef659a | 110 | rcu_lock_release(&rcu_callback_map); |
486e2593 | 111 | return 1; |
29c00b4a | 112 | } else { |
d4c08f2a | 113 | RCU_TRACE(trace_rcu_invoke_callback(rn, head)); |
29c00b4a | 114 | head->func(head); |
24ef659a | 115 | rcu_lock_release(&rcu_callback_map); |
486e2593 | 116 | return 0; |
29c00b4a PM |
117 | } |
118 | } | |
119 | ||
6bfc09e2 PM |
120 | #ifdef CONFIG_RCU_STALL_COMMON |
121 | ||
122 | extern int rcu_cpu_stall_suppress; | |
123 | int rcu_jiffies_till_stall_check(void); | |
124 | ||
125 | #endif /* #ifdef CONFIG_RCU_STALL_COMMON */ | |
126 | ||
0d752924 PM |
127 | /* |
128 | * Strings used in tracepoints need to be exported via the | |
129 | * tracing system such that tools like perf and trace-cmd can | |
130 | * translate the string address pointers to actual text. | |
131 | */ | |
132 | #define TPS(x) tracepoint_string(x) | |
133 | ||
29c00b4a | 134 | #endif /* __LINUX_RCU_H */ |