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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
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 : : *
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 : :
26 : : #ifdef CONFIG_RCU_TRACE
27 : : #define RCU_TRACE(stmt) stmt
28 : : #else /* #ifdef CONFIG_RCU_TRACE */
29 : : #define RCU_TRACE(stmt)
30 : : #endif /* #else #ifdef CONFIG_RCU_TRACE */
31 : :
32 : : /*
33 : : * Process-level increment to ->dynticks_nesting field. This allows for
34 : : * architectures that use half-interrupts and half-exceptions from
35 : : * process context.
36 : : *
37 : : * DYNTICK_TASK_NEST_MASK defines a field of width DYNTICK_TASK_NEST_WIDTH
38 : : * that counts the number of process-based reasons why RCU cannot
39 : : * consider the corresponding CPU to be idle, and DYNTICK_TASK_NEST_VALUE
40 : : * is the value used to increment or decrement this field.
41 : : *
42 : : * The rest of the bits could in principle be used to count interrupts,
43 : : * but this would mean that a negative-one value in the interrupt
44 : : * field could incorrectly zero out the DYNTICK_TASK_NEST_MASK field.
45 : : * We therefore provide a two-bit guard field defined by DYNTICK_TASK_MASK
46 : : * that is set to DYNTICK_TASK_FLAG upon initial exit from idle.
47 : : * The DYNTICK_TASK_EXIT_IDLE value is thus the combined value used upon
48 : : * initial exit from idle.
49 : : */
50 : : #define DYNTICK_TASK_NEST_WIDTH 7
51 : : #define DYNTICK_TASK_NEST_VALUE ((LLONG_MAX >> DYNTICK_TASK_NEST_WIDTH) + 1)
52 : : #define DYNTICK_TASK_NEST_MASK (LLONG_MAX - DYNTICK_TASK_NEST_VALUE + 1)
53 : : #define DYNTICK_TASK_FLAG ((DYNTICK_TASK_NEST_VALUE / 8) * 2)
54 : : #define DYNTICK_TASK_MASK ((DYNTICK_TASK_NEST_VALUE / 8) * 3)
55 : : #define DYNTICK_TASK_EXIT_IDLE (DYNTICK_TASK_NEST_VALUE + \
56 : : DYNTICK_TASK_FLAG)
57 : :
58 : : /*
59 : : * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally
60 : : * by call_rcu() and rcu callback execution, and are therefore not part of the
61 : : * RCU API. Leaving in rcupdate.h because they are used by all RCU flavors.
62 : : */
63 : :
64 : : #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
65 : : # define STATE_RCU_HEAD_READY 0
66 : : # define STATE_RCU_HEAD_QUEUED 1
67 : :
68 : : extern struct debug_obj_descr rcuhead_debug_descr;
69 : :
70 : : static inline int debug_rcu_head_queue(struct rcu_head *head)
71 : : {
72 : : int r1;
73 : :
74 : : r1 = debug_object_activate(head, &rcuhead_debug_descr);
75 : : debug_object_active_state(head, &rcuhead_debug_descr,
76 : : STATE_RCU_HEAD_READY,
77 : : STATE_RCU_HEAD_QUEUED);
78 : : return r1;
79 : : }
80 : :
81 : : static inline void debug_rcu_head_unqueue(struct rcu_head *head)
82 : : {
83 : : debug_object_active_state(head, &rcuhead_debug_descr,
84 : : STATE_RCU_HEAD_QUEUED,
85 : : STATE_RCU_HEAD_READY);
86 : : debug_object_deactivate(head, &rcuhead_debug_descr);
87 : : }
88 : : #else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
89 : : static inline int debug_rcu_head_queue(struct rcu_head *head)
90 : : {
91 : : return 0;
92 : : }
93 : :
94 : : static inline void debug_rcu_head_unqueue(struct rcu_head *head)
95 : : {
96 : : }
97 : : #endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
98 : :
99 : : void kfree(const void *);
100 : :
101 : : static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head)
102 : : {
103 : 10655057 : unsigned long offset = (unsigned long)head->func;
104 : :
105 : : rcu_lock_acquire(&rcu_callback_map);
106 [ + + ]: 10655057 : if (__is_kfree_rcu_offset(offset)) {
107 : : RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset));
108 : 560554 : kfree((void *)head - offset);
109 : : rcu_lock_release(&rcu_callback_map);
110 : : return 1;
111 : : } else {
112 : : RCU_TRACE(trace_rcu_invoke_callback(rn, head));
113 : 10094503 : head->func(head);
114 : : rcu_lock_release(&rcu_callback_map);
115 : : return 0;
116 : : }
117 : : }
118 : :
119 : : extern int rcu_expedited;
120 : :
121 : : #ifdef CONFIG_RCU_STALL_COMMON
122 : :
123 : : extern int rcu_cpu_stall_suppress;
124 : : int rcu_jiffies_till_stall_check(void);
125 : :
126 : : #endif /* #ifdef CONFIG_RCU_STALL_COMMON */
127 : :
128 : : /*
129 : : * Strings used in tracepoints need to be exported via the
130 : : * tracing system such that tools like perf and trace-cmd can
131 : : * translate the string address pointers to actual text.
132 : : */
133 : : #define TPS(x) tracepoint_string(x)
134 : :
135 : : #endif /* __LINUX_RCU_H */
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