diff options
Diffstat (limited to 'kernel/rcu/rcu.h')
-rw-r--r-- | kernel/rcu/rcu.h | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h new file mode 100644 index 000000000000..7859a0a3951e --- /dev/null +++ b/kernel/rcu/rcu.h | |||
@@ -0,0 +1,132 @@ | |||
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 | extern void kfree(const void *); | ||
100 | |||
101 | static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head) | ||
102 | { | ||
103 | unsigned long offset = (unsigned long)head->func; | ||
104 | |||
105 | if (__is_kfree_rcu_offset(offset)) { | ||
106 | RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset)); | ||
107 | kfree((void *)head - offset); | ||
108 | return 1; | ||
109 | } else { | ||
110 | RCU_TRACE(trace_rcu_invoke_callback(rn, head)); | ||
111 | head->func(head); | ||
112 | return 0; | ||
113 | } | ||
114 | } | ||
115 | |||
116 | extern int rcu_expedited; | ||
117 | |||
118 | #ifdef CONFIG_RCU_STALL_COMMON | ||
119 | |||
120 | extern int rcu_cpu_stall_suppress; | ||
121 | int rcu_jiffies_till_stall_check(void); | ||
122 | |||
123 | #endif /* #ifdef CONFIG_RCU_STALL_COMMON */ | ||
124 | |||
125 | /* | ||
126 | * Strings used in tracepoints need to be exported via the | ||
127 | * tracing system such that tools like perf and trace-cmd can | ||
128 | * translate the string address pointers to actual text. | ||
129 | */ | ||
130 | #define TPS(x) tracepoint_string(x) | ||
131 | |||
132 | #endif /* __LINUX_RCU_H */ | ||