aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/rcu/rcu_segcblist.h
blob: 581c12b6354434f7a847e7560514aaa58c7a3777 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
/*
 * RCU segmented callback lists, internal-to-rcu header file
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you can access it online at
 * http://www.gnu.org/licenses/gpl-2.0.html.
 *
 * Copyright IBM Corporation, 2017
 *
 * Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
 */

#include <linux/rcu_segcblist.h>

/*
 * Account for the fact that a previously dequeued callback turned out
 * to be marked as lazy.
 */
static inline void rcu_cblist_dequeued_lazy(struct rcu_cblist *rclp)
{
	rclp->len_lazy--;
}

void rcu_cblist_init(struct rcu_cblist *rclp);
struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp);

/*
 * Is the specified rcu_segcblist structure empty?
 *
 * But careful!  The fact that the ->head field is NULL does not
 * necessarily imply that there are no callbacks associated with
 * this structure.  When callbacks are being invoked, they are
 * removed as a group.  If callback invocation must be preempted,
 * the remaining callbacks will be added back to the list.  Either
 * way, the counts are updated later.
 *
 * So it is often the case that rcu_segcblist_n_cbs() should be used
 * instead.
 */
static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp)
{
	return !rsclp->head;
}

/* Return number of callbacks in segmented callback list. */
static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
{
	return READ_ONCE(rsclp->len);
}

/* Return number of lazy callbacks in segmented callback list. */
static inline long rcu_segcblist_n_lazy_cbs(struct rcu_segcblist *rsclp)
{
	return rsclp->len_lazy;
}

/* Return number of lazy callbacks in segmented callback list. */
static inline long rcu_segcblist_n_nonlazy_cbs(struct rcu_segcblist *rsclp)
{
	return rsclp->len - rsclp->len_lazy;
}

/*
 * Is the specified rcu_segcblist enabled, for example, not corresponding
 * to an offline or callback-offloaded CPU?
 */
static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
{
	return !!rsclp->tails[RCU_NEXT_TAIL];
}

/*
 * Are all segments following the specified segment of the specified
 * rcu_segcblist structure empty of callbacks?  (The specified
 * segment might well contain callbacks.)
 */
static inline bool rcu_segcblist_restempty(struct rcu_segcblist *rsclp, int seg)
{
	return !*rsclp->tails[seg];
}

/*
 * Interim function to return rcu_segcblist head pointer.  Longer term, the
 * rcu_segcblist will be used more pervasively, removing the need for this
 * function.
 */
static inline struct rcu_head *rcu_segcblist_head(struct rcu_segcblist *rsclp)
{
	return rsclp->head;
}

/*
 * Interim function to return rcu_segcblist head pointer.  Longer term, the
 * rcu_segcblist will be used more pervasively, removing the need for this
 * function.
 */
static inline struct rcu_head **rcu_segcblist_tail(struct rcu_segcblist *rsclp)
{
	WARN_ON_ONCE(rcu_segcblist_empty(rsclp));
	return rsclp->tails[RCU_NEXT_TAIL];
}

void rcu_segcblist_init(struct rcu_segcblist *rsclp);
void rcu_segcblist_disable(struct rcu_segcblist *rsclp);
bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp);
bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp);
struct rcu_head *rcu_segcblist_first_cb(struct rcu_segcblist *rsclp);
struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp);
void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp,
			   struct rcu_head *rhp, bool lazy);
bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp,
			   struct rcu_head *rhp, bool lazy);
void rcu_segcblist_extract_count(struct rcu_segcblist *rsclp,
				 struct rcu_cblist *rclp);
void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp,
				    struct rcu_cblist *rclp);
void rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp,
				    struct rcu_cblist *rclp);
void rcu_segcblist_insert_count(struct rcu_segcblist *rsclp,
				struct rcu_cblist *rclp);
void rcu_segcblist_insert_done_cbs(struct rcu_segcblist *rsclp,
				   struct rcu_cblist *rclp);
void rcu_segcblist_insert_pend_cbs(struct rcu_segcblist *rsclp,
				   struct rcu_cblist *rclp);
void rcu_segcblist_advance(struct rcu_segcblist *rsclp, unsigned long seq);
bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq);
bool rcu_segcblist_future_gp_needed(struct rcu_segcblist *rsclp,
				    unsigned long seq);
void rcu_segcblist_merge(struct rcu_segcblist *dst_rsclp,
			 struct rcu_segcblist *src_rsclp);