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1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/* delayacct.h - per-task delay accounting
3 *
4 * Copyright (C) Shailabh Nagar, IBM Corp. 2006
5 */
6
7#ifndef _LINUX_DELAYACCT_H
8#define _LINUX_DELAYACCT_H
9
10#include <uapi/linux/taskstats.h>
11
12/*
13 * Per-task flags relevant to delay accounting
14 * maintained privately to avoid exhausting similar flags in sched.h:PF_*
15 * Used to set current->delays->flags
16 */
17#define DELAYACCT_PF_SWAPIN 0x00000001 /* I am doing a swapin */
18#define DELAYACCT_PF_BLKIO 0x00000002 /* I am waiting on IO */
19
20#ifdef CONFIG_TASK_DELAY_ACCT
21struct task_delay_info {
22 raw_spinlock_t lock;
23 unsigned int flags; /* Private per-task flags */
24
25 /* For each stat XXX, add following, aligned appropriately
26 *
27 * struct timespec XXX_start, XXX_end;
28 * u64 XXX_delay;
29 * u32 XXX_count;
30 *
31 * Atomicity of updates to XXX_delay, XXX_count protected by
32 * single lock above (split into XXX_lock if contention is an issue).
33 */
34
35 /*
36 * XXX_count is incremented on every XXX operation, the delay
37 * associated with the operation is added to XXX_delay.
38 * XXX_delay contains the accumulated delay time in nanoseconds.
39 */
40 u64 blkio_start; /* Shared by blkio, swapin */
41 u64 blkio_delay; /* wait for sync block io completion */
42 u64 swapin_delay; /* wait for swapin block io completion */
43 u32 blkio_count; /* total count of the number of sync block */
44 /* io operations performed */
45 u32 swapin_count; /* total count of the number of swapin block */
46 /* io operations performed */
47
48 u64 freepages_start;
49 u64 freepages_delay; /* wait for memory reclaim */
50
51 u64 thrashing_start;
52 u64 thrashing_delay; /* wait for thrashing page */
53
54 u32 freepages_count; /* total count of memory reclaim */
55 u32 thrashing_count; /* total count of thrash waits */
56};
57#endif
58
59#include <linux/sched.h>
60#include <linux/slab.h>
61#include <linux/jump_label.h>
62
63#ifdef CONFIG_TASK_DELAY_ACCT
64DECLARE_STATIC_KEY_FALSE(delayacct_key);
65extern int delayacct_on; /* Delay accounting turned on/off */
66extern struct kmem_cache *delayacct_cache;
67extern void delayacct_init(void);
68
69extern int sysctl_delayacct(struct ctl_table *table, int write, void *buffer,
70 size_t *lenp, loff_t *ppos);
71
72extern void __delayacct_tsk_init(struct task_struct *);
73extern void __delayacct_tsk_exit(struct task_struct *);
74extern void __delayacct_blkio_start(void);
75extern void __delayacct_blkio_end(struct task_struct *);
76extern int delayacct_add_tsk(struct taskstats *, struct task_struct *);
77extern __u64 __delayacct_blkio_ticks(struct task_struct *);
78extern void __delayacct_freepages_start(void);
79extern void __delayacct_freepages_end(void);
80extern void __delayacct_thrashing_start(void);
81extern void __delayacct_thrashing_end(void);
82
83static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
84{
85 if (p->delays)
86 return (p->delays->flags & DELAYACCT_PF_BLKIO);
87 else
88 return 0;
89}
90
91static inline void delayacct_set_flag(struct task_struct *p, int flag)
92{
93 if (p->delays)
94 p->delays->flags |= flag;
95}
96
97static inline void delayacct_clear_flag(struct task_struct *p, int flag)
98{
99 if (p->delays)
100 p->delays->flags &= ~flag;
101}
102
103static inline void delayacct_tsk_init(struct task_struct *tsk)
104{
105 /* reinitialize in case parent's non-null pointer was dup'ed*/
106 tsk->delays = NULL;
107 if (delayacct_on)
108 __delayacct_tsk_init(tsk);
109}
110
111/* Free tsk->delays. Called from bad fork and __put_task_struct
112 * where there's no risk of tsk->delays being accessed elsewhere
113 */
114static inline void delayacct_tsk_free(struct task_struct *tsk)
115{
116 if (tsk->delays)
117 kmem_cache_free(delayacct_cache, tsk->delays);
118 tsk->delays = NULL;
119}
120
121static inline void delayacct_blkio_start(void)
122{
123 if (!static_branch_unlikely(&delayacct_key))
124 return;
125
126 delayacct_set_flag(current, DELAYACCT_PF_BLKIO);
127 if (current->delays)
128 __delayacct_blkio_start();
129}
130
131static inline void delayacct_blkio_end(struct task_struct *p)
132{
133 if (!static_branch_unlikely(&delayacct_key))
134 return;
135
136 if (p->delays)
137 __delayacct_blkio_end(p);
138 delayacct_clear_flag(p, DELAYACCT_PF_BLKIO);
139}
140
141static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
142{
143 if (tsk->delays)
144 return __delayacct_blkio_ticks(tsk);
145 return 0;
146}
147
148static inline void delayacct_freepages_start(void)
149{
150 if (current->delays)
151 __delayacct_freepages_start();
152}
153
154static inline void delayacct_freepages_end(void)
155{
156 if (current->delays)
157 __delayacct_freepages_end();
158}
159
160static inline void delayacct_thrashing_start(void)
161{
162 if (current->delays)
163 __delayacct_thrashing_start();
164}
165
166static inline void delayacct_thrashing_end(void)
167{
168 if (current->delays)
169 __delayacct_thrashing_end();
170}
171
172#else
173static inline void delayacct_set_flag(struct task_struct *p, int flag)
174{}
175static inline void delayacct_clear_flag(struct task_struct *p, int flag)
176{}
177static inline void delayacct_init(void)
178{}
179static inline void delayacct_tsk_init(struct task_struct *tsk)
180{}
181static inline void delayacct_tsk_free(struct task_struct *tsk)
182{}
183static inline void delayacct_blkio_start(void)
184{}
185static inline void delayacct_blkio_end(struct task_struct *p)
186{}
187static inline int delayacct_add_tsk(struct taskstats *d,
188 struct task_struct *tsk)
189{ return 0; }
190static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
191{ return 0; }
192static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
193{ return 0; }
194static inline void delayacct_freepages_start(void)
195{}
196static inline void delayacct_freepages_end(void)
197{}
198static inline void delayacct_thrashing_start(void)
199{}
200static inline void delayacct_thrashing_end(void)
201{}
202
203#endif /* CONFIG_TASK_DELAY_ACCT */
204
205#endif