Merge tag 'block-5.17-2022-01-28' of git://git.kernel.dk/linux-block
[linux-2.6-microblaze.git] / kernel / delayacct.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* delayacct.c - per-task delay accounting
3  *
4  * Copyright (C) Shailabh Nagar, IBM Corp. 2006
5  */
6
7 #include <linux/sched.h>
8 #include <linux/sched/task.h>
9 #include <linux/sched/cputime.h>
10 #include <linux/sched/clock.h>
11 #include <linux/slab.h>
12 #include <linux/taskstats.h>
13 #include <linux/sysctl.h>
14 #include <linux/delayacct.h>
15 #include <linux/module.h>
16
17 DEFINE_STATIC_KEY_FALSE(delayacct_key);
18 int delayacct_on __read_mostly; /* Delay accounting turned on/off */
19 struct kmem_cache *delayacct_cache;
20
21 static void set_delayacct(bool enabled)
22 {
23         if (enabled) {
24                 static_branch_enable(&delayacct_key);
25                 delayacct_on = 1;
26         } else {
27                 delayacct_on = 0;
28                 static_branch_disable(&delayacct_key);
29         }
30 }
31
32 static int __init delayacct_setup_enable(char *str)
33 {
34         delayacct_on = 1;
35         return 1;
36 }
37 __setup("delayacct", delayacct_setup_enable);
38
39 void delayacct_init(void)
40 {
41         delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT);
42         delayacct_tsk_init(&init_task);
43         set_delayacct(delayacct_on);
44 }
45
46 #ifdef CONFIG_PROC_SYSCTL
47 int sysctl_delayacct(struct ctl_table *table, int write, void *buffer,
48                      size_t *lenp, loff_t *ppos)
49 {
50         int state = delayacct_on;
51         struct ctl_table t;
52         int err;
53
54         if (write && !capable(CAP_SYS_ADMIN))
55                 return -EPERM;
56
57         t = *table;
58         t.data = &state;
59         err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
60         if (err < 0)
61                 return err;
62         if (write)
63                 set_delayacct(state);
64         return err;
65 }
66 #endif
67
68 void __delayacct_tsk_init(struct task_struct *tsk)
69 {
70         tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
71         if (tsk->delays)
72                 raw_spin_lock_init(&tsk->delays->lock);
73 }
74
75 /*
76  * Finish delay accounting for a statistic using its timestamps (@start),
77  * accumalator (@total) and @count
78  */
79 static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total, u32 *count)
80 {
81         s64 ns = local_clock() - *start;
82         unsigned long flags;
83
84         if (ns > 0) {
85                 raw_spin_lock_irqsave(lock, flags);
86                 *total += ns;
87                 (*count)++;
88                 raw_spin_unlock_irqrestore(lock, flags);
89         }
90 }
91
92 void __delayacct_blkio_start(void)
93 {
94         current->delays->blkio_start = local_clock();
95 }
96
97 /*
98  * We cannot rely on the `current` macro, as we haven't yet switched back to
99  * the process being woken.
100  */
101 void __delayacct_blkio_end(struct task_struct *p)
102 {
103         delayacct_end(&p->delays->lock,
104                       &p->delays->blkio_start,
105                       &p->delays->blkio_delay,
106                       &p->delays->blkio_count);
107 }
108
109 int delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
110 {
111         u64 utime, stime, stimescaled, utimescaled;
112         unsigned long long t2, t3;
113         unsigned long flags, t1;
114         s64 tmp;
115
116         task_cputime(tsk, &utime, &stime);
117         tmp = (s64)d->cpu_run_real_total;
118         tmp += utime + stime;
119         d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
120
121         task_cputime_scaled(tsk, &utimescaled, &stimescaled);
122         tmp = (s64)d->cpu_scaled_run_real_total;
123         tmp += utimescaled + stimescaled;
124         d->cpu_scaled_run_real_total =
125                 (tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp;
126
127         /*
128          * No locking available for sched_info (and too expensive to add one)
129          * Mitigate by taking snapshot of values
130          */
131         t1 = tsk->sched_info.pcount;
132         t2 = tsk->sched_info.run_delay;
133         t3 = tsk->se.sum_exec_runtime;
134
135         d->cpu_count += t1;
136
137         tmp = (s64)d->cpu_delay_total + t2;
138         d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
139
140         tmp = (s64)d->cpu_run_virtual_total + t3;
141         d->cpu_run_virtual_total =
142                 (tmp < (s64)d->cpu_run_virtual_total) ? 0 : tmp;
143
144         if (!tsk->delays)
145                 return 0;
146
147         /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
148
149         raw_spin_lock_irqsave(&tsk->delays->lock, flags);
150         tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
151         d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
152         tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
153         d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
154         tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
155         d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
156         tmp = d->thrashing_delay_total + tsk->delays->thrashing_delay;
157         d->thrashing_delay_total = (tmp < d->thrashing_delay_total) ? 0 : tmp;
158         tmp = d->compact_delay_total + tsk->delays->compact_delay;
159         d->compact_delay_total = (tmp < d->compact_delay_total) ? 0 : tmp;
160         d->blkio_count += tsk->delays->blkio_count;
161         d->swapin_count += tsk->delays->swapin_count;
162         d->freepages_count += tsk->delays->freepages_count;
163         d->thrashing_count += tsk->delays->thrashing_count;
164         d->compact_count += tsk->delays->compact_count;
165         raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
166
167         return 0;
168 }
169
170 __u64 __delayacct_blkio_ticks(struct task_struct *tsk)
171 {
172         __u64 ret;
173         unsigned long flags;
174
175         raw_spin_lock_irqsave(&tsk->delays->lock, flags);
176         ret = nsec_to_clock_t(tsk->delays->blkio_delay);
177         raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
178         return ret;
179 }
180
181 void __delayacct_freepages_start(void)
182 {
183         current->delays->freepages_start = local_clock();
184 }
185
186 void __delayacct_freepages_end(void)
187 {
188         delayacct_end(&current->delays->lock,
189                       &current->delays->freepages_start,
190                       &current->delays->freepages_delay,
191                       &current->delays->freepages_count);
192 }
193
194 void __delayacct_thrashing_start(void)
195 {
196         current->delays->thrashing_start = local_clock();
197 }
198
199 void __delayacct_thrashing_end(void)
200 {
201         delayacct_end(&current->delays->lock,
202                       &current->delays->thrashing_start,
203                       &current->delays->thrashing_delay,
204                       &current->delays->thrashing_count);
205 }
206
207 void __delayacct_swapin_start(void)
208 {
209         current->delays->swapin_start = local_clock();
210 }
211
212 void __delayacct_swapin_end(void)
213 {
214         delayacct_end(&current->delays->lock,
215                       &current->delays->swapin_start,
216                       &current->delays->swapin_delay,
217                       &current->delays->swapin_count);
218 }
219
220 void __delayacct_compact_start(void)
221 {
222         current->delays->compact_start = local_clock();
223 }
224
225 void __delayacct_compact_end(void)
226 {
227         delayacct_end(&current->delays->lock,
228                       &current->delays->compact_start,
229                       &current->delays->compact_delay,
230                       &current->delays->compact_count);
231 }