1// SPDX-License-Identifier: GPL-2.0
2#include <linux/cpumask.h>
3#include <linux/fs.h>
4#include <linux/init.h>
5#include <linux/interrupt.h>
6#include <linux/kernel_stat.h>
7#include <linux/proc_fs.h>
8#include <linux/sched.h>
9#include <linux/sched/stat.h>
10#include <linux/seq_file.h>
11#include <linux/slab.h>
12#include <linux/time.h>
13#include <linux/time_namespace.h>
14#include <linux/irqnr.h>
15#include <linux/sched/cputime.h>
16#include <linux/tick.h>
17
18#ifndef arch_irq_stat_cpu
19#define arch_irq_stat_cpu(cpu) 0
20#endif
21#ifndef arch_irq_stat
22#define arch_irq_stat() 0
23#endif
24
25u64 get_idle_time(struct kernel_cpustat *kcs, int cpu)
26{
27 u64 idle, idle_usecs = -1ULL;
28
29 if (cpu_online(cpu))
30 idle_usecs = get_cpu_idle_time_us(cpu, NULL);
31
32 if (idle_usecs == -1ULL)
33 /* !NO_HZ or cpu offline so we can rely on cpustat.idle */
34 idle = kcs->cpustat[CPUTIME_IDLE];
35 else
36 idle = idle_usecs * NSEC_PER_USEC;
37
38 return idle;
39}
40
41static u64 get_iowait_time(struct kernel_cpustat *kcs, int cpu)
42{
43 u64 iowait, iowait_usecs = -1ULL;
44
45 if (cpu_online(cpu))
46 iowait_usecs = get_cpu_iowait_time_us(cpu, NULL);
47
48 if (iowait_usecs == -1ULL)
49 /* !NO_HZ or cpu offline so we can rely on cpustat.iowait */
50 iowait = kcs->cpustat[CPUTIME_IOWAIT];
51 else
52 iowait = iowait_usecs * NSEC_PER_USEC;
53
54 return iowait;
55}
56
57static void show_irq_gap(struct seq_file *p, unsigned int gap)
58{
59 static const char zeros[] = " 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0";
60
61 while (gap > 0) {
62 unsigned int inc;
63
64 inc = min_t(unsigned int, gap, ARRAY_SIZE(zeros) / 2);
65 seq_write(seq: p, data: zeros, len: 2 * inc);
66 gap -= inc;
67 }
68}
69
70static void show_all_irqs(struct seq_file *p)
71{
72 unsigned int i, next = 0;
73
74 for_each_active_irq(i) {
75 show_irq_gap(p, gap: i - next);
76 seq_put_decimal_ull(m: p, delimiter: " ", num: kstat_irqs_usr(irq: i));
77 next = i + 1;
78 }
79 show_irq_gap(p, gap: irq_get_nr_irqs() - next);
80}
81
82static int show_stat(struct seq_file *p, void *v)
83{
84 int i, j;
85 u64 user, nice, system, idle, iowait, irq, softirq, steal;
86 u64 guest, guest_nice;
87 u64 sum = 0;
88 u64 sum_softirq = 0;
89 unsigned int per_softirq_sums[NR_SOFTIRQS] = {0};
90 struct timespec64 boottime;
91
92 user = nice = system = idle = iowait =
93 irq = softirq = steal = 0;
94 guest = guest_nice = 0;
95 getboottime64(ts: &boottime);
96 /* shift boot timestamp according to the timens offset */
97 timens_sub_boottime(ts: &boottime);
98
99 for_each_possible_cpu(i) {
100 struct kernel_cpustat kcpustat;
101 u64 *cpustat = kcpustat.cpustat;
102
103 kcpustat_cpu_fetch(dst: &kcpustat, cpu: i);
104
105 user += cpustat[CPUTIME_USER];
106 nice += cpustat[CPUTIME_NICE];
107 system += cpustat[CPUTIME_SYSTEM];
108 idle += get_idle_time(kcs: &kcpustat, cpu: i);
109 iowait += get_iowait_time(kcs: &kcpustat, cpu: i);
110 irq += cpustat[CPUTIME_IRQ];
111 softirq += cpustat[CPUTIME_SOFTIRQ];
112 steal += cpustat[CPUTIME_STEAL];
113 guest += cpustat[CPUTIME_GUEST];
114 guest_nice += cpustat[CPUTIME_GUEST_NICE];
115 sum += kstat_cpu_irqs_sum(cpu: i);
116 sum += arch_irq_stat_cpu(cpu: i);
117
118 for (j = 0; j < NR_SOFTIRQS; j++) {
119 unsigned int softirq_stat = kstat_softirqs_cpu(irq: j, cpu: i);
120
121 per_softirq_sums[j] += softirq_stat;
122 sum_softirq += softirq_stat;
123 }
124 }
125 sum += arch_irq_stat();
126
127 seq_put_decimal_ull(m: p, delimiter: "cpu ", num: nsec_to_clock_t(x: user));
128 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: nice));
129 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: system));
130 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: idle));
131 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: iowait));
132 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: irq));
133 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: softirq));
134 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: steal));
135 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: guest));
136 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: guest_nice));
137 seq_putc(m: p, c: '\n');
138
139 for_each_online_cpu(i) {
140 struct kernel_cpustat kcpustat;
141 u64 *cpustat = kcpustat.cpustat;
142
143 kcpustat_cpu_fetch(dst: &kcpustat, cpu: i);
144
145 /* Copy values here to work around gcc-2.95.3, gcc-2.96 */
146 user = cpustat[CPUTIME_USER];
147 nice = cpustat[CPUTIME_NICE];
148 system = cpustat[CPUTIME_SYSTEM];
149 idle = get_idle_time(kcs: &kcpustat, cpu: i);
150 iowait = get_iowait_time(kcs: &kcpustat, cpu: i);
151 irq = cpustat[CPUTIME_IRQ];
152 softirq = cpustat[CPUTIME_SOFTIRQ];
153 steal = cpustat[CPUTIME_STEAL];
154 guest = cpustat[CPUTIME_GUEST];
155 guest_nice = cpustat[CPUTIME_GUEST_NICE];
156 seq_printf(m: p, fmt: "cpu%d", i);
157 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: user));
158 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: nice));
159 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: system));
160 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: idle));
161 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: iowait));
162 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: irq));
163 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: softirq));
164 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: steal));
165 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: guest));
166 seq_put_decimal_ull(m: p, delimiter: " ", num: nsec_to_clock_t(x: guest_nice));
167 seq_putc(m: p, c: '\n');
168 }
169 seq_put_decimal_ull(m: p, delimiter: "intr ", num: (unsigned long long)sum);
170
171 show_all_irqs(p);
172
173 seq_printf(m: p,
174 fmt: "\nctxt %llu\n"
175 "btime %llu\n"
176 "processes %lu\n"
177 "procs_running %u\n"
178 "procs_blocked %u\n",
179 nr_context_switches(),
180 (unsigned long long)boottime.tv_sec,
181 total_forks,
182 nr_running(),
183 nr_iowait());
184
185 seq_put_decimal_ull(m: p, delimiter: "softirq ", num: (unsigned long long)sum_softirq);
186
187 for (i = 0; i < NR_SOFTIRQS; i++)
188 seq_put_decimal_ull(m: p, delimiter: " ", num: per_softirq_sums[i]);
189 seq_putc(m: p, c: '\n');
190
191 return 0;
192}
193
194static int stat_open(struct inode *inode, struct file *file)
195{
196 unsigned int size = 1024 + 128 * num_online_cpus();
197
198 /* minimum size to display an interrupt count : 2 bytes */
199 size += 2 * irq_get_nr_irqs();
200 return single_open_size(file, show_stat, NULL, size);
201}
202
203static const struct proc_ops stat_proc_ops = {
204 .proc_flags = PROC_ENTRY_PERMANENT,
205 .proc_open = stat_open,
206 .proc_read_iter = seq_read_iter,
207 .proc_lseek = seq_lseek,
208 .proc_release = single_release,
209};
210
211static int __init proc_stat_init(void)
212{
213 proc_create(name: "stat", mode: 0, NULL, proc_ops: &stat_proc_ops);
214 return 0;
215}
216fs_initcall(proc_stat_init);
217

source code of linux/fs/proc/stat.c