xref: /openbmc/linux/fs/proc/stat.c (revision d23015c1)
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/irqnr.h>
14 #include <linux/sched/cputime.h>
15 #include <linux/tick.h>
16 
17 #ifndef arch_irq_stat_cpu
18 #define arch_irq_stat_cpu(cpu) 0
19 #endif
20 #ifndef arch_irq_stat
21 #define arch_irq_stat() 0
22 #endif
23 
24 #ifdef arch_idle_time
25 
26 static u64 get_idle_time(struct kernel_cpustat *kcs, int cpu)
27 {
28 	u64 idle;
29 
30 	idle = kcs->cpustat[CPUTIME_IDLE];
31 	if (cpu_online(cpu) && !nr_iowait_cpu(cpu))
32 		idle += arch_idle_time(cpu);
33 	return idle;
34 }
35 
36 static u64 get_iowait_time(struct kernel_cpustat *kcs, int cpu)
37 {
38 	u64 iowait;
39 
40 	iowait = kcs->cpustat[CPUTIME_IOWAIT];
41 	if (cpu_online(cpu) && nr_iowait_cpu(cpu))
42 		iowait += arch_idle_time(cpu);
43 	return iowait;
44 }
45 
46 #else
47 
48 static u64 get_idle_time(struct kernel_cpustat *kcs, int cpu)
49 {
50 	u64 idle, idle_usecs = -1ULL;
51 
52 	if (cpu_online(cpu))
53 		idle_usecs = get_cpu_idle_time_us(cpu, NULL);
54 
55 	if (idle_usecs == -1ULL)
56 		/* !NO_HZ or cpu offline so we can rely on cpustat.idle */
57 		idle = kcs->cpustat[CPUTIME_IDLE];
58 	else
59 		idle = idle_usecs * NSEC_PER_USEC;
60 
61 	return idle;
62 }
63 
64 static u64 get_iowait_time(struct kernel_cpustat *kcs, int cpu)
65 {
66 	u64 iowait, iowait_usecs = -1ULL;
67 
68 	if (cpu_online(cpu))
69 		iowait_usecs = get_cpu_iowait_time_us(cpu, NULL);
70 
71 	if (iowait_usecs == -1ULL)
72 		/* !NO_HZ or cpu offline so we can rely on cpustat.iowait */
73 		iowait = kcs->cpustat[CPUTIME_IOWAIT];
74 	else
75 		iowait = iowait_usecs * NSEC_PER_USEC;
76 
77 	return iowait;
78 }
79 
80 #endif
81 
82 static void show_irq_gap(struct seq_file *p, unsigned int gap)
83 {
84 	static const char zeros[] = " 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0";
85 
86 	while (gap > 0) {
87 		unsigned int inc;
88 
89 		inc = min_t(unsigned int, gap, ARRAY_SIZE(zeros) / 2);
90 		seq_write(p, zeros, 2 * inc);
91 		gap -= inc;
92 	}
93 }
94 
95 static void show_all_irqs(struct seq_file *p)
96 {
97 	unsigned int i, next = 0;
98 
99 	for_each_active_irq(i) {
100 		show_irq_gap(p, i - next);
101 		seq_put_decimal_ull(p, " ", kstat_irqs_usr(i));
102 		next = i + 1;
103 	}
104 	show_irq_gap(p, nr_irqs - next);
105 }
106 
107 static int show_stat(struct seq_file *p, void *v)
108 {
109 	int i, j;
110 	u64 user, nice, system, idle, iowait, irq, softirq, steal;
111 	u64 guest, guest_nice;
112 	u64 sum = 0;
113 	u64 sum_softirq = 0;
114 	unsigned int per_softirq_sums[NR_SOFTIRQS] = {0};
115 	struct timespec64 boottime;
116 
117 	user = nice = system = idle = iowait =
118 		irq = softirq = steal = 0;
119 	guest = guest_nice = 0;
120 	getboottime64(&boottime);
121 
122 	for_each_possible_cpu(i) {
123 		struct kernel_cpustat kcpustat;
124 		u64 *cpustat = kcpustat.cpustat;
125 
126 		kcpustat_cpu_fetch(&kcpustat, i);
127 
128 		user		+= cpustat[CPUTIME_USER];
129 		nice		+= cpustat[CPUTIME_NICE];
130 		system		+= cpustat[CPUTIME_SYSTEM];
131 		idle		+= get_idle_time(&kcpustat, i);
132 		iowait		+= get_iowait_time(&kcpustat, i);
133 		irq		+= cpustat[CPUTIME_IRQ];
134 		softirq		+= cpustat[CPUTIME_SOFTIRQ];
135 		steal		+= cpustat[CPUTIME_STEAL];
136 		guest		+= cpustat[CPUTIME_GUEST];
137 		guest_nice	+= cpustat[CPUTIME_USER];
138 		sum		+= kstat_cpu_irqs_sum(i);
139 		sum		+= arch_irq_stat_cpu(i);
140 
141 		for (j = 0; j < NR_SOFTIRQS; j++) {
142 			unsigned int softirq_stat = kstat_softirqs_cpu(j, i);
143 
144 			per_softirq_sums[j] += softirq_stat;
145 			sum_softirq += softirq_stat;
146 		}
147 	}
148 	sum += arch_irq_stat();
149 
150 	seq_put_decimal_ull(p, "cpu  ", nsec_to_clock_t(user));
151 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));
152 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(system));
153 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle));
154 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait));
155 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq));
156 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq));
157 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal));
158 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest));
159 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice));
160 	seq_putc(p, '\n');
161 
162 	for_each_online_cpu(i) {
163 		struct kernel_cpustat kcpustat;
164 		u64 *cpustat = kcpustat.cpustat;
165 
166 		kcpustat_cpu_fetch(&kcpustat, i);
167 
168 		/* Copy values here to work around gcc-2.95.3, gcc-2.96 */
169 		user		= cpustat[CPUTIME_USER];
170 		nice		= cpustat[CPUTIME_NICE];
171 		system		= cpustat[CPUTIME_SYSTEM];
172 		idle		= get_idle_time(&kcpustat, i);
173 		iowait		= get_iowait_time(&kcpustat, i);
174 		irq		= cpustat[CPUTIME_IRQ];
175 		softirq		= cpustat[CPUTIME_SOFTIRQ];
176 		steal		= cpustat[CPUTIME_STEAL];
177 		guest		= cpustat[CPUTIME_GUEST];
178 		guest_nice	= cpustat[CPUTIME_USER];
179 		seq_printf(p, "cpu%d", i);
180 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(user));
181 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));
182 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(system));
183 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle));
184 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait));
185 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq));
186 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq));
187 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal));
188 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest));
189 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice));
190 		seq_putc(p, '\n');
191 	}
192 	seq_put_decimal_ull(p, "intr ", (unsigned long long)sum);
193 
194 	show_all_irqs(p);
195 
196 	seq_printf(p,
197 		"\nctxt %llu\n"
198 		"btime %llu\n"
199 		"processes %lu\n"
200 		"procs_running %lu\n"
201 		"procs_blocked %lu\n",
202 		nr_context_switches(),
203 		(unsigned long long)boottime.tv_sec,
204 		total_forks,
205 		nr_running(),
206 		nr_iowait());
207 
208 	seq_put_decimal_ull(p, "softirq ", (unsigned long long)sum_softirq);
209 
210 	for (i = 0; i < NR_SOFTIRQS; i++)
211 		seq_put_decimal_ull(p, " ", per_softirq_sums[i]);
212 	seq_putc(p, '\n');
213 
214 	return 0;
215 }
216 
217 static int stat_open(struct inode *inode, struct file *file)
218 {
219 	unsigned int size = 1024 + 128 * num_online_cpus();
220 
221 	/* minimum size to display an interrupt count : 2 bytes */
222 	size += 2 * nr_irqs;
223 	return single_open_size(file, show_stat, NULL, size);
224 }
225 
226 static const struct file_operations proc_stat_operations = {
227 	.open		= stat_open,
228 	.read		= seq_read,
229 	.llseek		= seq_lseek,
230 	.release	= single_release,
231 };
232 
233 static int __init proc_stat_init(void)
234 {
235 	proc_create("stat", 0, NULL, &proc_stat_operations);
236 	return 0;
237 }
238 fs_initcall(proc_stat_init);
239