xref: /openbmc/linux/fs/proc/stat.c (revision 1cc1e4c8)
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 
25 #ifdef arch_idle_time
26 
27 u64 get_idle_time(struct kernel_cpustat *kcs, int cpu)
28 {
29 	u64 idle;
30 
31 	idle = kcs->cpustat[CPUTIME_IDLE];
32 	if (cpu_online(cpu) && !nr_iowait_cpu(cpu))
33 		idle += arch_idle_time(cpu);
34 	return idle;
35 }
36 
37 static u64 get_iowait_time(struct kernel_cpustat *kcs, int cpu)
38 {
39 	u64 iowait;
40 
41 	iowait = kcs->cpustat[CPUTIME_IOWAIT];
42 	if (cpu_online(cpu) && nr_iowait_cpu(cpu))
43 		iowait += arch_idle_time(cpu);
44 	return iowait;
45 }
46 
47 #else
48 
49 u64 get_idle_time(struct kernel_cpustat *kcs, int cpu)
50 {
51 	u64 idle, idle_usecs = -1ULL;
52 
53 	if (cpu_online(cpu))
54 		idle_usecs = get_cpu_idle_time_us(cpu, NULL);
55 
56 	if (idle_usecs == -1ULL)
57 		/* !NO_HZ or cpu offline so we can rely on cpustat.idle */
58 		idle = kcs->cpustat[CPUTIME_IDLE];
59 	else
60 		idle = idle_usecs * NSEC_PER_USEC;
61 
62 	return idle;
63 }
64 
65 static u64 get_iowait_time(struct kernel_cpustat *kcs, int cpu)
66 {
67 	u64 iowait, iowait_usecs = -1ULL;
68 
69 	if (cpu_online(cpu))
70 		iowait_usecs = get_cpu_iowait_time_us(cpu, NULL);
71 
72 	if (iowait_usecs == -1ULL)
73 		/* !NO_HZ or cpu offline so we can rely on cpustat.iowait */
74 		iowait = kcs->cpustat[CPUTIME_IOWAIT];
75 	else
76 		iowait = iowait_usecs * NSEC_PER_USEC;
77 
78 	return iowait;
79 }
80 
81 #endif
82 
83 static void show_irq_gap(struct seq_file *p, unsigned int gap)
84 {
85 	static const char zeros[] = " 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0";
86 
87 	while (gap > 0) {
88 		unsigned int inc;
89 
90 		inc = min_t(unsigned int, gap, ARRAY_SIZE(zeros) / 2);
91 		seq_write(p, zeros, 2 * inc);
92 		gap -= inc;
93 	}
94 }
95 
96 static void show_all_irqs(struct seq_file *p)
97 {
98 	unsigned int i, next = 0;
99 
100 	for_each_active_irq(i) {
101 		show_irq_gap(p, i - next);
102 		seq_put_decimal_ull(p, " ", kstat_irqs_usr(i));
103 		next = i + 1;
104 	}
105 	show_irq_gap(p, nr_irqs - next);
106 }
107 
108 static int show_stat(struct seq_file *p, void *v)
109 {
110 	int i, j;
111 	u64 user, nice, system, idle, iowait, irq, softirq, steal;
112 	u64 guest, guest_nice;
113 	u64 sum = 0;
114 	u64 sum_softirq = 0;
115 	unsigned int per_softirq_sums[NR_SOFTIRQS] = {0};
116 	struct timespec64 boottime;
117 
118 	user = nice = system = idle = iowait =
119 		irq = softirq = steal = 0;
120 	guest = guest_nice = 0;
121 	getboottime64(&boottime);
122 	/* shift boot timestamp according to the timens offset */
123 	timens_sub_boottime(&boottime);
124 
125 	for_each_possible_cpu(i) {
126 		struct kernel_cpustat kcpustat;
127 		u64 *cpustat = kcpustat.cpustat;
128 
129 		kcpustat_cpu_fetch(&kcpustat, i);
130 
131 		user		+= cpustat[CPUTIME_USER];
132 		nice		+= cpustat[CPUTIME_NICE];
133 		system		+= cpustat[CPUTIME_SYSTEM];
134 		idle		+= get_idle_time(&kcpustat, i);
135 		iowait		+= get_iowait_time(&kcpustat, i);
136 		irq		+= cpustat[CPUTIME_IRQ];
137 		softirq		+= cpustat[CPUTIME_SOFTIRQ];
138 		steal		+= cpustat[CPUTIME_STEAL];
139 		guest		+= cpustat[CPUTIME_GUEST];
140 		guest_nice	+= cpustat[CPUTIME_GUEST_NICE];
141 		sum		+= kstat_cpu_irqs_sum(i);
142 		sum		+= arch_irq_stat_cpu(i);
143 
144 		for (j = 0; j < NR_SOFTIRQS; j++) {
145 			unsigned int softirq_stat = kstat_softirqs_cpu(j, i);
146 
147 			per_softirq_sums[j] += softirq_stat;
148 			sum_softirq += softirq_stat;
149 		}
150 	}
151 	sum += arch_irq_stat();
152 
153 	seq_put_decimal_ull(p, "cpu  ", nsec_to_clock_t(user));
154 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));
155 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(system));
156 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle));
157 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait));
158 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq));
159 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq));
160 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal));
161 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest));
162 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice));
163 	seq_putc(p, '\n');
164 
165 	for_each_online_cpu(i) {
166 		struct kernel_cpustat kcpustat;
167 		u64 *cpustat = kcpustat.cpustat;
168 
169 		kcpustat_cpu_fetch(&kcpustat, i);
170 
171 		/* Copy values here to work around gcc-2.95.3, gcc-2.96 */
172 		user		= cpustat[CPUTIME_USER];
173 		nice		= cpustat[CPUTIME_NICE];
174 		system		= cpustat[CPUTIME_SYSTEM];
175 		idle		= get_idle_time(&kcpustat, i);
176 		iowait		= get_iowait_time(&kcpustat, i);
177 		irq		= cpustat[CPUTIME_IRQ];
178 		softirq		= cpustat[CPUTIME_SOFTIRQ];
179 		steal		= cpustat[CPUTIME_STEAL];
180 		guest		= cpustat[CPUTIME_GUEST];
181 		guest_nice	= cpustat[CPUTIME_GUEST_NICE];
182 		seq_printf(p, "cpu%d", i);
183 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(user));
184 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));
185 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(system));
186 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle));
187 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait));
188 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq));
189 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq));
190 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal));
191 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest));
192 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice));
193 		seq_putc(p, '\n');
194 	}
195 	seq_put_decimal_ull(p, "intr ", (unsigned long long)sum);
196 
197 	show_all_irqs(p);
198 
199 	seq_printf(p,
200 		"\nctxt %llu\n"
201 		"btime %llu\n"
202 		"processes %lu\n"
203 		"procs_running %u\n"
204 		"procs_blocked %u\n",
205 		nr_context_switches(),
206 		(unsigned long long)boottime.tv_sec,
207 		total_forks,
208 		nr_running(),
209 		nr_iowait());
210 
211 	seq_put_decimal_ull(p, "softirq ", (unsigned long long)sum_softirq);
212 
213 	for (i = 0; i < NR_SOFTIRQS; i++)
214 		seq_put_decimal_ull(p, " ", per_softirq_sums[i]);
215 	seq_putc(p, '\n');
216 
217 	return 0;
218 }
219 
220 static int stat_open(struct inode *inode, struct file *file)
221 {
222 	unsigned int size = 1024 + 128 * num_online_cpus();
223 
224 	/* minimum size to display an interrupt count : 2 bytes */
225 	size += 2 * nr_irqs;
226 	return single_open_size(file, show_stat, NULL, size);
227 }
228 
229 static const struct proc_ops stat_proc_ops = {
230 	.proc_flags	= PROC_ENTRY_PERMANENT,
231 	.proc_open	= stat_open,
232 	.proc_read_iter	= seq_read_iter,
233 	.proc_lseek	= seq_lseek,
234 	.proc_release	= single_release,
235 };
236 
237 static int __init proc_stat_init(void)
238 {
239 	proc_create("stat", 0, NULL, &stat_proc_ops);
240 	return 0;
241 }
242 fs_initcall(proc_stat_init);
243