xref: /openbmc/linux/fs/proc/stat.c (revision 9aa2cba7)
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 u64 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 
41 static 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 
57 static 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(p, zeros, 2 * inc);
66 		gap -= inc;
67 	}
68 }
69 
70 static 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, i - next);
76 		seq_put_decimal_ull(p, " ", kstat_irqs_usr(i));
77 		next = i + 1;
78 	}
79 	show_irq_gap(p, nr_irqs - next);
80 }
81 
82 static 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(&boottime);
96 	/* shift boot timestamp according to the timens offset */
97 	timens_sub_boottime(&boottime);
98 
99 	for_each_possible_cpu(i) {
100 		struct kernel_cpustat kcpustat;
101 		u64 *cpustat = kcpustat.cpustat;
102 
103 		kcpustat_cpu_fetch(&kcpustat, i);
104 
105 		user		+= cpustat[CPUTIME_USER];
106 		nice		+= cpustat[CPUTIME_NICE];
107 		system		+= cpustat[CPUTIME_SYSTEM];
108 		idle		+= get_idle_time(&kcpustat, i);
109 		iowait		+= get_iowait_time(&kcpustat, 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(i);
116 		sum		+= arch_irq_stat_cpu(i);
117 
118 		for (j = 0; j < NR_SOFTIRQS; j++) {
119 			unsigned int softirq_stat = kstat_softirqs_cpu(j, 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(p, "cpu  ", nsec_to_clock_t(user));
128 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));
129 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(system));
130 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle));
131 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait));
132 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq));
133 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq));
134 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal));
135 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest));
136 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice));
137 	seq_putc(p, '\n');
138 
139 	for_each_online_cpu(i) {
140 		struct kernel_cpustat kcpustat;
141 		u64 *cpustat = kcpustat.cpustat;
142 
143 		kcpustat_cpu_fetch(&kcpustat, 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(&kcpustat, i);
150 		iowait		= get_iowait_time(&kcpustat, 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(p, "cpu%d", i);
157 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(user));
158 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));
159 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(system));
160 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle));
161 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait));
162 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq));
163 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq));
164 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal));
165 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest));
166 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice));
167 		seq_putc(p, '\n');
168 	}
169 	seq_put_decimal_ull(p, "intr ", (unsigned long long)sum);
170 
171 	show_all_irqs(p);
172 
173 	seq_printf(p,
174 		"\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(p, "softirq ", (unsigned long long)sum_softirq);
186 
187 	for (i = 0; i < NR_SOFTIRQS; i++)
188 		seq_put_decimal_ull(p, " ", per_softirq_sums[i]);
189 	seq_putc(p, '\n');
190 
191 	return 0;
192 }
193 
194 static 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 * nr_irqs;
200 	return single_open_size(file, show_stat, NULL, size);
201 }
202 
203 static 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 
211 static int __init proc_stat_init(void)
212 {
213 	proc_create("stat", 0, NULL, &stat_proc_ops);
214 	return 0;
215 }
216 fs_initcall(proc_stat_init);
217