1 // SPDX-License-Identifier: GPL-2.0 2 3 /* 4 * CPU accounting code for task groups. 5 * 6 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh 7 * (balbir@in.ibm.com). 8 */ 9 #include <linux/sched/cputime.h> 10 #include "sched.h" 11 12 /* Time spent by the tasks of the CPU accounting group executing in ... */ 13 enum cpuacct_stat_index { 14 CPUACCT_STAT_USER, /* ... user mode */ 15 CPUACCT_STAT_SYSTEM, /* ... kernel mode */ 16 17 CPUACCT_STAT_NSTATS, 18 }; 19 20 static const char * const cpuacct_stat_desc[] = { 21 [CPUACCT_STAT_USER] = "user", 22 [CPUACCT_STAT_SYSTEM] = "system", 23 }; 24 25 /* track CPU usage of a group of tasks and its child groups */ 26 struct cpuacct { 27 struct cgroup_subsys_state css; 28 /* cpuusage holds pointer to a u64-type object on every CPU */ 29 u64 __percpu *cpuusage; 30 struct kernel_cpustat __percpu *cpustat; 31 }; 32 33 static inline struct cpuacct *css_ca(struct cgroup_subsys_state *css) 34 { 35 return css ? container_of(css, struct cpuacct, css) : NULL; 36 } 37 38 /* Return CPU accounting group to which this task belongs */ 39 static inline struct cpuacct *task_ca(struct task_struct *tsk) 40 { 41 return css_ca(task_css(tsk, cpuacct_cgrp_id)); 42 } 43 44 static inline struct cpuacct *parent_ca(struct cpuacct *ca) 45 { 46 return css_ca(ca->css.parent); 47 } 48 49 static DEFINE_PER_CPU(u64, root_cpuacct_cpuusage); 50 static struct cpuacct root_cpuacct = { 51 .cpustat = &kernel_cpustat, 52 .cpuusage = &root_cpuacct_cpuusage, 53 }; 54 55 /* Create a new CPU accounting group */ 56 static struct cgroup_subsys_state * 57 cpuacct_css_alloc(struct cgroup_subsys_state *parent_css) 58 { 59 struct cpuacct *ca; 60 61 if (!parent_css) 62 return &root_cpuacct.css; 63 64 ca = kzalloc(sizeof(*ca), GFP_KERNEL); 65 if (!ca) 66 goto out; 67 68 ca->cpuusage = alloc_percpu(u64); 69 if (!ca->cpuusage) 70 goto out_free_ca; 71 72 ca->cpustat = alloc_percpu(struct kernel_cpustat); 73 if (!ca->cpustat) 74 goto out_free_cpuusage; 75 76 return &ca->css; 77 78 out_free_cpuusage: 79 free_percpu(ca->cpuusage); 80 out_free_ca: 81 kfree(ca); 82 out: 83 return ERR_PTR(-ENOMEM); 84 } 85 86 /* Destroy an existing CPU accounting group */ 87 static void cpuacct_css_free(struct cgroup_subsys_state *css) 88 { 89 struct cpuacct *ca = css_ca(css); 90 91 free_percpu(ca->cpustat); 92 free_percpu(ca->cpuusage); 93 kfree(ca); 94 } 95 96 static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu, 97 enum cpuacct_stat_index index) 98 { 99 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 100 u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat; 101 u64 data; 102 103 /* 104 * We allow index == CPUACCT_STAT_NSTATS here to read 105 * the sum of usages. 106 */ 107 if (WARN_ON_ONCE(index > CPUACCT_STAT_NSTATS)) 108 return 0; 109 110 #ifndef CONFIG_64BIT 111 /* 112 * Take rq->lock to make 64-bit read safe on 32-bit platforms. 113 */ 114 raw_spin_rq_lock_irq(cpu_rq(cpu)); 115 #endif 116 117 switch (index) { 118 case CPUACCT_STAT_USER: 119 data = cpustat[CPUTIME_USER] + cpustat[CPUTIME_NICE]; 120 break; 121 case CPUACCT_STAT_SYSTEM: 122 data = cpustat[CPUTIME_SYSTEM] + cpustat[CPUTIME_IRQ] + 123 cpustat[CPUTIME_SOFTIRQ]; 124 break; 125 case CPUACCT_STAT_NSTATS: 126 data = *cpuusage; 127 break; 128 } 129 130 #ifndef CONFIG_64BIT 131 raw_spin_rq_unlock_irq(cpu_rq(cpu)); 132 #endif 133 134 return data; 135 } 136 137 static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu) 138 { 139 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 140 u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat; 141 142 /* Don't allow to reset global kernel_cpustat */ 143 if (ca == &root_cpuacct) 144 return; 145 146 #ifndef CONFIG_64BIT 147 /* 148 * Take rq->lock to make 64-bit write safe on 32-bit platforms. 149 */ 150 raw_spin_rq_lock_irq(cpu_rq(cpu)); 151 #endif 152 *cpuusage = 0; 153 cpustat[CPUTIME_USER] = cpustat[CPUTIME_NICE] = 0; 154 cpustat[CPUTIME_SYSTEM] = cpustat[CPUTIME_IRQ] = 0; 155 cpustat[CPUTIME_SOFTIRQ] = 0; 156 157 #ifndef CONFIG_64BIT 158 raw_spin_rq_unlock_irq(cpu_rq(cpu)); 159 #endif 160 } 161 162 /* Return total CPU usage (in nanoseconds) of a group */ 163 static u64 __cpuusage_read(struct cgroup_subsys_state *css, 164 enum cpuacct_stat_index index) 165 { 166 struct cpuacct *ca = css_ca(css); 167 u64 totalcpuusage = 0; 168 int i; 169 170 for_each_possible_cpu(i) 171 totalcpuusage += cpuacct_cpuusage_read(ca, i, index); 172 173 return totalcpuusage; 174 } 175 176 static u64 cpuusage_user_read(struct cgroup_subsys_state *css, 177 struct cftype *cft) 178 { 179 return __cpuusage_read(css, CPUACCT_STAT_USER); 180 } 181 182 static u64 cpuusage_sys_read(struct cgroup_subsys_state *css, 183 struct cftype *cft) 184 { 185 return __cpuusage_read(css, CPUACCT_STAT_SYSTEM); 186 } 187 188 static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft) 189 { 190 return __cpuusage_read(css, CPUACCT_STAT_NSTATS); 191 } 192 193 static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft, 194 u64 val) 195 { 196 struct cpuacct *ca = css_ca(css); 197 int cpu; 198 199 /* 200 * Only allow '0' here to do a reset. 201 */ 202 if (val) 203 return -EINVAL; 204 205 for_each_possible_cpu(cpu) 206 cpuacct_cpuusage_write(ca, cpu); 207 208 return 0; 209 } 210 211 static int __cpuacct_percpu_seq_show(struct seq_file *m, 212 enum cpuacct_stat_index index) 213 { 214 struct cpuacct *ca = css_ca(seq_css(m)); 215 u64 percpu; 216 int i; 217 218 for_each_possible_cpu(i) { 219 percpu = cpuacct_cpuusage_read(ca, i, index); 220 seq_printf(m, "%llu ", (unsigned long long) percpu); 221 } 222 seq_printf(m, "\n"); 223 return 0; 224 } 225 226 static int cpuacct_percpu_user_seq_show(struct seq_file *m, void *V) 227 { 228 return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_USER); 229 } 230 231 static int cpuacct_percpu_sys_seq_show(struct seq_file *m, void *V) 232 { 233 return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_SYSTEM); 234 } 235 236 static int cpuacct_percpu_seq_show(struct seq_file *m, void *V) 237 { 238 return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_NSTATS); 239 } 240 241 static int cpuacct_all_seq_show(struct seq_file *m, void *V) 242 { 243 struct cpuacct *ca = css_ca(seq_css(m)); 244 int index; 245 int cpu; 246 247 seq_puts(m, "cpu"); 248 for (index = 0; index < CPUACCT_STAT_NSTATS; index++) 249 seq_printf(m, " %s", cpuacct_stat_desc[index]); 250 seq_puts(m, "\n"); 251 252 for_each_possible_cpu(cpu) { 253 seq_printf(m, "%d", cpu); 254 for (index = 0; index < CPUACCT_STAT_NSTATS; index++) 255 seq_printf(m, " %llu", 256 cpuacct_cpuusage_read(ca, cpu, index)); 257 seq_puts(m, "\n"); 258 } 259 return 0; 260 } 261 262 static int cpuacct_stats_show(struct seq_file *sf, void *v) 263 { 264 struct cpuacct *ca = css_ca(seq_css(sf)); 265 struct task_cputime cputime; 266 u64 val[CPUACCT_STAT_NSTATS]; 267 int cpu; 268 int stat; 269 270 memset(&cputime, 0, sizeof(cputime)); 271 for_each_possible_cpu(cpu) { 272 u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat; 273 274 cputime.utime += cpustat[CPUTIME_USER]; 275 cputime.utime += cpustat[CPUTIME_NICE]; 276 cputime.stime += cpustat[CPUTIME_SYSTEM]; 277 cputime.stime += cpustat[CPUTIME_IRQ]; 278 cputime.stime += cpustat[CPUTIME_SOFTIRQ]; 279 280 cputime.sum_exec_runtime += *per_cpu_ptr(ca->cpuusage, cpu); 281 } 282 283 cputime_adjust(&cputime, &seq_css(sf)->cgroup->prev_cputime, 284 &val[CPUACCT_STAT_USER], &val[CPUACCT_STAT_SYSTEM]); 285 286 for (stat = 0; stat < CPUACCT_STAT_NSTATS; stat++) { 287 seq_printf(sf, "%s %llu\n", cpuacct_stat_desc[stat], 288 nsec_to_clock_t(val[stat])); 289 } 290 291 return 0; 292 } 293 294 static struct cftype files[] = { 295 { 296 .name = "usage", 297 .read_u64 = cpuusage_read, 298 .write_u64 = cpuusage_write, 299 }, 300 { 301 .name = "usage_user", 302 .read_u64 = cpuusage_user_read, 303 }, 304 { 305 .name = "usage_sys", 306 .read_u64 = cpuusage_sys_read, 307 }, 308 { 309 .name = "usage_percpu", 310 .seq_show = cpuacct_percpu_seq_show, 311 }, 312 { 313 .name = "usage_percpu_user", 314 .seq_show = cpuacct_percpu_user_seq_show, 315 }, 316 { 317 .name = "usage_percpu_sys", 318 .seq_show = cpuacct_percpu_sys_seq_show, 319 }, 320 { 321 .name = "usage_all", 322 .seq_show = cpuacct_all_seq_show, 323 }, 324 { 325 .name = "stat", 326 .seq_show = cpuacct_stats_show, 327 }, 328 { } /* terminate */ 329 }; 330 331 /* 332 * charge this task's execution time to its accounting group. 333 * 334 * called with rq->lock held. 335 */ 336 void cpuacct_charge(struct task_struct *tsk, u64 cputime) 337 { 338 unsigned int cpu = task_cpu(tsk); 339 struct cpuacct *ca; 340 341 lockdep_assert_rq_held(cpu_rq(cpu)); 342 343 for (ca = task_ca(tsk); ca; ca = parent_ca(ca)) 344 *per_cpu_ptr(ca->cpuusage, cpu) += cputime; 345 } 346 347 /* 348 * Add user/system time to cpuacct. 349 * 350 * Note: it's the caller that updates the account of the root cgroup. 351 */ 352 void cpuacct_account_field(struct task_struct *tsk, int index, u64 val) 353 { 354 struct cpuacct *ca; 355 356 for (ca = task_ca(tsk); ca != &root_cpuacct; ca = parent_ca(ca)) 357 __this_cpu_add(ca->cpustat->cpustat[index], val); 358 } 359 360 struct cgroup_subsys cpuacct_cgrp_subsys = { 361 .css_alloc = cpuacct_css_alloc, 362 .css_free = cpuacct_css_free, 363 .legacy_cftypes = files, 364 .early_init = true, 365 }; 366