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