tools/perf/util/thread.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include "../perf.h"
   3 #include <errno.h>
   4 #include <stdlib.h>
   5 #include <stdio.h>
   6 #include <string.h>
   7 #include <linux/kernel.h>
   8 #include "session.h"
   9 #include "thread.h"
  10 #include "thread-stack.h"
  11 #include "util.h"
  12 #include "debug.h"
  13 #include "namespaces.h"
  14 #include "comm.h"
  15 #include "unwind.h"
  16
  17 #include <api/fs/fs.h>
  18
  19 int thread__init_map_groups(struct thread *thread, struct machine *machine)
  20 {
  21         pid_t pid = thread->pid_;
  22
  23         if (pid == thread->tid || pid == -1) {
  24                 thread->mg = map_groups__new(machine);
  25         } else {
  26                 struct thread *leader = __machine__findnew_thread(machine, pid, pid);
  27                 if (leader) {
  28                         thread->mg = map_groups__get(leader->mg);
  29                         thread__put(leader);
  30                 }
  31         }
  32
  33         return thread->mg ? 0 : -1;
  34 }
  35
  36 struct thread *thread__new(pid_t pid, pid_t tid)
  37 {
  38         char *comm_str;
  39         struct comm *comm;
  40         struct thread *thread = zalloc(sizeof(*thread));
  41
  42         if (thread != NULL) {
  43                 thread->pid_ = pid;
  44                 thread->tid = tid;
  45                 thread->ppid = -1;
  46                 thread->cpu = -1;
  47                 INIT_LIST_HEAD(&thread->namespaces_list);
  48                 INIT_LIST_HEAD(&thread->comm_list);
  49
  50                 comm_str = malloc(32);
  51                 if (!comm_str)
  52                         goto err_thread;
  53
  54                 snprintf(comm_str, 32, ":%d", tid);
  55                 comm = comm__new(comm_str, 0, false);
  56                 free(comm_str);
  57                 if (!comm)
  58                         goto err_thread;
  59
  60                 list_add(&comm->list, &thread->comm_list);
  61                 refcount_set(&thread->refcnt, 1);
  62                 RB_CLEAR_NODE(&thread->rb_node);
  63                 /* Thread holds first ref to nsdata. */
  64                 thread->nsinfo = nsinfo__new(pid);
  65         }
  66
  67         return thread;
  68
  69 err_thread:
  70         free(thread);
  71         return NULL;
  72 }
  73
  74 void thread__delete(struct thread *thread)
  75 {
  76         struct namespaces *namespaces, *tmp_namespaces;
  77         struct comm *comm, *tmp_comm;
  78
  79         BUG_ON(!RB_EMPTY_NODE(&thread->rb_node));
  80
  81         thread_stack__free(thread);
  82
  83         if (thread->mg) {
  84                 map_groups__put(thread->mg);
  85                 thread->mg = NULL;
  86         }
  87         list_for_each_entry_safe(namespaces, tmp_namespaces,
  88                                  &thread->namespaces_list, list) {
  89                 list_del(&namespaces->list);
  90                 namespaces__free(namespaces);
  91         }
  92         list_for_each_entry_safe(comm, tmp_comm, &thread->comm_list, list) {
  93                 list_del(&comm->list);
  94                 comm__free(comm);
  95         }
  96         unwind__finish_access(thread);
  97         nsinfo__zput(thread->nsinfo);
  98
  99         free(thread);
 100 }
 101
 102 struct thread *thread__get(struct thread *thread)
 103 {
 104         if (thread)
 105                 refcount_inc(&thread->refcnt);
 106         return thread;
 107 }
 108
 109 void thread__put(struct thread *thread)
 110 {
 111         if (thread && refcount_dec_and_test(&thread->refcnt)) {
 112                 /*
 113                  * Remove it from the dead_threads list, as last reference
 114                  * is gone.
 115                  */
 116                 list_del_init(&thread->node);
 117                 thread__delete(thread);
 118         }
 119 }
 120
 121 struct namespaces *thread__namespaces(const struct thread *thread)
 122 {
 123         if (list_empty(&thread->namespaces_list))
 124                 return NULL;
 125
 126         return list_first_entry(&thread->namespaces_list, struct namespaces, list);
 127 }
 128
 129 int thread__set_namespaces(struct thread *thread, u64 timestamp,
 130                            struct namespaces_event *event)
 131 {
 132         struct namespaces *new, *curr = thread__namespaces(thread);
 133
 134         new = namespaces__new(event);
 135         if (!new)
 136                 return -ENOMEM;
 137
 138         list_add(&new->list, &thread->namespaces_list);
 139
 140         if (timestamp && curr) {
 141                 /*
 142                  * setns syscall must have changed few or all the namespaces
 143                  * of this thread. Update end time for the namespaces
 144                  * previously used.
 145                  */
 146                 curr = list_next_entry(new, list);
 147                 curr->end_time = timestamp;
 148         }
 149
 150         return 0;
 151 }
 152
 153 struct comm *thread__comm(const struct thread *thread)
 154 {
 155         if (list_empty(&thread->comm_list))
 156                 return NULL;
 157
 158         return list_first_entry(&thread->comm_list, struct comm, list);
 159 }
 160
 161 struct comm *thread__exec_comm(const struct thread *thread)
 162 {
 163         struct comm *comm, *last = NULL;
 164
 165         list_for_each_entry(comm, &thread->comm_list, list) {
 166                 if (comm->exec)
 167                         return comm;
 168                 last = comm;
 169         }
 170
 171         return last;
 172 }
 173
 174 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
 175                        bool exec)
 176 {
 177         struct comm *new, *curr = thread__comm(thread);
 178
 179         /* Override the default :tid entry */
 180         if (!thread->comm_set) {
 181                 int err = comm__override(curr, str, timestamp, exec);
 182                 if (err)
 183                         return err;
 184         } else {
 185                 new = comm__new(str, timestamp, exec);
 186                 if (!new)
 187                         return -ENOMEM;
 188                 list_add(&new->list, &thread->comm_list);
 189
 190                 if (exec)
 191                         unwind__flush_access(thread);
 192         }
 193
 194         thread->comm_set = true;
 195
 196         return 0;
 197 }
 198
 199 int thread__set_comm_from_proc(struct thread *thread)
 200 {
 201         char path[64];
 202         char *comm = NULL;
 203         size_t sz;
 204         int err = -1;
 205
 206         if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
 207                        thread->pid_, thread->tid) >= (int)sizeof(path)) &&
 208             procfs__read_str(path, &comm, &sz) == 0) {
 209                 comm[sz - 1] = '\0';
 210                 err = thread__set_comm(thread, comm, 0);
 211         }
 212
 213         return err;
 214 }
 215
 216 const char *thread__comm_str(const struct thread *thread)
 217 {
 218         const struct comm *comm = thread__comm(thread);
 219
 220         if (!comm)
 221                 return NULL;
 222
 223         return comm__str(comm);
 224 }
 225
 226 /* CHECKME: it should probably better return the max comm len from its comm list */
 227 int thread__comm_len(struct thread *thread)
 228 {
 229         if (!thread->comm_len) {
 230                 const char *comm = thread__comm_str(thread);
 231                 if (!comm)
 232                         return 0;
 233                 thread->comm_len = strlen(comm);
 234         }
 235
 236         return thread->comm_len;
 237 }
 238
 239 size_t thread__fprintf(struct thread *thread, FILE *fp)
 240 {
 241         return fprintf(fp, "Thread %d %s\n", thread->tid, thread__comm_str(thread)) +
 242                map_groups__fprintf(thread->mg, fp);
 243 }
 244
 245 int thread__insert_map(struct thread *thread, struct map *map)
 246 {
 247         int ret;
 248
 249         ret = unwind__prepare_access(thread, map, NULL);
 250         if (ret)
 251                 return ret;
 252
 253         map_groups__fixup_overlappings(thread->mg, map, stderr);
 254         map_groups__insert(thread->mg, map);
 255
 256         return 0;
 257 }
 258
 259 static int __thread__prepare_access(struct thread *thread)
 260 {
 261         bool initialized = false;
 262         int i, err = 0;
 263
 264         for (i = 0; i < MAP__NR_TYPES; ++i) {
 265                 struct maps *maps = &thread->mg->maps[i];
 266                 struct map *map;
 267
 268                 pthread_rwlock_rdlock(&maps->lock);
 269
 270                 for (map = maps__first(maps); map; map = map__next(map)) {
 271                         err = unwind__prepare_access(thread, map, &initialized);
 272                         if (err || initialized)
 273                                 break;
 274                 }
 275
 276                 pthread_rwlock_unlock(&maps->lock);
 277         }
 278
 279         return err;
 280 }
 281
 282 static int thread__prepare_access(struct thread *thread)
 283 {
 284         int err = 0;
 285
 286         if (symbol_conf.use_callchain)
 287                 err = __thread__prepare_access(thread);
 288
 289         return err;
 290 }
 291
 292 static int thread__clone_map_groups(struct thread *thread,
 293                                     struct thread *parent)
 294 {
 295         int i;
 296
 297         /* This is new thread, we share map groups for process. */
 298         if (thread->pid_ == parent->pid_)
 299                 return thread__prepare_access(thread);
 300
 301         if (thread->mg == parent->mg) {
 302                 pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
 303                          thread->pid_, thread->tid, parent->pid_, parent->tid);
 304                 return 0;
 305         }
 306
 307         /* But this one is new process, copy maps. */
 308         for (i = 0; i < MAP__NR_TYPES; ++i)
 309                 if (map_groups__clone(thread, parent->mg, i) < 0)
 310                         return -ENOMEM;
 311
 312         return 0;
 313 }
 314
 315 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp)
 316 {
 317         if (parent->comm_set) {
 318                 const char *comm = thread__comm_str(parent);
 319                 int err;
 320                 if (!comm)
 321                         return -ENOMEM;
 322                 err = thread__set_comm(thread, comm, timestamp);
 323                 if (err)
 324                         return err;
 325         }
 326
 327         thread->ppid = parent->tid;
 328         return thread__clone_map_groups(thread, parent);
 329 }
 330
 331 void thread__find_cpumode_addr_location(struct thread *thread,
 332                                         enum map_type type, u64 addr,
 333                                         struct addr_location *al)
 334 {
 335         size_t i;
 336         const u8 cpumodes[] = {
 337                 PERF_RECORD_MISC_USER,
 338                 PERF_RECORD_MISC_KERNEL,
 339                 PERF_RECORD_MISC_GUEST_USER,
 340                 PERF_RECORD_MISC_GUEST_KERNEL
 341         };
 342
 343         for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
 344                 thread__find_addr_location(thread, cpumodes[i], type, addr, al);
 345                 if (al->map)
 346                         break;
 347         }
 348 }
 349
 350 struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
 351 {
 352         if (thread->pid_ == thread->tid)
 353                 return thread__get(thread);
 354
 355         if (thread->pid_ == -1)
 356                 return NULL;
 357
 358         return machine__find_thread(machine, thread->pid_, thread->pid_);
 359 }