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, *second_last = NULL;
 164
 165         list_for_each_entry(comm, &thread->comm_list, list) {
 166                 if (comm->exec)
 167                         return comm;
 168                 second_last = last;
 169                 last = comm;
 170         }
 171
 172         /*
 173          * 'last' with no start time might be the parent's comm of a synthesized
 174          * thread (created by processing a synthesized fork event). For a main
 175          * thread, that is very probably wrong. Prefer a later comm to avoid
 176          * that case.
 177          */
 178         if (second_last && !last->start && thread->pid_ == thread->tid)
 179                 return second_last;
 180
 181         return last;
 182 }
 183
 184 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
 185                        bool exec)
 186 {
 187         struct comm *new, *curr = thread__comm(thread);
 188
 189         /* Override the default :tid entry */
 190         if (!thread->comm_set) {
 191                 int err = comm__override(curr, str, timestamp, exec);
 192                 if (err)
 193                         return err;
 194         } else {
 195                 new = comm__new(str, timestamp, exec);
 196                 if (!new)
 197                         return -ENOMEM;
 198                 list_add(&new->list, &thread->comm_list);
 199
 200                 if (exec)
 201                         unwind__flush_access(thread);
 202         }
 203
 204         thread->comm_set = true;
 205
 206         return 0;
 207 }
 208
 209 int thread__set_comm_from_proc(struct thread *thread)
 210 {
 211         char path[64];
 212         char *comm = NULL;
 213         size_t sz;
 214         int err = -1;
 215
 216         if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
 217                        thread->pid_, thread->tid) >= (int)sizeof(path)) &&
 218             procfs__read_str(path, &comm, &sz) == 0) {
 219                 comm[sz - 1] = '\0';
 220                 err = thread__set_comm(thread, comm, 0);
 221         }
 222
 223         return err;
 224 }
 225
 226 const char *thread__comm_str(const struct thread *thread)
 227 {
 228         const struct comm *comm = thread__comm(thread);
 229
 230         if (!comm)
 231                 return NULL;
 232
 233         return comm__str(comm);
 234 }
 235
 236 /* CHECKME: it should probably better return the max comm len from its comm list */
 237 int thread__comm_len(struct thread *thread)
 238 {
 239         if (!thread->comm_len) {
 240                 const char *comm = thread__comm_str(thread);
 241                 if (!comm)
 242                         return 0;
 243                 thread->comm_len = strlen(comm);
 244         }
 245
 246         return thread->comm_len;
 247 }
 248
 249 size_t thread__fprintf(struct thread *thread, FILE *fp)
 250 {
 251         return fprintf(fp, "Thread %d %s\n", thread->tid, thread__comm_str(thread)) +
 252                map_groups__fprintf(thread->mg, fp);
 253 }
 254
 255 int thread__insert_map(struct thread *thread, struct map *map)
 256 {
 257         int ret;
 258
 259         ret = unwind__prepare_access(thread, map, NULL);
 260         if (ret)
 261                 return ret;
 262
 263         map_groups__fixup_overlappings(thread->mg, map, stderr);
 264         map_groups__insert(thread->mg, map);
 265
 266         return 0;
 267 }
 268
 269 static int __thread__prepare_access(struct thread *thread)
 270 {
 271         bool initialized = false;
 272         int i, err = 0;
 273
 274         for (i = 0; i < MAP__NR_TYPES; ++i) {
 275                 struct maps *maps = &thread->mg->maps[i];
 276                 struct map *map;
 277
 278                 pthread_rwlock_rdlock(&maps->lock);
 279
 280                 for (map = maps__first(maps); map; map = map__next(map)) {
 281                         err = unwind__prepare_access(thread, map, &initialized);
 282                         if (err || initialized)
 283                                 break;
 284                 }
 285
 286                 pthread_rwlock_unlock(&maps->lock);
 287         }
 288
 289         return err;
 290 }
 291
 292 static int thread__prepare_access(struct thread *thread)
 293 {
 294         int err = 0;
 295
 296         if (symbol_conf.use_callchain)
 297                 err = __thread__prepare_access(thread);
 298
 299         return err;
 300 }
 301
 302 static int thread__clone_map_groups(struct thread *thread,
 303                                     struct thread *parent)
 304 {
 305         int i;
 306
 307         /* This is new thread, we share map groups for process. */
 308         if (thread->pid_ == parent->pid_)
 309                 return thread__prepare_access(thread);
 310
 311         if (thread->mg == parent->mg) {
 312                 pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
 313                          thread->pid_, thread->tid, parent->pid_, parent->tid);
 314                 return 0;
 315         }
 316
 317         /* But this one is new process, copy maps. */
 318         for (i = 0; i < MAP__NR_TYPES; ++i)
 319                 if (map_groups__clone(thread, parent->mg, i) < 0)
 320                         return -ENOMEM;
 321
 322         return 0;
 323 }
 324
 325 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp)
 326 {
 327         if (parent->comm_set) {
 328                 const char *comm = thread__comm_str(parent);
 329                 int err;
 330                 if (!comm)
 331                         return -ENOMEM;
 332                 err = thread__set_comm(thread, comm, timestamp);
 333                 if (err)
 334                         return err;
 335         }
 336
 337         thread->ppid = parent->tid;
 338         return thread__clone_map_groups(thread, parent);
 339 }
 340
 341 void thread__find_cpumode_addr_location(struct thread *thread,
 342                                         enum map_type type, u64 addr,
 343                                         struct addr_location *al)
 344 {
 345         size_t i;
 346         const u8 cpumodes[] = {
 347                 PERF_RECORD_MISC_USER,
 348                 PERF_RECORD_MISC_KERNEL,
 349                 PERF_RECORD_MISC_GUEST_USER,
 350                 PERF_RECORD_MISC_GUEST_KERNEL
 351         };
 352
 353         for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
 354                 thread__find_addr_location(thread, cpumodes[i], type, addr, al);
 355                 if (al->map)
 356                         break;
 357         }
 358 }
 359
 360 struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
 361 {
 362         if (thread->pid_ == thread->tid)
 363                 return thread__get(thread);
 364
 365         if (thread->pid_ == -1)
 366                 return NULL;
 367
 368         return machine__find_thread(machine, thread->pid_, thread->pid_);
 369 }