tools/perf/util/thread.c

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