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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-24 17:59:32 +00:00
![Jin Yao](/assets/img/avatar_default.png)
If we execute 'perf stat --per-thread' with non-root account (even set kernel.perf_event_paranoid = -1 yet), it reports the error: jinyao@skl:~$ perf stat --per-thread Error: You may not have permission to collect system-wide stats. Consider tweaking /proc/sys/kernel/perf_event_paranoid, which controls use of the performance events system by unprivileged users (without CAP_SYS_ADMIN). The current value is 2: -1: Allow use of (almost) all events by all users Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK >= 0: Disallow ftrace function tracepoint by users without CAP_SYS_ADMIN Disallow raw tracepoint access by users without CAP_SYS_ADMIN >= 1: Disallow CPU event access by users without CAP_SYS_ADMIN >= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN To make this setting permanent, edit /etc/sysctl.conf too, e.g.: kernel.perf_event_paranoid = -1 Perhaps the ptrace rule doesn't allow to trace some processes. But anyway the global --per-thread mode had better ignore such errors and continue working on other threads. This patch will record the index of error thread in perf_evsel__open() and remove this thread before retrying. For example (run with non-root, kernel.perf_event_paranoid isn't set): jinyao@skl:~$ perf stat --per-thread ^C Performance counter stats for 'system wide': vmstat-3458 6.171984 cpu-clock:u (msec) # 0.000 CPUs utilized perf-3670 0.515599 cpu-clock:u (msec) # 0.000 CPUs utilized vmstat-3458 1,163,643 cycles:u # 0.189 GHz perf-3670 40,881 cycles:u # 0.079 GHz vmstat-3458 1,410,238 instructions:u # 1.21 insn per cycle perf-3670 3,536 instructions:u # 0.09 insn per cycle vmstat-3458 288,937 branches:u # 46.814 M/sec perf-3670 936 branches:u # 1.815 M/sec vmstat-3458 15,195 branch-misses:u # 5.26% of all branches perf-3670 76 branch-misses:u # 8.12% of all branches 12.651675247 seconds time elapsed Signed-off-by: Jin Yao <yao.jin@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1516117388-10120-1-git-send-email-yao.jin@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
489 lines
9.8 KiB
C
489 lines
9.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <dirent.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include "string2.h"
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#include "strlist.h"
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#include <string.h>
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#include <api/fs/fs.h>
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#include "asm/bug.h"
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#include "thread_map.h"
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#include "util.h"
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#include "debug.h"
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#include "event.h"
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/* Skip "." and ".." directories */
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static int filter(const struct dirent *dir)
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{
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if (dir->d_name[0] == '.')
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return 0;
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else
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return 1;
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}
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static void thread_map__reset(struct thread_map *map, int start, int nr)
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{
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size_t size = (nr - start) * sizeof(map->map[0]);
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memset(&map->map[start], 0, size);
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map->err_thread = -1;
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}
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static struct thread_map *thread_map__realloc(struct thread_map *map, int nr)
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{
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size_t size = sizeof(*map) + sizeof(map->map[0]) * nr;
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int start = map ? map->nr : 0;
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map = realloc(map, size);
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/*
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* We only realloc to add more items, let's reset new items.
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*/
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if (map)
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thread_map__reset(map, start, nr);
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return map;
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}
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#define thread_map__alloc(__nr) thread_map__realloc(NULL, __nr)
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struct thread_map *thread_map__new_by_pid(pid_t pid)
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{
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struct thread_map *threads;
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char name[256];
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int items;
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struct dirent **namelist = NULL;
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int i;
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sprintf(name, "/proc/%d/task", pid);
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items = scandir(name, &namelist, filter, NULL);
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if (items <= 0)
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return NULL;
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threads = thread_map__alloc(items);
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if (threads != NULL) {
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for (i = 0; i < items; i++)
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thread_map__set_pid(threads, i, atoi(namelist[i]->d_name));
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threads->nr = items;
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refcount_set(&threads->refcnt, 1);
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}
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for (i=0; i<items; i++)
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zfree(&namelist[i]);
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free(namelist);
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return threads;
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}
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struct thread_map *thread_map__new_by_tid(pid_t tid)
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{
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struct thread_map *threads = thread_map__alloc(1);
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if (threads != NULL) {
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thread_map__set_pid(threads, 0, tid);
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threads->nr = 1;
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refcount_set(&threads->refcnt, 1);
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}
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return threads;
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}
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static struct thread_map *__thread_map__new_all_cpus(uid_t uid)
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{
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DIR *proc;
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int max_threads = 32, items, i;
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char path[NAME_MAX + 1 + 6];
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struct dirent *dirent, **namelist = NULL;
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struct thread_map *threads = thread_map__alloc(max_threads);
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if (threads == NULL)
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goto out;
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proc = opendir("/proc");
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if (proc == NULL)
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goto out_free_threads;
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threads->nr = 0;
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refcount_set(&threads->refcnt, 1);
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while ((dirent = readdir(proc)) != NULL) {
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char *end;
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bool grow = false;
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pid_t pid = strtol(dirent->d_name, &end, 10);
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if (*end) /* only interested in proper numerical dirents */
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continue;
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snprintf(path, sizeof(path), "/proc/%s", dirent->d_name);
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if (uid != UINT_MAX) {
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struct stat st;
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if (stat(path, &st) != 0 || st.st_uid != uid)
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continue;
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}
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snprintf(path, sizeof(path), "/proc/%d/task", pid);
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items = scandir(path, &namelist, filter, NULL);
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if (items <= 0)
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goto out_free_closedir;
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while (threads->nr + items >= max_threads) {
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max_threads *= 2;
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grow = true;
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}
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if (grow) {
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struct thread_map *tmp;
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tmp = thread_map__realloc(threads, max_threads);
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if (tmp == NULL)
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goto out_free_namelist;
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threads = tmp;
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}
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for (i = 0; i < items; i++) {
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thread_map__set_pid(threads, threads->nr + i,
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atoi(namelist[i]->d_name));
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}
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for (i = 0; i < items; i++)
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zfree(&namelist[i]);
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free(namelist);
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threads->nr += items;
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}
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out_closedir:
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closedir(proc);
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out:
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return threads;
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out_free_threads:
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free(threads);
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return NULL;
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out_free_namelist:
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for (i = 0; i < items; i++)
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zfree(&namelist[i]);
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free(namelist);
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out_free_closedir:
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zfree(&threads);
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goto out_closedir;
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}
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struct thread_map *thread_map__new_all_cpus(void)
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{
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return __thread_map__new_all_cpus(UINT_MAX);
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}
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struct thread_map *thread_map__new_by_uid(uid_t uid)
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{
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return __thread_map__new_all_cpus(uid);
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}
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struct thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid)
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{
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if (pid != -1)
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return thread_map__new_by_pid(pid);
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if (tid == -1 && uid != UINT_MAX)
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return thread_map__new_by_uid(uid);
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return thread_map__new_by_tid(tid);
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}
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static struct thread_map *thread_map__new_by_pid_str(const char *pid_str)
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{
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struct thread_map *threads = NULL, *nt;
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char name[256];
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int items, total_tasks = 0;
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struct dirent **namelist = NULL;
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int i, j = 0;
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pid_t pid, prev_pid = INT_MAX;
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char *end_ptr;
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struct str_node *pos;
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struct strlist_config slist_config = { .dont_dupstr = true, };
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struct strlist *slist = strlist__new(pid_str, &slist_config);
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if (!slist)
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return NULL;
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strlist__for_each_entry(pos, slist) {
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pid = strtol(pos->s, &end_ptr, 10);
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if (pid == INT_MIN || pid == INT_MAX ||
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(*end_ptr != '\0' && *end_ptr != ','))
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goto out_free_threads;
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if (pid == prev_pid)
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continue;
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sprintf(name, "/proc/%d/task", pid);
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items = scandir(name, &namelist, filter, NULL);
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if (items <= 0)
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goto out_free_threads;
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total_tasks += items;
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nt = thread_map__realloc(threads, total_tasks);
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if (nt == NULL)
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goto out_free_namelist;
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threads = nt;
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for (i = 0; i < items; i++) {
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thread_map__set_pid(threads, j++, atoi(namelist[i]->d_name));
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zfree(&namelist[i]);
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}
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threads->nr = total_tasks;
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free(namelist);
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}
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out:
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strlist__delete(slist);
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if (threads)
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refcount_set(&threads->refcnt, 1);
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return threads;
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out_free_namelist:
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for (i = 0; i < items; i++)
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zfree(&namelist[i]);
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free(namelist);
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out_free_threads:
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zfree(&threads);
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goto out;
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}
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struct thread_map *thread_map__new_dummy(void)
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{
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struct thread_map *threads = thread_map__alloc(1);
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if (threads != NULL) {
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thread_map__set_pid(threads, 0, -1);
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threads->nr = 1;
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refcount_set(&threads->refcnt, 1);
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}
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return threads;
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}
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struct thread_map *thread_map__new_by_tid_str(const char *tid_str)
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{
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struct thread_map *threads = NULL, *nt;
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int ntasks = 0;
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pid_t tid, prev_tid = INT_MAX;
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char *end_ptr;
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struct str_node *pos;
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struct strlist_config slist_config = { .dont_dupstr = true, };
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struct strlist *slist;
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/* perf-stat expects threads to be generated even if tid not given */
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if (!tid_str)
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return thread_map__new_dummy();
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slist = strlist__new(tid_str, &slist_config);
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if (!slist)
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return NULL;
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strlist__for_each_entry(pos, slist) {
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tid = strtol(pos->s, &end_ptr, 10);
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if (tid == INT_MIN || tid == INT_MAX ||
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(*end_ptr != '\0' && *end_ptr != ','))
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goto out_free_threads;
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if (tid == prev_tid)
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continue;
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ntasks++;
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nt = thread_map__realloc(threads, ntasks);
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if (nt == NULL)
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goto out_free_threads;
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threads = nt;
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thread_map__set_pid(threads, ntasks - 1, tid);
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threads->nr = ntasks;
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}
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out:
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if (threads)
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refcount_set(&threads->refcnt, 1);
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return threads;
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out_free_threads:
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zfree(&threads);
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strlist__delete(slist);
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goto out;
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}
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struct thread_map *thread_map__new_str(const char *pid, const char *tid,
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uid_t uid, bool all_threads)
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{
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if (pid)
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return thread_map__new_by_pid_str(pid);
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if (!tid && uid != UINT_MAX)
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return thread_map__new_by_uid(uid);
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if (all_threads)
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return thread_map__new_all_cpus();
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return thread_map__new_by_tid_str(tid);
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}
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static void thread_map__delete(struct thread_map *threads)
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{
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if (threads) {
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int i;
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WARN_ONCE(refcount_read(&threads->refcnt) != 0,
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"thread map refcnt unbalanced\n");
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for (i = 0; i < threads->nr; i++)
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free(thread_map__comm(threads, i));
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free(threads);
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}
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}
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struct thread_map *thread_map__get(struct thread_map *map)
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{
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if (map)
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refcount_inc(&map->refcnt);
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return map;
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}
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void thread_map__put(struct thread_map *map)
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{
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if (map && refcount_dec_and_test(&map->refcnt))
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thread_map__delete(map);
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}
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size_t thread_map__fprintf(struct thread_map *threads, FILE *fp)
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{
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int i;
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size_t printed = fprintf(fp, "%d thread%s: ",
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threads->nr, threads->nr > 1 ? "s" : "");
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for (i = 0; i < threads->nr; ++i)
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printed += fprintf(fp, "%s%d", i ? ", " : "", thread_map__pid(threads, i));
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return printed + fprintf(fp, "\n");
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}
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static int get_comm(char **comm, pid_t pid)
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{
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char *path;
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size_t size;
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int err;
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if (asprintf(&path, "%s/%d/comm", procfs__mountpoint(), pid) == -1)
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return -ENOMEM;
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err = filename__read_str(path, comm, &size);
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if (!err) {
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/*
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* We're reading 16 bytes, while filename__read_str
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* allocates data per BUFSIZ bytes, so we can safely
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* mark the end of the string.
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*/
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(*comm)[size] = 0;
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rtrim(*comm);
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}
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free(path);
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return err;
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}
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static void comm_init(struct thread_map *map, int i)
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{
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pid_t pid = thread_map__pid(map, i);
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char *comm = NULL;
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/* dummy pid comm initialization */
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if (pid == -1) {
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map->map[i].comm = strdup("dummy");
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return;
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}
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/*
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* The comm name is like extra bonus ;-),
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* so just warn if we fail for any reason.
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*/
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if (get_comm(&comm, pid))
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pr_warning("Couldn't resolve comm name for pid %d\n", pid);
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map->map[i].comm = comm;
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}
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void thread_map__read_comms(struct thread_map *threads)
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{
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int i;
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for (i = 0; i < threads->nr; ++i)
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comm_init(threads, i);
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}
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static void thread_map__copy_event(struct thread_map *threads,
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struct thread_map_event *event)
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{
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unsigned i;
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threads->nr = (int) event->nr;
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for (i = 0; i < event->nr; i++) {
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thread_map__set_pid(threads, i, (pid_t) event->entries[i].pid);
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threads->map[i].comm = strndup(event->entries[i].comm, 16);
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}
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refcount_set(&threads->refcnt, 1);
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}
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struct thread_map *thread_map__new_event(struct thread_map_event *event)
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{
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struct thread_map *threads;
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threads = thread_map__alloc(event->nr);
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if (threads)
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thread_map__copy_event(threads, event);
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return threads;
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}
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bool thread_map__has(struct thread_map *threads, pid_t pid)
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{
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int i;
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for (i = 0; i < threads->nr; ++i) {
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if (threads->map[i].pid == pid)
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return true;
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}
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return false;
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}
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int thread_map__remove(struct thread_map *threads, int idx)
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{
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int i;
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if (threads->nr < 1)
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return -EINVAL;
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if (idx >= threads->nr)
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return -EINVAL;
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/*
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* Free the 'idx' item and shift the rest up.
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*/
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free(threads->map[idx].comm);
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for (i = idx; i < threads->nr - 1; i++)
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threads->map[i] = threads->map[i + 1];
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threads->nr--;
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return 0;
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}
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