Using signalfd fd for tracking SIGCHLD signals as
notification for perf session termination.
Suggested-by: Alexei Budankov <abudan...@huawei.com>
Signed-off-by: Jiri Olsa <jo...@kernel.org>
---
tools/perf/builtin-daemon.c | 142 ++++++++++++++++++++++++++++++++++--
1 file changed, 137 insertions(+), 5 deletions(-)
diff --git a/tools/perf/builtin-daemon.c b/tools/perf/builtin-daemon.c
index 16b24c30722d..644f196d7f39 100644
--- a/tools/perf/builtin-daemon.c
+++ b/tools/perf/builtin-daemon.c
@@ -31,6 +31,7 @@
#include "asm/bug.h"
#include "util.h"
#include <api/fs/fs.h>
+#include <sys/signalfd.h>
#define SESSION_OUTPUT "output"
@@ -58,6 +59,7 @@ struct daemon {
struct list_head sessions;
FILE *out;
char perf[PATH_MAX];
+ int signal_fd;
};
static struct daemon __daemon = {
@@ -317,9 +319,110 @@ static void session__remove(struct session *session)
session__free(session);
}
-static void session__kill(struct session *session)
+static pid_t handle_signalfd(struct daemon *daemon)
+{
+ struct signalfd_siginfo si;
+ struct session *session;
+ ssize_t err;
+ int status;
+ pid_t pid;
+
+ err = read(daemon->signal_fd, &si, sizeof(struct signalfd_siginfo));
+ if (err != sizeof(struct signalfd_siginfo))
+ return -1;
+
+ list_for_each_entry(session, &daemon->sessions, list) {
+
+ if (session->pid != (int) si.ssi_pid)
+ continue;
+
+ pid = waitpid(session->pid, &status, 0);
+ if (pid == session->pid) {
+ if (WIFEXITED(status)) {
+ pr_info("session '%s' exited, status=%d\n",
+ session->name, WEXITSTATUS(status));
+ } else if (WIFSIGNALED(status)) {
+ pr_info("session '%s' killed (signal %d)\n",
+ session->name, WTERMSIG(status));
+ } else if (WIFSTOPPED(status)) {
+ pr_info("session '%s' stopped (signal %d)\n",
+ session->name, WSTOPSIG(status));
+ } else {
+ pr_info("session '%s' Unexpected status
(0x%x)\n",
+ session->name, status);
+ }
+ }
+
+ session->state = SESSION_STATE__KILL;
+ session->pid = -1;
+ return pid;
+ }
+
+ return 0;
+}
+
+static int session__wait(struct session *session, struct daemon *daemon, int
secs)
+{
+ struct pollfd pollfd = {
+ .fd = daemon->signal_fd,
+ .events = POLLIN,
+ };
+ pid_t wpid = 0, pid = session->pid;
+ time_t start;
+
+ start = time(NULL);
+
+ do {
+ if (poll(&pollfd, 1, 1000))
+ wpid = handle_signalfd(daemon);
+
+ if (start + secs < time(NULL))
+ return -1;
+ } while (wpid != pid);
+
+ return 0;
+}
+
+static bool daemon__has_alive_session(struct daemon *daemon)
+{
+ struct session *session;
+
+ list_for_each_entry(session, &daemon->sessions, list) {
+ if (session->state == SESSION_STATE__OK)
+ return true;
+ }
+
+ return false;
+}
+
+static int daemon__wait(struct daemon *daemon, int secs)
+{
+ struct pollfd pollfd = {
+ .fd = daemon->signal_fd,
+ .events = POLLIN,
+ };
+ time_t start;
+
+ start = time(NULL);
+
+ do {
+ if (poll(&pollfd, 1, 1000))
+ handle_signalfd(daemon);
+
+ if (start + secs < time(NULL))
+ return -1;
+ } while (daemon__has_alive_session(daemon));
+
+ return 0;
+}
+
+static void session__kill(struct session *session, struct daemon *daemon)
{
session__signal(session, SIGTERM);
+ if (session__wait(session, daemon, 10)) {
+ session__signal(session, SIGKILL);
+ session__wait(session, daemon, 10);
+ }
}
static int daemon__reconfig(struct daemon *daemon)
@@ -334,7 +437,7 @@ static int daemon__reconfig(struct daemon *daemon)
/* Remove session. */
if (session->state == SESSION_STATE__KILL) {
if (session->pid > 0) {
- session__kill(session);
+ session__kill(session, daemon);
pr_info("reconfig: session '%s' killed\n",
session->name);
}
session__remove(session);
@@ -344,7 +447,7 @@ static int daemon__reconfig(struct daemon *daemon)
/* Reconfig session. */
pr_debug2("reconfig: session '%s' start\n", session->name);
if (session->pid > 0) {
- session__kill(session);
+ session__kill(session, daemon);
pr_info("reconfig: session '%s' killed\n",
session->name);
}
if (session__run(session, daemon))
@@ -359,6 +462,10 @@ static int daemon__reconfig(struct daemon *daemon)
static void daemon__kill(struct daemon *daemon)
{
daemon__signal(daemon, SIGTERM);
+ if (daemon__wait(daemon, 10)) {
+ daemon__signal(daemon, SIGKILL);
+ daemon__wait(daemon, 10);
+ }
}
static void daemon__free(struct daemon *daemon)
@@ -679,6 +786,20 @@ static int setup_config(struct daemon *daemon)
return daemon->config_real ? 0 : -1;
}
+static int setup_signalfd(struct daemon *daemon)
+{
+ sigset_t mask;
+
+ sigemptyset(&mask);
+ sigaddset(&mask, SIGCHLD);
+
+ if (sigprocmask(SIG_BLOCK, &mask, NULL) == -1)
+ return -1;
+
+ daemon->signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
+ return daemon->signal_fd;
+}
+
static int __cmd_start(struct daemon *daemon, struct option parent_options[],
int argc, const char **argv)
{
@@ -688,7 +809,7 @@ static int __cmd_start(struct daemon *daemon, struct option
parent_options[],
OPT_PARENT(parent_options),
OPT_END()
};
- int sock_pos, file_pos, sock_fd, conf_fd;
+ int sock_pos, file_pos, signal_pos, sock_fd, conf_fd, signal_fd;
struct fdarray fda;
int err = 0;
@@ -720,8 +841,12 @@ static int __cmd_start(struct daemon *daemon, struct
option parent_options[],
if (conf_fd < 0)
return -1;
+ signal_fd = setup_signalfd(daemon);
+ if (signal_fd < 0)
+ return -1;
+
/* socket, inotify */
- fdarray__init(&fda, 2);
+ fdarray__init(&fda, 3);
sock_pos = fdarray__add(&fda, sock_fd, POLLIN|POLLERR|POLLHUP, 0);
if (sock_pos < 0)
@@ -731,6 +856,10 @@ static int __cmd_start(struct daemon *daemon, struct
option parent_options[],
if (file_pos < 0)
return -1;
+ signal_pos = fdarray__add(&fda, signal_fd, POLLIN|POLLERR|POLLHUP, 0);
+ if (signal_pos < 0)
+ return -1;
+
signal(SIGINT, sig_handler);
signal(SIGTERM, sig_handler);
@@ -744,6 +873,8 @@ static int __cmd_start(struct daemon *daemon, struct option
parent_options[],
err = handle_server_socket(daemon, sock_fd);
if (fda.entries[file_pos].revents & POLLIN)
err = handle_config_changes(daemon, conf_fd,
&reconfig);
+ if (fda.entries[signal_pos].revents & POLLIN)
+ err = handle_signalfd(daemon) < 0;
if (reconfig)
err = setup_server_config(daemon);
@@ -755,6 +886,7 @@ static int __cmd_start(struct daemon *daemon, struct option
parent_options[],
close(sock_fd);
close(conf_fd);
+ close(signal_fd);
return err;
}
--
2.26.2
