From 12c1a415eb8dc258a33f04d6a4df288e0cc4e200 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 8 Feb 2021 21:08:53 +0100 Subject: [PATCH] perf daemon: Add signalfd support Use a signalfd fd to track SIGCHLD signals as notifications for perf session termination. This way we don't need to actively check for child status, being notified if there's change. Suggested-by: Alexei Budankov Signed-off-by: Jiri Olsa Cc: Alexander Shishkin Cc: Ian Rogers Cc: Ingo Molnar Cc: Mark Rutland Cc: Michael Petlan Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20210208200908.1019149-10-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-daemon.c | 161 ++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 155 insertions(+), 6 deletions(-) diff --git a/tools/perf/builtin-daemon.c b/tools/perf/builtin-daemon.c index 2241d0e..c77668b 100644 --- a/tools/perf/builtin-daemon.c +++ b/tools/perf/builtin-daemon.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -18,6 +19,8 @@ #include #include #include +#include +#include #include #include #include "builtin.h" @@ -83,6 +86,7 @@ struct daemon { struct list_head sessions; FILE *out; char perf[PATH_MAX]; + int signal_fd; }; static struct daemon __daemon = { @@ -368,6 +372,116 @@ static int daemon_session__run(struct daemon_session *session, return -1; } +static pid_t handle_signalfd(struct daemon *daemon) +{ + struct daemon_session *session; + struct signalfd_siginfo si; + 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 = KILL; + session->pid = -1; + return pid; + } + + return 0; +} + +static int daemon_session__wait(struct daemon_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 { + int err = poll(&pollfd, 1, 1000); + + if (err > 0) { + wpid = handle_signalfd(daemon); + } else if (err < 0) { + perror("failed: poll\n"); + return -1; + } + + if (start + secs < time(NULL)) + return -1; + } while (wpid != pid); + + return 0; +} + +static bool daemon__has_alive_session(struct daemon *daemon) +{ + struct daemon_session *session; + + list_for_each_entry(session, &daemon->sessions, list) { + if (session->pid != -1) + 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 { + int err = poll(&pollfd, 1, 1000); + + if (err > 0) { + handle_signalfd(daemon); + } else if (err < 0) { + perror("failed: poll\n"); + return -1; + } + + if (start + secs < time(NULL)) + return -1; + } while (daemon__has_alive_session(daemon)); + + return 0; +} + static int setup_server_socket(struct daemon *daemon) { struct sockaddr_un addr; @@ -493,9 +607,14 @@ static int daemon_session__signal(struct daemon_session *session, int sig) return kill(session->pid, sig); } -static void daemon_session__kill(struct daemon_session *session) +static void daemon_session__kill(struct daemon_session *session, + struct daemon *daemon) { daemon_session__signal(session, SIGTERM); + if (daemon_session__wait(session, daemon, 10)) { + daemon_session__signal(session, SIGKILL); + daemon_session__wait(session, daemon, 10); + } } static void daemon__signal(struct daemon *daemon, int sig) @@ -523,6 +642,10 @@ static void daemon_session__remove(struct daemon_session *session) 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__exit(struct daemon *daemon) @@ -549,7 +672,7 @@ static int daemon__reconfig(struct daemon *daemon) /* Remove session. */ if (session->state == KILL) { if (session->pid > 0) { - daemon_session__kill(session); + daemon_session__kill(session, daemon); pr_info("reconfig: session '%s' killed\n", session->name); } daemon_session__remove(session); @@ -558,7 +681,7 @@ static int daemon__reconfig(struct daemon *daemon) /* Reconfig session. */ if (session->pid > 0) { - daemon_session__kill(session); + daemon_session__kill(session, daemon); pr_info("reconfig: session '%s' killed\n", session->name); } if (daemon_session__run(session, daemon)) @@ -724,6 +847,20 @@ static int go_background(struct daemon *daemon) return 0; } +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) { @@ -733,8 +870,8 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[], OPT_PARENT(parent_options), OPT_END() }; - int sock_fd = -1, conf_fd = -1; - int sock_pos, file_pos; + int sock_fd = -1, conf_fd = -1, signal_fd = -1; + int sock_pos, file_pos, signal_pos; struct fdarray fda; int err = 0; @@ -766,7 +903,7 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[], pr_info("daemon started (pid %d)\n", getpid()); - fdarray__init(&fda, 2); + fdarray__init(&fda, 3); sock_fd = setup_server_socket(daemon); if (sock_fd < 0) @@ -776,6 +913,10 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[], if (conf_fd < 0) goto out; + signal_fd = setup_signalfd(daemon); + if (signal_fd < 0) + goto out; + sock_pos = fdarray__add(&fda, sock_fd, POLLIN|POLLERR|POLLHUP, 0); if (sock_pos < 0) goto out; @@ -784,6 +925,10 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[], if (file_pos < 0) goto out; + signal_pos = fdarray__add(&fda, signal_fd, POLLIN|POLLERR|POLLHUP, 0); + if (signal_pos < 0) + goto out; + signal(SIGINT, sig_handler); signal(SIGTERM, sig_handler); @@ -797,6 +942,8 @@ 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); @@ -813,6 +960,8 @@ out: close(sock_fd); if (conf_fd != -1) close(conf_fd); + if (conf_fd != -1) + close(signal_fd); pr_info("daemon exited\n"); fclose(daemon->out); -- 2.7.4