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Message-Id: <20210208200908.1019149-8-jolsa@kernel.org>
Date: Mon, 8 Feb 2021 21:08:51 +0100
From: Jiri Olsa <jolsa@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: lkml <linux-kernel@...r.kernel.org>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Ingo Molnar <mingo@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Namhyung Kim <namhyung@...nel.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Michael Petlan <mpetlan@...hat.com>,
Ian Rogers <irogers@...gle.com>,
Alexei Budankov <abudankov@...wei.com>
Subject: [PATCH 07/24] perf daemon: Add config file change check
Adding support to detect daemon's config file changes
and re-read the configuration when that happens.
Using inotify file descriptor plugged into the main
fdarray object for polling.
Example:
# cat ~/.perfconfig
[daemon]
base=/opt/perfdata
[session-cycles]
run = -m 10M -e cycles --overwrite --switch-output -a
Starting the daemon:
# perf daemon start
Check sessions:
# perf daemon
[772262:daemon] base: /opt/perfdata
[772263:cycles] perf record -m 10M -e cycles --overwrite --switch-output -a
Change '-m 10M' to '-m 20M', and check daemon log:
# tail -f /opt/perfdata/output
[2021-01-02 20:31:41.234045] daemon started (pid 772262)
[2021-01-02 20:31:41.235072] reconfig: ruining session [cycles:772263]: -m 10M -e cycles --overwrite --switch-output -a
[2021-01-02 20:32:08.310137] reconfig: session 'cycles' killed
[2021-01-02 20:32:08.310847] reconfig: ruining session [cycles:772338]: -m 20M -e cycles --overwrite --switch-output -a
And the session list:
# perf daemon
[772262:daemon] base: /opt/perfdata
[772338:cycles] perf record -m 20M -e cycles --overwrite --switch-output -a
Note the changed '-m 20M' option is in place.
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
tools/perf/builtin-daemon.c | 100 ++++++++++++++++++++++++++++++++++--
1 file changed, 97 insertions(+), 3 deletions(-)
diff --git a/tools/perf/builtin-daemon.c b/tools/perf/builtin-daemon.c
index 15b328f6bd9a..bdddaa2ea388 100644
--- a/tools/perf/builtin-daemon.c
+++ b/tools/perf/builtin-daemon.c
@@ -12,6 +12,8 @@
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
+#include <sys/inotify.h>
+#include <libgen.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
@@ -75,6 +77,7 @@ struct daemon_session {
struct daemon {
const char *config;
char *config_real;
+ char *config_base;
const char *base_user;
char *base;
struct list_head sessions;
@@ -530,6 +533,7 @@ static void daemon__exit(struct daemon *daemon)
daemon_session__remove(session);
free(daemon->config_real);
+ free(daemon->config_base);
free(daemon->base);
}
@@ -566,6 +570,84 @@ static int daemon__reconfig(struct daemon *daemon)
return 0;
}
+static int setup_config_changes(struct daemon *daemon)
+{
+ char *basen = strdup(daemon->config_real);
+ char *dirn = strdup(daemon->config_real);
+ char *base, *dir;
+ int fd, wd = -1;
+
+ if (!dirn || !basen)
+ goto out;
+
+ fd = inotify_init1(IN_NONBLOCK|O_CLOEXEC);
+ if (fd < 0) {
+ perror("failed: inotify_init");
+ goto out;
+ }
+
+ dir = dirname(dirn);
+ base = basename(basen);
+ pr_debug("config file: %s, dir: %s\n", base, dir);
+
+ wd = inotify_add_watch(fd, dir, IN_CLOSE_WRITE);
+ if (wd >= 0) {
+ daemon->config_base = strdup(base);
+ if (!daemon->config_base) {
+ close(fd);
+ wd = -1;
+ }
+ } else {
+ perror("failed: inotify_add_watch");
+ }
+
+out:
+ free(basen);
+ free(dirn);
+ return wd < 0 ? -1 : fd;
+}
+
+static bool process_inotify_event(struct daemon *daemon, char *buf, ssize_t len)
+{
+ char *p = buf;
+
+ while (p < (buf + len)) {
+ struct inotify_event *event = (struct inotify_event *) p;
+
+ /*
+ * We monitor config directory, check if our
+ * config file was changes.
+ */
+ if ((event->mask & IN_CLOSE_WRITE) &&
+ !(event->mask & IN_ISDIR)) {
+ if (!strcmp(event->name, daemon->config_base))
+ return true;
+ }
+ p += sizeof(*event) + event->len;
+ }
+ return false;
+}
+
+static int handle_config_changes(struct daemon *daemon, int conf_fd,
+ bool *config_changed)
+{
+ char buf[4096];
+ ssize_t len;
+
+ while (!(*config_changed)) {
+ len = read(conf_fd, buf, sizeof(buf));
+ if (len == -1) {
+ if (errno != EAGAIN) {
+ perror("failed: read");
+ return -1;
+ }
+ return 0;
+ }
+ *config_changed = process_inotify_event(daemon, buf, len);
+ }
+ return 0;
+}
+
static int setup_config(struct daemon *daemon)
{
if (daemon->base_user) {
@@ -600,8 +682,8 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[],
OPT_PARENT(parent_options),
OPT_END()
};
- int sock_fd = -1;
- int sock_pos;
+ int sock_fd = -1, conf_fd = -1;
+ int sock_pos, file_pos;
struct fdarray fda;
int err = 0;
@@ -622,16 +704,24 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[],
pr_info("daemon started (pid %d)\n", getpid());
- fdarray__init(&fda, 1);
+ fdarray__init(&fda, 2);
sock_fd = setup_server_socket(daemon);
if (sock_fd < 0)
goto out;
+ conf_fd = setup_config_changes(daemon);
+ if (conf_fd < 0)
+ goto out;
+
sock_pos = fdarray__add(&fda, sock_fd, POLLIN|POLLERR|POLLHUP, 0);
if (sock_pos < 0)
goto out;
+ file_pos = fdarray__add(&fda, conf_fd, POLLIN|POLLERR|POLLHUP, 0);
+ if (file_pos < 0)
+ goto out;
+
signal(SIGINT, sig_handler);
signal(SIGTERM, sig_handler);
@@ -643,6 +733,8 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[],
if (fda.entries[sock_pos].revents & POLLIN)
err = handle_server_socket(daemon, sock_fd);
+ if (fda.entries[file_pos].revents & POLLIN)
+ err = handle_config_changes(daemon, conf_fd, &reconfig);
if (reconfig)
err = setup_server_config(daemon);
@@ -657,6 +749,8 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[],
if (sock_fd != -1)
close(sock_fd);
+ if (conf_fd != -1)
+ close(conf_fd);
pr_info("daemon exited\n");
fclose(daemon->out);
--
2.29.2
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