From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 91376C433DB for ; Sat, 2 Jan 2021 22:06:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 60B4320798 for ; Sat, 2 Jan 2021 22:06:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727359AbhABWG0 convert rfc822-to-8bit (ORCPT ); Sat, 2 Jan 2021 17:06:26 -0500 Received: from us-smtp-delivery-44.mimecast.com ([205.139.111.44]:57601 "EHLO us-smtp-delivery-44.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727280AbhABWGZ (ORCPT ); Sat, 2 Jan 2021 17:06:25 -0500 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-304-qCLXG6HDNd26471zNmt5YQ-1; Sat, 02 Jan 2021 17:05:28 -0500 X-MC-Unique: qCLXG6HDNd26471zNmt5YQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C7040107ACE3; Sat, 2 Jan 2021 22:05:26 +0000 (UTC) Received: from krava.redhat.com (unknown [10.40.192.22]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8DF3B19727; Sat, 2 Jan 2021 22:05:22 +0000 (UTC) From: Jiri Olsa To: Arnaldo Carvalho de Melo Cc: lkml , Peter Zijlstra , Ingo Molnar , Mark Rutland , Namhyung Kim , Alexander Shishkin , Michael Petlan , Ian Rogers , Stephane Eranian , Alexei Budankov Subject: [PATCH 12/22] perf daemon: Allow only one daemon over base directory Date: Sat, 2 Jan 2021 23:04:31 +0100 Message-Id: <20210102220441.794923-13-jolsa@kernel.org> In-Reply-To: <20210102220441.794923-1-jolsa@kernel.org> References: <20210102220441.794923-1-jolsa@kernel.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jolsa@kernel.org X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: kernel.org Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset=WINDOWS-1252 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add 'lock' file under daemon base and flock it, so only one perf daemon can run on top of it. Example: # cat ~/.perfconfig [daemon] base=/opt/perfdata [session-cycles] run = -m 10M -e cycles --overwrite --switch-output -a [session-sched] run = -m 20M -e sched:* --overwrite --switch-output -a Starting the daemon: # perf daemon start And try once more: # perf daemon start failed: another perf daemon (pid 775594) owns /opt/perfdata will end up with an error, because there's already one running on top of /opt/perfdata. Signed-off-by: Jiri Olsa --- tools/perf/builtin-daemon.c | 49 +++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) diff --git a/tools/perf/builtin-daemon.c b/tools/perf/builtin-daemon.c index 45748bb471ec..1982eedd3f3f 100644 --- a/tools/perf/builtin-daemon.c +++ b/tools/perf/builtin-daemon.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -562,12 +563,18 @@ static int cmd_session_list(struct daemon *daemon, union cmd *cmd, FILE *out) /* output */ csv_sep, daemon->base, SESSION_OUTPUT); + fprintf(out, "%c%s/%s", + /* lock */ + csv_sep, daemon->base, "lock"); + fprintf(out, "\n"); } else { fprintf(out, "[%d:daemon] base: %s\n", getpid(), daemon->base); if (cmd->list.verbose) { fprintf(out, " output: %s/%s\n", daemon->base, SESSION_OUTPUT); + fprintf(out, " lock: %s/lock\n", + daemon->base); } } @@ -761,6 +768,42 @@ static int handle_config_changes(struct daemon *daemon, int conf_fd, return 0; } +static int check_lock(struct daemon *daemon) +{ + char path[PATH_MAX]; + char buf[20]; + int fd, pid; + ssize_t len; + + scnprintf(path, sizeof(path), "%s/lock", daemon->base); + + fd = open(path, O_RDWR|O_CREAT|O_CLOEXEC, 0640); + if (fd < 0) + return -1; + + if (lockf(fd, F_TLOCK, 0) < 0) { + filename__read_int(path, &pid); + fprintf(stderr, "failed: another perf daemon (pid %d) owns %s\n", + pid, daemon->base); + return -1; + } + + scnprintf(buf, sizeof(buf), "%d", getpid()); + len = strlen(buf); + + if (write(fd, buf, len) != len) { + perror("write failed"); + return -1; + } + + if (ftruncate(fd, len)) { + perror("ftruncate failed"); + return -1; + } + + return 0; +} + static int go_background(struct daemon *daemon) { int pid, fd; @@ -775,6 +818,9 @@ static int go_background(struct daemon *daemon) if (setsid() < 0) return -1; + if (check_lock(daemon)) + return -1; + umask(0); if (chdir(daemon->base)) { @@ -861,6 +907,9 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[], if (setup_server_config(daemon)) return -1; + if (foreground && check_lock(daemon)) + return -1; + if (!foreground && go_background(daemon)) return -1; -- 2.26.2