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=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 602C9C433E6 for ; Thu, 11 Feb 2021 13:41:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C7CF64DBA for ; Thu, 11 Feb 2021 13:41:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230209AbhBKNk6 (ORCPT ); Thu, 11 Feb 2021 08:40:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:33256 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231695AbhBKNVD (ORCPT ); Thu, 11 Feb 2021 08:21:03 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id DCAD664E7A; Thu, 11 Feb 2021 13:20:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1613049621; bh=8uHnF8chlIvP+4xo52R4mAyVueiT8FN7qv0ldkJ0cwo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EcvTzta8NUiDuFjCjekoE2rz/F6Hw8DmtEHy8UqYkJgSoKzw8oiEE6P3ODUEclpKj EUWfu8Dt1skUEguPs8pAo/c2GnDe2uT8QsS2gCa/ECRmtNVYLECxxG4MYCIao68WYM vunqXL7JEeIVHm4tBmkTgXLxrAqJqjLnd+Ysgz9va/egYMcfPYxXSlrhfa02iUuhRY Dciv9sHYYGWZm3iyZzE/3UiLKaZ4kx1hZ4+Qyfh7o7QhETSUVvKxGnf4bLRSbjKy+C Z2BjYRIfL85DkJn05pel+v7WTGCaxr++x0/qO20meg0dQMqFJiG0sp4dW2RluQiA8X 6SvRpoMQvgcsQ== Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 794BA40513; Thu, 11 Feb 2021 10:20:18 -0300 (-03) Date: Thu, 11 Feb 2021 10:20:18 -0300 From: Arnaldo Carvalho de Melo To: Jiri Olsa Cc: lkml , Peter Zijlstra , Ingo Molnar , Mark Rutland , Namhyung Kim , Alexander Shishkin , Michael Petlan , Ian Rogers , Alexei Budankov Subject: Re: [PATCH 13/24] perf daemon: Allow only one daemon over base directory Message-ID: <20210211132018.GE1131885@kernel.org> References: <20210208200908.1019149-1-jolsa@kernel.org> <20210208200908.1019149-14-jolsa@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210208200908.1019149-14-jolsa@kernel.org> X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Mon, Feb 08, 2021 at 09:08:57PM +0100, Jiri Olsa escreveu: > Add 'lock' file under daemon base and flock it, so only one > perf daemon can run on top of it. > > Each daemon tries to create and lock BASE/lock file, if it's > successful we are sure we're the only daemon running over > the BASE. > > Once daemon is finished, file descriptor to lock file is > closed and lock is released. > > 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. Had to add this: Committer notes: Provide lockf(F_TLOCK) when not available, i.e. transform: lockf(fd, F_TLOCK, 0); into: flock(fd, LOCK_EX | LOCK_NB); Which should be equivalent. Noticed when cross building to some odd Android NDK. ------ Patch: [acme@five perf]$ git diff diff --git a/tools/perf/builtin-daemon.c b/tools/perf/builtin-daemon.c index 1c17c9e10ca6a656..2890573540f7d027 100644 --- a/tools/perf/builtin-daemon.c +++ b/tools/perf/builtin-daemon.c @@ -914,6 +914,20 @@ static int setup_config(struct daemon *daemon) return daemon->config_real ? 0 : -1; } +#ifndef F_TLOCK +#define F_TLOCK 2 + +#include + +static int lockf(int fd, int cmd, off_t len) +{ + if (cmd != F_TLOCK || len != 0) + return -1; + + return flock(fd, LOCK_EX | LOCK_NB); +} +#endif // F_TLOCK + /* * Each daemon tries to create and lock BASE/lock file, * if it's successful we are sure we're the only daemon [acme@five perf]$