From patchwork Wed Jun 14 16:33:36 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Beau Belgrave X-Patchwork-Id: 13280220 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4AC48EB64D8 for ; Wed, 14 Jun 2023 16:33:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234379AbjFNQds (ORCPT ); Wed, 14 Jun 2023 12:33:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46844 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234236AbjFNQdn (ORCPT ); Wed, 14 Jun 2023 12:33:43 -0400 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 327EF1FDC; Wed, 14 Jun 2023 09:33:42 -0700 (PDT) Received: from W11-BEAU-MD.localdomain (unknown [76.135.27.212]) by linux.microsoft.com (Postfix) with ESMTPSA id A63B320FEB2B; Wed, 14 Jun 2023 09:33:41 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com A63B320FEB2B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1686760421; bh=L6ewCnTLmvd3IAdzmYn9pAB0e+CkfQZzUgJPoFiFoKw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HEasVLt6aR+pIq1LBr9t8DKN/CTK4zMPwQNz2URzNu/kzusgo0Or5zhpKXPVqFq0L xs0ONMe7OEuXUks1Oui2TH6zEhXq6GBUoAB7K+uEalcjPQ/HkWb8MH1WcRzTPN8opn 1n5IU50pQ7Vrrry1XmfMjiaBtmVDT/OAowWn75hk= From: Beau Belgrave To: rostedt@goodmis.org, mhiramat@kernel.org Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, ast@kernel.org, dcook@linux.microsoft.com Subject: [PATCH v3 6/6] tracing/user_events: Document auto-cleanup and remove dyn_event refs Date: Wed, 14 Jun 2023 09:33:36 -0700 Message-Id: <20230614163336.5797-7-beaub@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230614163336.5797-1-beaub@linux.microsoft.com> References: <20230614163336.5797-1-beaub@linux.microsoft.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org Now user_events auto-cleanup upon the last reference by default. This makes it not possible to use the dynamics event file via tracefs. Document that auto-cleanup is enabled by default and remove the refernce to /sys/kernel/tracing/dynamic_events file to make this clear. Signed-off-by: Beau Belgrave --- Documentation/trace/user_events.rst | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/Documentation/trace/user_events.rst b/Documentation/trace/user_events.rst index f79987e16cf4..e7b07313550a 100644 --- a/Documentation/trace/user_events.rst +++ b/Documentation/trace/user_events.rst @@ -14,10 +14,6 @@ Programs can view status of the events via /sys/kernel/tracing/user_events_status and can both register and write data out via /sys/kernel/tracing/user_events_data. -Programs can also use /sys/kernel/tracing/dynamic_events to register and -delete user based events via the u: prefix. The format of the command to -dynamic_events is the same as the ioctl with the u: prefix applied. - Typically programs will register a set of events that they wish to expose to tools that can read trace_events (such as ftrace and perf). The registration process tells the kernel which address and bit to reflect if any tool has @@ -144,6 +140,9 @@ its name. Delete will only succeed if there are no references left to the event (in both user and kernel space). User programs should use a separate file to request deletes than the one used for registration due to this. +**NOTE:** By default events will auto-delete when there are no references left +to the event. Flags in the future may change this logic. + Unregistering ------------- If after registering an event it is no longer wanted to be updated then it can