From nobody Sun Feb 8 18:15:25 2026 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 EE72AEB64D9 for ; Thu, 15 Jun 2023 13:36:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344432AbjFONgg (ORCPT ); Thu, 15 Jun 2023 09:36:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44230 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344169AbjFONfb (ORCPT ); Thu, 15 Jun 2023 09:35:31 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F9C22D4C for ; Thu, 15 Jun 2023 06:35:00 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E751263BBE for ; Thu, 15 Jun 2023 13:34:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C481CC433CD; Thu, 15 Jun 2023 13:34:18 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.96) (envelope-from ) id 1q9n7B-000TtA-2s; Thu, 15 Jun 2023 09:34:17 -0400 Message-ID: <20230615133417.709819338@goodmis.org> User-Agent: quilt/0.66 Date: Thu, 15 Jun 2023 09:05:46 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Andrew Morton , Beau Belgrave Subject: [for-linus][PATCH 15/15] tracing/user_events: Document auto-cleanup and remove dyn_event refs References: <20230615130531.200384328@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Beau Belgrave 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. Link: https://lkml.kernel.org/r/20230614163336.5797-7-beaub@linux.microsoft= .com Signed-off-by: Beau Belgrave Signed-off-by: Steven Rostedt (Google) --- 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. =20 -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 registrati= on 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 refe= rences 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. =20 +**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 --=20 2.39.2