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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 966F9C433E0 for ; Thu, 7 Jan 2021 16:38:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5C21823403 for ; Thu, 7 Jan 2021 16:38:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727327AbhAGQhw (ORCPT ); Thu, 7 Jan 2021 11:37:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:46334 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726541AbhAGQhv (ORCPT ); Thu, 7 Jan 2021 11:37:51 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E72422342C; Thu, 7 Jan 2021 16:37:10 +0000 (UTC) Date: Thu, 7 Jan 2021 11:37:09 -0500 From: Steven Rostedt To: "Tzvetomir Stoyanov (VMware)" Cc: linux-trace-devel@vger.kernel.org Subject: Re: [PATCH 4/6] libtracefs: Documentation for enable / disable tracing APIs Message-ID: <20210107113709.16d05842@gandalf.local.home> In-Reply-To: <20210107083250.16295-5-tz.stoyanov@gmail.com> References: <20210107083250.16295-1-tz.stoyanov@gmail.com> <20210107083250.16295-5-tz.stoyanov@gmail.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On Thu, 7 Jan 2021 10:32:48 +0200 "Tzvetomir Stoyanov (VMware)" wrote: > New man pages with documentation about: > tracefs_trace_is_on(); > tracefs_trace_on(); > tracefs_trace_off(); > tracefs_trace_on_fd(); > tracefs_trace_off_fd(); > > Signed-off-by: Tzvetomir Stoyanov (VMware) > --- > Documentation/libtracefs-traceon.txt | 143 +++++++++++++++++++++++++++ > 1 file changed, 143 insertions(+) > create mode 100644 Documentation/libtracefs-traceon.txt > > diff --git a/Documentation/libtracefs-traceon.txt b/Documentation/libtracefs-traceon.txt > new file mode 100644 > index 0000000..af4b7f7 > --- /dev/null > +++ b/Documentation/libtracefs-traceon.txt > @@ -0,0 +1,143 @@ > +libtracefs(3) > +============= > + > +NAME > +---- > +tracefs_trace_is_on, tracefs_trace_on, tracefs_trace_off, tracefs_trace_on_fd, > +tracefs_trace_off_fd - Functions to enable or disable tracing. > + > +SYNOPSIS > +-------- > +[verse] > +-- > +*#include * > + > +int *tracefs_trace_is_on*(struct tracefs_instance pass:[*]_instance_); > +int *tracefs_trace_on*(struct tracefs_instance pass:[*]_instance_); > +int *tracefs_trace_off*(struct tracefs_instance pass:[*]_instance_); > +int *tracefs_trace_on_fd*(int _fd_); > +int *tracefs_trace_off_fd*(int _fd_); > +-- > + > +DESCRIPTION > +----------- > +This set of functions can be used to check, enable or disable writing to the ring buffer in > +the given trace instance. The tracing is enabled when writing to the ring buffer is enabled. > + > +The _tracefs_trace_is_on()_ function checks if tracing is enabled for the given _instance_. If > +_instance_ is NULL, the top instance is used. > + > +The _tracefs_trace_on()_ and _tracefs_trace_off()_ functions set the tracing in the _instance_ > +to enable or disable state. If _instance_ is NULL, the top instance is used. > + > +The _tracefs_trace_on_fd()_ and _tracefs_trace_off_fd()_ functions set the tracing state to enable > +or disable using the given _fd_. This file descriptor must be opened for writing with > +*tracefs_instance_file_open*(3) for *tracing_on* file from desired trace instance. These functions > +are faster than *tracefs_trace_on* and *tracefs_trace_off*. Hmm, I think this should also add "tracefs_trace_on_get_fd()" that returns a file descriptor on "tracing_on" on the given instance opened with O_RDWR. fd = tracefs_trace_on_get_fd(NULL); tracefs_trace_on_fd(fd); close(fd); Would be the same as: tracefs_trace_on(NULL); -- Steve