From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423215AbeBPDVd (ORCPT ); Thu, 15 Feb 2018 22:21:33 -0500 Received: from mga18.intel.com ([134.134.136.126]:1689 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757384AbeBPDVO (ORCPT ); Thu, 15 Feb 2018 22:21:14 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,519,1511856000"; d="scan'208";a="18576212" From: changbin.du@intel.com To: corbet@lwn.net, rostedt@goodmis.org, mingo@kernel.org Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Changbin Du Subject: [PATCH 3/3] Documentation: add ftrace-uses.rst to doc tree Date: Fri, 16 Feb 2018 11:12:19 +0800 Message-Id: <1518750739-12514-4-git-send-email-changbin.du@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1518750739-12514-1-git-send-email-changbin.du@intel.com> References: <1518750739-12514-1-git-send-email-changbin.du@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Changbin Du Signed-off-by: Changbin Du --- Documentation/trace/ftrace-uses.rst | 23 ++++++++++++----------- Documentation/trace/index.rst | 1 + 2 files changed, 13 insertions(+), 11 deletions(-) diff --git a/Documentation/trace/ftrace-uses.rst b/Documentation/trace/ftrace-uses.rst index 3aed560..998a60a 100644 --- a/Documentation/trace/ftrace-uses.rst +++ b/Documentation/trace/ftrace-uses.rst @@ -21,13 +21,14 @@ how to use ftrace to implement your own function callbacks. The ftrace context ================== +.. warning:: -WARNING: The ability to add a callback to almost any function within the -kernel comes with risks. A callback can be called from any context -(normal, softirq, irq, and NMI). Callbacks can also be called just before -going to idle, during CPU bring up and takedown, or going to user space. -This requires extra care to what can be done inside a callback. A callback -can be called outside the protective scope of RCU. + The ability to add a callback to almost any function within the + kernel comes with risks. A callback can be called from any context + (normal, softirq, irq, and NMI). Callbacks can also be called just before + going to idle, during CPU bring up and takedown, or going to user space. + This requires extra care to what can be done inside a callback. A callback + can be called outside the protective scope of RCU. The ftrace infrastructure has some protections agains recursions and RCU but one must still be very careful how they use the callbacks. @@ -54,15 +55,15 @@ an ftrace_ops with ftrace: Both .flags and .private are optional. Only .func is required. -To enable tracing call:: +To enable tracing call: .. c:function:: register_ftrace_function(&ops); -To disable tracing call:: +To disable tracing call: .. c:function:: unregister_ftrace_function(&ops); -The above is defined by including the header:: +The above is defined by including the header: .. c:function:: #include @@ -200,7 +201,7 @@ match a specific pattern. See Filter Commands in :file:`Documentation/trace/ftrace.txt`. -To just trace the schedule function:: +To just trace the schedule function: .. code-block:: c @@ -210,7 +211,7 @@ To add more functions, call the ftrace_set_filter() more than once with the @reset parameter set to zero. To remove the current filter set and replace it with new functions defined by @buf, have @reset be non-zero. -To remove all the filtered functions and trace all functions:: +To remove all the filtered functions and trace all functions: .. code-block:: c diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst index c8000ba..aa2baad 100644 --- a/Documentation/trace/index.rst +++ b/Documentation/trace/index.rst @@ -6,3 +6,4 @@ Linux Tracing Technologies :maxdepth: 2 ftrace-design + ftrace-uses -- 2.7.4