Commit 29e36c9f authored by Jim Cromie's avatar Jim Cromie Committed by Greg Kroah-Hartman

dynamic_debug: update Documentation/*, Kconfig.debug

In dynamic-debug-howto.txt:

- add section: Debug Messages at Module Initialization Time
- update flags indicators in example outputs to include '='
- make flags descriptions tabular
- add item on '_' flag-char
- add dyndbg, boot-args examples
- rewrap some paragraphs with long lines

In Kconfig.debug, note that compiling with -DDEBUG enables all
pr_debug()s in that code.

In kernel-parameters.txt, add dyndbg and module.dyndbg items,
and deprecate ddebug_query.
Signed-off-by: default avatarJim Cromie <jim.cromie@gmail.com>
Acked-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8e59b5cf
This diff is collapsed.
......@@ -610,7 +610,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
time. See Documentation/dynamic-debug-howto.txt for
details.
details. Deprecated, see dyndbg.
debug [KNL] Enable kernel debugging (events log level).
......@@ -730,6 +730,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
dscc4.setup= [NET]
dyndbg[="val"] [KNL,DYNAMIC_DEBUG]
module.dyndbg[="val"]
Enable debug messages at boot time. See
Documentation/dynamic-debug-howto.txt for details.
earlycon= [KNL] Output early console device and options.
uart[8250],io,<addr>[,options]
uart[8250],mmio,<addr>[,options]
......
......@@ -1205,8 +1205,13 @@ config DYNAMIC_DEBUG
otherwise be available at runtime. These messages can then be
enabled/disabled based on various levels of scope - per source file,
function, module, format string, and line number. This mechanism
implicitly enables all pr_debug() and dev_dbg() calls. The impact of
this compile option is a larger kernel text size of about 2%.
implicitly compiles in all pr_debug() and dev_dbg() calls, which
enlarges the kernel text size by about 2%.
If a source file is compiled with DEBUG flag set, any
pr_debug() calls in it are enabled by default, but can be
disabled at runtime as below. Note that DEBUG flag is
turned on by many CONFIG_*DEBUG* options.
Usage:
......@@ -1223,16 +1228,16 @@ config DYNAMIC_DEBUG
lineno : line number of the debug statement
module : module that contains the debug statement
function : function that contains the debug statement
flags : 'p' means the line is turned 'on' for printing
flags : '=p' means the line is turned 'on' for printing
format : the format used for the debug statement
From a live system:
nullarbor:~ # cat <debugfs>/dynamic_debug/control
# filename:lineno [module]function flags format
fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
Example usage:
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment