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: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 11 insertions, 6 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 6777153f18f3..ef8192bc0c33 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -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: