From: Jim Cromie <jim.cromie@gmail.com>
To: jbaron@akamai.com, linux-kernel@vger.kernel.org,
akpm@linuxfoundation.org, gregkh@linuxfoundation.org
Cc: linux@rasmusvillemoes.dk, Jim Cromie <jim.cromie@gmail.com>
Subject: [PATCH v2 24/24] kset-example: use pr_debug_n to create example print-classes
Date: Sat, 13 Jun 2020 09:57:38 -0600 [thread overview]
Message-ID: <20200613155738.2249399-25-jim.cromie@gmail.com> (raw)
In-Reply-To: <20200613155738.2249399-1-jim.cromie@gmail.com>
Here is a (counter?) use-case for debug-print-classes. It adds
read,write print-classes, and marks all pr_debugs in *_show and
*_store functions accordingly.
this allows manipulation of those categories as:
echo "module kset-example mflags 1 +p" > /proc/dynamic_debug/control
echo "module kset-example mflags 2 +p" > /proc/dynamic_debug/control
But this marking completely duplicates the callsite sets definable by:
#> cat enable-show-store
module kset-example function *_show +p
module kset-example function *_store +p
#> cat enable-show-store > /proc/dynamic_debug/control
IOW, dont over-use debug-print-class. Your arbitrary subset of
pr-debug calls can be recreated by an N line script.
---
samples/kobject/kset-example.c | 33 +++++++++++++++++++++++++++------
1 file changed, 27 insertions(+), 6 deletions(-)
diff --git a/samples/kobject/kset-example.c b/samples/kobject/kset-example.c
index 27c9b1beec28..61d016cb6b4d 100644
--- a/samples/kobject/kset-example.c
+++ b/samples/kobject/kset-example.c
@@ -42,6 +42,27 @@ struct foo_attribute {
};
#define to_foo_attr(x) container_of(x, struct foo_attribute, attr)
+/*
+ * This module also uses pr_debug() to provide debug logging that
+ * makes it easy to see the module operating. Just invoke as:
+ * #> dmesg -w &
+ * #> modprobe kset-example dyndbg=+pfml
+ *
+ * Further, we *arbitrarily* use pr_debug_n() to create 2 separate
+ * (non-default) print-classes, in the *_show and *_store functions.
+ *
+ * This allows selection by those categories:
+ * echo "module kset-example mflags 1 +p" > dynamic_debug/control
+ * echo "module kset-example mflags 2 +p" > dynamic_debug/control
+ * but that is clearer as:
+ * echo "module kset-example function *_show +p" > dynamic_debug/control
+ * echo "module kset-example function *_store +p" > dynamic_debug/control
+ *
+ * IOW - mostly you dont need non-default print-classes
+ */
+#define prCATr 1 /* print-class for show (r=read) */
+#define prCATw 2 /* print-class for store (w=write) */
+
/*
* The default show function that must be passed to sysfs. This will be
* called by sysfs for whenever a show function is called by the user on a
@@ -56,7 +77,7 @@ static ssize_t foo_attr_show(struct kobject *kobj,
struct foo_attribute *attribute;
struct foo_obj *foo;
- pr_debug("called");
+ pr_debug_n(prCATr, "called");
attribute = to_foo_attr(attr);
foo = to_foo_obj(kobj);
@@ -77,7 +98,7 @@ static ssize_t foo_attr_store(struct kobject *kobj,
struct foo_attribute *attribute;
struct foo_obj *foo;
- pr_debug("called");
+ pr_debug_n(prCATw, "called");
attribute = to_foo_attr(attr);
foo = to_foo_obj(kobj);
@@ -115,7 +136,7 @@ static void foo_release(struct kobject *kobj)
static ssize_t foo_show(struct foo_obj *foo_obj, struct foo_attribute *attr,
char *buf)
{
- pr_debug("called");
+ pr_debug_n(prCATr, "called");
return sprintf(buf, "%d\n", foo_obj->foo);
}
@@ -124,7 +145,7 @@ static ssize_t foo_store(struct foo_obj *foo_obj, struct foo_attribute *attr,
{
int ret;
- pr_debug("called");
+ pr_debug_n(prCATw, "called");
ret = kstrtoint(buf, 10, &foo_obj->foo);
if (ret < 0)
return ret;
@@ -145,7 +166,7 @@ static ssize_t b_show(struct foo_obj *foo_obj, struct foo_attribute *attr,
{
int var;
- pr_debug("called");
+ pr_debug_n(prCATr, "called");
if (strcmp(attr->attr.name, "baz") == 0)
var = foo_obj->baz;
else
@@ -158,7 +179,7 @@ static ssize_t b_store(struct foo_obj *foo_obj, struct foo_attribute *attr,
{
int var, ret;
- pr_debug("called");
+ pr_debug_n(prCATw, "called");
ret = kstrtoint(buf, 10, &var);
if (ret < 0)
return ret;
--
2.26.2
prev parent reply other threads:[~2020-06-13 15:58 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-13 15:57 [PATCH v2 00/24] dynamic_debug cleanups, query features, WIP print-classes Jim Cromie
2020-06-13 15:57 ` [PATCH v2 01/24] dyndbg-docs: eschew file /full/path query in docs Jim Cromie
2020-06-14 6:04 ` Greg KH
2020-06-14 14:24 ` jim.cromie
2020-06-13 15:57 ` [PATCH v2 02/24] dyndbg-docs: initialization is done early, not arch Jim Cromie
2020-06-13 15:57 ` [PATCH v2 03/24] dyndbg: drop obsolete comment on ddebug_proc_open Jim Cromie
2020-06-13 15:57 ` [PATCH v2 04/24] dyndbg: refine debug verbosity; 1 is basic, 2 more chatty Jim Cromie
2020-06-13 15:57 ` [PATCH v2 05/24] dyndbg: rename __verbose section to __dyndbg Jim Cromie
2020-06-13 15:57 ` [PATCH v2 06/24] dyndbg: fix overcounting of ram used by dyndbg Jim Cromie
2020-06-13 15:57 ` [PATCH v2 07/24] dyndbg: fix a BUG_ON in ddebug_describe_flags Jim Cromie
2020-06-15 13:20 ` Petr Mladek
2020-06-15 21:53 ` jim.cromie
2020-06-13 15:57 ` [PATCH v2 08/24] dyndbg: make ddebug_tables list LIFO for add/remove_module Jim Cromie
2020-06-13 15:57 ` [PATCH v2 09/24] dyndbg: add maybe(str,"") macro to reduce code Jim Cromie
2020-06-13 16:14 ` Joe Perches
2020-06-15 20:50 ` jim.cromie
2020-06-15 13:28 ` Petr Mladek
2020-06-15 20:52 ` jim.cromie
2020-06-13 15:57 ` [PATCH v2 10/24] dyndbg: refactor parse_linerange out of ddebug_parse_query Jim Cromie
2020-06-15 13:37 ` Petr Mladek
2020-06-15 22:37 ` jim.cromie
2020-06-13 15:57 ` [PATCH v2 11/24] dyndbg: accept 'file foo.c:func1' and 'file foo.c:10-100' Jim Cromie
2020-06-15 14:46 ` Petr Mladek
2020-06-13 15:57 ` [PATCH v2 12/24] dyndbg: refactor ddebug_read_flags out of ddebug_parse_flags Jim Cromie
2020-06-13 15:57 ` [PATCH v2 13/24] dyndbg: combine flags & mask into a struct, use that Jim Cromie
2020-06-15 15:14 ` Petr Mladek
2020-06-16 5:47 ` jim.cromie
2020-06-16 11:34 ` Petr Mladek
2020-06-13 15:57 ` [PATCH v2 14/24] dyndbg: add filter parameter to ddebug_parse_flags Jim Cromie
2020-06-15 15:17 ` Petr Mladek
2020-06-13 15:57 ` [PATCH v2 15/24] dyndbg: extend ddebug_parse_flags to accept optional leading filter-flags Jim Cromie
2020-06-15 15:37 ` Petr Mladek
2020-06-13 15:57 ` [PATCH v2 16/24] dyndbg: prefer declarative init in caller, to memset in callee Jim Cromie
2020-06-13 15:57 ` [PATCH v2 17/24] dyndbg: add user-flag, negating-flags, and filtering on flags Jim Cromie
2020-06-16 11:41 ` Petr Mladek
2020-06-13 15:57 ` [PATCH v2 18/24] dyndbg: allow negating flag-chars in modflags Jim Cromie
2020-06-16 11:47 ` Petr Mladek
2020-06-13 15:57 ` [PATCH v2 19/24] dyndbg: accept query terms like module:foo and file=bar Jim Cromie
2020-06-16 11:57 ` Petr Mladek
2020-06-16 20:08 ` jim.cromie
2020-06-17 12:11 ` Petr Mladek
2020-06-17 13:32 ` jim.cromie
2020-06-17 14:01 ` Greg KH
2020-06-13 15:57 ` [PATCH v2 20/24] dyndbg: WIP towards debug-print-class based callsite controls Jim Cromie
2020-06-13 19:22 ` Joe Perches
2020-06-16 13:45 ` Petr Mladek
2020-06-16 21:05 ` Joe Perches
2020-06-17 9:31 ` Daniel Thompson
2020-06-17 9:52 ` Petr Mladek
2020-06-17 13:23 ` jim.cromie
2020-06-18 12:20 ` Petr Mladek
2020-06-16 21:13 ` jim.cromie
2020-06-16 21:25 ` jim.cromie
2020-06-13 15:57 ` [PATCH v2 21/24] dyndbg: adapt header macros to pass print-class Jim Cromie
2020-06-13 17:11 ` kernel test robot
2020-06-13 20:25 ` kernel test robot
2020-06-13 15:57 ` [PATCH v2 22/24] dyndbg: add print-class as trailing number to control output Jim Cromie
2020-06-13 15:57 ` [PATCH v2 23/24] kset-example: add pr_debug()s for easy visibility of its operation Jim Cromie
2020-06-14 6:05 ` Greg KH
2020-06-15 22:18 ` jim.cromie
2020-06-16 6:37 ` Greg KH
2020-06-13 15:57 ` Jim Cromie [this message]
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