lkml.org 
[lkml]   [2011]   [Sep]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Date
SubjectRe: [PATCH 25/26] dynamic_debug: add pr_fmt_dbg() for dynamic_pr_debug
On Tue, Sep 27, 2011 at 10:51 PM, Joe Perches <joe@perches.com> wrote:
> On Tue, 2011-09-27 at 20:54 -0600, Jim Cromie wrote:
>> Cleanest way is to drop the original synonym, and just use
>> warn (its shorter), but that creates some churn (havent grepped to see
>> how much).
>> I picked what looked like least effort & fewest corner-cases.
>> ICBW..
>
> #ifndef pr_fmt_warning
> #define pr_fmt_warning pr_fmt_warn
> #endif
>

you've made it conditional, where line 203 is not. why ?
201 #define pr_warning(fmt, ...) \
202 printk(KERN_WARNING pr_fmt_warn(fmt), ##__VA_ARGS__)
203 #define pr_warn pr_warning
204 #define pr_notice(fmt, ...) \

Also, though minor, 203 adds pr_warn as the shortcut,
youve suggested the opposite. I presume this is an oversight.

>> > What did you think of avoiding all of this and
>> > having __dynamic_pr_debug move the fmt pointer over
>> > any initial KBUILD_MODULE ": "
>> >
>> > int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
>> > {
>> > [...]
>> >        size_t modsize = strlen(descriptor->modname);
>> >        if (0 == strncmp(fmt, descriptor->modname, modsize) &&
>> >            0 == strncmp(fmt + modsize, ": ", 2))
>> >                fmt += modsize + 2;
>> >        vprintk(fmt, ...)
>> > ?
>>
>> I was getting to that... ;-)
>> Im not crazy about it.  It feels like too much ..
>> Its a runtime workaround for what I think is a
>> problem in users' (or header's) #defines.
>
> I think exactly the opposite myself.
>
> I think all of the '#define pr_fmt(fmt) KBUILD_MODNAME ": "'
> are effectivly useless and I will eventually delete them.
>
> The printk subsystem should look up the module name and
> prefix them to the printk akin to how the dynamic_debug
> system does.  Except the module name should be a singleton.

hmm, maybe Ive missed something in your argument.

For non-dynamic-debug builds, it seems you still want
the MODNAME in the pr_(crit|warn|info|debug) output,
you just dont like the hundreds of defines throughout drivers/*
linux-2.6]$ grep -r pr_fmt drivers/ |wc
427 2556 32040
linux-2.6]$ grep -r pr_fmt drivers/ | grep KBUILD_MODNAME |wc
303 1827 22567
Your runtime check-and-skip-MODNAME code above
fixes dynamic-debug so that works around user defines
doing:
#define pr_fmt(fmt) KBUILD_MODNAME ": "

This would let user of a dynamic-debug enabled kernel
add MODNAME selectively, with +m >$CONTROL


But ISTM this does the same:

diff --git a/include/linux/printk.h b/include/linux/printk.h
index e21de7e..cf17986 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -148,8 +148,17 @@ static inline void setup_log_buf(int early)

extern void dump_stack(void) __cold;

+/* Set pr_fmt default to most common, useful case */
#ifndef pr_fmt
-#define pr_fmt(fmt) fmt
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#endif
+/* except for dynamic-debug, where user can enable it, and we dont
+ want to print it 2x
+ */
+#if defined(CONFIG_DYNAMIC_DEBUG)
+#ifndef pr_fmt_debug
+#define pr_fmt_debug(fmt) fmt
+#endif
#endif

#ifndef pr_fmt_emerg

This sets default to work for the 303 common cases,
allowing the removal of their defines:
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

It also allows existing non-standard uses to work as is:
drivers/sh/intc/dynamic.c:#define pr_fmt(fmt) "intc: " fmt

Your suggested pr_fmt_warning, etc allow severity specific
customizations to override, w/o changing all the others..

And in dynamic-debug kernels, the default pr_fmt_debug
is reset so MODNAME isnt printed, except by the user:
~]# echo +m > $CONTROL
IOW, it seems to take care of everything, w/o runtime workarounds.
With agreement on this, I can fold above patch into 25/26
(which Ive updated here to also fix pr_*_once, pr_*_ratelimited macros),
and we can move against those 303 irritants at our leisure (there is
no flag day)

thanks
Jim
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2011-09-28 19:29    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site