Re: [PATCH 2.6.12] printk: add sysctl to control printk_time

From: randy_dunlap
Date: Wed Jul 20 2005 - 23:44:21 EST


On Wed, 20 Jul 2005 16:08:35 -0400 (EDT) Mark Whittington wrote:

> Added a sysctl (KERN_PRINTK_TIME) and by proxy an entry in
> /proc/sys/kernel to enable and disable printk interval information when
> CONFIG_PRINTK_TIME is compiled in.

1/ That explains "what." How about "why?"

2/ The patch does not apply cleanly. It looks like some tabs
are messed up, but I'm not sure about it.

rddunlap@midway:linux-2612> patch -p1 -b --dry-run < ~/fixes/printk_time.patch
patching file Documentation/sysctl/kernel.txt
Hunk #1 FAILED at 39.
Hunk #2 FAILED at 261.
2 out of 2 hunks FAILED -- saving rejects to file Documentation/sysctl/kernel.txt.rej
patching file include/linux/sysctl.h
Hunk #1 FAILED at 136.
1 out of 1 hunk FAILED -- saving rejects to file include/linux/sysctl.h.rej
patching file kernel/printk.c
Hunk #1 FAILED at 473.
1 out of 1 hunk FAILED -- saving rejects to file kernel/printk.c.rej
patching file kernel/sysctl.c
Hunk #1 FAILED at 63.
Hunk #2 FAILED at 590.
2 out of 2 hunks FAILED -- saving rejects to file kernel/sysctl.c.rej
patching file lib/Kconfig.debug
Hunk #1 FAILED at 6.
1 out of 1 hunk FAILED -- saving rejects to file lib/Kconfig.debug.rej

3/ The patch should be made against a more recent kernel version,
like 2.6.13-rc3 or 2.6.13-rc3-git4.


> Signed-off-by: Mark Whittington <markc@xxxxxxxxxxxx>
>
> diff -ruN linux-2.6.12/kernel/printk.c linux-2.6.12-work/kernel/printk.c
> --- linux-2.6.12/kernel/printk.c 2005-06-17 15:48:29.000000000 -0400
> +++ linux-2.6.12-work/kernel/printk.c 2005-07-20 15:32:03.000000000 -0400
> @@ -473,7 +473,8 @@
> }
>
> #if defined(CONFIG_PRINTK_TIME)
> -static int printk_time = 1;
> +int printk_time = 1;
> +EXPORT_SYMBOL(printk_time);

I wouldn't think that the EXPORT_SYMBOL() is needed. That just
makes it visible to modules. Not being 'static' should be enough
to make it visible to other built-in-kernel files...
so, did you try it without the EXPORT_SYMBOL()?

> #else
> static int printk_time = 0;
> #endif
> diff -ruN linux-2.6.12/lib/Kconfig.debug linux-2.6.12-work/lib/Kconfig.debug
> --- linux-2.6.12/lib/Kconfig.debug 2005-06-17 15:48:29.000000000 -0400
> +++ linux-2.6.12-work/lib/Kconfig.debug 2005-07-20 15:09:07.000000000 -0400
> @@ -6,7 +6,9 @@
> included in printk output. This allows you to measure
> the interval between kernel operations, including bootup
> operations. This is useful for identifying long delays
> - in kernel startup.
> + in kernel startup. If this option is enabled, you can turn
> + off and on the timing information by echoing a 1 or 0 to
> + /proc/kernel/sys/printk_time.

Those last 2 lines should line up with the lines above them.
However, the last 2 lines use only spaces and not tab(s),
which is incorrect.

Basically, fix your email client and justify the patch.

---
~Randy
-
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