Re: [PATCH] xfs: allow disabling xfs tracepoints via Kconfig

From: Rasmus Villemoes
Date: Mon Feb 04 2019 - 17:13:03 EST


On 04/02/2019 22.53, Dave Chinner wrote:
> On Mon, Feb 04, 2019 at 10:20:35PM +0100, Rasmus Villemoes wrote:
>> linux/tracepoints.h allows individual subsystems to disable their
>> tracepoints. Add such a knob for xfs. Disabling XFS_TRACEPOINTS
>> reduces the resident size of xfs.ko by about a third, or ~350 KiB.
>
> Ok, now we can't debug typical problems on live production systems
> if tracepoints are turned off on the user/distro kernels. So under
> what circumstances would we ever want to turn off tracepoints on
> XFS?

I don't expect any mainstream distros to turn it off. But for embedded
systems that use a hand-tuned .config, being able to shave off 100s of K
of the kernel image is quite valuable. Tracing _is_ useful,
also/especially when doing embedded development, which is why "just turn
off CONFIG_TRACING" isn't really an option.

Would the knob be more acceptable if it was under CONFIG_EXPERT?

Rasmus