Re: [PATCH] reduce the time of finding symbols for module

From: Miroslav Benes
Date: Tue Mar 28 2017 - 05:02:33 EST



Hi,

On Tue, 28 Mar 2017, Zhou Chengming wrote:

> It's reported that the time of insmoding a klp.ko for one of our
> out-tree modules is too long.
>
> ~ time sudo insmod klp.ko
> real 0m23.799s
> user 0m0.036s
> sys 0m21.256s

Is this stable through several (>=10) runs? 23 seconds are really
suspicious. Yes, there is a linear search through all the kallsyms in
kallsyms_on_each_symbol(), but there are something like 70k symbols on my
machine (that is, way less than 1M). 23 seconds are somewhat unexpected.

If it is a problem, can we fix kallsyms_on_each_symbol() and replace the
linear search with something better? All users would benefit...

Thanks,
Miroslav