On Thu, Sep 08, 2022 at 09:09:29PM +0800, Zhen Lei wrote:

Currently, to search for a symbol, we need to expand the symbols in
'kallsyms_names' one by one, and then use the expanded string for
comparison. This is very slow.

In fact, we can first compress the name being looked up and then use
it for comparison when traversing 'kallsyms_names'.

This patch series optimizes the performance of function kallsyms_lookup_name(),
and function klp_find_object_symbol() in the livepatch module. Based on the
test results, the performance overhead is reduced to 5%. That is, the
performance of these functions is improved by 20 times.

To avoid increasing the kernel size in non-debug mode, the optimization is only
for the case CONFIG_KALLSYMS_ALL=y.

WIthout having time yet to reveiw the implementation details, it would
seem this is an area we may want to test for future improvements easily,
so a selftest better yet a kunit test may be nice for this. Can you
write one so we can easily gather a simple metric for "how long does
this take"?

  Luis