alistair23-linux/kernel/livepatch
Zhou Chengming 72f04b50d6 livepatch: Reduce the time of finding module symbols
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

Then we found the reason: our out-tree module used a lot of static local
variables, so klp.ko has a lot of relocation records which reference the
module. Then for each such entry klp_find_object_symbol() is called to
resolve it, but this function uses the interface kallsyms_on_each_symbol()
even for finding module symbols, so will waste a lot of time on walking
through vmlinux kallsyms table many times.

This patch changes it to use module_kallsyms_on_each_symbol() for modules
symbols. After we apply this patch, the sys time reduced dramatically.

~ time sudo insmod klp.ko
real	0m1.007s
user	0m0.032s
sys	0m0.924s

Signed-off-by: Zhou Chengming <zhouchengming1@huawei.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Jessica Yu <jeyu@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2017-03-30 10:41:38 +02:00
..
core.c livepatch: Reduce the time of finding module symbols 2017-03-30 10:41:38 +02:00
Kconfig livepatch: rename config to CONFIG_LIVEPATCH 2015-02-04 11:25:51 +01:00
Makefile livepatch: rename config to CONFIG_LIVEPATCH 2015-02-04 11:25:51 +01:00