+++ Zhou Chengming [28/03/17 21:10 +0800]:
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@xxxxxxxxxx>
Limiting the search space for symbol lookups is a valid improvement, so: Acked-by: Jessica Yu <jeyu@xxxxxxxxxx>
--- kernel/livepatch/core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index af46438..b4b8bb0 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -182,7 +182,10 @@ static int klp_find_object_symbol(const char *objname, const char *name, }; mutex_lock(&module_mutex); - kallsyms_on_each_symbol(klp_find_callback, &args); + if (objname) + module_kallsyms_on_each_symbol(klp_find_callback, &args); + else + kallsyms_on_each_symbol(klp_find_callback, &args); mutex_unlock(&module_mutex); /* -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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