tools/runqslower: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK

Explicitly set libbpf 1.0 API mode, then we can avoid using the deprecated
RLIMIT_MEMLOCK.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220409125958.92629-5-laoar.shao@gmail.com

tools/bpf/runqslower/runqslower.c

@@ -4,7 +4,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <sys/resource.h>
 #include <time.h>
 #include <bpf/libbpf.h>
 #include <bpf/bpf.h>
@@ -88,16 +87,6 @@ int libbpf_print_fn(enum libbpf_print_level level,
 	return vfprintf(stderr, format, args);
 }
 
-static int bump_memlock_rlimit(void)
-{
-	struct rlimit rlim_new = {
-		.rlim_cur	= RLIM_INFINITY,
-		.rlim_max	= RLIM_INFINITY,
-	};
-
-	return setrlimit(RLIMIT_MEMLOCK, &rlim_new);
-}
-
 void handle_event(void *ctx, int cpu, void *data, __u32 data_sz)
 {
 	const struct runq_event *e = data;
@@ -133,11 +122,8 @@ int main(int argc, char **argv)
 
 	libbpf_set_print(libbpf_print_fn);
 
-	err = bump_memlock_rlimit();
-	if (err) {
-		fprintf(stderr, "failed to increase rlimit: %d", err);
-		return 1;
-	}
+	/* Use libbpf 1.0 API mode */
+	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
 
 	obj = runqslower_bpf__open();
 	if (!obj) {