lib: bitmap: add performance test for bitmap_print_to_pagebuf

Functional tests for bitmap_print_to_pagebuf() are provided
in lib/test_printf.c. This patch adds performance test for
a case of fully set bitmap.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

lib/test_bitmap.c

@@ -446,6 +446,42 @@ static void __init test_bitmap_parselist(void)
 	}
 }
 
+static void __init test_bitmap_printlist(void)
+{
+	unsigned long *bmap = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	char expected[256];
+	int ret, slen;
+	ktime_t time;
+
+	if (!buf || !bmap)
+		goto out;
+
+	memset(bmap, -1, PAGE_SIZE);
+	slen = snprintf(expected, 256, "0-%ld", PAGE_SIZE * 8 - 1);
+	if (slen < 0)
+		goto out;
+
+	time = ktime_get();
+	ret = bitmap_print_to_pagebuf(true, buf, bmap, PAGE_SIZE * 8);
+	time = ktime_get() - time;
+
+	if (ret != slen + 1) {
+		pr_err("bitmap_print_to_pagebuf: result is %d, expected %d\n", ret, slen);
+		goto out;
+	}
+
+	if (strncmp(buf, expected, slen)) {
+		pr_err("bitmap_print_to_pagebuf: result is %s, expected %s\n", buf, expected);
+		goto out;
+	}
+
+	pr_err("bitmap_print_to_pagebuf: input is '%s', Time: %llu\n", buf, time);
+out:
+	kfree(buf);
+	kfree(bmap);
+}
+
 static const unsigned long parse_test[] __initconst = {
 	BITMAP_FROM_U64(0),
 	BITMAP_FROM_U64(1),
@@ -818,6 +854,7 @@ static void __init selftest(void)
 	test_bitmap_arr32();
 	test_bitmap_parse();
 	test_bitmap_parselist();
+	test_bitmap_printlist();
 	test_mem_optimisations();
 	test_for_each_set_clump8();
 	test_bitmap_cut();