[PATCH v6 1/2] lib: bitmap: add tests for bitmap_find_next_zero_area_off()
From: Yi Sun
Date: Thu Jun 18 2026 - 09:36:25 EST
Add functional and performance tests
for bitmap_find_next_zero_area_off().
performance tests partial output:
Start testing find_bit() with random-filled bitmap
[ 0.310073] bitmap_find_next_zero_area_off: 852731 ns, 1154 iterations
[ 0.311435] find_next_bit: 1356654 ns, 163975 iterations
Start testing find_bit() with sparse bitmap
[ 0.316267] bitmap_find_next_zero_area_off: 4426808 ns, 322479 iterations
[ 0.316292] find_next_bit: 15154 ns, 656 iterations
Signed-off-by: Yi Sun <yi.sun@xxxxxxxxxx>
---
lib/find_bit_benchmark.c | 31 ++++++++++++++++++++++++-------
lib/test_bitmap.c | 38 ++++++++++++++++++++++++++++++++++++++
2 files changed, 62 insertions(+), 7 deletions(-)
diff --git a/lib/find_bit_benchmark.c b/lib/find_bit_benchmark.c
index 00d9dc61cd46..cde7c09de05c 100644
--- a/lib/find_bit_benchmark.c
+++ b/lib/find_bit_benchmark.c
@@ -46,7 +46,7 @@ static int __init test_find_first_bit(const void *bitmap, unsigned long len)
__clear_bit(i, cp);
}
time = ktime_get() - time;
- pr_err("find_first_bit: %18llu ns, %6ld iterations\n", time, cnt);
+ pr_err("find_first_bit: %14llu ns, %6ld iterations\n", time, cnt);
return 0;
}
@@ -66,7 +66,7 @@ static int __init test_find_first_and_bit(const void *bitmap, const void *bitmap
__clear_bit(i, cp);
}
time = ktime_get() - time;
- pr_err("find_first_and_bit: %18llu ns, %6ld iterations\n", time, cnt);
+ pr_err("find_first_and_bit: %14llu ns, %6ld iterations\n", time, cnt);
return 0;
}
@@ -80,7 +80,7 @@ static int __init test_find_next_bit(const void *bitmap, unsigned long len)
for (cnt = i = 0; i < BITMAP_LEN; cnt++)
i = find_next_bit(bitmap, BITMAP_LEN, i) + 1;
time = ktime_get() - time;
- pr_err("find_next_bit: %18llu ns, %6ld iterations\n", time, cnt);
+ pr_err("find_next_bit: %14llu ns, %6ld iterations\n", time, cnt);
return 0;
}
@@ -94,7 +94,7 @@ static int __init test_find_next_zero_bit(const void *bitmap, unsigned long len)
for (cnt = i = 0; i < BITMAP_LEN; cnt++)
i = find_next_zero_bit(bitmap, len, i) + 1;
time = ktime_get() - time;
- pr_err("find_next_zero_bit: %18llu ns, %6ld iterations\n", time, cnt);
+ pr_err("find_next_zero_bit: %14llu ns, %6ld iterations\n", time, cnt);
return 0;
}
@@ -113,7 +113,7 @@ static int __init test_find_last_bit(const void *bitmap, unsigned long len)
len = l;
} while (len);
time = ktime_get() - time;
- pr_err("find_last_bit: %18llu ns, %6ld iterations\n", time, cnt);
+ pr_err("find_last_bit: %14llu ns, %6ld iterations\n", time, cnt);
return 0;
}
@@ -129,7 +129,7 @@ static int __init test_find_nth_bit(const unsigned long *bitmap, unsigned long l
WARN_ON(l >= len);
}
time = ktime_get() - time;
- pr_err("find_nth_bit: %18llu ns, %6ld iterations\n", time, w);
+ pr_err("find_nth_bit: %14llu ns, %6ld iterations\n", time, w);
return 0;
}
@@ -144,7 +144,22 @@ static int __init test_find_next_and_bit(const void *bitmap,
for (cnt = i = 0; i < BITMAP_LEN; cnt++)
i = find_next_and_bit(bitmap, bitmap2, BITMAP_LEN, i + 1);
time = ktime_get() - time;
- pr_err("find_next_and_bit: %18llu ns, %6ld iterations\n", time, cnt);
+ pr_err("find_next_and_bit: %14llu ns, %6ld iterations\n", time, cnt);
+
+ return 0;
+}
+
+static int __init
+test_bitmap_find_next_zero_area_off(unsigned long *bitmap, unsigned long len)
+{
+ unsigned long i, cnt;
+ ktime_t time;
+
+ time = ktime_get();
+ for (cnt = i = 0; i < BITMAP_LEN; cnt++)
+ i = bitmap_find_next_zero_area_off(bitmap, BITMAP_LEN, i, 8, 0, 0) + 1;
+ time = ktime_get() - time;
+ pr_err("bitmap_find_next_zero_area_off: %14llu ns, %6ld iterations\n", time, cnt);
return 0;
}
@@ -158,6 +173,7 @@ static int __init find_bit_test(void)
get_random_bytes(bitmap, sizeof(bitmap));
get_random_bytes(bitmap2, sizeof(bitmap2));
+ test_bitmap_find_next_zero_area_off(bitmap, BITMAP_LEN);
test_find_next_bit(bitmap, BITMAP_LEN);
test_find_next_zero_bit(bitmap, BITMAP_LEN);
test_find_last_bit(bitmap, BITMAP_LEN);
@@ -181,6 +197,7 @@ static int __init find_bit_test(void)
__set_bit(get_random_u32_below(BITMAP_LEN), bitmap2);
}
+ test_bitmap_find_next_zero_area_off(bitmap, BITMAP_LEN);
test_find_next_bit(bitmap, BITMAP_LEN);
test_find_next_zero_bit(bitmap, BITMAP_LEN);
test_find_last_bit(bitmap, BITMAP_LEN);
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 69813c10e6c0..8665df77c960 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -234,6 +234,43 @@ static void __init test_find_nth_bit(void)
}
}
+static void __init
+test_bitmap_find_next_zero_area_off(void)
+{
+ DECLARE_BITMAP(bmap, 192);
+
+ bitmap_set(bmap, 0, 192);
+
+ bitmap_clear(bmap, 0, 8);
+ __clear_bit(50, bmap);
+ bitmap_clear(bmap, 60, 18);
+ __set_bit(69, bmap);
+ __clear_bit(80, bmap);
+ bitmap_clear(bmap, 100, 10);
+ __clear_bit(120, bmap);
+ bitmap_clear(bmap, 145, 8);
+ bitmap_clear(bmap, 160, 32);
+
+ expect_eq_uint(0,
+ bitmap_find_next_zero_area_off(bmap, 192, 0, 8, 0, 0));
+ expect_eq_uint(0,
+ bitmap_find_next_zero_area_off(bmap, 192, 0, 8, 3, 0));
+ expect_eq_uint(163,
+ bitmap_find_next_zero_area_off(bmap, 192, 0, 8, 3, 1));
+ expect_eq_uint(60,
+ bitmap_find_next_zero_area_off(bmap, 192, 1, 8, 0, 0));
+ expect_eq_uint(160,
+ bitmap_find_next_zero_area_off(bmap, 192, 1, 8, 7, 0));
+ expect_eq_uint(60,
+ bitmap_find_next_zero_area_off(bmap, 192, 1, 8, 7, 4));
+ expect_eq_uint(100,
+ bitmap_find_next_zero_area_off(bmap, 192, 0, 10, 0, 0));
+ expect_eq_uint(160,
+ bitmap_find_next_zero_area_off(bmap, 192, 0, 32, 0, 0));
+ expect_eq_uint(1,
+ !!(bitmap_find_next_zero_area_off(bmap, 192, 0, 33, 0, 0) >= 192));
+}
+
static void __init test_fill_set(void)
{
DECLARE_BITMAP(bmap, 1024);
@@ -1559,6 +1596,7 @@ static void __init selftest(void)
test_for_each_clear_bitrange_from();
test_for_each_set_clump8();
test_for_each_set_bit_wrap();
+ test_bitmap_find_next_zero_area_off();
}
KSTM_MODULE_LOADERS(test_bitmap);
--
2.34.1