v4.19.13 snapshot.
diff --git a/lib/find_bit_benchmark.c b/lib/find_bit_benchmark.c
new file mode 100644
index 0000000..5367ffa
--- /dev/null
+++ b/lib/find_bit_benchmark.c
@@ -0,0 +1,167 @@
+/*
+ * Test for find_*_bit functions.
+ *
+ * Copyright (c) 2017 Cavium.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+/*
+ * find_bit functions are widely used in kernel, so the successful boot
+ * is good enough test for correctness.
+ *
+ * This test is focused on performance of traversing bitmaps. Two typical
+ * scenarios are reproduced:
+ * - randomly filled bitmap with approximately equal number of set and
+ * cleared bits;
+ * - sparse bitmap with few set bits at random positions.
+ */
+
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/random.h>
+
+#define BITMAP_LEN (4096UL * 8 * 10)
+#define SPARSE 500
+
+static DECLARE_BITMAP(bitmap, BITMAP_LEN) __initdata;
+static DECLARE_BITMAP(bitmap2, BITMAP_LEN) __initdata;
+
+/*
+ * This is Schlemiel the Painter's algorithm. It should be called after
+ * all other tests for the same bitmap because it sets all bits of bitmap to 1.
+ */
+static int __init test_find_first_bit(void *bitmap, unsigned long len)
+{
+ unsigned long i, cnt;
+ ktime_t time;
+
+ time = ktime_get();
+ for (cnt = i = 0; i < len; cnt++) {
+ i = find_first_bit(bitmap, len);
+ __clear_bit(i, bitmap);
+ }
+ time = ktime_get() - time;
+ pr_err("find_first_bit: %18llu ns, %6ld iterations\n", time, cnt);
+
+ return 0;
+}
+
+static int __init test_find_next_bit(const void *bitmap, unsigned long len)
+{
+ unsigned long i, cnt;
+ ktime_t time;
+
+ time = ktime_get();
+ 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);
+
+ return 0;
+}
+
+static int __init test_find_next_zero_bit(const void *bitmap, unsigned long len)
+{
+ unsigned long i, cnt;
+ ktime_t time;
+
+ time = ktime_get();
+ 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);
+
+ return 0;
+}
+
+static int __init test_find_last_bit(const void *bitmap, unsigned long len)
+{
+ unsigned long l, cnt = 0;
+ ktime_t time;
+
+ time = ktime_get();
+ do {
+ cnt++;
+ l = find_last_bit(bitmap, len);
+ if (l >= len)
+ break;
+ len = l;
+ } while (len);
+ time = ktime_get() - time;
+ pr_err("find_last_bit: %18llu ns, %6ld iterations\n", time, cnt);
+
+ return 0;
+}
+
+static int __init test_find_next_and_bit(const void *bitmap,
+ const void *bitmap2, unsigned long len)
+{
+ unsigned long i, cnt;
+ cycles_t cycles;
+
+ cycles = get_cycles();
+ for (cnt = i = 0; i < BITMAP_LEN; cnt++)
+ i = find_next_and_bit(bitmap, bitmap2, BITMAP_LEN, i+1);
+ cycles = get_cycles() - cycles;
+ pr_err("find_next_and_bit:\t\t%llu cycles, %ld iterations\n",
+ (u64)cycles, cnt);
+
+ return 0;
+}
+
+static int __init find_bit_test(void)
+{
+ unsigned long nbits = BITMAP_LEN / SPARSE;
+
+ pr_err("\nStart testing find_bit() with random-filled bitmap\n");
+
+ get_random_bytes(bitmap, sizeof(bitmap));
+ get_random_bytes(bitmap2, sizeof(bitmap2));
+
+ test_find_next_bit(bitmap, BITMAP_LEN);
+ test_find_next_zero_bit(bitmap, BITMAP_LEN);
+ test_find_last_bit(bitmap, BITMAP_LEN);
+
+ /*
+ * test_find_first_bit() may take some time, so
+ * traverse only part of bitmap to avoid soft lockup.
+ */
+ test_find_first_bit(bitmap, BITMAP_LEN / 10);
+ test_find_next_and_bit(bitmap, bitmap2, BITMAP_LEN);
+
+ pr_err("\nStart testing find_bit() with sparse bitmap\n");
+
+ bitmap_zero(bitmap, BITMAP_LEN);
+ bitmap_zero(bitmap2, BITMAP_LEN);
+
+ while (nbits--) {
+ __set_bit(prandom_u32() % BITMAP_LEN, bitmap);
+ __set_bit(prandom_u32() % BITMAP_LEN, bitmap2);
+ }
+
+ test_find_next_bit(bitmap, BITMAP_LEN);
+ test_find_next_zero_bit(bitmap, BITMAP_LEN);
+ test_find_last_bit(bitmap, BITMAP_LEN);
+ test_find_first_bit(bitmap, BITMAP_LEN);
+ test_find_next_and_bit(bitmap, bitmap2, BITMAP_LEN);
+
+ /*
+ * Everything is OK. Return error just to let user run benchmark
+ * again without annoying rmmod.
+ */
+ return -EINVAL;
+}
+module_init(find_bit_test);
+
+MODULE_LICENSE("GPL");