add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/crypto/xor.c
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@@ -1,3 +1,4 @@
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+// SPDX-License-Identifier: GPL-2.0-or-later
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 /*
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  * xor.c : Multiple Devices driver for Linux
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  *
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@@ -5,15 +6,6 @@
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  * Ingo Molnar, Matti Aarnio, Jakub Jelinek, Richard Henderson.
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  *
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  * Dispatch optimized RAID-5 checksumming functions.
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- *
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- * This program is free software; you can redistribute it and/or modify
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- * it under the terms of the GNU General Public License as published by
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- * the Free Software Foundation; either version 2, or (at your option)
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- * any later version.
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- *
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- * You should have received a copy of the GNU General Public License
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- * (for example /usr/src/linux/COPYING); if not, write to the Free
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- * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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  */
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10
 
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 #define BH_TRACE 0
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@@ -62,49 +54,65 @@
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 /* Set of all registered templates.  */
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 static struct xor_block_template *__initdata template_list;
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-#define BENCH_SIZE (PAGE_SIZE)
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+#ifndef MODULE
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+static void __init do_xor_register(struct xor_block_template *tmpl)
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+{
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+	tmpl->next = template_list;
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+	template_list = tmpl;
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+}
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+
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+static int __init register_xor_blocks(void)
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+{
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+	active_template = XOR_SELECT_TEMPLATE(NULL);
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+
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+	if (!active_template) {
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+#define xor_speed	do_xor_register
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+		// register all the templates and pick the first as the default
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+		XOR_TRY_TEMPLATES;
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+#undef xor_speed
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+		active_template = template_list;
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+	}
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+	return 0;
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+}
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+#endif
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+
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+#define BENCH_SIZE	4096
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+#define REPS		800U
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 static void __init
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 do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
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 {
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 	int speed;
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-	unsigned long now, j;
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-	int i, count, max;
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+	int i, j;
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+	ktime_t min, start, diff;
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 	tmpl->next = template_list;
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 	template_list = tmpl;
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 	preempt_disable();
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-	/*
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-	 * Count the number of XORs done during a whole jiffy, and use
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-	 * this to calculate the speed of checksumming.  We use a 2-page
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-	 * allocation to have guaranteed color L1-cache layout.
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-	 */
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-	max = 0;
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-	for (i = 0; i < 5; i++) {
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-		j = jiffies;
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-		count = 0;
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-		while ((now = jiffies) == j)
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-			cpu_relax();
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-		while (time_before(jiffies, now + 1)) {
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+	min = (ktime_t)S64_MAX;
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+	for (i = 0; i < 3; i++) {
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+		start = ktime_get();
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+		for (j = 0; j < REPS; j++) {
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 			mb(); /* prevent loop optimzation */
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 			tmpl->do_2(BENCH_SIZE, b1, b2);
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 			mb();
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-			count++;
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-			mb();
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 		}
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-		if (count > max)
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-			max = count;
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+		diff = ktime_sub(ktime_get(), start);
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+		if (diff < min)
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+			min = diff;
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 	}
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 	preempt_enable();
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-	speed = max * (HZ * BENCH_SIZE / 1024);
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+	// bytes/ns == GB/s, multiply by 1000 to get MB/s [not MiB/s]
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+	if (!min)
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+		min = 1;
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+	speed = (1000 * REPS * BENCH_SIZE) / (unsigned int)ktime_to_ns(min);
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 	tmpl->speed = speed;
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-	printk(KERN_INFO "   %-10s: %5d.%03d MB/sec\n", tmpl->name,
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-	       speed / 1000, speed % 1000);
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+	pr_info("   %-16s: %5d MB/sec\n", tmpl->name, speed);
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 }
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 static int __init
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@@ -137,14 +145,15 @@
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 #define xor_speed(templ)	do_xor_speed((templ), b1, b2)
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 	printk(KERN_INFO "xor: measuring software checksum speed\n");
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+	template_list = NULL;
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 	XOR_TRY_TEMPLATES;
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 	fastest = template_list;
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 	for (f = fastest; f; f = f->next)
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 		if (f->speed > fastest->speed)
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 			fastest = f;
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-	printk(KERN_INFO "xor: using function: %s (%d.%03d MB/sec)\n",
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-	       fastest->name, fastest->speed / 1000, fastest->speed % 1000);
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+	pr_info("xor: using function: %s (%d MB/sec)\n",
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+	       fastest->name, fastest->speed);
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 #undef xor_speed
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@@ -158,6 +167,10 @@
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 MODULE_LICENSE("GPL");
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+#ifndef MODULE
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 /* when built-in xor.o must initialize before drivers/md/md.o */
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-core_initcall(calibrate_xor_blocks);
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+core_initcall(register_xor_blocks);
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+#endif
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+
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+module_init(calibrate_xor_blocks);
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 module_exit(xor_exit);