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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * xor.c : Multiple Devices driver for Linux
3 *
4 * Copyright (C) 1996, 1997, 1998, 1999, 2000,
5 * Ingo Molnar, Matti Aarnio, Jakub Jelinek, Richard Henderson.
6 *
7 * Dispatch optimized RAID-5 checksumming functions.
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2, or (at your option)
12 * any later version.
13 *
14 * You should have received a copy of the GNU General Public License
15 * (for example /usr/src/linux/COPYING); if not, write to the Free
16 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19#define BH_TRACE 0
20#include <linux/module.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090021#include <linux/gfp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/raid/xor.h>
NeilBrownbff61972009-03-31 14:33:13 +110023#include <linux/jiffies.h>
Jim Kukunas56a51992012-05-22 13:54:04 +100024#include <linux/preempt.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <asm/xor.h>
26
Herbert Xu27c4d542016-08-26 23:19:39 +080027#ifndef XOR_SELECT_TEMPLATE
28#define XOR_SELECT_TEMPLATE(x) (x)
29#endif
30
Linus Torvalds1da177e2005-04-16 15:20:36 -070031/* The xor routines to use. */
32static struct xor_block_template *active_template;
33
34void
Dan Williams9bc89cd2007-01-02 11:10:44 -070035xor_blocks(unsigned int src_count, unsigned int bytes, void *dest, void **srcs)
Linus Torvalds1da177e2005-04-16 15:20:36 -070036{
Dan Williams9bc89cd2007-01-02 11:10:44 -070037 unsigned long *p1, *p2, *p3, *p4;
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
Dan Williams9bc89cd2007-01-02 11:10:44 -070039 p1 = (unsigned long *) srcs[0];
40 if (src_count == 1) {
41 active_template->do_2(bytes, dest, p1);
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 return;
43 }
44
Dan Williams9bc89cd2007-01-02 11:10:44 -070045 p2 = (unsigned long *) srcs[1];
46 if (src_count == 2) {
47 active_template->do_3(bytes, dest, p1, p2);
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 return;
49 }
50
Dan Williams9bc89cd2007-01-02 11:10:44 -070051 p3 = (unsigned long *) srcs[2];
52 if (src_count == 3) {
53 active_template->do_4(bytes, dest, p1, p2, p3);
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 return;
55 }
56
Dan Williams9bc89cd2007-01-02 11:10:44 -070057 p4 = (unsigned long *) srcs[3];
58 active_template->do_5(bytes, dest, p1, p2, p3, p4);
Linus Torvalds1da177e2005-04-16 15:20:36 -070059}
Dan Williams685784a2007-07-09 11:56:42 -070060EXPORT_SYMBOL(xor_blocks);
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
62/* Set of all registered templates. */
Jan Beulichaf7cf252012-10-11 13:42:32 +110063static struct xor_block_template *__initdata template_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -070064
65#define BENCH_SIZE (PAGE_SIZE)
66
Jan Beulichaf7cf252012-10-11 13:42:32 +110067static void __init
Linus Torvalds1da177e2005-04-16 15:20:36 -070068do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
69{
70 int speed;
Jim Kukunas6a328472012-05-22 13:54:03 +100071 unsigned long now, j;
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 int i, count, max;
73
74 tmpl->next = template_list;
75 template_list = tmpl;
76
Jim Kukunas56a51992012-05-22 13:54:04 +100077 preempt_disable();
78
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 /*
80 * Count the number of XORs done during a whole jiffy, and use
81 * this to calculate the speed of checksumming. We use a 2-page
82 * allocation to have guaranteed color L1-cache layout.
83 */
84 max = 0;
85 for (i = 0; i < 5; i++) {
Jim Kukunas6a328472012-05-22 13:54:03 +100086 j = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 count = 0;
Jim Kukunas6a328472012-05-22 13:54:03 +100088 while ((now = jiffies) == j)
89 cpu_relax();
90 while (time_before(jiffies, now + 1)) {
Dan Williams685784a2007-07-09 11:56:42 -070091 mb(); /* prevent loop optimzation */
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 tmpl->do_2(BENCH_SIZE, b1, b2);
93 mb();
94 count++;
95 mb();
96 }
97 if (count > max)
98 max = count;
99 }
100
Jim Kukunas56a51992012-05-22 13:54:04 +1000101 preempt_enable();
102
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 speed = max * (HZ * BENCH_SIZE / 1024);
104 tmpl->speed = speed;
105
Dan Williams685784a2007-07-09 11:56:42 -0700106 printk(KERN_INFO " %-10s: %5d.%03d MB/sec\n", tmpl->name,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 speed / 1000, speed % 1000);
108}
109
Dan Williams685784a2007-07-09 11:56:42 -0700110static int __init
111calibrate_xor_blocks(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112{
113 void *b1, *b2;
114 struct xor_block_template *f, *fastest;
115
Herbert Xu27c4d542016-08-26 23:19:39 +0800116 fastest = XOR_SELECT_TEMPLATE(NULL);
Martin Schwidefsky39457ac2016-08-19 14:19:30 +0200117
Martin Schwidefsky39457ac2016-08-19 14:19:30 +0200118 if (fastest) {
119 printk(KERN_INFO "xor: automatically using best "
120 "checksumming function %-10s\n",
121 fastest->name);
122 goto out;
123 }
Martin Schwidefsky39457ac2016-08-19 14:19:30 +0200124
Levin, Alexander (Sasha Levin)75f296d2017-11-15 17:35:54 -0800125 b1 = (void *) __get_free_pages(GFP_KERNEL, 2);
Dan Williams685784a2007-07-09 11:56:42 -0700126 if (!b1) {
127 printk(KERN_WARNING "xor: Yikes! No memory available.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 return -ENOMEM;
129 }
130 b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE;
131
132 /*
Dan Williams685784a2007-07-09 11:56:42 -0700133 * If this arch/cpu has a short-circuited selection, don't loop through
134 * all the possible functions, just test the best one
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 */
136
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137#define xor_speed(templ) do_xor_speed((templ), b1, b2)
138
Martin Schwidefsky39457ac2016-08-19 14:19:30 +0200139 printk(KERN_INFO "xor: measuring software checksum speed\n");
140 XOR_TRY_TEMPLATES;
141 fastest = template_list;
142 for (f = fastest; f; f = f->next)
143 if (f->speed > fastest->speed)
144 fastest = f;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
Dan Williams685784a2007-07-09 11:56:42 -0700146 printk(KERN_INFO "xor: using function: %s (%d.%03d MB/sec)\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 fastest->name, fastest->speed / 1000, fastest->speed % 1000);
148
149#undef xor_speed
150
151 free_pages((unsigned long)b1, 2);
Martin Schwidefsky39457ac2016-08-19 14:19:30 +0200152out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 active_template = fastest;
154 return 0;
155}
156
157static __exit void xor_exit(void) { }
158
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159MODULE_LICENSE("GPL");
160
Dan Williams685784a2007-07-09 11:56:42 -0700161/* when built-in xor.o must initialize before drivers/md/md.o */
162core_initcall(calibrate_xor_blocks);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163module_exit(xor_exit);