Commit | Line | Data |
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af1a8899 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * xor.c : Multiple Devices driver for Linux | |
4 | * | |
5 | * Copyright (C) 1996, 1997, 1998, 1999, 2000, | |
6 | * Ingo Molnar, Matti Aarnio, Jakub Jelinek, Richard Henderson. | |
7 | * | |
8 | * Dispatch optimized RAID-5 checksumming functions. | |
1da177e4 LT |
9 | */ |
10 | ||
11 | #define BH_TRACE 0 | |
12 | #include <linux/module.h> | |
5a0e3ad6 | 13 | #include <linux/gfp.h> |
1da177e4 | 14 | #include <linux/raid/xor.h> |
bff61975 | 15 | #include <linux/jiffies.h> |
56a51991 | 16 | #include <linux/preempt.h> |
1da177e4 LT |
17 | #include <asm/xor.h> |
18 | ||
27c4d548 HX |
19 | #ifndef XOR_SELECT_TEMPLATE |
20 | #define XOR_SELECT_TEMPLATE(x) (x) | |
21 | #endif | |
22 | ||
1da177e4 LT |
23 | /* The xor routines to use. */ |
24 | static struct xor_block_template *active_template; | |
25 | ||
26 | void | |
9bc89cd8 | 27 | xor_blocks(unsigned int src_count, unsigned int bytes, void *dest, void **srcs) |
1da177e4 | 28 | { |
9bc89cd8 | 29 | unsigned long *p1, *p2, *p3, *p4; |
1da177e4 | 30 | |
9bc89cd8 DW |
31 | p1 = (unsigned long *) srcs[0]; |
32 | if (src_count == 1) { | |
33 | active_template->do_2(bytes, dest, p1); | |
1da177e4 LT |
34 | return; |
35 | } | |
36 | ||
9bc89cd8 DW |
37 | p2 = (unsigned long *) srcs[1]; |
38 | if (src_count == 2) { | |
39 | active_template->do_3(bytes, dest, p1, p2); | |
1da177e4 LT |
40 | return; |
41 | } | |
42 | ||
9bc89cd8 DW |
43 | p3 = (unsigned long *) srcs[2]; |
44 | if (src_count == 3) { | |
45 | active_template->do_4(bytes, dest, p1, p2, p3); | |
1da177e4 LT |
46 | return; |
47 | } | |
48 | ||
9bc89cd8 DW |
49 | p4 = (unsigned long *) srcs[3]; |
50 | active_template->do_5(bytes, dest, p1, p2, p3, p4); | |
1da177e4 | 51 | } |
685784aa | 52 | EXPORT_SYMBOL(xor_blocks); |
1da177e4 LT |
53 | |
54 | /* Set of all registered templates. */ | |
af7cf25d | 55 | static struct xor_block_template *__initdata template_list; |
1da177e4 LT |
56 | |
57 | #define BENCH_SIZE (PAGE_SIZE) | |
58 | ||
af7cf25d | 59 | static void __init |
1da177e4 LT |
60 | do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2) |
61 | { | |
62 | int speed; | |
6a328475 | 63 | unsigned long now, j; |
1da177e4 LT |
64 | int i, count, max; |
65 | ||
66 | tmpl->next = template_list; | |
67 | template_list = tmpl; | |
68 | ||
56a51991 JK |
69 | preempt_disable(); |
70 | ||
1da177e4 LT |
71 | /* |
72 | * Count the number of XORs done during a whole jiffy, and use | |
73 | * this to calculate the speed of checksumming. We use a 2-page | |
74 | * allocation to have guaranteed color L1-cache layout. | |
75 | */ | |
76 | max = 0; | |
77 | for (i = 0; i < 5; i++) { | |
6a328475 | 78 | j = jiffies; |
1da177e4 | 79 | count = 0; |
6a328475 JK |
80 | while ((now = jiffies) == j) |
81 | cpu_relax(); | |
82 | while (time_before(jiffies, now + 1)) { | |
685784aa | 83 | mb(); /* prevent loop optimzation */ |
1da177e4 LT |
84 | tmpl->do_2(BENCH_SIZE, b1, b2); |
85 | mb(); | |
86 | count++; | |
87 | mb(); | |
88 | } | |
89 | if (count > max) | |
90 | max = count; | |
91 | } | |
92 | ||
56a51991 JK |
93 | preempt_enable(); |
94 | ||
1da177e4 LT |
95 | speed = max * (HZ * BENCH_SIZE / 1024); |
96 | tmpl->speed = speed; | |
97 | ||
685784aa | 98 | printk(KERN_INFO " %-10s: %5d.%03d MB/sec\n", tmpl->name, |
1da177e4 LT |
99 | speed / 1000, speed % 1000); |
100 | } | |
101 | ||
685784aa DW |
102 | static int __init |
103 | calibrate_xor_blocks(void) | |
1da177e4 LT |
104 | { |
105 | void *b1, *b2; | |
106 | struct xor_block_template *f, *fastest; | |
107 | ||
27c4d548 | 108 | fastest = XOR_SELECT_TEMPLATE(NULL); |
39457acd | 109 | |
39457acd MS |
110 | if (fastest) { |
111 | printk(KERN_INFO "xor: automatically using best " | |
112 | "checksumming function %-10s\n", | |
113 | fastest->name); | |
114 | goto out; | |
115 | } | |
39457acd | 116 | |
75f296d9 | 117 | b1 = (void *) __get_free_pages(GFP_KERNEL, 2); |
685784aa DW |
118 | if (!b1) { |
119 | printk(KERN_WARNING "xor: Yikes! No memory available.\n"); | |
1da177e4 LT |
120 | return -ENOMEM; |
121 | } | |
122 | b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE; | |
123 | ||
124 | /* | |
685784aa DW |
125 | * If this arch/cpu has a short-circuited selection, don't loop through |
126 | * all the possible functions, just test the best one | |
1da177e4 LT |
127 | */ |
128 | ||
1da177e4 LT |
129 | #define xor_speed(templ) do_xor_speed((templ), b1, b2) |
130 | ||
39457acd MS |
131 | printk(KERN_INFO "xor: measuring software checksum speed\n"); |
132 | XOR_TRY_TEMPLATES; | |
133 | fastest = template_list; | |
134 | for (f = fastest; f; f = f->next) | |
135 | if (f->speed > fastest->speed) | |
136 | fastest = f; | |
1da177e4 | 137 | |
685784aa | 138 | printk(KERN_INFO "xor: using function: %s (%d.%03d MB/sec)\n", |
1da177e4 LT |
139 | fastest->name, fastest->speed / 1000, fastest->speed % 1000); |
140 | ||
141 | #undef xor_speed | |
142 | ||
143 | free_pages((unsigned long)b1, 2); | |
39457acd | 144 | out: |
1da177e4 LT |
145 | active_template = fastest; |
146 | return 0; | |
147 | } | |
148 | ||
149 | static __exit void xor_exit(void) { } | |
150 | ||
1da177e4 LT |
151 | MODULE_LICENSE("GPL"); |
152 | ||
685784aa DW |
153 | /* when built-in xor.o must initialize before drivers/md/md.o */ |
154 | core_initcall(calibrate_xor_blocks); | |
1da177e4 | 155 | module_exit(xor_exit); |