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1da177e4 LT |
1 | /* -*- linux-c -*- ------------------------------------------------------- * |
2 | * | |
3 | * Copyright 2002 H. Peter Anvin - All Rights Reserved | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation, Inc., 53 Temple Place Ste 330, | |
93ed05e2 | 8 | * Boston MA 02111-1307, USA; either version 2 of the License, or |
1da177e4 LT |
9 | * (at your option) any later version; incorporated herein by reference. |
10 | * | |
11 | * ----------------------------------------------------------------------- */ | |
12 | ||
13 | /* | |
a8e026c7 | 14 | * raid6/algos.c |
1da177e4 LT |
15 | * |
16 | * Algorithm list and algorithm selection for RAID-6 | |
17 | */ | |
18 | ||
f701d589 | 19 | #include <linux/raid/pq.h> |
1da177e4 LT |
20 | #ifndef __KERNEL__ |
21 | #include <sys/mman.h> | |
d7e70ba4 | 22 | #include <stdio.h> |
f701d589 | 23 | #else |
f674ef7b | 24 | #include <linux/module.h> |
d5302fe4 | 25 | #include <linux/gfp.h> |
f701d589 DW |
26 | #if !RAID6_USE_EMPTY_ZERO_PAGE |
27 | /* In .bss so it's zeroed */ | |
28 | const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256))); | |
29 | EXPORT_SYMBOL(raid6_empty_zero_page); | |
30 | #endif | |
1da177e4 LT |
31 | #endif |
32 | ||
33 | struct raid6_calls raid6_call; | |
f701d589 | 34 | EXPORT_SYMBOL_GPL(raid6_call); |
1da177e4 | 35 | |
1da177e4 LT |
36 | const struct raid6_calls * const raid6_algos[] = { |
37 | &raid6_intx1, | |
38 | &raid6_intx2, | |
39 | &raid6_intx4, | |
40 | &raid6_intx8, | |
41 | #if defined(__ia64__) | |
42 | &raid6_intx16, | |
43 | &raid6_intx32, | |
44 | #endif | |
ca5cd877 | 45 | #if defined(__i386__) && !defined(__arch_um__) |
1da177e4 LT |
46 | &raid6_mmxx1, |
47 | &raid6_mmxx2, | |
48 | &raid6_sse1x1, | |
49 | &raid6_sse1x2, | |
50 | &raid6_sse2x1, | |
51 | &raid6_sse2x2, | |
52 | #endif | |
ca5cd877 | 53 | #if defined(__x86_64__) && !defined(__arch_um__) |
1da177e4 LT |
54 | &raid6_sse2x1, |
55 | &raid6_sse2x2, | |
56 | &raid6_sse2x4, | |
57 | #endif | |
58 | #ifdef CONFIG_ALTIVEC | |
59 | &raid6_altivec1, | |
60 | &raid6_altivec2, | |
61 | &raid6_altivec4, | |
62 | &raid6_altivec8, | |
63 | #endif | |
64 | NULL | |
65 | }; | |
66 | ||
048a8b8c JK |
67 | void (*raid6_2data_recov)(int, size_t, int, int, void **); |
68 | EXPORT_SYMBOL_GPL(raid6_2data_recov); | |
69 | ||
70 | void (*raid6_datap_recov)(int, size_t, int, void **); | |
71 | EXPORT_SYMBOL_GPL(raid6_datap_recov); | |
72 | ||
73 | const struct raid6_recov_calls *const raid6_recov_algos[] = { | |
74 | #if (defined(__i386__) || defined(__x86_64__)) && !defined(__arch_um__) | |
75 | &raid6_recov_ssse3, | |
76 | #endif | |
77 | &raid6_recov_intx1, | |
78 | NULL | |
79 | }; | |
80 | ||
1da177e4 LT |
81 | #ifdef __KERNEL__ |
82 | #define RAID6_TIME_JIFFIES_LG2 4 | |
83 | #else | |
84 | /* Need more time to be stable in userspace */ | |
85 | #define RAID6_TIME_JIFFIES_LG2 9 | |
f701d589 | 86 | #define time_before(x, y) ((x) < (y)) |
1da177e4 LT |
87 | #endif |
88 | ||
048a8b8c JK |
89 | static inline void raid6_choose_recov(void) |
90 | { | |
91 | const struct raid6_recov_calls *const *algo; | |
92 | const struct raid6_recov_calls *best; | |
93 | ||
94 | for (best = NULL, algo = raid6_recov_algos; *algo; algo++) | |
95 | if (!best || (*algo)->priority > best->priority) | |
96 | if (!(*algo)->valid || (*algo)->valid()) | |
97 | best = *algo; | |
98 | ||
99 | if (best) { | |
100 | raid6_2data_recov = best->data2; | |
101 | raid6_datap_recov = best->datap; | |
102 | ||
103 | printk("raid6: using %s recovery algorithm\n", best->name); | |
104 | } else | |
105 | printk("raid6: Yikes! No recovery algorithm found!\n"); | |
106 | } | |
107 | ||
108 | ||
1da177e4 LT |
109 | /* Try to pick the best algorithm */ |
110 | /* This code uses the gfmul table as convenient data set to abuse */ | |
111 | ||
112 | int __init raid6_select_algo(void) | |
113 | { | |
114 | const struct raid6_calls * const * algo; | |
115 | const struct raid6_calls * best; | |
116 | char *syndromes; | |
117 | void *dptrs[(65536/PAGE_SIZE)+2]; | |
118 | int i, disks; | |
119 | unsigned long perf, bestperf; | |
120 | int bestprefer; | |
121 | unsigned long j0, j1; | |
122 | ||
123 | disks = (65536/PAGE_SIZE)+2; | |
124 | for ( i = 0 ; i < disks-2 ; i++ ) { | |
125 | dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i; | |
126 | } | |
127 | ||
128 | /* Normal code - use a 2-page allocation to avoid D$ conflict */ | |
129 | syndromes = (void *) __get_free_pages(GFP_KERNEL, 1); | |
130 | ||
131 | if ( !syndromes ) { | |
132 | printk("raid6: Yikes! No memory available.\n"); | |
133 | return -ENOMEM; | |
134 | } | |
135 | ||
136 | dptrs[disks-2] = syndromes; | |
137 | dptrs[disks-1] = syndromes + PAGE_SIZE; | |
138 | ||
139 | bestperf = 0; bestprefer = 0; best = NULL; | |
140 | ||
141 | for ( algo = raid6_algos ; *algo ; algo++ ) { | |
142 | if ( !(*algo)->valid || (*algo)->valid() ) { | |
143 | perf = 0; | |
144 | ||
145 | preempt_disable(); | |
146 | j0 = jiffies; | |
147 | while ( (j1 = jiffies) == j0 ) | |
148 | cpu_relax(); | |
62b0559a JL |
149 | while (time_before(jiffies, |
150 | j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { | |
1da177e4 LT |
151 | (*algo)->gen_syndrome(disks, PAGE_SIZE, dptrs); |
152 | perf++; | |
153 | } | |
154 | preempt_enable(); | |
155 | ||
156 | if ( (*algo)->prefer > bestprefer || | |
157 | ((*algo)->prefer == bestprefer && | |
158 | perf > bestperf) ) { | |
159 | best = *algo; | |
160 | bestprefer = best->prefer; | |
161 | bestperf = perf; | |
162 | } | |
163 | printk("raid6: %-8s %5ld MB/s\n", (*algo)->name, | |
164 | (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); | |
165 | } | |
166 | } | |
167 | ||
a5d6839b | 168 | if (best) { |
1da177e4 LT |
169 | printk("raid6: using algorithm %s (%ld MB/s)\n", |
170 | best->name, | |
171 | (bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); | |
a5d6839b AB |
172 | raid6_call = *best; |
173 | } else | |
1da177e4 LT |
174 | printk("raid6: Yikes! No algorithm found!\n"); |
175 | ||
1da177e4 LT |
176 | free_pages((unsigned long)syndromes, 1); |
177 | ||
048a8b8c JK |
178 | /* select raid recover functions */ |
179 | raid6_choose_recov(); | |
180 | ||
1da177e4 LT |
181 | return best ? 0 : -EINVAL; |
182 | } | |
f701d589 DW |
183 | |
184 | static void raid6_exit(void) | |
185 | { | |
186 | do { } while (0); | |
187 | } | |
188 | ||
189 | subsys_initcall(raid6_select_algo); | |
190 | module_exit(raid6_exit); | |
191 | MODULE_LICENSE("GPL"); | |
0efb9e61 | 192 | MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); |