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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 | /* | |
14 | * raid6algos.c | |
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 DW |
23 | #else |
24 | #if !RAID6_USE_EMPTY_ZERO_PAGE | |
25 | /* In .bss so it's zeroed */ | |
26 | const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256))); | |
27 | EXPORT_SYMBOL(raid6_empty_zero_page); | |
28 | #endif | |
1da177e4 LT |
29 | #endif |
30 | ||
31 | struct raid6_calls raid6_call; | |
f701d589 | 32 | EXPORT_SYMBOL_GPL(raid6_call); |
1da177e4 | 33 | |
1da177e4 LT |
34 | const struct raid6_calls * const raid6_algos[] = { |
35 | &raid6_intx1, | |
36 | &raid6_intx2, | |
37 | &raid6_intx4, | |
38 | &raid6_intx8, | |
39 | #if defined(__ia64__) | |
40 | &raid6_intx16, | |
41 | &raid6_intx32, | |
42 | #endif | |
ca5cd877 | 43 | #if defined(__i386__) && !defined(__arch_um__) |
1da177e4 LT |
44 | &raid6_mmxx1, |
45 | &raid6_mmxx2, | |
46 | &raid6_sse1x1, | |
47 | &raid6_sse1x2, | |
48 | &raid6_sse2x1, | |
49 | &raid6_sse2x2, | |
50 | #endif | |
ca5cd877 | 51 | #if defined(__x86_64__) && !defined(__arch_um__) |
1da177e4 LT |
52 | &raid6_sse2x1, |
53 | &raid6_sse2x2, | |
54 | &raid6_sse2x4, | |
55 | #endif | |
56 | #ifdef CONFIG_ALTIVEC | |
57 | &raid6_altivec1, | |
58 | &raid6_altivec2, | |
59 | &raid6_altivec4, | |
60 | &raid6_altivec8, | |
61 | #endif | |
62 | NULL | |
63 | }; | |
64 | ||
65 | #ifdef __KERNEL__ | |
66 | #define RAID6_TIME_JIFFIES_LG2 4 | |
67 | #else | |
68 | /* Need more time to be stable in userspace */ | |
69 | #define RAID6_TIME_JIFFIES_LG2 9 | |
f701d589 | 70 | #define time_before(x, y) ((x) < (y)) |
1da177e4 LT |
71 | #endif |
72 | ||
73 | /* Try to pick the best algorithm */ | |
74 | /* This code uses the gfmul table as convenient data set to abuse */ | |
75 | ||
76 | int __init raid6_select_algo(void) | |
77 | { | |
78 | const struct raid6_calls * const * algo; | |
79 | const struct raid6_calls * best; | |
80 | char *syndromes; | |
81 | void *dptrs[(65536/PAGE_SIZE)+2]; | |
82 | int i, disks; | |
83 | unsigned long perf, bestperf; | |
84 | int bestprefer; | |
85 | unsigned long j0, j1; | |
86 | ||
87 | disks = (65536/PAGE_SIZE)+2; | |
88 | for ( i = 0 ; i < disks-2 ; i++ ) { | |
89 | dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i; | |
90 | } | |
91 | ||
92 | /* Normal code - use a 2-page allocation to avoid D$ conflict */ | |
93 | syndromes = (void *) __get_free_pages(GFP_KERNEL, 1); | |
94 | ||
95 | if ( !syndromes ) { | |
96 | printk("raid6: Yikes! No memory available.\n"); | |
97 | return -ENOMEM; | |
98 | } | |
99 | ||
100 | dptrs[disks-2] = syndromes; | |
101 | dptrs[disks-1] = syndromes + PAGE_SIZE; | |
102 | ||
103 | bestperf = 0; bestprefer = 0; best = NULL; | |
104 | ||
105 | for ( algo = raid6_algos ; *algo ; algo++ ) { | |
106 | if ( !(*algo)->valid || (*algo)->valid() ) { | |
107 | perf = 0; | |
108 | ||
109 | preempt_disable(); | |
110 | j0 = jiffies; | |
111 | while ( (j1 = jiffies) == j0 ) | |
112 | cpu_relax(); | |
62b0559a JL |
113 | while (time_before(jiffies, |
114 | j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { | |
1da177e4 LT |
115 | (*algo)->gen_syndrome(disks, PAGE_SIZE, dptrs); |
116 | perf++; | |
117 | } | |
118 | preempt_enable(); | |
119 | ||
120 | if ( (*algo)->prefer > bestprefer || | |
121 | ((*algo)->prefer == bestprefer && | |
122 | perf > bestperf) ) { | |
123 | best = *algo; | |
124 | bestprefer = best->prefer; | |
125 | bestperf = perf; | |
126 | } | |
127 | printk("raid6: %-8s %5ld MB/s\n", (*algo)->name, | |
128 | (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); | |
129 | } | |
130 | } | |
131 | ||
a5d6839b | 132 | if (best) { |
1da177e4 LT |
133 | printk("raid6: using algorithm %s (%ld MB/s)\n", |
134 | best->name, | |
135 | (bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); | |
a5d6839b AB |
136 | raid6_call = *best; |
137 | } else | |
1da177e4 LT |
138 | printk("raid6: Yikes! No algorithm found!\n"); |
139 | ||
1da177e4 LT |
140 | free_pages((unsigned long)syndromes, 1); |
141 | ||
142 | return best ? 0 : -EINVAL; | |
143 | } | |
f701d589 DW |
144 | |
145 | static void raid6_exit(void) | |
146 | { | |
147 | do { } while (0); | |
148 | } | |
149 | ||
150 | subsys_initcall(raid6_select_algo); | |
151 | module_exit(raid6_exit); | |
152 | MODULE_LICENSE("GPL"); |