Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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, |
Atsushi SAKAI | 93ed05e | 2009-03-31 14:57:37 +1100 | [diff] [blame] | 8 | * Boston MA 02111-1307, USA; either version 2 of the License, or |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Dan Williams | f701d58 | 2009-03-31 15:09:39 +1100 | [diff] [blame] | 19 | #include <linux/raid/pq.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #ifndef __KERNEL__ |
| 21 | #include <sys/mman.h> |
H. Peter Anvin | d7e70ba | 2005-09-16 19:27:29 -0700 | [diff] [blame] | 22 | #include <stdio.h> |
Dan Williams | f701d58 | 2009-03-31 15:09:39 +1100 | [diff] [blame] | 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 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #endif |
| 30 | |
| 31 | struct raid6_calls raid6_call; |
Dan Williams | f701d58 | 2009-03-31 15:09:39 +1100 | [diff] [blame] | 32 | EXPORT_SYMBOL_GPL(raid6_call); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 |
Al Viro | ca5cd87 | 2007-10-29 04:31:16 +0000 | [diff] [blame] | 43 | #if defined(__i386__) && !defined(__arch_um__) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | &raid6_mmxx1, |
| 45 | &raid6_mmxx2, |
| 46 | &raid6_sse1x1, |
| 47 | &raid6_sse1x2, |
| 48 | &raid6_sse2x1, |
| 49 | &raid6_sse2x2, |
| 50 | #endif |
Al Viro | ca5cd87 | 2007-10-29 04:31:16 +0000 | [diff] [blame] | 51 | #if defined(__x86_64__) && !defined(__arch_um__) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 |
Dan Williams | f701d58 | 2009-03-31 15:09:39 +1100 | [diff] [blame] | 70 | #define time_before(x, y) ((x) < (y)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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(); |
Julia Lawall | 62b0559 | 2008-04-28 02:15:56 -0700 | [diff] [blame] | 113 | while (time_before(jiffies, |
| 114 | j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Adrian Bunk | a5d6839 | 2006-06-23 02:05:59 -0700 | [diff] [blame] | 132 | if (best) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | printk("raid6: using algorithm %s (%ld MB/s)\n", |
| 134 | best->name, |
| 135 | (bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); |
Adrian Bunk | a5d6839 | 2006-06-23 02:05:59 -0700 | [diff] [blame] | 136 | raid6_call = *best; |
| 137 | } else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | printk("raid6: Yikes! No algorithm found!\n"); |
| 139 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | free_pages((unsigned long)syndromes, 1); |
| 141 | |
| 142 | return best ? 0 : -EINVAL; |
| 143 | } |
Dan Williams | f701d58 | 2009-03-31 15:09:39 +1100 | [diff] [blame] | 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"); |
NeilBrown | 0efb9e6 | 2009-12-14 12:49:58 +1100 | [diff] [blame] | 153 | MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); |