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, 8 * Boston MA 02111-1307, USA; either version 2 of the License, or 9 * (at your option) any later version; incorporated herein by reference. 10 * 11 * ----------------------------------------------------------------------- */ 12 13 /* 14 * raid6/algos.c 15 * 16 * Algorithm list and algorithm selection for RAID-6 17 */ 18 19 #include <linux/raid/pq.h> 20 #ifndef __KERNEL__ 21 #include <sys/mman.h> 22 #include <stdio.h> 23 #else 24 #include <linux/module.h> 25 #include <linux/gfp.h> 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 31 #endif 32 33 struct raid6_calls raid6_call; 34 EXPORT_SYMBOL_GPL(raid6_call); 35 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 45 #if defined(__i386__) && !defined(__arch_um__) 46 &raid6_mmxx1, 47 &raid6_mmxx2, 48 &raid6_sse1x1, 49 &raid6_sse1x2, 50 &raid6_sse2x1, 51 &raid6_sse2x2, 52 #endif 53 #if defined(__x86_64__) && !defined(__arch_um__) 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 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 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 86 #define time_before(x, y) ((x) < (y)) 87 #endif 88 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 } 107 108 109 /* 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(); 149 while (time_before(jiffies, 150 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 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 } 167 168 if (best) { 169 printk("raid6: using algorithm %s (%ld MB/s)\n", 170 best->name, 171 (bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 172 raid6_call = *best; 173 } else 174 printk("raid6: Yikes! No algorithm found!\n"); 175 176 free_pages((unsigned long)syndromes, 1); 177 178 /* select raid recover functions */ 179 raid6_choose_recov(); 180 181 return best ? 0 : -EINVAL; 182 } 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"); 192 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 193