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 #if defined(__ia64__) 38 &raid6_intx16, 39 &raid6_intx32, 40 #endif 41 #if defined(__i386__) && !defined(__arch_um__) 42 &raid6_mmxx1, 43 &raid6_mmxx2, 44 &raid6_sse1x1, 45 &raid6_sse1x2, 46 &raid6_sse2x1, 47 &raid6_sse2x2, 48 #endif 49 #if defined(__x86_64__) && !defined(__arch_um__) 50 &raid6_sse2x1, 51 &raid6_sse2x2, 52 &raid6_sse2x4, 53 #endif 54 #ifdef CONFIG_ALTIVEC 55 &raid6_altivec1, 56 &raid6_altivec2, 57 &raid6_altivec4, 58 &raid6_altivec8, 59 #endif 60 &raid6_intx1, 61 &raid6_intx2, 62 &raid6_intx4, 63 &raid6_intx8, 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 const struct raid6_recov_calls *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 return best; 108 } 109 110 static inline const struct raid6_calls *raid6_choose_gen( 111 void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks) 112 { 113 unsigned long perf, bestperf, j0, j1; 114 const struct raid6_calls *const *algo; 115 const struct raid6_calls *best; 116 117 for (bestperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) { 118 if (!best || (*algo)->prefer >= best->prefer) { 119 if ((*algo)->valid && !(*algo)->valid()) 120 continue; 121 122 perf = 0; 123 124 preempt_disable(); 125 j0 = jiffies; 126 while ((j1 = jiffies) == j0) 127 cpu_relax(); 128 while (time_before(jiffies, 129 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 130 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs); 131 perf++; 132 } 133 preempt_enable(); 134 135 if (perf > bestperf) { 136 bestperf = perf; 137 best = *algo; 138 } 139 printk("raid6: %-8s %5ld MB/s\n", (*algo)->name, 140 (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 141 } 142 } 143 144 if (best) { 145 printk("raid6: using algorithm %s (%ld MB/s)\n", 146 best->name, 147 (bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 148 raid6_call = *best; 149 } else 150 printk("raid6: Yikes! No algorithm found!\n"); 151 152 return best; 153 } 154 155 156 /* Try to pick the best algorithm */ 157 /* This code uses the gfmul table as convenient data set to abuse */ 158 159 int __init raid6_select_algo(void) 160 { 161 const int disks = (65536/PAGE_SIZE)+2; 162 163 const struct raid6_calls *gen_best; 164 const struct raid6_recov_calls *rec_best; 165 char *syndromes; 166 void *dptrs[(65536/PAGE_SIZE)+2]; 167 int i; 168 169 for (i = 0; i < disks-2; i++) 170 dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i; 171 172 /* Normal code - use a 2-page allocation to avoid D$ conflict */ 173 syndromes = (void *) __get_free_pages(GFP_KERNEL, 1); 174 175 if (!syndromes) { 176 printk("raid6: Yikes! No memory available.\n"); 177 return -ENOMEM; 178 } 179 180 dptrs[disks-2] = syndromes; 181 dptrs[disks-1] = syndromes + PAGE_SIZE; 182 183 /* select raid gen_syndrome function */ 184 gen_best = raid6_choose_gen(&dptrs, disks); 185 186 /* select raid recover functions */ 187 rec_best = raid6_choose_recov(); 188 189 free_pages((unsigned long)syndromes, 1); 190 191 return gen_best && rec_best ? 0 : -EINVAL; 192 } 193 194 static void raid6_exit(void) 195 { 196 do { } while (0); 197 } 198 199 subsys_initcall(raid6_select_algo); 200 module_exit(raid6_exit); 201 MODULE_LICENSE("GPL"); 202 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 203