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 #ifdef CONFIG_AS_AVX2 49 &raid6_avx2x1, 50 &raid6_avx2x2, 51 #endif 52 #endif 53 #if defined(__x86_64__) && !defined(__arch_um__) 54 &raid6_sse2x1, 55 &raid6_sse2x2, 56 &raid6_sse2x4, 57 #ifdef CONFIG_AS_AVX2 58 &raid6_avx2x1, 59 &raid6_avx2x2, 60 &raid6_avx2x4, 61 #endif 62 #endif 63 #ifdef CONFIG_ALTIVEC 64 &raid6_altivec1, 65 &raid6_altivec2, 66 &raid6_altivec4, 67 &raid6_altivec8, 68 #endif 69 &raid6_intx1, 70 &raid6_intx2, 71 &raid6_intx4, 72 &raid6_intx8, 73 NULL 74 }; 75 76 void (*raid6_2data_recov)(int, size_t, int, int, void **); 77 EXPORT_SYMBOL_GPL(raid6_2data_recov); 78 79 void (*raid6_datap_recov)(int, size_t, int, void **); 80 EXPORT_SYMBOL_GPL(raid6_datap_recov); 81 82 const struct raid6_recov_calls *const raid6_recov_algos[] = { 83 #if (defined(__i386__) || defined(__x86_64__)) && !defined(__arch_um__) 84 #ifdef CONFIG_AS_AVX2 85 &raid6_recov_avx2, 86 #endif 87 &raid6_recov_ssse3, 88 #endif 89 &raid6_recov_intx1, 90 NULL 91 }; 92 93 #ifdef __KERNEL__ 94 #define RAID6_TIME_JIFFIES_LG2 4 95 #else 96 /* Need more time to be stable in userspace */ 97 #define RAID6_TIME_JIFFIES_LG2 9 98 #define time_before(x, y) ((x) < (y)) 99 #endif 100 101 static inline const struct raid6_recov_calls *raid6_choose_recov(void) 102 { 103 const struct raid6_recov_calls *const *algo; 104 const struct raid6_recov_calls *best; 105 106 for (best = NULL, algo = raid6_recov_algos; *algo; algo++) 107 if (!best || (*algo)->priority > best->priority) 108 if (!(*algo)->valid || (*algo)->valid()) 109 best = *algo; 110 111 if (best) { 112 raid6_2data_recov = best->data2; 113 raid6_datap_recov = best->datap; 114 115 printk("raid6: using %s recovery algorithm\n", best->name); 116 } else 117 printk("raid6: Yikes! No recovery algorithm found!\n"); 118 119 return best; 120 } 121 122 static inline const struct raid6_calls *raid6_choose_gen( 123 void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks) 124 { 125 unsigned long perf, bestperf, j0, j1; 126 const struct raid6_calls *const *algo; 127 const struct raid6_calls *best; 128 129 for (bestperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) { 130 if (!best || (*algo)->prefer >= best->prefer) { 131 if ((*algo)->valid && !(*algo)->valid()) 132 continue; 133 134 perf = 0; 135 136 preempt_disable(); 137 j0 = jiffies; 138 while ((j1 = jiffies) == j0) 139 cpu_relax(); 140 while (time_before(jiffies, 141 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 142 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs); 143 perf++; 144 } 145 preempt_enable(); 146 147 if (perf > bestperf) { 148 bestperf = perf; 149 best = *algo; 150 } 151 printk("raid6: %-8s %5ld MB/s\n", (*algo)->name, 152 (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 153 } 154 } 155 156 if (best) { 157 printk("raid6: using algorithm %s (%ld MB/s)\n", 158 best->name, 159 (bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 160 raid6_call = *best; 161 } else 162 printk("raid6: Yikes! No algorithm found!\n"); 163 164 return best; 165 } 166 167 168 /* Try to pick the best algorithm */ 169 /* This code uses the gfmul table as convenient data set to abuse */ 170 171 int __init raid6_select_algo(void) 172 { 173 const int disks = (65536/PAGE_SIZE)+2; 174 175 const struct raid6_calls *gen_best; 176 const struct raid6_recov_calls *rec_best; 177 char *syndromes; 178 void *dptrs[(65536/PAGE_SIZE)+2]; 179 int i; 180 181 for (i = 0; i < disks-2; i++) 182 dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i; 183 184 /* Normal code - use a 2-page allocation to avoid D$ conflict */ 185 syndromes = (void *) __get_free_pages(GFP_KERNEL, 1); 186 187 if (!syndromes) { 188 printk("raid6: Yikes! No memory available.\n"); 189 return -ENOMEM; 190 } 191 192 dptrs[disks-2] = syndromes; 193 dptrs[disks-1] = syndromes + PAGE_SIZE; 194 195 /* select raid gen_syndrome function */ 196 gen_best = raid6_choose_gen(&dptrs, disks); 197 198 /* select raid recover functions */ 199 rec_best = raid6_choose_recov(); 200 201 free_pages((unsigned long)syndromes, 1); 202 203 return gen_best && rec_best ? 0 : -EINVAL; 204 } 205 206 static void raid6_exit(void) 207 { 208 do { } while (0); 209 } 210 211 subsys_initcall(raid6_select_algo); 212 module_exit(raid6_exit); 213 MODULE_LICENSE("GPL"); 214 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 215