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 #ifdef CONFIG_KERNEL_MODE_NEON 74 &raid6_neonx1, 75 &raid6_neonx2, 76 &raid6_neonx4, 77 &raid6_neonx8, 78 #endif 79 NULL 80 }; 81 82 void (*raid6_2data_recov)(int, size_t, int, int, void **); 83 EXPORT_SYMBOL_GPL(raid6_2data_recov); 84 85 void (*raid6_datap_recov)(int, size_t, int, void **); 86 EXPORT_SYMBOL_GPL(raid6_datap_recov); 87 88 const struct raid6_recov_calls *const raid6_recov_algos[] = { 89 #if (defined(__i386__) || defined(__x86_64__)) && !defined(__arch_um__) 90 #ifdef CONFIG_AS_AVX2 91 &raid6_recov_avx2, 92 #endif 93 &raid6_recov_ssse3, 94 #endif 95 &raid6_recov_intx1, 96 NULL 97 }; 98 99 #ifdef __KERNEL__ 100 #define RAID6_TIME_JIFFIES_LG2 4 101 #else 102 /* Need more time to be stable in userspace */ 103 #define RAID6_TIME_JIFFIES_LG2 9 104 #define time_before(x, y) ((x) < (y)) 105 #endif 106 107 static inline const struct raid6_recov_calls *raid6_choose_recov(void) 108 { 109 const struct raid6_recov_calls *const *algo; 110 const struct raid6_recov_calls *best; 111 112 for (best = NULL, algo = raid6_recov_algos; *algo; algo++) 113 if (!best || (*algo)->priority > best->priority) 114 if (!(*algo)->valid || (*algo)->valid()) 115 best = *algo; 116 117 if (best) { 118 raid6_2data_recov = best->data2; 119 raid6_datap_recov = best->datap; 120 121 printk("raid6: using %s recovery algorithm\n", best->name); 122 } else 123 printk("raid6: Yikes! No recovery algorithm found!\n"); 124 125 return best; 126 } 127 128 static inline const struct raid6_calls *raid6_choose_gen( 129 void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks) 130 { 131 unsigned long perf, bestperf, j0, j1; 132 const struct raid6_calls *const *algo; 133 const struct raid6_calls *best; 134 135 for (bestperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) { 136 if (!best || (*algo)->prefer >= best->prefer) { 137 if ((*algo)->valid && !(*algo)->valid()) 138 continue; 139 140 perf = 0; 141 142 preempt_disable(); 143 j0 = jiffies; 144 while ((j1 = jiffies) == j0) 145 cpu_relax(); 146 while (time_before(jiffies, 147 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 148 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs); 149 perf++; 150 } 151 preempt_enable(); 152 153 if (perf > bestperf) { 154 bestperf = perf; 155 best = *algo; 156 } 157 printk("raid6: %-8s %5ld MB/s\n", (*algo)->name, 158 (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 159 } 160 } 161 162 if (best) { 163 printk("raid6: using algorithm %s (%ld MB/s)\n", 164 best->name, 165 (bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 166 raid6_call = *best; 167 } else 168 printk("raid6: Yikes! No algorithm found!\n"); 169 170 return best; 171 } 172 173 174 /* Try to pick the best algorithm */ 175 /* This code uses the gfmul table as convenient data set to abuse */ 176 177 int __init raid6_select_algo(void) 178 { 179 const int disks = (65536/PAGE_SIZE)+2; 180 181 const struct raid6_calls *gen_best; 182 const struct raid6_recov_calls *rec_best; 183 char *syndromes; 184 void *dptrs[(65536/PAGE_SIZE)+2]; 185 int i; 186 187 for (i = 0; i < disks-2; i++) 188 dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i; 189 190 /* Normal code - use a 2-page allocation to avoid D$ conflict */ 191 syndromes = (void *) __get_free_pages(GFP_KERNEL, 1); 192 193 if (!syndromes) { 194 printk("raid6: Yikes! No memory available.\n"); 195 return -ENOMEM; 196 } 197 198 dptrs[disks-2] = syndromes; 199 dptrs[disks-1] = syndromes + PAGE_SIZE; 200 201 /* select raid gen_syndrome function */ 202 gen_best = raid6_choose_gen(&dptrs, disks); 203 204 /* select raid recover functions */ 205 rec_best = raid6_choose_recov(); 206 207 free_pages((unsigned long)syndromes, 1); 208 209 return gen_best && rec_best ? 0 : -EINVAL; 210 } 211 212 static void raid6_exit(void) 213 { 214 do { } while (0); 215 } 216 217 subsys_initcall(raid6_select_algo); 218 module_exit(raid6_exit); 219 MODULE_LICENSE("GPL"); 220 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 221