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(__i386__) && !defined(__arch_um__) 38 #ifdef CONFIG_AS_AVX512 39 &raid6_avx512x2, 40 &raid6_avx512x1, 41 #endif 42 #ifdef CONFIG_AS_AVX2 43 &raid6_avx2x2, 44 &raid6_avx2x1, 45 #endif 46 &raid6_sse2x2, 47 &raid6_sse2x1, 48 &raid6_sse1x2, 49 &raid6_sse1x1, 50 &raid6_mmxx2, 51 &raid6_mmxx1, 52 #endif 53 #if defined(__x86_64__) && !defined(__arch_um__) 54 #ifdef CONFIG_AS_AVX512 55 &raid6_avx512x4, 56 &raid6_avx512x2, 57 &raid6_avx512x1, 58 #endif 59 #ifdef CONFIG_AS_AVX2 60 &raid6_avx2x4, 61 &raid6_avx2x2, 62 &raid6_avx2x1, 63 #endif 64 &raid6_sse2x4, 65 &raid6_sse2x2, 66 &raid6_sse2x1, 67 #endif 68 #ifdef CONFIG_ALTIVEC 69 &raid6_vpermxor8, 70 &raid6_vpermxor4, 71 &raid6_vpermxor2, 72 &raid6_vpermxor1, 73 &raid6_altivec8, 74 &raid6_altivec4, 75 &raid6_altivec2, 76 &raid6_altivec1, 77 #endif 78 #if defined(CONFIG_S390) 79 &raid6_s390vx8, 80 #endif 81 #ifdef CONFIG_KERNEL_MODE_NEON 82 &raid6_neonx8, 83 &raid6_neonx4, 84 &raid6_neonx2, 85 &raid6_neonx1, 86 #endif 87 #if defined(__ia64__) 88 &raid6_intx32, 89 &raid6_intx16, 90 #endif 91 &raid6_intx8, 92 &raid6_intx4, 93 &raid6_intx2, 94 &raid6_intx1, 95 NULL 96 }; 97 98 void (*raid6_2data_recov)(int, size_t, int, int, void **); 99 EXPORT_SYMBOL_GPL(raid6_2data_recov); 100 101 void (*raid6_datap_recov)(int, size_t, int, void **); 102 EXPORT_SYMBOL_GPL(raid6_datap_recov); 103 104 const struct raid6_recov_calls *const raid6_recov_algos[] = { 105 #ifdef CONFIG_AS_AVX512 106 &raid6_recov_avx512, 107 #endif 108 #ifdef CONFIG_AS_AVX2 109 &raid6_recov_avx2, 110 #endif 111 #ifdef CONFIG_AS_SSSE3 112 &raid6_recov_ssse3, 113 #endif 114 #ifdef CONFIG_S390 115 &raid6_recov_s390xc, 116 #endif 117 #if defined(CONFIG_KERNEL_MODE_NEON) 118 &raid6_recov_neon, 119 #endif 120 &raid6_recov_intx1, 121 NULL 122 }; 123 124 #ifdef __KERNEL__ 125 #define RAID6_TIME_JIFFIES_LG2 4 126 #else 127 /* Need more time to be stable in userspace */ 128 #define RAID6_TIME_JIFFIES_LG2 9 129 #define time_before(x, y) ((x) < (y)) 130 #endif 131 132 static inline const struct raid6_recov_calls *raid6_choose_recov(void) 133 { 134 const struct raid6_recov_calls *const *algo; 135 const struct raid6_recov_calls *best; 136 137 for (best = NULL, algo = raid6_recov_algos; *algo; algo++) 138 if (!best || (*algo)->priority > best->priority) 139 if (!(*algo)->valid || (*algo)->valid()) 140 best = *algo; 141 142 if (best) { 143 raid6_2data_recov = best->data2; 144 raid6_datap_recov = best->datap; 145 146 pr_info("raid6: using %s recovery algorithm\n", best->name); 147 } else 148 pr_err("raid6: Yikes! No recovery algorithm found!\n"); 149 150 return best; 151 } 152 153 static inline const struct raid6_calls *raid6_choose_gen( 154 void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks) 155 { 156 unsigned long perf, bestgenperf, bestxorperf, j0, j1; 157 int start = (disks>>1)-1, stop = disks-3; /* work on the second half of the disks */ 158 const struct raid6_calls *const *algo; 159 const struct raid6_calls *best; 160 161 for (bestgenperf = 0, bestxorperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) { 162 if (!best || (*algo)->prefer >= best->prefer) { 163 if ((*algo)->valid && !(*algo)->valid()) 164 continue; 165 166 if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) { 167 best = *algo; 168 break; 169 } 170 171 perf = 0; 172 173 preempt_disable(); 174 j0 = jiffies; 175 while ((j1 = jiffies) == j0) 176 cpu_relax(); 177 while (time_before(jiffies, 178 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 179 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs); 180 perf++; 181 } 182 preempt_enable(); 183 184 if (perf > bestgenperf) { 185 bestgenperf = perf; 186 best = *algo; 187 } 188 pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name, 189 (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 190 191 if (!(*algo)->xor_syndrome) 192 continue; 193 194 perf = 0; 195 196 preempt_disable(); 197 j0 = jiffies; 198 while ((j1 = jiffies) == j0) 199 cpu_relax(); 200 while (time_before(jiffies, 201 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 202 (*algo)->xor_syndrome(disks, start, stop, 203 PAGE_SIZE, *dptrs); 204 perf++; 205 } 206 preempt_enable(); 207 208 if (best == *algo) 209 bestxorperf = perf; 210 211 pr_info("raid6: %-8s xor() %5ld MB/s\n", (*algo)->name, 212 (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1)); 213 } 214 } 215 216 if (best) { 217 pr_info("raid6: using algorithm %s gen() %ld MB/s\n", 218 best->name, 219 (bestgenperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 220 if (best->xor_syndrome) 221 pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n", 222 (bestxorperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1)); 223 raid6_call = *best; 224 } else 225 pr_err("raid6: Yikes! No algorithm found!\n"); 226 227 return best; 228 } 229 230 231 /* Try to pick the best algorithm */ 232 /* This code uses the gfmul table as convenient data set to abuse */ 233 234 int __init raid6_select_algo(void) 235 { 236 const int disks = (65536/PAGE_SIZE)+2; 237 238 const struct raid6_calls *gen_best; 239 const struct raid6_recov_calls *rec_best; 240 char *syndromes; 241 void *dptrs[(65536/PAGE_SIZE)+2]; 242 int i; 243 244 for (i = 0; i < disks-2; i++) 245 dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i; 246 247 /* Normal code - use a 2-page allocation to avoid D$ conflict */ 248 syndromes = (void *) __get_free_pages(GFP_KERNEL, 1); 249 250 if (!syndromes) { 251 pr_err("raid6: Yikes! No memory available.\n"); 252 return -ENOMEM; 253 } 254 255 dptrs[disks-2] = syndromes; 256 dptrs[disks-1] = syndromes + PAGE_SIZE; 257 258 /* select raid gen_syndrome function */ 259 gen_best = raid6_choose_gen(&dptrs, disks); 260 261 /* select raid recover functions */ 262 rec_best = raid6_choose_recov(); 263 264 free_pages((unsigned long)syndromes, 1); 265 266 return gen_best && rec_best ? 0 : -EINVAL; 267 } 268 269 static void raid6_exit(void) 270 { 271 do { } while (0); 272 } 273 274 subsys_initcall(raid6_select_algo); 275 module_exit(raid6_exit); 276 MODULE_LICENSE("GPL"); 277 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 278