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 #ifdef CONFIG_AS_AVX512 53 &raid6_avx512x1, 54 &raid6_avx512x2, 55 #endif 56 #endif 57 #if defined(__x86_64__) && !defined(__arch_um__) 58 &raid6_sse2x1, 59 &raid6_sse2x2, 60 &raid6_sse2x4, 61 #ifdef CONFIG_AS_AVX2 62 &raid6_avx2x1, 63 &raid6_avx2x2, 64 &raid6_avx2x4, 65 #endif 66 #ifdef CONFIG_AS_AVX512 67 &raid6_avx512x1, 68 &raid6_avx512x2, 69 &raid6_avx512x4, 70 #endif 71 #endif 72 #ifdef CONFIG_ALTIVEC 73 &raid6_altivec1, 74 &raid6_altivec2, 75 &raid6_altivec4, 76 &raid6_altivec8, 77 #endif 78 #if defined(CONFIG_TILEGX) 79 &raid6_tilegx8, 80 #endif 81 #if defined(CONFIG_S390) 82 &raid6_s390vx8, 83 #endif 84 &raid6_intx1, 85 &raid6_intx2, 86 &raid6_intx4, 87 &raid6_intx8, 88 #ifdef CONFIG_KERNEL_MODE_NEON 89 &raid6_neonx1, 90 &raid6_neonx2, 91 &raid6_neonx4, 92 &raid6_neonx8, 93 #endif 94 NULL 95 }; 96 97 void (*raid6_2data_recov)(int, size_t, int, int, void **); 98 EXPORT_SYMBOL_GPL(raid6_2data_recov); 99 100 void (*raid6_datap_recov)(int, size_t, int, void **); 101 EXPORT_SYMBOL_GPL(raid6_datap_recov); 102 103 const struct raid6_recov_calls *const raid6_recov_algos[] = { 104 #ifdef CONFIG_AS_AVX512 105 &raid6_recov_avx512, 106 #endif 107 #ifdef CONFIG_AS_AVX2 108 &raid6_recov_avx2, 109 #endif 110 #ifdef CONFIG_AS_SSSE3 111 &raid6_recov_ssse3, 112 #endif 113 #ifdef CONFIG_S390 114 &raid6_recov_s390xc, 115 #endif 116 #if defined(CONFIG_KERNEL_MODE_NEON) 117 &raid6_recov_neon, 118 #endif 119 &raid6_recov_intx1, 120 NULL 121 }; 122 123 #ifdef __KERNEL__ 124 #define RAID6_TIME_JIFFIES_LG2 4 125 #else 126 /* Need more time to be stable in userspace */ 127 #define RAID6_TIME_JIFFIES_LG2 9 128 #define time_before(x, y) ((x) < (y)) 129 #endif 130 131 static inline const struct raid6_recov_calls *raid6_choose_recov(void) 132 { 133 const struct raid6_recov_calls *const *algo; 134 const struct raid6_recov_calls *best; 135 136 for (best = NULL, algo = raid6_recov_algos; *algo; algo++) 137 if (!best || (*algo)->priority > best->priority) 138 if (!(*algo)->valid || (*algo)->valid()) 139 best = *algo; 140 141 if (best) { 142 raid6_2data_recov = best->data2; 143 raid6_datap_recov = best->datap; 144 145 pr_info("raid6: using %s recovery algorithm\n", best->name); 146 } else 147 pr_err("raid6: Yikes! No recovery algorithm found!\n"); 148 149 return best; 150 } 151 152 static inline const struct raid6_calls *raid6_choose_gen( 153 void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks) 154 { 155 unsigned long perf, bestgenperf, bestxorperf, j0, j1; 156 int start = (disks>>1)-1, stop = disks-3; /* work on the second half of the disks */ 157 const struct raid6_calls *const *algo; 158 const struct raid6_calls *best; 159 160 for (bestgenperf = 0, bestxorperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) { 161 if (!best || (*algo)->prefer >= best->prefer) { 162 if ((*algo)->valid && !(*algo)->valid()) 163 continue; 164 165 perf = 0; 166 167 preempt_disable(); 168 j0 = jiffies; 169 while ((j1 = jiffies) == j0) 170 cpu_relax(); 171 while (time_before(jiffies, 172 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 173 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs); 174 perf++; 175 } 176 preempt_enable(); 177 178 if (perf > bestgenperf) { 179 bestgenperf = perf; 180 best = *algo; 181 } 182 pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name, 183 (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 184 185 if (!(*algo)->xor_syndrome) 186 continue; 187 188 perf = 0; 189 190 preempt_disable(); 191 j0 = jiffies; 192 while ((j1 = jiffies) == j0) 193 cpu_relax(); 194 while (time_before(jiffies, 195 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 196 (*algo)->xor_syndrome(disks, start, stop, 197 PAGE_SIZE, *dptrs); 198 perf++; 199 } 200 preempt_enable(); 201 202 if (best == *algo) 203 bestxorperf = perf; 204 205 pr_info("raid6: %-8s xor() %5ld MB/s\n", (*algo)->name, 206 (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1)); 207 } 208 } 209 210 if (best) { 211 pr_info("raid6: using algorithm %s gen() %ld MB/s\n", 212 best->name, 213 (bestgenperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 214 if (best->xor_syndrome) 215 pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n", 216 (bestxorperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1)); 217 raid6_call = *best; 218 } else 219 pr_err("raid6: Yikes! No algorithm found!\n"); 220 221 return best; 222 } 223 224 225 /* Try to pick the best algorithm */ 226 /* This code uses the gfmul table as convenient data set to abuse */ 227 228 int __init raid6_select_algo(void) 229 { 230 const int disks = (65536/PAGE_SIZE)+2; 231 232 const struct raid6_calls *gen_best; 233 const struct raid6_recov_calls *rec_best; 234 char *syndromes; 235 void *dptrs[(65536/PAGE_SIZE)+2]; 236 int i; 237 238 for (i = 0; i < disks-2; i++) 239 dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i; 240 241 /* Normal code - use a 2-page allocation to avoid D$ conflict */ 242 syndromes = (void *) __get_free_pages(GFP_KERNEL, 1); 243 244 if (!syndromes) { 245 pr_err("raid6: Yikes! No memory available.\n"); 246 return -ENOMEM; 247 } 248 249 dptrs[disks-2] = syndromes; 250 dptrs[disks-1] = syndromes + PAGE_SIZE; 251 252 /* select raid gen_syndrome function */ 253 gen_best = raid6_choose_gen(&dptrs, disks); 254 255 /* select raid recover functions */ 256 rec_best = raid6_choose_recov(); 257 258 free_pages((unsigned long)syndromes, 1); 259 260 return gen_best && rec_best ? 0 : -EINVAL; 261 } 262 263 static void raid6_exit(void) 264 { 265 do { } while (0); 266 } 267 268 subsys_initcall(raid6_select_algo); 269 module_exit(raid6_exit); 270 MODULE_LICENSE("GPL"); 271 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 272