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 &raid6_recov_intx1, 117 NULL 118 }; 119 120 #ifdef __KERNEL__ 121 #define RAID6_TIME_JIFFIES_LG2 4 122 #else 123 /* Need more time to be stable in userspace */ 124 #define RAID6_TIME_JIFFIES_LG2 9 125 #define time_before(x, y) ((x) < (y)) 126 #endif 127 128 static inline const struct raid6_recov_calls *raid6_choose_recov(void) 129 { 130 const struct raid6_recov_calls *const *algo; 131 const struct raid6_recov_calls *best; 132 133 for (best = NULL, algo = raid6_recov_algos; *algo; algo++) 134 if (!best || (*algo)->priority > best->priority) 135 if (!(*algo)->valid || (*algo)->valid()) 136 best = *algo; 137 138 if (best) { 139 raid6_2data_recov = best->data2; 140 raid6_datap_recov = best->datap; 141 142 pr_info("raid6: using %s recovery algorithm\n", best->name); 143 } else 144 pr_err("raid6: Yikes! No recovery algorithm found!\n"); 145 146 return best; 147 } 148 149 static inline const struct raid6_calls *raid6_choose_gen( 150 void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks) 151 { 152 unsigned long perf, bestgenperf, bestxorperf, j0, j1; 153 int start = (disks>>1)-1, stop = disks-3; /* work on the second half of the disks */ 154 const struct raid6_calls *const *algo; 155 const struct raid6_calls *best; 156 157 for (bestgenperf = 0, bestxorperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) { 158 if (!best || (*algo)->prefer >= best->prefer) { 159 if ((*algo)->valid && !(*algo)->valid()) 160 continue; 161 162 perf = 0; 163 164 preempt_disable(); 165 j0 = jiffies; 166 while ((j1 = jiffies) == j0) 167 cpu_relax(); 168 while (time_before(jiffies, 169 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 170 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs); 171 perf++; 172 } 173 preempt_enable(); 174 175 if (perf > bestgenperf) { 176 bestgenperf = perf; 177 best = *algo; 178 } 179 pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name, 180 (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 181 182 if (!(*algo)->xor_syndrome) 183 continue; 184 185 perf = 0; 186 187 preempt_disable(); 188 j0 = jiffies; 189 while ((j1 = jiffies) == j0) 190 cpu_relax(); 191 while (time_before(jiffies, 192 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 193 (*algo)->xor_syndrome(disks, start, stop, 194 PAGE_SIZE, *dptrs); 195 perf++; 196 } 197 preempt_enable(); 198 199 if (best == *algo) 200 bestxorperf = perf; 201 202 pr_info("raid6: %-8s xor() %5ld MB/s\n", (*algo)->name, 203 (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1)); 204 } 205 } 206 207 if (best) { 208 pr_info("raid6: using algorithm %s gen() %ld MB/s\n", 209 best->name, 210 (bestgenperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 211 if (best->xor_syndrome) 212 pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n", 213 (bestxorperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1)); 214 raid6_call = *best; 215 } else 216 pr_err("raid6: Yikes! No algorithm found!\n"); 217 218 return best; 219 } 220 221 222 /* Try to pick the best algorithm */ 223 /* This code uses the gfmul table as convenient data set to abuse */ 224 225 int __init raid6_select_algo(void) 226 { 227 const int disks = (65536/PAGE_SIZE)+2; 228 229 const struct raid6_calls *gen_best; 230 const struct raid6_recov_calls *rec_best; 231 char *syndromes; 232 void *dptrs[(65536/PAGE_SIZE)+2]; 233 int i; 234 235 for (i = 0; i < disks-2; i++) 236 dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i; 237 238 /* Normal code - use a 2-page allocation to avoid D$ conflict */ 239 syndromes = (void *) __get_free_pages(GFP_KERNEL, 1); 240 241 if (!syndromes) { 242 pr_err("raid6: Yikes! No memory available.\n"); 243 return -ENOMEM; 244 } 245 246 dptrs[disks-2] = syndromes; 247 dptrs[disks-1] = syndromes + PAGE_SIZE; 248 249 /* select raid gen_syndrome function */ 250 gen_best = raid6_choose_gen(&dptrs, disks); 251 252 /* select raid recover functions */ 253 rec_best = raid6_choose_recov(); 254 255 free_pages((unsigned long)syndromes, 1); 256 257 return gen_best && rec_best ? 0 : -EINVAL; 258 } 259 260 static void raid6_exit(void) 261 { 262 do { } while (0); 263 } 264 265 subsys_initcall(raid6_select_algo); 266 module_exit(raid6_exit); 267 MODULE_LICENSE("GPL"); 268 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 269