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