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 #if defined(CONFIG_TILEGX) 70 &raid6_tilegx8, 71 #endif 72 &raid6_intx1, 73 &raid6_intx2, 74 &raid6_intx4, 75 &raid6_intx8, 76 #ifdef CONFIG_KERNEL_MODE_NEON 77 &raid6_neonx1, 78 &raid6_neonx2, 79 &raid6_neonx4, 80 &raid6_neonx8, 81 #endif 82 NULL 83 }; 84 85 void (*raid6_2data_recov)(int, size_t, int, int, void **); 86 EXPORT_SYMBOL_GPL(raid6_2data_recov); 87 88 void (*raid6_datap_recov)(int, size_t, int, void **); 89 EXPORT_SYMBOL_GPL(raid6_datap_recov); 90 91 const struct raid6_recov_calls *const raid6_recov_algos[] = { 92 #if (defined(__i386__) || defined(__x86_64__)) && !defined(__arch_um__) 93 #ifdef CONFIG_AS_AVX2 94 &raid6_recov_avx2, 95 #endif 96 &raid6_recov_ssse3, 97 #endif 98 &raid6_recov_intx1, 99 NULL 100 }; 101 102 #ifdef __KERNEL__ 103 #define RAID6_TIME_JIFFIES_LG2 4 104 #else 105 /* Need more time to be stable in userspace */ 106 #define RAID6_TIME_JIFFIES_LG2 9 107 #define time_before(x, y) ((x) < (y)) 108 #endif 109 110 static inline const struct raid6_recov_calls *raid6_choose_recov(void) 111 { 112 const struct raid6_recov_calls *const *algo; 113 const struct raid6_recov_calls *best; 114 115 for (best = NULL, algo = raid6_recov_algos; *algo; algo++) 116 if (!best || (*algo)->priority > best->priority) 117 if (!(*algo)->valid || (*algo)->valid()) 118 best = *algo; 119 120 if (best) { 121 raid6_2data_recov = best->data2; 122 raid6_datap_recov = best->datap; 123 124 pr_info("raid6: using %s recovery algorithm\n", best->name); 125 } else 126 pr_err("raid6: Yikes! No recovery algorithm found!\n"); 127 128 return best; 129 } 130 131 static inline const struct raid6_calls *raid6_choose_gen( 132 void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks) 133 { 134 unsigned long perf, bestperf, j0, j1; 135 const struct raid6_calls *const *algo; 136 const struct raid6_calls *best; 137 138 for (bestperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) { 139 if (!best || (*algo)->prefer >= best->prefer) { 140 if ((*algo)->valid && !(*algo)->valid()) 141 continue; 142 143 perf = 0; 144 145 preempt_disable(); 146 j0 = jiffies; 147 while ((j1 = jiffies) == j0) 148 cpu_relax(); 149 while (time_before(jiffies, 150 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 151 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs); 152 perf++; 153 } 154 preempt_enable(); 155 156 if (perf > bestperf) { 157 bestperf = perf; 158 best = *algo; 159 } 160 pr_info("raid6: %-8s %5ld MB/s\n", (*algo)->name, 161 (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 162 } 163 } 164 165 if (best) { 166 pr_info("raid6: using algorithm %s (%ld MB/s)\n", 167 best->name, 168 (bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 169 raid6_call = *best; 170 } else 171 pr_err("raid6: Yikes! No algorithm found!\n"); 172 173 return best; 174 } 175 176 177 /* Try to pick the best algorithm */ 178 /* This code uses the gfmul table as convenient data set to abuse */ 179 180 int __init raid6_select_algo(void) 181 { 182 const int disks = (65536/PAGE_SIZE)+2; 183 184 const struct raid6_calls *gen_best; 185 const struct raid6_recov_calls *rec_best; 186 char *syndromes; 187 void *dptrs[(65536/PAGE_SIZE)+2]; 188 int i; 189 190 for (i = 0; i < disks-2; i++) 191 dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i; 192 193 /* Normal code - use a 2-page allocation to avoid D$ conflict */ 194 syndromes = (void *) __get_free_pages(GFP_KERNEL, 1); 195 196 if (!syndromes) { 197 pr_err("raid6: Yikes! No memory available.\n"); 198 return -ENOMEM; 199 } 200 201 dptrs[disks-2] = syndromes; 202 dptrs[disks-1] = syndromes + PAGE_SIZE; 203 204 /* select raid gen_syndrome function */ 205 gen_best = raid6_choose_gen(&dptrs, disks); 206 207 /* select raid recover functions */ 208 rec_best = raid6_choose_recov(); 209 210 free_pages((unsigned long)syndromes, 1); 211 212 return gen_best && rec_best ? 0 : -EINVAL; 213 } 214 215 static void raid6_exit(void) 216 { 217 do { } while (0); 218 } 219 220 subsys_initcall(raid6_select_algo); 221 module_exit(raid6_exit); 222 MODULE_LICENSE("GPL"); 223 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 224