projects/linux·blob v3.13 · refs

223 lines · 5.2 KiB

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 */
28const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
29EXPORT_SYMBOL(raid6_empty_zero_page);
30#endif
31#endif
32
33struct raid6_calls raid6_call;
34EXPORT_SYMBOL_GPL(raid6_call);
35
36const 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
85void (*raid6_2data_recov)(int, size_t, int, int, void **);
86EXPORT_SYMBOL_GPL(raid6_2data_recov);
87
88void (*raid6_datap_recov)(int, size_t, int, void **);
89EXPORT_SYMBOL_GPL(raid6_datap_recov);
90
91const 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
110static 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 printk("raid6: using %s recovery algorithm\n", best->name);
125 } else
126 printk("raid6: Yikes! No recovery algorithm found!\n");
127
128 return best;
129}
130
131static 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 printk("raid6: %-8s %5ld MB/s\n", (*algo)->name,
161 (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
162 }
163 }
164
165 if (best) {
166 printk("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 printk("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
180int __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 printk("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
215static void raid6_exit(void)
216{
217 do { } while (0);
218}
219
220subsys_initcall(raid6_select_algo);
221module_exit(raid6_exit);
222MODULE_LICENSE("GPL");
223MODULE_DESCRIPTION("RAID6 Q-syndrome calculations");