diff options
Diffstat (limited to 'lib/raid6/algos.c')
| -rw-r--r-- | lib/raid6/algos.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c new file mode 100644 index 000000000..975c6e043 --- /dev/null +++ b/lib/raid6/algos.c @@ -0,0 +1,250 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright 2002 H. Peter Anvin - All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, Inc., 53 Temple Place Ste 330, + * Boston MA 02111-1307, USA; either version 2 of the License, or + * (at your option) any later version; incorporated herein by reference. + * + * ----------------------------------------------------------------------- */ + +/* + * raid6/algos.c + * + * Algorithm list and algorithm selection for RAID-6 + */ + +#include <linux/raid/pq.h> +#ifndef __KERNEL__ +#include <sys/mman.h> +#include <stdio.h> +#else +#include <linux/module.h> +#include <linux/gfp.h> +#if !RAID6_USE_EMPTY_ZERO_PAGE +/* In .bss so it's zeroed */ +const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256))); +EXPORT_SYMBOL(raid6_empty_zero_page); +#endif +#endif + +struct raid6_calls raid6_call; +EXPORT_SYMBOL_GPL(raid6_call); + +const struct raid6_calls * const raid6_algos[] = { +#if defined(__ia64__) + &raid6_intx16, + &raid6_intx32, +#endif +#if defined(__i386__) && !defined(__arch_um__) + &raid6_mmxx1, + &raid6_mmxx2, + &raid6_sse1x1, + &raid6_sse1x2, + &raid6_sse2x1, + &raid6_sse2x2, +#ifdef CONFIG_AS_AVX2 + &raid6_avx2x1, + &raid6_avx2x2, +#endif +#endif +#if defined(__x86_64__) && !defined(__arch_um__) + &raid6_sse2x1, + &raid6_sse2x2, + &raid6_sse2x4, +#ifdef CONFIG_AS_AVX2 + &raid6_avx2x1, + &raid6_avx2x2, + &raid6_avx2x4, +#endif +#endif +#ifdef CONFIG_ALTIVEC + &raid6_altivec1, + &raid6_altivec2, + &raid6_altivec4, + &raid6_altivec8, +#endif +#if defined(CONFIG_TILEGX) + &raid6_tilegx8, +#endif + &raid6_intx1, + &raid6_intx2, + &raid6_intx4, + &raid6_intx8, +#ifdef CONFIG_KERNEL_MODE_NEON + &raid6_neonx1, + &raid6_neonx2, + &raid6_neonx4, + &raid6_neonx8, +#endif + NULL +}; + +void (*raid6_2data_recov)(int, size_t, int, int, void **); +EXPORT_SYMBOL_GPL(raid6_2data_recov); + +void (*raid6_datap_recov)(int, size_t, int, void **); +EXPORT_SYMBOL_GPL(raid6_datap_recov); + +const struct raid6_recov_calls *const raid6_recov_algos[] = { +#ifdef CONFIG_AS_AVX2 + &raid6_recov_avx2, +#endif +#ifdef CONFIG_AS_SSSE3 + &raid6_recov_ssse3, +#endif + &raid6_recov_intx1, + NULL +}; + +#ifdef __KERNEL__ +#define RAID6_TIME_JIFFIES_LG2 4 +#else +/* Need more time to be stable in userspace */ +#define RAID6_TIME_JIFFIES_LG2 9 +#define time_before(x, y) ((x) < (y)) +#endif + +static inline const struct raid6_recov_calls *raid6_choose_recov(void) +{ + const struct raid6_recov_calls *const *algo; + const struct raid6_recov_calls *best; + + for (best = NULL, algo = raid6_recov_algos; *algo; algo++) + if (!best || (*algo)->priority > best->priority) + if (!(*algo)->valid || (*algo)->valid()) + best = *algo; + + if (best) { + raid6_2data_recov = best->data2; + raid6_datap_recov = best->datap; + + pr_info("raid6: using %s recovery algorithm\n", best->name); + } else + pr_err("raid6: Yikes! No recovery algorithm found!\n"); + + return best; +} + +static inline const struct raid6_calls *raid6_choose_gen( + void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks) +{ + unsigned long perf, bestgenperf, bestxorperf, j0, j1; + int start = (disks>>1)-1, stop = disks-3; /* work on the second half of the disks */ + const struct raid6_calls *const *algo; + const struct raid6_calls *best; + + for (bestgenperf = 0, bestxorperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) { + if (!best || (*algo)->prefer >= best->prefer) { + if ((*algo)->valid && !(*algo)->valid()) + continue; + + perf = 0; + + preempt_disable(); + j0 = jiffies; + while ((j1 = jiffies) == j0) + cpu_relax(); + while (time_before(jiffies, + j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { + (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs); + perf++; + } + preempt_enable(); + + if (perf > bestgenperf) { + bestgenperf = perf; + best = *algo; + } + pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name, + (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); + + if (!(*algo)->xor_syndrome) + continue; + + perf = 0; + + preempt_disable(); + j0 = jiffies; + while ((j1 = jiffies) == j0) + cpu_relax(); + while (time_before(jiffies, + j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { + (*algo)->xor_syndrome(disks, start, stop, + PAGE_SIZE, *dptrs); + perf++; + } + preempt_enable(); + + if (best == *algo) + bestxorperf = perf; + + pr_info("raid6: %-8s xor() %5ld MB/s\n", (*algo)->name, + (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1)); + } + } + + if (best) { + pr_info("raid6: using algorithm %s gen() %ld MB/s\n", + best->name, + (bestgenperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); + if (best->xor_syndrome) + pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n", + (bestxorperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1)); + raid6_call = *best; + } else + pr_err("raid6: Yikes! No algorithm found!\n"); + + return best; +} + + +/* Try to pick the best algorithm */ +/* This code uses the gfmul table as convenient data set to abuse */ + +int __init raid6_select_algo(void) +{ + const int disks = (65536/PAGE_SIZE)+2; + + const struct raid6_calls *gen_best; + const struct raid6_recov_calls *rec_best; + char *syndromes; + void *dptrs[(65536/PAGE_SIZE)+2]; + int i; + + for (i = 0; i < disks-2; i++) + dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i; + + /* Normal code - use a 2-page allocation to avoid D$ conflict */ + syndromes = (void *) __get_free_pages(GFP_KERNEL, 1); + + if (!syndromes) { + pr_err("raid6: Yikes! No memory available.\n"); + return -ENOMEM; + } + + dptrs[disks-2] = syndromes; + dptrs[disks-1] = syndromes + PAGE_SIZE; + + /* select raid gen_syndrome function */ + gen_best = raid6_choose_gen(&dptrs, disks); + + /* select raid recover functions */ + rec_best = raid6_choose_recov(); + + free_pages((unsigned long)syndromes, 1); + + return gen_best && rec_best ? 0 : -EINVAL; +} + +static void raid6_exit(void) +{ + do { } while (0); +} + +subsys_initcall(raid6_select_algo); +module_exit(raid6_exit); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); |