/* -*- 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");