282 lines
6.2 KiB
C
282 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* -*- linux-c -*- ------------------------------------------------------- *
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*
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* Copyright 2002 H. Peter Anvin - All Rights Reserved
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*
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* ----------------------------------------------------------------------- */
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/*
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* raid6/algos.c
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*
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* Algorithm list and algorithm selection for RAID-6
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*/
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#include <linux/raid/pq.h>
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#ifndef __KERNEL__
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#include <sys/mman.h>
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#include <stdio.h>
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#else
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#include <linux/module.h>
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#include <linux/gfp.h>
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#if !RAID6_USE_EMPTY_ZERO_PAGE
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/* In .bss so it's zeroed */
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const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
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EXPORT_SYMBOL(raid6_empty_zero_page);
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#endif
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#endif
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struct raid6_calls raid6_call;
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EXPORT_SYMBOL_GPL(raid6_call);
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const struct raid6_calls * const raid6_algos[] = {
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#if defined(__i386__) && !defined(__arch_um__)
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#ifdef CONFIG_AS_AVX512
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&raid6_avx512x2,
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&raid6_avx512x1,
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#endif
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&raid6_avx2x2,
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&raid6_avx2x1,
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&raid6_sse2x2,
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&raid6_sse2x1,
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&raid6_sse1x2,
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&raid6_sse1x1,
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&raid6_mmxx2,
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&raid6_mmxx1,
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#endif
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#if defined(__x86_64__) && !defined(__arch_um__)
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#ifdef CONFIG_AS_AVX512
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&raid6_avx512x4,
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&raid6_avx512x2,
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&raid6_avx512x1,
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#endif
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&raid6_avx2x4,
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&raid6_avx2x2,
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&raid6_avx2x1,
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&raid6_sse2x4,
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&raid6_sse2x2,
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&raid6_sse2x1,
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#endif
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#ifdef CONFIG_ALTIVEC
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&raid6_vpermxor8,
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&raid6_vpermxor4,
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&raid6_vpermxor2,
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&raid6_vpermxor1,
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&raid6_altivec8,
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&raid6_altivec4,
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&raid6_altivec2,
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&raid6_altivec1,
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#endif
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#if defined(CONFIG_S390)
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&raid6_s390vx8,
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#endif
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#ifdef CONFIG_KERNEL_MODE_NEON
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&raid6_neonx8,
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&raid6_neonx4,
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&raid6_neonx2,
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&raid6_neonx1,
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#endif
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#if defined(__ia64__)
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&raid6_intx32,
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&raid6_intx16,
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#endif
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&raid6_intx8,
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&raid6_intx4,
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&raid6_intx2,
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&raid6_intx1,
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NULL
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};
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void (*raid6_2data_recov)(int, size_t, int, int, void **);
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EXPORT_SYMBOL_GPL(raid6_2data_recov);
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void (*raid6_datap_recov)(int, size_t, int, void **);
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EXPORT_SYMBOL_GPL(raid6_datap_recov);
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const struct raid6_recov_calls *const raid6_recov_algos[] = {
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#ifdef CONFIG_X86
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#ifdef CONFIG_AS_AVX512
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&raid6_recov_avx512,
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#endif
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&raid6_recov_avx2,
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&raid6_recov_ssse3,
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#endif
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#ifdef CONFIG_S390
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&raid6_recov_s390xc,
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#endif
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#if defined(CONFIG_KERNEL_MODE_NEON)
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&raid6_recov_neon,
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#endif
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&raid6_recov_intx1,
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NULL
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};
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#ifdef __KERNEL__
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#define RAID6_TIME_JIFFIES_LG2 4
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#else
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/* Need more time to be stable in userspace */
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#define RAID6_TIME_JIFFIES_LG2 9
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#define time_before(x, y) ((x) < (y))
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#endif
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#define RAID6_TEST_DISKS 8
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#define RAID6_TEST_DISKS_ORDER 3
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static inline const struct raid6_recov_calls *raid6_choose_recov(void)
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{
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const struct raid6_recov_calls *const *algo;
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const struct raid6_recov_calls *best;
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for (best = NULL, algo = raid6_recov_algos; *algo; algo++)
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if (!best || (*algo)->priority > best->priority)
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if (!(*algo)->valid || (*algo)->valid())
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best = *algo;
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if (best) {
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raid6_2data_recov = best->data2;
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raid6_datap_recov = best->datap;
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pr_info("raid6: using %s recovery algorithm\n", best->name);
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} else
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pr_err("raid6: Yikes! No recovery algorithm found!\n");
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return best;
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}
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static inline const struct raid6_calls *raid6_choose_gen(
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void *(*const dptrs)[RAID6_TEST_DISKS], const int disks)
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{
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unsigned long perf, bestgenperf, j0, j1;
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int start = (disks>>1)-1, stop = disks-3; /* work on the second half of the disks */
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const struct raid6_calls *const *algo;
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const struct raid6_calls *best;
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for (bestgenperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) {
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if (!best || (*algo)->prefer >= best->prefer) {
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if ((*algo)->valid && !(*algo)->valid())
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continue;
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if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) {
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best = *algo;
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break;
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}
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perf = 0;
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preempt_disable();
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j0 = jiffies;
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while ((j1 = jiffies) == j0)
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cpu_relax();
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while (time_before(jiffies,
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j1 + (1<<RAID6_TIME_JIFFIES_LG2))) {
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(*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs);
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perf++;
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}
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preempt_enable();
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if (perf > bestgenperf) {
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bestgenperf = perf;
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best = *algo;
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}
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pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name,
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(perf * HZ * (disks-2)) >>
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(20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2));
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}
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}
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if (!best) {
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pr_err("raid6: Yikes! No algorithm found!\n");
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goto out;
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}
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raid6_call = *best;
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if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) {
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pr_info("raid6: skipped pq benchmark and selected %s\n",
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best->name);
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goto out;
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}
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pr_info("raid6: using algorithm %s gen() %ld MB/s\n",
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best->name,
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(bestgenperf * HZ * (disks - 2)) >>
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(20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2));
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if (best->xor_syndrome) {
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perf = 0;
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preempt_disable();
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j0 = jiffies;
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while ((j1 = jiffies) == j0)
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cpu_relax();
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while (time_before(jiffies,
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j1 + (1 << RAID6_TIME_JIFFIES_LG2))) {
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best->xor_syndrome(disks, start, stop,
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PAGE_SIZE, *dptrs);
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perf++;
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}
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preempt_enable();
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pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n",
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(perf * HZ * (disks - 2)) >>
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(20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2 + 1));
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}
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out:
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return best;
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}
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/* Try to pick the best algorithm */
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/* This code uses the gfmul table as convenient data set to abuse */
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int __init raid6_select_algo(void)
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{
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const int disks = RAID6_TEST_DISKS;
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const struct raid6_calls *gen_best;
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const struct raid6_recov_calls *rec_best;
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char *disk_ptr, *p;
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void *dptrs[RAID6_TEST_DISKS];
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int i, cycle;
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/* prepare the buffer and fill it circularly with gfmul table */
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disk_ptr = (char *)__get_free_pages(GFP_KERNEL, RAID6_TEST_DISKS_ORDER);
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if (!disk_ptr) {
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pr_err("raid6: Yikes! No memory available.\n");
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return -ENOMEM;
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}
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p = disk_ptr;
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for (i = 0; i < disks; i++)
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dptrs[i] = p + PAGE_SIZE * i;
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cycle = ((disks - 2) * PAGE_SIZE) / 65536;
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for (i = 0; i < cycle; i++) {
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memcpy(p, raid6_gfmul, 65536);
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p += 65536;
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}
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if ((disks - 2) * PAGE_SIZE % 65536)
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memcpy(p, raid6_gfmul, (disks - 2) * PAGE_SIZE % 65536);
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/* select raid gen_syndrome function */
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gen_best = raid6_choose_gen(&dptrs, disks);
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/* select raid recover functions */
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rec_best = raid6_choose_recov();
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free_pages((unsigned long)disk_ptr, RAID6_TEST_DISKS_ORDER);
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return gen_best && rec_best ? 0 : -EINVAL;
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}
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static void raid6_exit(void)
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{
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do { } while (0);
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}
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subsys_initcall(raid6_select_algo);
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module_exit(raid6_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("RAID6 Q-syndrome calculations");
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