// SPDX-License-Identifier: GPL-2.0-or-later /* -*- linux-c -*- ------------------------------------------------------- * * * Copyright 2002 H. Peter Anvin - All Rights Reserved * * ----------------------------------------------------------------------- */ /* * raid6/algos.c * * Algorithm list and algorithm selection for RAID-6 */ #include #ifndef __KERNEL__ #include #include #else #include #include /* In .bss so it's zeroed */ const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256))); EXPORT_SYMBOL(raid6_empty_zero_page); #endif struct raid6_calls raid6_call; EXPORT_SYMBOL_GPL(raid6_call); const struct raid6_calls * const raid6_algos[] = { #if defined(__i386__) && !defined(__arch_um__) #ifdef CONFIG_AS_AVX512 &raid6_avx512x2, &raid6_avx512x1, #endif &raid6_avx2x2, &raid6_avx2x1, &raid6_sse2x2, &raid6_sse2x1, &raid6_sse1x2, &raid6_sse1x1, &raid6_mmxx2, &raid6_mmxx1, #endif #if defined(__x86_64__) && !defined(__arch_um__) #ifdef CONFIG_AS_AVX512 &raid6_avx512x4, &raid6_avx512x2, &raid6_avx512x1, #endif &raid6_avx2x4, &raid6_avx2x2, &raid6_avx2x1, &raid6_sse2x4, &raid6_sse2x2, &raid6_sse2x1, #endif #ifdef CONFIG_ALTIVEC &raid6_vpermxor8, &raid6_vpermxor4, &raid6_vpermxor2, &raid6_vpermxor1, &raid6_altivec8, &raid6_altivec4, &raid6_altivec2, &raid6_altivec1, #endif #if defined(CONFIG_S390) &raid6_s390vx8, #endif #ifdef CONFIG_KERNEL_MODE_NEON &raid6_neonx8, &raid6_neonx4, &raid6_neonx2, &raid6_neonx1, #endif #ifdef CONFIG_LOONGARCH #ifdef CONFIG_CPU_HAS_LASX &raid6_lasx, #endif #ifdef CONFIG_CPU_HAS_LSX &raid6_lsx, #endif #endif &raid6_intx8, &raid6_intx4, &raid6_intx2, &raid6_intx1, 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_X86 #ifdef CONFIG_AS_AVX512 &raid6_recov_avx512, #endif &raid6_recov_avx2, &raid6_recov_ssse3, #endif #ifdef CONFIG_S390 &raid6_recov_s390xc, #endif #if defined(CONFIG_KERNEL_MODE_NEON) &raid6_recov_neon, #endif #ifdef CONFIG_LOONGARCH #ifdef CONFIG_CPU_HAS_LASX &raid6_recov_lasx, #endif #ifdef CONFIG_CPU_HAS_LSX &raid6_recov_lsx, #endif #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 #define RAID6_TEST_DISKS 8 #define RAID6_TEST_DISKS_ORDER 3 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)[RAID6_TEST_DISKS], const int disks) { unsigned long perf, bestgenperf, 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, best = NULL, algo = raid6_algos; *algo; algo++) { if (!best || (*algo)->priority >= best->priority) { if ((*algo)->valid && !(*algo)->valid()) continue; if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) { best = *algo; break; } perf = 0; preempt_disable(); j0 = jiffies; while ((j1 = jiffies) == j0) cpu_relax(); while (time_before(jiffies, j1 + (1<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 * (disks-2)) >> (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2)); } } if (!best) { pr_err("raid6: Yikes! No algorithm found!\n"); goto out; } raid6_call = *best; if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) { pr_info("raid6: skipped pq benchmark and selected %s\n", best->name); goto out; } pr_info("raid6: using algorithm %s gen() %ld MB/s\n", best->name, (bestgenperf * HZ * (disks - 2)) >> (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2)); if (best->xor_syndrome) { perf = 0; preempt_disable(); j0 = jiffies; while ((j1 = jiffies) == j0) cpu_relax(); while (time_before(jiffies, j1 + (1 << RAID6_TIME_JIFFIES_LG2))) { best->xor_syndrome(disks, start, stop, PAGE_SIZE, *dptrs); perf++; } preempt_enable(); pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n", (perf * HZ * (disks - 2)) >> (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2 + 1)); } out: 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 = RAID6_TEST_DISKS; const struct raid6_calls *gen_best; const struct raid6_recov_calls *rec_best; char *disk_ptr, *p; void *dptrs[RAID6_TEST_DISKS]; int i, cycle; /* prepare the buffer and fill it circularly with gfmul table */ disk_ptr = (char *)__get_free_pages(GFP_KERNEL, RAID6_TEST_DISKS_ORDER); if (!disk_ptr) { pr_err("raid6: Yikes! No memory available.\n"); return -ENOMEM; } p = disk_ptr; for (i = 0; i < disks; i++) dptrs[i] = p + PAGE_SIZE * i; cycle = ((disks - 2) * PAGE_SIZE) / 65536; for (i = 0; i < cycle; i++) { memcpy(p, raid6_gfmul, 65536); p += 65536; } if ((disks - 2) * PAGE_SIZE % 65536) memcpy(p, raid6_gfmul, (disks - 2) * PAGE_SIZE % 65536); /* 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)disk_ptr, RAID6_TEST_DISKS_ORDER); 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");