linux/lib/raid6/algos.c
Linus Torvalds 4d7696f1b0 md update for v3.12
Headline item is multithreading for RAID5 so that more
 IO/sec can be supported on fast (SSD) devices.
 Also TILE-Gx SIMD suppor for RAID6 calculations and an
 assortment of bug fixes.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2.0.19 (GNU/Linux)
 
 iQIVAwUAUi6dRTnsnt1WYoG5AQIqMBAAm/XUEqfyBNUiTPHmIU/OyReOlfsp8A2o
 xtcmSzaCtIUz4btPszUrw3PShqnk+lXXX2AB0rp3PzfOgyNYXBRKbzOf3eGr2VEp
 L/Cm0iSWHqQ7V7MoV5ZrqtvuyJV1a7FK3a3VaoKaUk424o4sZ7P67t/YZAnTCP/i
 9wQoPeIOJ8YjZsaAQjzI3q7yRMRE8ytyBnF4NdgeMyr2p17w2e9pnmNfCTo4wnWs
 Nu2wPr2QCPQXr/FoIhdIVEy3kVatqH8qXG8Fw+5n07HJYxGCvQZLDuoOVDYyFeoW
 gnNq2MMgLZm/7Nzqd1bN+QQZuBCd5JL4VJ2G4vLfYrn3ZSdSysrVKQXFKYG3Gkua
 1KP4Pv0hndAl4DtGbUk8CiZp6b+c5qeWvq+sO2NuhUGmumFMK2q4DJhITNexjmrs
 Eg4opnR8JMLDkYD6o52Ziu5KQR/q1PKRLj80eoVuqB2QQM5+NPb4s3k2WN+53lQD
 L9fH2alUxxSK+5R8ykk923QQ/XErMUwXaka+O/gGFAlYvaaW/GKTxFnKn/GIXAkc
 tKW88zB+zA5EZEFec+K43z1UjtGxMWsryvDN55ON2iV+LIZBISm7krroBeR55cyO
 +3tHlPsga0pO+9DdSm7hvZeWRrq5ZJTiZmL/e2FYygrC5tFAY0p+z49fK3e9Th13
 C85G7fg3yDY=
 =zLxh
 -----END PGP SIGNATURE-----

Merge tag 'md/3.12' of git://neil.brown.name/md

Pull md update from Neil Brown:
 "Headline item is multithreading for RAID5 so that more IO/sec can be
  supported on fast (SSD) devices.  Also TILE-Gx SIMD suppor for RAID6
  calculations and an assortment of bug fixes"

* tag 'md/3.12' of git://neil.brown.name/md:
  raid5: only wakeup necessary threads
  md/raid5: flush out all pending requests before proceeding with reshape.
  md/raid5: use seqcount to protect access to shape in make_request.
  raid5: sysfs entry to control worker thread number
  raid5: offload stripe handle to workqueue
  raid5: fix stripe release order
  raid5: make release_stripe lockless
  md: avoid deadlock when dirty buffers during md_stop.
  md: Don't test all of mddev->flags at once.
  md: Fix apparent cut-and-paste error in super_90_validate
  raid6/test: replace echo -e with printf
  RAID: add tilegx SIMD implementation of raid6
  md: fix safe_mode buglet.
  md: don't call md_allow_write in get_bitmap_file.
2013-09-10 13:03:41 -07:00

224 lines
5.2 KiB
C

/* -*- 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[] = {
#if (defined(__i386__) || defined(__x86_64__)) && !defined(__arch_um__)
#ifdef CONFIG_AS_AVX2
&raid6_recov_avx2,
#endif
&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;
printk("raid6: using %s recovery algorithm\n", best->name);
} else
printk("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, bestperf, j0, j1;
const struct raid6_calls *const *algo;
const struct raid6_calls *best;
for (bestperf = 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 > bestperf) {
bestperf = perf;
best = *algo;
}
printk("raid6: %-8s %5ld MB/s\n", (*algo)->name,
(perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
}
}
if (best) {
printk("raid6: using algorithm %s (%ld MB/s)\n",
best->name,
(bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
raid6_call = *best;
} else
printk("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) {
printk("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");