87ed2b7f5a
The block cache implementation in loader has proven to be almost useless, and in worst case even slowing down the disk reads due to insufficient cache size and extra memory copy. Also the current cache implementation does not cache reads from CDs, or work with zfs built on top of multiple disks. Instead of an LRU, this code uses a simple hash (O(1) read from cache), and instead of a single global cache, a separate cache per block device. The cache also implements limited read-ahead to increase performance. To simplify read ahead management, the read ahead will not wrap over bcache end, so in worst case, single block physical read will be performed to fill the last block in bcache. Booting from a virtual CD over IPMI: 0ms latency, before: 27 second, after: 7 seconds 60ms latency, before: over 12 minutes, after: under 5 minutes. Submitted by: Toomas Soome <tsoome@me.com> Reviewed by: delphij (previous version), emaste (previous version) Relnotes: yes Differential Revision: https://reviews.freebsd.org/D4713
126 lines
3.0 KiB
C
126 lines
3.0 KiB
C
/*-
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* Copyright (C) 2014 Nathan Whitehorn
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <stdarg.h>
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#include "bootstrap.h"
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#include "host_syscall.h"
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static int hostdisk_init(void);
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static int hostdisk_strategy(void *devdata, int flag, daddr_t dblk,
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size_t offset, size_t size, char *buf, size_t *rsize);
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static int hostdisk_open(struct open_file *f, ...);
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static int hostdisk_close(struct open_file *f);
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static int hostdisk_ioctl(struct open_file *f, u_long cmd, void *data);
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static void hostdisk_print(int verbose);
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struct devsw hostdisk = {
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"/dev",
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DEVT_DISK,
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hostdisk_init,
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hostdisk_strategy,
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hostdisk_open,
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hostdisk_close,
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hostdisk_ioctl,
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hostdisk_print,
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};
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static int
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hostdisk_init(void)
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{
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return (0);
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}
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static int
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hostdisk_strategy(void *devdata, int flag, daddr_t dblk, size_t offset,
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size_t size, char *buf, size_t *rsize)
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{
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struct devdesc *desc = devdata;
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daddr_t pos;
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int n;
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pos = dblk * 512;
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if (host_seek(desc->d_unit, pos, 0) < 0) {
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printf("Seek error\n");
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return (EIO);
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}
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n = host_read(desc->d_unit, buf, size);
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if (n < 0)
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return (EIO);
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*rsize = n;
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return (0);
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}
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static int
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hostdisk_open(struct open_file *f, ...)
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{
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struct devdesc *desc;
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va_list vl;
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va_start(vl, f);
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desc = va_arg(vl, struct devdesc *);
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va_end(vl);
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desc->d_unit = host_open(desc->d_opendata, O_RDONLY, 0);
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if (desc->d_unit <= 0) {
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printf("hostdisk_open: couldn't open %s: %d\n",
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desc->d_opendata, desc->d_unit);
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return (ENOENT);
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}
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return (0);
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}
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static int
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hostdisk_close(struct open_file *f)
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{
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struct devdesc *desc = f->f_devdata;
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host_close(desc->d_unit);
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return (0);
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}
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static int
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hostdisk_ioctl(struct open_file *f, u_long cmd, void *data)
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{
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return (EINVAL);
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}
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static void
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hostdisk_print(int verbose)
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{
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}
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