bufobj.h revision 136746 
1/*-
2 * Copyright (c) 2004 Poul-Henning Kamp
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/sys/sys/bufobj.h 136745 2004-10-21 12:24:38Z phk $
27 */
28
29/*
30 * Architectural notes:
31 *
32 * bufobj is a new object which is what buffers hang from in the buffer
33 * cache.
34 *
35 * This used to be vnodes, but we need non-vnode code to be able
36 * to use the buffer cache as well, specifically geom classes like gbde,
37 * raid3 and raid5.
38 *
39 * All vnodes will contain a bufobj initially, but down the road we may
40 * want to only allocate bufobjs when they are needed.  There could be a
41 * large number of vnodes in the system which wouldn't need a bufobj during
42 * their lifetime.
43 *
44 * The exact relationship to the vmobject is not determined at this point,
45 * it may in fact bee that we find them to be two sides of the same object
46 * once things starts to crystalize.
47 */
48
49#ifndef _SYS_BUFOBJ_H_
50#define _SYS_BUFOBJ_H_
51
52#if defined(_KERNEL) || defined(_KVM_VNODE)
53
54#include <sys/queue.h>
55
56TAILQ_HEAD(buflists, buf);
57
58/* A Buffer splay list */
59struct bufv {
60	struct buflists	bv_hd;		/* Sorted blocklist */
61	struct buf	*bv_root;	/* Buf splay tree */
62	int		bv_cnt;		/* Number of buffers */
63};
64
65struct bufobj {
66	struct mtx	*bo_mtx;	/* Mutex which protects "i" things */
67	struct bufv	bo_clean;	/* i Clean buffers */
68	struct bufv	bo_dirty;	/* i Dirty buffers */
69};
70
71#endif /* defined(_KERNEL) || defined(_KVM_VNODE) */
72#endif /* _SYS_BUFOBJ_H_ */
73
74
75