kernel - Introduce lightweight buffers
[dragonfly.git] / sys / kern / kern_sfbuf.c
CommitLineData
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1/*
2 * Copyright (c) 1998 David Greenman. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 *
ba39e2e0 25 * $DragonFly: src/sys/kern/kern_sfbuf.c,v 1.15 2007/04/30 07:18:53 dillon Exp $
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26 */
27
28#include <sys/param.h>
29#include <sys/types.h>
30#include <sys/systm.h>
31#include <sys/kernel.h>
32#include <sys/malloc.h>
4860553a 33#include <sys/sfbuf.h>
5c5185ae
SG
34#include <sys/objcache.h>
35
36#include <cpu/lwbuf.h>
37
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38#include <vm/vm.h>
39#include <vm/vm_extern.h>
40#include <vm/vm_kern.h>
41#include <vm/vm_page.h>
42#include <vm/pmap.h>
43
44static void sf_buf_init(void *arg);
ba39e2e0 45SYSINIT(sock_sf, SI_BOOT2_MACHDEP, SI_ORDER_ANY, sf_buf_init, NULL)
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46
47LIST_HEAD(sf_buf_list, sf_buf);
48
5c5185ae 49static struct objcache *sf_buf_cache;
ad9e1baa 50
5c5185ae
SG
51MALLOC_DEFINE(M_SFBUF, "sfbuf", "Sendfile buffer structures");
52struct objcache_malloc_args sf_buf_malloc_args = { sizeof(struct sf_buf), M_SFBUF };
4860553a 53
4860553a 54
5c5185ae
SG
55static boolean_t
56sf_buf_cache_ctor(void *obj, void *pdata, int ocflags)
b89e3239 57{
5c5185ae 58 struct sf_buf *sf = (struct sf_buf *)obj;
b89e3239 59
5c5185ae
SG
60 sf->lwbuf = NULL;
61 sf->refs = 0;
62
63 return (TRUE);
b89e3239
MD
64}
65
4860553a 66/*
5c5185ae 67 * Init objcache of sf_bufs (sendfile(2) or "super-fast" if you prefer. :-))
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68 */
69static void
70sf_buf_init(void *arg)
71{
5c5185ae
SG
72 sf_buf_cache = objcache_create("sf_buf", 0, 0,
73 sf_buf_cache_ctor, NULL, NULL,
74 objcache_malloc_alloc, objcache_malloc_free,
75 &sf_buf_malloc_args);
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76}
77
78/*
5c5185ae 79 * Acquire an sf_buf reference for a vm_page.
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80 */
81struct sf_buf *
5c5185ae 82sf_buf_alloc(struct vm_page *m)
4860553a 83{
4860553a 84 struct sf_buf *sf;
5c5185ae
SG
85
86 if ((sf = objcache_get(sf_buf_cache, M_WAITOK)) == NULL)
87 goto done;
88
89 if ((sf->lwbuf = lwbuf_alloc(m)) == NULL) {
90 objcache_put(sf_buf_cache, sf);
91 sf = NULL;
92 goto done;
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93 }
94
95 /*
5c5185ae 96 * Force invalidation of the TLB entry on all CPU's
4860553a 97 */
5c5185ae
SG
98 lwbuf_set_global(sf->lwbuf);
99
100 sf->refs = 1;
101
4860553a 102done:
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103 return (sf);
104}
105
b4caac98 106void
5c5185ae 107sf_buf_ref(void *arg)
b4caac98 108{
5c5185ae 109 struct sf_buf *sf = arg;
4860553a 110
5c5185ae
SG
111 atomic_add_int(&sf->refs, 1);
112}
83befd2d 113
4860553a 114/*
5c5185ae 115 * Detach mapped page and release resources back to the system.
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116 *
117 * Must be called at splimp.
118 */
5c5185ae
SG
119int
120sf_buf_free(void *arg)
4860553a 121{
5c5185ae
SG
122 struct sf_buf *sf = arg;
123
124 KKASSERT(sf->refs > 0);
125 if (atomic_fetchadd_int(&sf->refs, -1) == 1) {
126 lwbuf_free(sf->lwbuf);
127 objcache_put(sf_buf_cache, sf);
128 return (0);
4860553a 129 }
b4caac98 130
5c5185ae
SG
131 return (1);
132}