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[dragonfly.git] / sys / kern / kern_sfbuf.c
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1 /*
2 * Copyright (c) 1998 David Greenman. All rights reserved.
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.
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.
25 * $DragonFly: src/sys/kern/kern_sfbuf.c,v 1.15 2007/04/30 07:18:53 dillon Exp $
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>
33 #include <sys/queue.h>
34 #include <sys/sfbuf.h>
35 #include <sys/globaldata.h>
36 #include <sys/thread.h>
37 #include <sys/sysctl.h>
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 #include <sys/thread2.h>
45 static void sf_buf_init(void *arg);
46 SYSINIT(sock_sf, SI_BOOT2_MACHDEP, SI_ORDER_ANY, sf_buf_init, NULL)
48 LIST_HEAD(sf_buf_list, sf_buf);
50 SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufs, CTLFLAG_RD, &nsfbufs, 0,
51 "Maximum number of sf_bufs available to the system");
54 * A hash table of active sendfile(2) buffers
56 static struct sf_buf_list *sf_buf_hashtable;
57 static u_long sf_buf_hashmask;
59 static TAILQ_HEAD(, sf_buf) sf_buf_freelist;
60 static u_int sf_buf_alloc_want;
62 static vm_offset_t sf_base;
63 static struct sf_buf *sf_bufs;
65 static int sfbuf_quick = 1;
66 SYSCTL_INT(_debug, OID_AUTO, sfbuf_quick, CTLFLAG_RW, &sfbuf_quick, 0, "");
67 static int nsffree;
68 SYSCTL_INT(_kern_ipc, OID_AUTO, nsffree, CTLFLAG_RD, &nsffree, 0,
69 "Number of free sf_bufs available to the system");
71 static __inline
72 int
73 sf_buf_hash(vm_page_t m)
75 int hv;
77 hv = ((int)m / sizeof(vm_page_t)) + ((int)m >> 12);
78 return(hv & sf_buf_hashmask);
82 * Allocate a pool of sf_bufs (sendfile(2) or "super-fast" if you prefer. :-))
84 static void
85 sf_buf_init(void *arg)
87 int i;
89 sf_buf_hashtable = hashinit(nsfbufs, M_TEMP, &sf_buf_hashmask);
90 TAILQ_INIT(&sf_buf_freelist);
91 sf_base = kmem_alloc_nofault(&kernel_map, nsfbufs * PAGE_SIZE);
92 sf_bufs = kmalloc(nsfbufs * sizeof(struct sf_buf), M_TEMP,
93 M_WAITOK | M_ZERO);
94 for (i = 0; i < nsfbufs; i++) {
95 sf_bufs[i].kva = sf_base + i * PAGE_SIZE;
96 sf_bufs[i].flags |= SFBA_ONFREEQ;
97 TAILQ_INSERT_TAIL(&sf_buf_freelist, &sf_bufs[i], free_entry);
98 ++nsffree;
103 * Get an sf_buf from the freelist. Will block if none are available.
105 struct sf_buf *
106 sf_buf_alloc(struct vm_page *m, int flags)
108 struct sf_buf_list *hash_chain;
109 struct sf_buf *sf;
110 globaldata_t gd;
111 int error;
112 int pflags;
114 gd = mycpu;
115 crit_enter();
116 hash_chain = &sf_buf_hashtable[sf_buf_hash(m)];
117 LIST_FOREACH(sf, hash_chain, list_entry) {
118 if (sf->m == m) {
120 * cache hit
122 * We must invalidate the TLB entry based on whether
123 * it need only be valid on the local cpu (SFB_CPUPRIVATE),
124 * or on all cpus. This is conditionalized and in
125 * most cases no system-wide invalidation should be
126 * needed.
128 * Note: we do not remove the entry from the freelist
129 * on the 0->1 transition.
131 ++sf->refcnt;
132 if ((flags & SFB_CPUPRIVATE) && sfbuf_quick) {
133 if ((sf->cpumask & gd->gd_cpumask) == 0) {
134 pmap_kenter_sync_quick(sf->kva);
135 sf->cpumask |= gd->gd_cpumask;
137 } else {
138 if (sf->cpumask != (cpumask_t)-1) {
139 pmap_kenter_sync(sf->kva);
140 sf->cpumask = (cpumask_t)-1;
143 goto done; /* found existing mapping */
148 * Didn't find old mapping. Get a buffer off the freelist. We
149 * may have to remove and skip buffers with non-zero ref counts
150 * that were lazily allocated.
152 for (;;) {
153 if ((sf = TAILQ_FIRST(&sf_buf_freelist)) == NULL) {
154 pflags = (flags & SFB_CATCH) ? PCATCH : 0;
155 ++sf_buf_alloc_want;
156 error = tsleep(&sf_buf_freelist, pflags, "sfbufa", 0);
157 --sf_buf_alloc_want;
158 if (error)
159 goto done;
160 } else {
162 * We may have to do delayed removals for referenced
163 * sf_buf's here in addition to locating a sf_buf
164 * to reuse. The sf_bufs must be removed.
166 * We are finished when we find an sf_buf with a
167 * refcnt of 0. We theoretically do not have to
168 * remove it from the freelist but it's a good idea
169 * to do so to preserve LRU operation for the
170 * (1) never before seen before case and (2)
171 * accidently recycled due to prior cached uses not
172 * removing the buffer case.
174 KKASSERT(sf->flags & SFBA_ONFREEQ);
175 TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
176 --nsffree;
177 sf->flags &= ~SFBA_ONFREEQ;
178 if (sf->refcnt == 0)
179 break;
182 if (sf->m != NULL) /* remove previous mapping from hash table */
183 LIST_REMOVE(sf, list_entry);
184 LIST_INSERT_HEAD(hash_chain, sf, list_entry);
185 sf->refcnt = 1;
186 sf->m = m;
187 if ((flags & SFB_CPUPRIVATE) && sfbuf_quick) {
188 pmap_kenter_quick(sf->kva, sf->m->phys_addr);
189 sf->cpumask = gd->gd_cpumask;
190 } else {
191 pmap_kenter(sf->kva, sf->m->phys_addr);
192 sf->cpumask = (cpumask_t)-1;
194 done:
195 crit_exit();
196 return (sf);
199 #if 0
202 * Add a reference to a buffer (currently unused)
204 void
205 sf_buf_ref(struct sf_buf *sf)
207 if (sf->refcnt == 0)
208 panic("sf_buf_ref: referencing a free sf_buf");
209 crit_enter();
210 sf->refcnt++;
211 crit_exit();
214 #endif
217 * Lose a reference to an sf_buf. When none left, detach mapped page
218 * and release resources back to the system. Note that the sfbuf's
219 * removal from the freelist is delayed, so it may in fact already be
220 * on the free list. This is the optimal (and most likely) scenario.
222 * Must be called at splimp.
224 void
225 sf_buf_free(struct sf_buf *sf)
227 if (sf->refcnt == 0)
228 panic("sf_buf_free: freeing free sf_buf");
229 crit_enter();
230 sf->refcnt--;
231 if (sf->refcnt == 0 && (sf->flags & SFBA_ONFREEQ) == 0) {
232 TAILQ_INSERT_TAIL(&sf_buf_freelist, sf, free_entry);
233 ++nsffree;
234 sf->flags |= SFBA_ONFREEQ;
235 if (sf_buf_alloc_want > 0)
236 wakeup_one(&sf_buf_freelist);
238 crit_exit();