1 /*-
2 * Copyright (c) 2014 Gleb Smirnoff <glebius@FreeBSD.org>
3 * Copyright (c) 2003, 2005 Alan L. Cox <alc@cs.rice.edu>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/param.h>
29 #include <sys/kernel.h>
30 #include <sys/lock.h>
31 #include <sys/malloc.h>
32 #include <sys/mutex.h>
33 #include <sys/proc.h>
34 #include <sys/sf_buf.h>
35 #include <sys/smp.h>
36 #include <sys/sysctl.h>
37
38 #include <vm/vm.h>
39 #include <vm/vm_extern.h>
40 #include <vm/vm_page.h>
41
42 #ifndef NSFBUFS
43 #define NSFBUFS (512 + maxusers * 16)
44 #endif
45
46 static int nsfbufs;
47 static int nsfbufspeak;
48 static int nsfbufsused;
49
50 SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufs, CTLFLAG_RDTUN, &nsfbufs, 0,
51 "Maximum number of sendfile(2) sf_bufs available");
52 SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufspeak, CTLFLAG_RD, &nsfbufspeak, 0,
53 "Number of sendfile(2) sf_bufs at peak usage");
54 SYSCTL_INT(_kern_ipc, OID_AUTO, nsfbufsused, CTLFLAG_RD, &nsfbufsused, 0,
55 "Number of sendfile(2) sf_bufs in use");
56
57 static void sf_buf_init(void *arg);
58 SYSINIT(sock_sf, SI_SUB_MBUF, SI_ORDER_ANY, sf_buf_init, NULL);
59
60 LIST_HEAD(sf_head, sf_buf);
61
62 /*
63 * A hash table of active sendfile(2) buffers
64 */
65 static struct sf_head *sf_buf_active;
66 static u_long sf_buf_hashmask;
67
68 #define SF_BUF_HASH(m) (((m) - vm_page_array) & sf_buf_hashmask)
69
70 static TAILQ_HEAD(, sf_buf) sf_buf_freelist;
71 static u_int sf_buf_alloc_want;
72
73 /*
74 * A lock used to synchronize access to the hash table and free list
75 */
76 static struct mtx sf_buf_lock;
77
78 /*
79 * Allocate a pool of sf_bufs (sendfile(2) or "super-fast" if you prefer. :-))
80 */
81 static void
sf_buf_init(void * arg)82 sf_buf_init(void *arg)
83 {
84 struct sf_buf *sf_bufs;
85 vm_offset_t sf_base;
86 int i;
87
88 if (PMAP_HAS_DMAP)
89 return;
90
91 nsfbufs = NSFBUFS;
92 TUNABLE_INT_FETCH("kern.ipc.nsfbufs", &nsfbufs);
93
94 sf_buf_active = hashinit(nsfbufs, M_TEMP, &sf_buf_hashmask);
95 TAILQ_INIT(&sf_buf_freelist);
96 sf_base = kva_alloc(nsfbufs * PAGE_SIZE);
97 sf_bufs = malloc(nsfbufs * sizeof(struct sf_buf), M_TEMP,
98 M_WAITOK | M_ZERO);
99 for (i = 0; i < nsfbufs; i++) {
100 sf_bufs[i].kva = sf_base + i * PAGE_SIZE;
101 TAILQ_INSERT_TAIL(&sf_buf_freelist, &sf_bufs[i], free_entry);
102 }
103 sf_buf_alloc_want = 0;
104 mtx_init(&sf_buf_lock, "sf_buf", NULL, MTX_DEF);
105 }
106
107 /*
108 * Get an sf_buf from the freelist. May block if none are available.
109 */
110 struct sf_buf *
sf_buf_alloc(struct vm_page * m,int flags)111 sf_buf_alloc(struct vm_page *m, int flags)
112 {
113 struct sf_head *hash_list;
114 struct sf_buf *sf;
115 int error;
116
117 if (PMAP_HAS_DMAP)
118 return ((struct sf_buf *)m);
119
120 KASSERT(curthread->td_pinned > 0 || (flags & SFB_CPUPRIVATE) == 0,
121 ("sf_buf_alloc(SFB_CPUPRIVATE): curthread not pinned"));
122 hash_list = &sf_buf_active[SF_BUF_HASH(m)];
123 mtx_lock(&sf_buf_lock);
124 LIST_FOREACH(sf, hash_list, list_entry) {
125 if (sf->m == m) {
126 sf->ref_count++;
127 if (sf->ref_count == 1) {
128 TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
129 nsfbufsused++;
130 nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
131 }
132 #if defined(SMP) && defined(SFBUF_CPUSET)
133 sf_buf_shootdown(sf, flags);
134 #endif
135 goto done;
136 }
137 }
138 while ((sf = TAILQ_FIRST(&sf_buf_freelist)) == NULL) {
139 if (flags & SFB_NOWAIT)
140 goto done;
141 sf_buf_alloc_want++;
142 SFSTAT_INC(sf_allocwait);
143 error = msleep(&sf_buf_freelist, &sf_buf_lock,
144 (flags & SFB_CATCH) ? PCATCH | PVM : PVM, "sfbufa", 0);
145 sf_buf_alloc_want--;
146
147 /*
148 * If we got a signal, don't risk going back to sleep.
149 */
150 if (error)
151 goto done;
152 }
153 TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
154 if (sf->m != NULL)
155 LIST_REMOVE(sf, list_entry);
156 LIST_INSERT_HEAD(hash_list, sf, list_entry);
157 sf->ref_count = 1;
158 sf->m = m;
159 nsfbufsused++;
160 nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
161 sf_buf_map(sf, flags);
162 done:
163 mtx_unlock(&sf_buf_lock);
164 return (sf);
165 }
166
167 /*
168 * Remove a reference from the given sf_buf, adding it to the free
169 * list when its reference count reaches zero. A freed sf_buf still,
170 * however, retains its virtual-to-physical mapping until it is
171 * recycled or reactivated by sf_buf_alloc(9).
172 */
173 void
sf_buf_free(struct sf_buf * sf)174 sf_buf_free(struct sf_buf *sf)
175 {
176
177 if (PMAP_HAS_DMAP)
178 return;
179
180 mtx_lock(&sf_buf_lock);
181 sf->ref_count--;
182 if (sf->ref_count == 0) {
183 TAILQ_INSERT_TAIL(&sf_buf_freelist, sf, free_entry);
184 nsfbufsused--;
185 if (sf_buf_unmap(sf)) {
186 sf->m = NULL;
187 LIST_REMOVE(sf, list_entry);
188 }
189 if (sf_buf_alloc_want > 0)
190 wakeup(&sf_buf_freelist);
191 }
192 mtx_unlock(&sf_buf_lock);
193 }
194
195 void
sf_buf_ref(struct sf_buf * sf)196 sf_buf_ref(struct sf_buf *sf)
197 {
198
199 if (PMAP_HAS_DMAP)
200 return;
201
202 mtx_lock(&sf_buf_lock);
203 KASSERT(sf->ref_count > 0, ("%s: sf %p not allocated", __func__, sf));
204 sf->ref_count++;
205 mtx_unlock(&sf_buf_lock);
206 }
207
208 #ifdef SFBUF_PROCESS_PAGE
209 /*
210 * Run callback function on sf_buf that holds a certain page.
211 */
212 boolean_t
sf_buf_process_page(vm_page_t m,void (* cb)(struct sf_buf *))213 sf_buf_process_page(vm_page_t m, void (*cb)(struct sf_buf *))
214 {
215 struct sf_head *hash_list;
216 struct sf_buf *sf;
217
218 hash_list = &sf_buf_active[SF_BUF_HASH(m)];
219 mtx_lock(&sf_buf_lock);
220 LIST_FOREACH(sf, hash_list, list_entry) {
221 if (sf->m == m) {
222 cb(sf);
223 mtx_unlock(&sf_buf_lock);
224 return (TRUE);
225 }
226 }
227 mtx_unlock(&sf_buf_lock);
228 return (FALSE);
229 }
230 #endif /* SFBUF_PROCESS_PAGE */
231