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 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 * 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 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 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 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