1 /* $NetBSD: tmpfs_mem.c,v 1.2 2010/06/28 19:32:43 rmind Exp $ */ 2 3 /* 4 * Copyright (c) 2010 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* 30 * tmpfs memory allocation routines. 31 * Implements memory usage accounting and limiting. 32 */ 33 34 #include <sys/cdefs.h> 35 __KERNEL_RCSID(0, "$NetBSD: tmpfs_mem.c,v 1.2 2010/06/28 19:32:43 rmind Exp $"); 36 37 #include <sys/param.h> 38 #include <sys/atomic.h> 39 #include <sys/kmem.h> 40 #include <sys/namei.h> 41 #include <sys/pool.h> 42 43 #include <fs/tmpfs/tmpfs.h> 44 45 void 46 tmpfs_mntmem_init(struct tmpfs_mount *mp, uint64_t memlimit) 47 { 48 49 sprintf(mp->tm_dwchan, "tmpfs_dirent_%p", mp); 50 pool_init(&mp->tm_dirent_pool, sizeof(struct tmpfs_dirent), 0, 0, 0, 51 mp->tm_dwchan, &pool_allocator_nointr, IPL_NONE); 52 53 sprintf(mp->tm_nwchan, "tmpfs_node_%p", mp); 54 pool_init(&mp->tm_node_pool, sizeof(struct tmpfs_node), 0, 0, 0, 55 mp->tm_dwchan, &pool_allocator_nointr, IPL_NONE); 56 57 mutex_init(&mp->tm_acc_lock, MUTEX_DEFAULT, IPL_NONE); 58 mp->tm_mem_limit = memlimit; 59 mp->tm_bytes_used = 0; 60 } 61 62 void 63 tmpfs_mntmem_destroy(struct tmpfs_mount *mp) 64 { 65 66 KASSERT(mp->tm_bytes_used == 0); 67 mutex_destroy(&mp->tm_acc_lock); 68 pool_destroy(&mp->tm_dirent_pool); 69 pool_destroy(&mp->tm_node_pool); 70 } 71 72 /* 73 * tmpfs_mem_info: return the number of available memory pages. 74 * 75 * => If 'total' is true, then return _total_ amount of pages. 76 * => If false, then return the amount of _free_ memory pages. 77 * 78 * Remember to remove TMPFS_PAGES_RESERVED from the returned value to avoid 79 * excessive memory usage. 80 */ 81 size_t 82 tmpfs_mem_info(bool total) 83 { 84 size_t size = 0; 85 86 /* XXX: unlocked */ 87 size += uvmexp.swpgavail; 88 if (!total) { 89 size -= uvmexp.swpgonly; 90 } 91 size += uvmexp.free; 92 size += uvmexp.filepages; 93 if (size > uvmexp.wired) { 94 size -= uvmexp.wired; 95 } else { 96 size = 0; 97 } 98 return size; 99 } 100 101 uint64_t 102 tmpfs_bytes_max(struct tmpfs_mount *mp) 103 { 104 size_t freepages = tmpfs_mem_info(false); 105 uint64_t avail_mem; 106 107 if (freepages < TMPFS_PAGES_RESERVED) { 108 freepages = 0; 109 } else { 110 freepages -= TMPFS_PAGES_RESERVED; 111 } 112 avail_mem = round_page(mp->tm_bytes_used) + (freepages << PAGE_SHIFT); 113 return MIN(mp->tm_mem_limit, avail_mem); 114 } 115 116 size_t 117 tmpfs_pages_avail(struct tmpfs_mount *mp) 118 { 119 120 return (tmpfs_bytes_max(mp) - mp->tm_bytes_used) >> PAGE_SHIFT; 121 } 122 123 bool 124 tmpfs_mem_incr(struct tmpfs_mount *mp, size_t sz) 125 { 126 uint64_t lim; 127 128 mutex_enter(&mp->tm_acc_lock); 129 lim = tmpfs_bytes_max(mp); 130 if (mp->tm_bytes_used + sz >= lim) { 131 mutex_exit(&mp->tm_acc_lock); 132 return false; 133 } 134 mp->tm_bytes_used += sz; 135 mutex_exit(&mp->tm_acc_lock); 136 return true; 137 } 138 139 void 140 tmpfs_mem_decr(struct tmpfs_mount *mp, size_t sz) 141 { 142 143 mutex_enter(&mp->tm_acc_lock); 144 KASSERT(mp->tm_bytes_used >= sz); 145 mp->tm_bytes_used -= sz; 146 mutex_exit(&mp->tm_acc_lock); 147 } 148 149 struct tmpfs_dirent * 150 tmpfs_dirent_get(struct tmpfs_mount *mp) 151 { 152 153 if (!tmpfs_mem_incr(mp, sizeof(struct tmpfs_dirent))) { 154 return NULL; 155 } 156 return pool_get(&mp->tm_dirent_pool, PR_WAITOK); 157 } 158 159 void 160 tmpfs_dirent_put(struct tmpfs_mount *mp, struct tmpfs_dirent *de) 161 { 162 163 tmpfs_mem_decr(mp, sizeof(struct tmpfs_dirent)); 164 pool_put(&mp->tm_dirent_pool, de); 165 } 166 167 struct tmpfs_node * 168 tmpfs_node_get(struct tmpfs_mount *mp) 169 { 170 171 if (!tmpfs_mem_incr(mp, sizeof(struct tmpfs_node))) { 172 return NULL; 173 } 174 return pool_get(&mp->tm_node_pool, PR_WAITOK); 175 } 176 177 void 178 tmpfs_node_put(struct tmpfs_mount *mp, struct tmpfs_node *tn) 179 { 180 181 tmpfs_mem_decr(mp, sizeof(struct tmpfs_node)); 182 pool_put(&mp->tm_node_pool, tn); 183 } 184 185 /* 186 * Quantum size to round-up the tmpfs names in order to reduce re-allocations. 187 */ 188 189 #define TMPFS_NAME_QUANTUM (32) 190 191 char * 192 tmpfs_strname_alloc(struct tmpfs_mount *mp, size_t len) 193 { 194 const size_t sz = roundup2(len, TMPFS_NAME_QUANTUM); 195 196 KASSERT(sz > 0 && sz <= 1024); 197 if (!tmpfs_mem_incr(mp, sz)) { 198 return NULL; 199 } 200 return kmem_alloc(sz, KM_SLEEP); 201 } 202 203 void 204 tmpfs_strname_free(struct tmpfs_mount *mp, char *str, size_t len) 205 { 206 const size_t sz = roundup2(len, TMPFS_NAME_QUANTUM); 207 208 KASSERT(sz > 0 && sz <= 1024); 209 tmpfs_mem_decr(mp, sz); 210 kmem_free(str, sz); 211 } 212 213 bool 214 tmpfs_strname_neqlen(struct componentname *fcnp, struct componentname *tcnp) 215 { 216 const size_t fln = roundup2(fcnp->cn_namelen, TMPFS_NAME_QUANTUM); 217 const size_t tln = roundup2(tcnp->cn_namelen, TMPFS_NAME_QUANTUM); 218 219 return (fln != tln) || memcmp(fcnp->cn_nameptr, tcnp->cn_nameptr, fln); 220 } 221