1 /* $NetBSD: tmpfs_mem.c,v 1.4 2011/05/24 01:09:47 rmind Exp $ */ 2 3 /* 4 * Copyright (c) 2010, 2011 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Mindaugas Rasiukevicius. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * tmpfs memory allocation routines. 34 * Implements memory usage accounting and limiting. 35 */ 36 37 #include <sys/cdefs.h> 38 __KERNEL_RCSID(0, "$NetBSD: tmpfs_mem.c,v 1.4 2011/05/24 01:09:47 rmind Exp $"); 39 40 #include <sys/param.h> 41 #include <sys/atomic.h> 42 #include <sys/kmem.h> 43 #include <sys/namei.h> 44 #include <sys/pool.h> 45 46 #include <fs/tmpfs/tmpfs.h> 47 48 extern struct pool tmpfs_dirent_pool; 49 extern struct pool tmpfs_node_pool; 50 51 void 52 tmpfs_mntmem_init(struct tmpfs_mount *mp, uint64_t memlimit) 53 { 54 55 mutex_init(&mp->tm_acc_lock, MUTEX_DEFAULT, IPL_NONE); 56 mp->tm_mem_limit = memlimit; 57 mp->tm_bytes_used = 0; 58 } 59 60 void 61 tmpfs_mntmem_destroy(struct tmpfs_mount *mp) 62 { 63 64 KASSERT(mp->tm_bytes_used == 0); 65 mutex_destroy(&mp->tm_acc_lock); 66 } 67 68 /* 69 * tmpfs_mem_info: return the number of available memory pages. 70 * 71 * => If 'total' is true, then return _total_ amount of pages. 72 * => If false, then return the amount of _free_ memory pages. 73 * 74 * Remember to remove TMPFS_PAGES_RESERVED from the returned value to avoid 75 * excessive memory usage. 76 */ 77 size_t 78 tmpfs_mem_info(bool total) 79 { 80 size_t size = 0; 81 82 /* XXX: unlocked */ 83 size += uvmexp.swpgavail; 84 if (!total) { 85 size -= uvmexp.swpgonly; 86 } 87 size += uvmexp.free; 88 size += uvmexp.filepages; 89 if (size > uvmexp.wired) { 90 size -= uvmexp.wired; 91 } else { 92 size = 0; 93 } 94 return size; 95 } 96 97 uint64_t 98 tmpfs_bytes_max(struct tmpfs_mount *mp) 99 { 100 size_t freepages = tmpfs_mem_info(false); 101 uint64_t avail_mem; 102 103 if (freepages < TMPFS_PAGES_RESERVED) { 104 freepages = 0; 105 } else { 106 freepages -= TMPFS_PAGES_RESERVED; 107 } 108 avail_mem = round_page(mp->tm_bytes_used) + (freepages << PAGE_SHIFT); 109 return MIN(mp->tm_mem_limit, avail_mem); 110 } 111 112 size_t 113 tmpfs_pages_avail(struct tmpfs_mount *mp) 114 { 115 116 return (tmpfs_bytes_max(mp) - mp->tm_bytes_used) >> PAGE_SHIFT; 117 } 118 119 bool 120 tmpfs_mem_incr(struct tmpfs_mount *mp, size_t sz) 121 { 122 uint64_t lim; 123 124 mutex_enter(&mp->tm_acc_lock); 125 lim = tmpfs_bytes_max(mp); 126 if (mp->tm_bytes_used + sz >= lim) { 127 mutex_exit(&mp->tm_acc_lock); 128 return false; 129 } 130 mp->tm_bytes_used += sz; 131 mutex_exit(&mp->tm_acc_lock); 132 return true; 133 } 134 135 void 136 tmpfs_mem_decr(struct tmpfs_mount *mp, size_t sz) 137 { 138 139 mutex_enter(&mp->tm_acc_lock); 140 KASSERT(mp->tm_bytes_used >= sz); 141 mp->tm_bytes_used -= sz; 142 mutex_exit(&mp->tm_acc_lock); 143 } 144 145 struct tmpfs_dirent * 146 tmpfs_dirent_get(struct tmpfs_mount *mp) 147 { 148 149 if (!tmpfs_mem_incr(mp, sizeof(struct tmpfs_dirent))) { 150 return NULL; 151 } 152 return pool_get(&tmpfs_dirent_pool, PR_WAITOK); 153 } 154 155 void 156 tmpfs_dirent_put(struct tmpfs_mount *mp, struct tmpfs_dirent *de) 157 { 158 159 tmpfs_mem_decr(mp, sizeof(struct tmpfs_dirent)); 160 pool_put(&tmpfs_dirent_pool, de); 161 } 162 163 struct tmpfs_node * 164 tmpfs_node_get(struct tmpfs_mount *mp) 165 { 166 167 if (atomic_inc_uint_nv(&mp->tm_nodes_cnt) >= mp->tm_nodes_max) { 168 atomic_dec_uint(&mp->tm_nodes_cnt); 169 return NULL; 170 } 171 if (!tmpfs_mem_incr(mp, sizeof(struct tmpfs_node))) { 172 return NULL; 173 } 174 return pool_get(&tmpfs_node_pool, PR_WAITOK); 175 } 176 177 void 178 tmpfs_node_put(struct tmpfs_mount *mp, struct tmpfs_node *tn) 179 { 180 181 atomic_dec_uint(&mp->tm_nodes_cnt); 182 tmpfs_mem_decr(mp, sizeof(struct tmpfs_node)); 183 pool_put(&tmpfs_node_pool, tn); 184 } 185 186 /* 187 * Quantum size to round-up the tmpfs names in order to reduce re-allocations. 188 */ 189 190 #define TMPFS_NAME_QUANTUM (32) 191 192 char * 193 tmpfs_strname_alloc(struct tmpfs_mount *mp, size_t len) 194 { 195 const size_t sz = roundup2(len, TMPFS_NAME_QUANTUM); 196 197 KASSERT(sz > 0 && sz <= 1024); 198 if (!tmpfs_mem_incr(mp, sz)) { 199 return NULL; 200 } 201 return kmem_alloc(sz, KM_SLEEP); 202 } 203 204 void 205 tmpfs_strname_free(struct tmpfs_mount *mp, char *str, size_t len) 206 { 207 const size_t sz = roundup2(len, TMPFS_NAME_QUANTUM); 208 209 KASSERT(sz > 0 && sz <= 1024); 210 tmpfs_mem_decr(mp, sz); 211 kmem_free(str, sz); 212 } 213 214 bool 215 tmpfs_strname_neqlen(struct componentname *fcnp, struct componentname *tcnp) 216 { 217 const size_t fln = roundup2(fcnp->cn_namelen, TMPFS_NAME_QUANTUM); 218 const size_t tln = roundup2(tcnp->cn_namelen, TMPFS_NAME_QUANTUM); 219 220 return (fln != tln) || memcmp(fcnp->cn_nameptr, tcnp->cn_nameptr, fln); 221 } 222