1 /* $NetBSD: tmpfs_mem.c,v 1.12 2019/12/31 13:07:13 ad 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 1.12 2019/12/31 13:07:13 ad 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 int 69 tmpfs_mntmem_set(struct tmpfs_mount *mp, uint64_t memlimit) 70 { 71 int error; 72 73 mutex_enter(&mp->tm_acc_lock); 74 if (round_page(mp->tm_bytes_used) >= memlimit) 75 error = EBUSY; 76 else { 77 error = 0; 78 mp->tm_mem_limit = memlimit; 79 } 80 mutex_exit(&mp->tm_acc_lock); 81 return error; 82 } 83 84 85 86 /* 87 * tmpfs_mem_info: return the number of available memory pages. 88 * 89 * => If 'total' is true, then return _total_ amount of pages. 90 * => If false, then return the amount of _free_ memory pages. 91 * 92 * Remember to remove uvmexp.freetarg from the returned value to avoid 93 * excessive memory usage. 94 */ 95 size_t 96 tmpfs_mem_info(bool total) 97 { 98 size_t size = 0; 99 100 /* XXX: unlocked */ 101 size += uvmexp.swpgavail; 102 if (!total) { 103 size -= uvmexp.swpgonly; 104 } 105 size += uvm_availmem(); 106 size += uvmexp.filepages; 107 if (size > uvmexp.wired) { 108 size -= uvmexp.wired; 109 } else { 110 size = 0; 111 } 112 return size; 113 } 114 115 uint64_t 116 tmpfs_bytes_max(struct tmpfs_mount *mp) 117 { 118 psize_t freepages = tmpfs_mem_info(false); 119 int freetarg = uvmexp.freetarg; // XXX unlocked 120 uint64_t avail_mem; 121 122 if (freepages < freetarg) { 123 freepages = 0; 124 } else { 125 freepages -= freetarg; 126 } 127 avail_mem = round_page(mp->tm_bytes_used) + (freepages << PAGE_SHIFT); 128 return MIN(mp->tm_mem_limit, avail_mem); 129 } 130 131 size_t 132 tmpfs_pages_avail(struct tmpfs_mount *mp) 133 { 134 135 return (tmpfs_bytes_max(mp) - mp->tm_bytes_used) >> PAGE_SHIFT; 136 } 137 138 bool 139 tmpfs_mem_incr(struct tmpfs_mount *mp, size_t sz) 140 { 141 uint64_t lim; 142 143 mutex_enter(&mp->tm_acc_lock); 144 lim = tmpfs_bytes_max(mp); 145 if (mp->tm_bytes_used + sz >= lim) { 146 mutex_exit(&mp->tm_acc_lock); 147 return false; 148 } 149 mp->tm_bytes_used += sz; 150 mutex_exit(&mp->tm_acc_lock); 151 return true; 152 } 153 154 void 155 tmpfs_mem_decr(struct tmpfs_mount *mp, size_t sz) 156 { 157 158 mutex_enter(&mp->tm_acc_lock); 159 KASSERT(mp->tm_bytes_used >= sz); 160 mp->tm_bytes_used -= sz; 161 mutex_exit(&mp->tm_acc_lock); 162 } 163 164 struct tmpfs_dirent * 165 tmpfs_dirent_get(struct tmpfs_mount *mp) 166 { 167 168 if (!tmpfs_mem_incr(mp, sizeof(struct tmpfs_dirent))) { 169 return NULL; 170 } 171 return pool_get(&tmpfs_dirent_pool, PR_WAITOK); 172 } 173 174 void 175 tmpfs_dirent_put(struct tmpfs_mount *mp, struct tmpfs_dirent *de) 176 { 177 178 tmpfs_mem_decr(mp, sizeof(struct tmpfs_dirent)); 179 pool_put(&tmpfs_dirent_pool, de); 180 } 181 182 struct tmpfs_node * 183 tmpfs_node_get(struct tmpfs_mount *mp) 184 { 185 186 if (atomic_inc_uint_nv(&mp->tm_nodes_cnt) >= mp->tm_nodes_max) { 187 atomic_dec_uint(&mp->tm_nodes_cnt); 188 return NULL; 189 } 190 if (!tmpfs_mem_incr(mp, sizeof(struct tmpfs_node))) { 191 atomic_dec_uint(&mp->tm_nodes_cnt); 192 return NULL; 193 } 194 return pool_get(&tmpfs_node_pool, PR_WAITOK); 195 } 196 197 void 198 tmpfs_node_put(struct tmpfs_mount *mp, struct tmpfs_node *tn) 199 { 200 201 atomic_dec_uint(&mp->tm_nodes_cnt); 202 tmpfs_mem_decr(mp, sizeof(struct tmpfs_node)); 203 pool_put(&tmpfs_node_pool, tn); 204 } 205 206 /* 207 * Quantum size to round-up the tmpfs names in order to reduce re-allocations. 208 */ 209 210 #define TMPFS_NAME_QUANTUM (32) 211 212 char * 213 tmpfs_strname_alloc(struct tmpfs_mount *mp, size_t len) 214 { 215 const size_t sz = roundup2(len, TMPFS_NAME_QUANTUM); 216 217 KASSERT(sz > 0 && sz <= 1024); 218 if (!tmpfs_mem_incr(mp, sz)) { 219 return NULL; 220 } 221 return kmem_alloc(sz, KM_SLEEP); 222 } 223 224 void 225 tmpfs_strname_free(struct tmpfs_mount *mp, char *str, size_t len) 226 { 227 const size_t sz = roundup2(len, TMPFS_NAME_QUANTUM); 228 229 KASSERT(sz > 0 && sz <= 1024); 230 tmpfs_mem_decr(mp, sz); 231 kmem_free(str, sz); 232 } 233 234 bool 235 tmpfs_strname_neqlen(struct componentname *fcnp, struct componentname *tcnp) 236 { 237 const size_t fln = fcnp->cn_namelen; 238 const size_t tln = tcnp->cn_namelen; 239 240 return (fln != tln) || memcmp(fcnp->cn_nameptr, tcnp->cn_nameptr, fln); 241 } 242