1 /* $NetBSD: tmpfs_mem.c,v 1.13 2020/06/11 19:20:46 ad Exp $ */ 2 3 /* 4 * Copyright (c) 2010, 2011, 2020 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 1.13 2020/06/11 19:20:46 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 size += uvmexp.swpgavail; 101 if (!total) { 102 size -= uvmexp.swpgonly; 103 } 104 size += uvm_availmem(true); 105 size += uvmexp.filepages; 106 if (size > uvmexp.wired) { 107 size -= uvmexp.wired; 108 } else { 109 size = 0; 110 } 111 return size; 112 } 113 114 uint64_t 115 tmpfs_bytes_max(struct tmpfs_mount *mp) 116 { 117 psize_t freepages = tmpfs_mem_info(false); 118 int freetarg = uvmexp.freetarg; // XXX unlocked 119 uint64_t avail_mem; 120 121 if (freepages < freetarg) { 122 freepages = 0; 123 } else { 124 freepages -= freetarg; 125 } 126 avail_mem = round_page(mp->tm_bytes_used) + (freepages << PAGE_SHIFT); 127 return MIN(mp->tm_mem_limit, avail_mem); 128 } 129 130 size_t 131 tmpfs_pages_avail(struct tmpfs_mount *mp) 132 { 133 134 return (tmpfs_bytes_max(mp) - mp->tm_bytes_used) >> PAGE_SHIFT; 135 } 136 137 bool 138 tmpfs_mem_incr(struct tmpfs_mount *mp, size_t sz) 139 { 140 uint64_t lim; 141 142 mutex_enter(&mp->tm_acc_lock); 143 lim = tmpfs_bytes_max(mp); 144 if (mp->tm_bytes_used + sz >= lim) { 145 mutex_exit(&mp->tm_acc_lock); 146 return false; 147 } 148 mp->tm_bytes_used += sz; 149 mutex_exit(&mp->tm_acc_lock); 150 return true; 151 } 152 153 void 154 tmpfs_mem_decr(struct tmpfs_mount *mp, size_t sz) 155 { 156 157 mutex_enter(&mp->tm_acc_lock); 158 KASSERT(mp->tm_bytes_used >= sz); 159 mp->tm_bytes_used -= sz; 160 mutex_exit(&mp->tm_acc_lock); 161 } 162 163 struct tmpfs_dirent * 164 tmpfs_dirent_get(struct tmpfs_mount *mp) 165 { 166 167 if (!tmpfs_mem_incr(mp, sizeof(struct tmpfs_dirent))) { 168 return NULL; 169 } 170 return pool_get(&tmpfs_dirent_pool, PR_WAITOK); 171 } 172 173 void 174 tmpfs_dirent_put(struct tmpfs_mount *mp, struct tmpfs_dirent *de) 175 { 176 177 tmpfs_mem_decr(mp, sizeof(struct tmpfs_dirent)); 178 pool_put(&tmpfs_dirent_pool, de); 179 } 180 181 struct tmpfs_node * 182 tmpfs_node_get(struct tmpfs_mount *mp) 183 { 184 185 if (atomic_inc_uint_nv(&mp->tm_nodes_cnt) >= mp->tm_nodes_max) { 186 atomic_dec_uint(&mp->tm_nodes_cnt); 187 return NULL; 188 } 189 if (!tmpfs_mem_incr(mp, sizeof(struct tmpfs_node))) { 190 atomic_dec_uint(&mp->tm_nodes_cnt); 191 return NULL; 192 } 193 return pool_get(&tmpfs_node_pool, PR_WAITOK); 194 } 195 196 void 197 tmpfs_node_put(struct tmpfs_mount *mp, struct tmpfs_node *tn) 198 { 199 200 atomic_dec_uint(&mp->tm_nodes_cnt); 201 tmpfs_mem_decr(mp, sizeof(struct tmpfs_node)); 202 pool_put(&tmpfs_node_pool, tn); 203 } 204 205 /* 206 * Quantum size to round-up the tmpfs names in order to reduce re-allocations. 207 */ 208 209 #define TMPFS_NAME_QUANTUM (32) 210 211 char * 212 tmpfs_strname_alloc(struct tmpfs_mount *mp, size_t len) 213 { 214 const size_t sz = roundup2(len, TMPFS_NAME_QUANTUM); 215 216 KASSERT(sz > 0 && sz <= 1024); 217 if (!tmpfs_mem_incr(mp, sz)) { 218 return NULL; 219 } 220 return kmem_alloc(sz, KM_SLEEP); 221 } 222 223 void 224 tmpfs_strname_free(struct tmpfs_mount *mp, char *str, size_t len) 225 { 226 const size_t sz = roundup2(len, TMPFS_NAME_QUANTUM); 227 228 KASSERT(sz > 0 && sz <= 1024); 229 tmpfs_mem_decr(mp, sz); 230 kmem_free(str, sz); 231 } 232 233 bool 234 tmpfs_strname_neqlen(struct componentname *fcnp, struct componentname *tcnp) 235 { 236 const size_t fln = fcnp->cn_namelen; 237 const size_t tln = tcnp->cn_namelen; 238 239 return (fln != tln) || memcmp(fcnp->cn_nameptr, tcnp->cn_nameptr, fln); 240 } 241