1 | /* $NetBSD: tmpfs_mem.c,v 1.9 2016/08/22 23:07:36 skrll 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 1.9 2016/08/22 23:07:36 skrll 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 += uvmexp.free; |
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 = roundup2(fcnp->cn_namelen, TMPFS_NAME_QUANTUM); |
238 | const size_t tln = roundup2(tcnp->cn_namelen, TMPFS_NAME_QUANTUM); |
239 | |
240 | return (fln != tln) || memcmp(fcnp->cn_nameptr, tcnp->cn_nameptr, fln); |
241 | } |
242 | |