1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1980, 1986, 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)param.c 8.3 (Berkeley) 8/20/94
37 */
38
39 #include <sys/cdefs.h>
40 #include "opt_param.h"
41 #include "opt_msgbuf.h"
42 #include "opt_maxphys.h"
43 #include "opt_maxusers.h"
44
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/buf.h>
48 #include <sys/kernel.h>
49 #include <sys/limits.h>
50 #include <sys/msgbuf.h>
51 #include <sys/sysctl.h>
52 #include <sys/proc.h>
53 #include <sys/vnode.h>
54
55 #include <vm/vm.h>
56 #include <vm/vm_param.h>
57 #include <vm/pmap.h>
58
59 /*
60 * System parameter formulae.
61 */
62
63 #ifndef HZ
64 # if defined(__mips__) || defined(__arm__)
65 # define HZ 100
66 # else
67 # define HZ 1000
68 # endif
69 # ifndef HZ_VM
70 # define HZ_VM 100
71 # endif
72 #else
73 # ifndef HZ_VM
74 # define HZ_VM HZ
75 # endif
76 #endif
77 #define NPROC (20 + 16 * maxusers)
78 #ifndef NBUF
79 #define NBUF 0
80 #endif
81 #ifndef MAXFILES
82 #define MAXFILES (40 + 32 * maxusers)
83 #endif
84
85 static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
86
87 int hz; /* system clock's frequency */
88 int tick; /* usec per tick (1000000 / hz) */
89 time_t tick_seconds_max; /* max hz * seconds an integer can hold */
90 struct bintime tick_bt; /* bintime per tick (1s / hz) */
91 sbintime_t tick_sbt;
92 int maxusers; /* base tunable */
93 int maxproc; /* maximum # of processes */
94 int maxprocperuid; /* max # of procs per user */
95 int maxfiles; /* sys. wide open files limit */
96 int maxfilesperproc; /* per-proc open files limit */
97 int msgbufsize; /* size of kernel message buffer */
98 int nbuf; /* number of bcache bufs */
99 int bio_transient_maxcnt;
100 int ngroups_max; /* max # groups per process */
101 int nswbuf;
102 pid_t pid_max = PID_MAX;
103 u_long maxswzone; /* max swmeta KVA storage */
104 u_long maxbcache; /* max buffer cache KVA storage */
105 u_long maxpipekva; /* Limit on pipe KVA */
106 u_long maxphys; /* max raw I/O transfer size */
107 int vm_guest = VM_GUEST_NO; /* Running as virtual machine guest? */
108 u_long maxtsiz; /* max text size */
109 u_long dfldsiz; /* initial data size limit */
110 u_long maxdsiz; /* max data size */
111 u_long dflssiz; /* initial stack size limit */
112 u_long maxssiz; /* max stack size */
113 u_long sgrowsiz; /* amount to grow stack */
114
115 SYSCTL_INT(_kern, OID_AUTO, hz, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &hz, 0,
116 "Number of clock ticks per second");
117 SYSCTL_INT(_kern, OID_AUTO, hz_max, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, HZ_MAXIMUM,
118 "Maximum hz value supported");
119 SYSCTL_INT(_kern, OID_AUTO, hz_min, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, HZ_MINIMUM,
120 "Minimum hz value supported");
121 SYSCTL_INT(_kern, OID_AUTO, nbuf, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &nbuf, 0,
122 "Number of buffers in the buffer cache");
123 SYSCTL_INT(_kern, OID_AUTO, nswbuf, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &nswbuf, 0,
124 "Number of swap buffers");
125 SYSCTL_INT(_kern, OID_AUTO, msgbufsize, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &msgbufsize, 0,
126 "Size of the kernel message buffer");
127 SYSCTL_LONG(_kern, OID_AUTO, maxswzone, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &maxswzone, 0,
128 "Maximum memory for swap metadata");
129 SYSCTL_LONG(_kern, OID_AUTO, maxbcache, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &maxbcache, 0,
130 "Maximum value of vfs.maxbufspace");
131 SYSCTL_INT(_kern, OID_AUTO, bio_transient_maxcnt, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
132 &bio_transient_maxcnt, 0,
133 "Maximum number of transient BIOs mappings");
134 SYSCTL_ULONG(_kern, OID_AUTO, maxtsiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &maxtsiz, 0,
135 "Maximum text size");
136 SYSCTL_ULONG(_kern, OID_AUTO, dfldsiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &dfldsiz, 0,
137 "Initial data size limit");
138 SYSCTL_ULONG(_kern, OID_AUTO, maxdsiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &maxdsiz, 0,
139 "Maximum data size");
140 SYSCTL_ULONG(_kern, OID_AUTO, dflssiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &dflssiz, 0,
141 "Initial stack size limit");
142 SYSCTL_ULONG(_kern, OID_AUTO, maxssiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &maxssiz, 0,
143 "Maximum stack size");
144 SYSCTL_ULONG(_kern, OID_AUTO, sgrowsiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &sgrowsiz, 0,
145 "Amount to grow stack on a stack fault");
146 SYSCTL_PROC(_kern, OID_AUTO, vm_guest,
147 CTLFLAG_RD | CTLTYPE_STRING | CTLFLAG_MPSAFE, NULL, 0,
148 sysctl_kern_vm_guest, "A",
149 "Virtual machine guest detected?");
150
151 /*
152 * The elements of this array are ordered based upon the values of the
153 * corresponding enum VM_GUEST members.
154 */
155 static const char *const vm_guest_sysctl_names[] = {
156 [VM_GUEST_NO] = "none",
157 [VM_GUEST_VM] = "generic",
158 [VM_GUEST_XEN] = "xen",
159 [VM_GUEST_HV] = "hv",
160 [VM_GUEST_VMWARE] = "vmware",
161 [VM_GUEST_KVM] = "kvm",
162 [VM_GUEST_BHYVE] = "bhyve",
163 [VM_GUEST_VBOX] = "vbox",
164 [VM_GUEST_PARALLELS] = "parallels",
165 [VM_GUEST_NVMM] = "nvmm",
166 [VM_LAST] = NULL
167 };
168 CTASSERT(nitems(vm_guest_sysctl_names) - 1 == VM_LAST);
169
170 /*
171 * Boot time overrides that are not scaled against main memory
172 */
173 void
init_param1(void)174 init_param1(void)
175 {
176
177 TSENTER();
178
179 /*
180 * arm64 and riscv currently hard-code the thread0 kstack size
181 * to KSTACK_PAGES, ignoring the tunable.
182 */
183 #if !defined(__mips__)
184 TUNABLE_INT_FETCH("kern.kstack_pages", &kstack_pages);
185 #endif
186
187 hz = -1;
188 TUNABLE_INT_FETCH("kern.hz", &hz);
189 if (hz == -1)
190 hz = vm_guest > VM_GUEST_NO ? HZ_VM : HZ;
191
192 /* range check the "hz" value */
193 if (__predict_false(hz < HZ_MINIMUM))
194 hz = HZ_MINIMUM;
195 else if (__predict_false(hz > HZ_MAXIMUM))
196 hz = HZ_MAXIMUM;
197
198 tick = 1000000 / hz;
199 tick_sbt = SBT_1S / hz;
200 tick_bt = sbttobt(tick_sbt);
201 tick_seconds_max = INT_MAX / hz;
202
203 /*
204 * Arrange for ticks to wrap 10 minutes after boot to help catch
205 * sign problems sooner.
206 */
207 ticks = INT_MAX - (hz * 10 * 60);
208
209 vn_lock_pair_pause_max = hz / 100;
210 if (vn_lock_pair_pause_max == 0)
211 vn_lock_pair_pause_max = 1;
212
213 #ifdef VM_SWZONE_SIZE_MAX
214 maxswzone = VM_SWZONE_SIZE_MAX;
215 #endif
216 TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone);
217 #ifdef VM_BCACHE_SIZE_MAX
218 maxbcache = VM_BCACHE_SIZE_MAX;
219 #endif
220 TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache);
221 msgbufsize = MSGBUF_SIZE;
222 TUNABLE_INT_FETCH("kern.msgbufsize", &msgbufsize);
223
224 maxtsiz = MAXTSIZ;
225 TUNABLE_ULONG_FETCH("kern.maxtsiz", &maxtsiz);
226 dfldsiz = DFLDSIZ;
227 TUNABLE_ULONG_FETCH("kern.dfldsiz", &dfldsiz);
228 maxdsiz = MAXDSIZ;
229 TUNABLE_ULONG_FETCH("kern.maxdsiz", &maxdsiz);
230 dflssiz = DFLSSIZ;
231 TUNABLE_ULONG_FETCH("kern.dflssiz", &dflssiz);
232 maxssiz = MAXSSIZ;
233 TUNABLE_ULONG_FETCH("kern.maxssiz", &maxssiz);
234 sgrowsiz = SGROWSIZ;
235 TUNABLE_ULONG_FETCH("kern.sgrowsiz", &sgrowsiz);
236
237 /*
238 * Let the administrator set {NGROUPS_MAX}.
239 *
240 * Values less than NGROUPS_MAX would violate POSIX/SuS (see the
241 * specification for <limits.h>, paragraph "Runtime Increasable
242 * Values").
243 *
244 * On the other hand, INT_MAX would result in an overflow for the common
245 * 'ngroups_max + 1' computation (to obtain the size of the internal
246 * groups array, its first element being reserved for the effective
247 * GID). Also, the number of allocated bytes for the group array must
248 * not overflow on 32-bit machines. For all these reasons, we limit the
249 * number of supplementary groups to some very high number that we
250 * expect will never be reached in all practical uses and ensures we
251 * avoid the problems just exposed, even if 'gid_t' was to be enlarged
252 * by a magnitude.
253 */
254 ngroups_max = NGROUPS_MAX;
255 TUNABLE_INT_FETCH("kern.ngroups", &ngroups_max);
256 if (ngroups_max < NGROUPS_MAX)
257 ngroups_max = NGROUPS_MAX;
258 else {
259 const int ngroups_max_max = (1 << 24) - 1;
260
261 if (ngroups_max > ngroups_max_max)
262 ngroups_max = ngroups_max_max;
263 }
264
265 /*
266 * Only allow to lower the maximal pid.
267 * Prevent setting up a non-bootable system if pid_max is too low.
268 */
269 TUNABLE_INT_FETCH("kern.pid_max", &pid_max);
270 if (pid_max > PID_MAX)
271 pid_max = PID_MAX;
272 else if (pid_max < 300)
273 pid_max = 300;
274
275 TUNABLE_INT_FETCH("vfs.unmapped_buf_allowed", &unmapped_buf_allowed);
276 }
277
278 /*
279 * Boot time overrides that are scaled against main memory
280 */
281 void
init_param2(long physpages)282 init_param2(long physpages)
283 {
284
285 /* Base parameters */
286 maxusers = MAXUSERS;
287 TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
288 if (maxusers == 0) {
289 maxusers = physpages / (2 * 1024 * 1024 / PAGE_SIZE);
290 if (maxusers < 32)
291 maxusers = 32;
292 #ifdef VM_MAX_AUTOTUNE_MAXUSERS
293 if (maxusers > VM_MAX_AUTOTUNE_MAXUSERS)
294 maxusers = VM_MAX_AUTOTUNE_MAXUSERS;
295 #endif
296 /*
297 * Scales down the function in which maxusers grows once
298 * we hit 384.
299 */
300 if (maxusers > 384)
301 maxusers = 384 + ((maxusers - 384) / 8);
302 }
303
304 /*
305 * The following can be overridden after boot via sysctl. Note:
306 * unless overridden, these macros are ultimately based on maxusers.
307 * Limit maxproc so that kmap entries cannot be exhausted by
308 * processes.
309 */
310 maxproc = NPROC;
311 TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
312 if (maxproc > (physpages / 12))
313 maxproc = physpages / 12;
314 if (maxproc > pid_max)
315 maxproc = pid_max;
316 maxprocperuid = (maxproc * 9) / 10;
317
318 /*
319 * The default limit for maxfiles is 1/12 of the number of
320 * physical page but not less than 16 times maxusers.
321 * At most it can be 1/6 the number of physical pages.
322 */
323 maxfiles = imax(MAXFILES, physpages / 8);
324 TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
325 if (maxfiles > (physpages / 4))
326 maxfiles = physpages / 4;
327 maxfilesperproc = (maxfiles / 10) * 9;
328 TUNABLE_INT_FETCH("kern.maxfilesperproc", &maxfilesperproc);
329
330 /*
331 * Cannot be changed after boot.
332 */
333 nbuf = NBUF;
334 TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
335 TUNABLE_INT_FETCH("kern.bio_transient_maxcnt", &bio_transient_maxcnt);
336 maxphys = MAXPHYS;
337 TUNABLE_ULONG_FETCH("kern.maxphys", &maxphys);
338 if (maxphys == 0) {
339 maxphys = MAXPHYS;
340 } else if (__bitcountl(maxphys) != 1) { /* power of two */
341 if (flsl(maxphys) == NBBY * sizeof(maxphys))
342 maxphys = MAXPHYS;
343 else
344 maxphys = 1UL << flsl(maxphys);
345 }
346 if (maxphys < PAGE_SIZE)
347 maxphys = MAXPHYS;
348
349 /*
350 * Physical buffers are pre-allocated buffers (struct buf) that
351 * are used as temporary holders for I/O, such as paging I/O.
352 */
353 TUNABLE_INT_FETCH("kern.nswbuf", &nswbuf);
354
355 /*
356 * The default for maxpipekva is min(1/64 of the kernel address space,
357 * max(1/64 of main memory, 512KB)). See sys_pipe.c for more details.
358 */
359 maxpipekva = ptoa(physpages / 64);
360 TUNABLE_LONG_FETCH("kern.ipc.maxpipekva", &maxpipekva);
361 if (maxpipekva < 512 * 1024)
362 maxpipekva = 512 * 1024;
363 if (maxpipekva > (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / 64)
364 maxpipekva = (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) /
365 64;
366 }
367
368 /*
369 * Sysctl stringifying handler for kern.vm_guest.
370 */
371 static int
sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)372 sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)
373 {
374 return (SYSCTL_OUT_STR(req, vm_guest_sysctl_names[vm_guest]));
375 }
376