2 * SPDX-License-Identifier: BSD-3-Clause
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.
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
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.
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
36 * @(#)param.c 8.3 (Berkeley) 8/20/94
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
42 #include "opt_param.h"
43 #include "opt_msgbuf.h"
44 #include "opt_maxphys.h"
45 #include "opt_maxusers.h"
47 #include <sys/param.h>
48 #include <sys/systm.h>
50 #include <sys/kernel.h>
51 #include <sys/limits.h>
52 #include <sys/msgbuf.h>
53 #include <sys/sysctl.h>
55 #include <sys/vnode.h>
58 #include <vm/vm_param.h>
62 * System parameter formulae.
75 #define NPROC (20 + 16 * maxusers)
80 #define MAXFILES (40 + 32 * maxusers)
83 static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
85 int hz; /* system clock's frequency */
86 int tick; /* usec per tick (1000000 / hz) */
87 struct bintime tick_bt; /* bintime per tick (1s / hz) */
89 int maxusers; /* base tunable */
90 int maxproc; /* maximum # of processes */
91 int maxprocperuid; /* max # of procs per user */
92 int maxfiles; /* sys. wide open files limit */
93 int maxfilesperproc; /* per-proc open files limit */
94 int msgbufsize; /* size of kernel message buffer */
95 int nbuf; /* number of bcache bufs */
96 int bio_transient_maxcnt;
97 int ngroups_max; /* max # groups per process */
99 pid_t pid_max = PID_MAX;
100 u_long maxswzone; /* max swmeta KVA storage */
101 u_long maxbcache; /* max buffer cache KVA storage */
102 u_long maxpipekva; /* Limit on pipe KVA */
103 u_long maxphys; /* max raw I/O transfer size */
104 int vm_guest = VM_GUEST_NO; /* Running as virtual machine guest? */
105 u_long maxtsiz; /* max text size */
106 u_long dfldsiz; /* initial data size limit */
107 u_long maxdsiz; /* max data size */
108 u_long dflssiz; /* initial stack size limit */
109 u_long maxssiz; /* max stack size */
110 u_long sgrowsiz; /* amount to grow stack */
112 SYSCTL_INT(_kern, OID_AUTO, hz, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &hz, 0,
113 "Number of clock ticks per second");
114 SYSCTL_INT(_kern, OID_AUTO, nbuf, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &nbuf, 0,
115 "Number of buffers in the buffer cache");
116 SYSCTL_INT(_kern, OID_AUTO, nswbuf, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &nswbuf, 0,
117 "Number of swap buffers");
118 SYSCTL_INT(_kern, OID_AUTO, msgbufsize, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &msgbufsize, 0,
119 "Size of the kernel message buffer");
120 SYSCTL_LONG(_kern, OID_AUTO, maxswzone, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &maxswzone, 0,
121 "Maximum memory for swap metadata");
122 SYSCTL_LONG(_kern, OID_AUTO, maxbcache, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &maxbcache, 0,
123 "Maximum value of vfs.maxbufspace");
124 SYSCTL_INT(_kern, OID_AUTO, bio_transient_maxcnt, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
125 &bio_transient_maxcnt, 0,
126 "Maximum number of transient BIOs mappings");
127 SYSCTL_ULONG(_kern, OID_AUTO, maxtsiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &maxtsiz, 0,
128 "Maximum text size");
129 SYSCTL_ULONG(_kern, OID_AUTO, dfldsiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &dfldsiz, 0,
130 "Initial data size limit");
131 SYSCTL_ULONG(_kern, OID_AUTO, maxdsiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &maxdsiz, 0,
132 "Maximum data size");
133 SYSCTL_ULONG(_kern, OID_AUTO, dflssiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &dflssiz, 0,
134 "Initial stack size limit");
135 SYSCTL_ULONG(_kern, OID_AUTO, maxssiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &maxssiz, 0,
136 "Maximum stack size");
137 SYSCTL_ULONG(_kern, OID_AUTO, sgrowsiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &sgrowsiz, 0,
138 "Amount to grow stack on a stack fault");
139 SYSCTL_PROC(_kern, OID_AUTO, vm_guest,
140 CTLFLAG_RD | CTLTYPE_STRING | CTLFLAG_MPSAFE, NULL, 0,
141 sysctl_kern_vm_guest, "A",
142 "Virtual machine guest detected?");
145 * The elements of this array are ordered based upon the values of the
146 * corresponding enum VM_GUEST members.
148 static const char *const vm_guest_sysctl_names[] = {
149 [VM_GUEST_NO] = "none",
150 [VM_GUEST_VM] = "generic",
151 [VM_GUEST_XEN] = "xen",
152 [VM_GUEST_HV] = "hv",
153 [VM_GUEST_VMWARE] = "vmware",
154 [VM_GUEST_KVM] = "kvm",
155 [VM_GUEST_BHYVE] = "bhyve",
156 [VM_GUEST_VBOX] = "vbox",
157 [VM_GUEST_PARALLELS] = "parallels",
160 CTASSERT(nitems(vm_guest_sysctl_names) - 1 == VM_LAST);
163 * Boot time overrides that are not scaled against main memory
169 #if !defined(__mips__) && !defined(__arm64__)
170 TUNABLE_INT_FETCH("kern.kstack_pages", &kstack_pages);
173 TUNABLE_INT_FETCH("kern.hz", &hz);
175 hz = vm_guest > VM_GUEST_NO ? HZ_VM : HZ;
177 tick_sbt = SBT_1S / hz;
178 tick_bt = sbttobt(tick_sbt);
181 * Arrange for ticks to wrap 10 minutes after boot to help catch
182 * sign problems sooner.
184 ticks = INT_MAX - (hz * 10 * 60);
186 vn_lock_pair_pause_max = hz / 100;
187 if (vn_lock_pair_pause_max == 0)
188 vn_lock_pair_pause_max = 1;
190 #ifdef VM_SWZONE_SIZE_MAX
191 maxswzone = VM_SWZONE_SIZE_MAX;
193 TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone);
194 #ifdef VM_BCACHE_SIZE_MAX
195 maxbcache = VM_BCACHE_SIZE_MAX;
197 TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache);
198 msgbufsize = MSGBUF_SIZE;
199 TUNABLE_INT_FETCH("kern.msgbufsize", &msgbufsize);
202 TUNABLE_ULONG_FETCH("kern.maxtsiz", &maxtsiz);
204 TUNABLE_ULONG_FETCH("kern.dfldsiz", &dfldsiz);
206 TUNABLE_ULONG_FETCH("kern.maxdsiz", &maxdsiz);
208 TUNABLE_ULONG_FETCH("kern.dflssiz", &dflssiz);
210 TUNABLE_ULONG_FETCH("kern.maxssiz", &maxssiz);
212 TUNABLE_ULONG_FETCH("kern.sgrowsiz", &sgrowsiz);
215 * Let the administrator set {NGROUPS_MAX}, but disallow values
216 * less than NGROUPS_MAX which would violate POSIX.1-2008 or
217 * greater than INT_MAX-1 which would result in overflow.
219 ngroups_max = NGROUPS_MAX;
220 TUNABLE_INT_FETCH("kern.ngroups", &ngroups_max);
221 if (ngroups_max < NGROUPS_MAX)
222 ngroups_max = NGROUPS_MAX;
225 * Only allow to lower the maximal pid.
226 * Prevent setting up a non-bootable system if pid_max is too low.
228 TUNABLE_INT_FETCH("kern.pid_max", &pid_max);
229 if (pid_max > PID_MAX)
231 else if (pid_max < 300)
234 TUNABLE_INT_FETCH("vfs.unmapped_buf_allowed", &unmapped_buf_allowed);
238 * Boot time overrides that are scaled against main memory
241 init_param2(long physpages)
244 /* Base parameters */
246 TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
248 maxusers = physpages / (2 * 1024 * 1024 / PAGE_SIZE);
251 #ifdef VM_MAX_AUTOTUNE_MAXUSERS
252 if (maxusers > VM_MAX_AUTOTUNE_MAXUSERS)
253 maxusers = VM_MAX_AUTOTUNE_MAXUSERS;
256 * Scales down the function in which maxusers grows once
260 maxusers = 384 + ((maxusers - 384) / 8);
264 * The following can be overridden after boot via sysctl. Note:
265 * unless overriden, these macros are ultimately based on maxusers.
266 * Limit maxproc so that kmap entries cannot be exhausted by
270 TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
271 if (maxproc > (physpages / 12))
272 maxproc = physpages / 12;
273 if (maxproc > pid_max)
275 maxprocperuid = (maxproc * 9) / 10;
278 * The default limit for maxfiles is 1/12 of the number of
279 * physical page but not less than 16 times maxusers.
280 * At most it can be 1/6 the number of physical pages.
282 maxfiles = imax(MAXFILES, physpages / 8);
283 TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
284 if (maxfiles > (physpages / 4))
285 maxfiles = physpages / 4;
286 maxfilesperproc = (maxfiles / 10) * 9;
287 TUNABLE_INT_FETCH("kern.maxfilesperproc", &maxfilesperproc);
290 * Cannot be changed after boot.
293 TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
294 TUNABLE_INT_FETCH("kern.bio_transient_maxcnt", &bio_transient_maxcnt);
296 TUNABLE_ULONG_FETCH("kern.maxphys", &maxphys);
299 } else if (__bitcountl(maxphys) != 1) { /* power of two */
300 if (flsl(maxphys) == NBBY * sizeof(maxphys))
303 maxphys = 1UL << flsl(maxphys);
305 if (maxphys < PAGE_SIZE)
309 * Physical buffers are pre-allocated buffers (struct buf) that
310 * are used as temporary holders for I/O, such as paging I/O.
312 TUNABLE_INT_FETCH("kern.nswbuf", &nswbuf);
315 * The default for maxpipekva is min(1/64 of the kernel address space,
316 * max(1/64 of main memory, 512KB)). See sys_pipe.c for more details.
318 maxpipekva = ptoa(physpages / 64);
319 TUNABLE_LONG_FETCH("kern.ipc.maxpipekva", &maxpipekva);
320 if (maxpipekva < 512 * 1024)
321 maxpipekva = 512 * 1024;
322 if (maxpipekva > (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / 64)
323 maxpipekva = (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) /
328 * Sysctl stringifying handler for kern.vm_guest.
331 sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)
333 return (SYSCTL_OUT_STR(req, vm_guest_sysctl_names[vm_guest]));