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34 * @(#)param.c 8.3 (Berkeley) 8/20/94
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
40 #include "opt_param.h"
41 #include "opt_msgbuf.h"
42 #include "opt_maxusers.h"
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kernel.h>
47 #include <sys/limits.h>
48 #include <sys/msgbuf.h>
49 #include <sys/sysctl.h>
53 #include <vm/vm_param.h>
57 * System parameter formulae.
61 # if defined(__mips__) || defined(__arm__)
74 #define NPROC (20 + 16 * maxusers)
79 #define MAXFILES (maxproc * 2)
82 static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
86 int maxusers; /* base tunable */
87 int maxproc; /* maximum # of processes */
88 int maxprocperuid; /* max # of procs per user */
89 int maxfiles; /* sys. wide open files limit */
90 int maxfilesperproc; /* per-proc open files limit */
91 int msgbufsize; /* size of kernel message buffer */
92 int ncallout; /* maximum # of timer events */
94 int bio_transient_maxcnt;
95 int ngroups_max; /* max # groups per process */
97 pid_t pid_max = PID_MAX;
98 long maxswzone; /* max swmeta KVA storage */
99 long maxbcache; /* max buffer cache KVA storage */
100 long maxpipekva; /* Limit on pipe KVA */
101 int vm_guest; /* Running as virtual machine guest? */
102 u_long maxtsiz; /* max text size */
103 u_long dfldsiz; /* initial data size limit */
104 u_long maxdsiz; /* max data size */
105 u_long dflssiz; /* initial stack size limit */
106 u_long maxssiz; /* max stack size */
107 u_long sgrowsiz; /* amount to grow stack */
109 SYSCTL_INT(_kern, OID_AUTO, hz, CTLFLAG_RDTUN, &hz, 0,
110 "Number of clock ticks per second");
111 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN, &ncallout, 0,
112 "Number of pre-allocated timer events");
113 SYSCTL_INT(_kern, OID_AUTO, nbuf, CTLFLAG_RDTUN, &nbuf, 0,
114 "Number of buffers in the buffer cache");
115 SYSCTL_INT(_kern, OID_AUTO, nswbuf, CTLFLAG_RDTUN, &nswbuf, 0,
116 "Number of swap buffers");
117 SYSCTL_INT(_kern, OID_AUTO, msgbufsize, CTLFLAG_RDTUN, &msgbufsize, 0,
118 "Size of the kernel message buffer");
119 SYSCTL_LONG(_kern, OID_AUTO, maxswzone, CTLFLAG_RDTUN, &maxswzone, 0,
120 "Maximum memory for swap metadata");
121 SYSCTL_LONG(_kern, OID_AUTO, maxbcache, CTLFLAG_RDTUN, &maxbcache, 0,
122 "Maximum value of vfs.maxbufspace");
123 SYSCTL_INT(_kern, OID_AUTO, bio_transient_maxcnt, CTLFLAG_RDTUN,
124 &bio_transient_maxcnt, 0,
125 "Maximum number of transient BIOs mappings");
126 SYSCTL_ULONG(_kern, OID_AUTO, maxtsiz, CTLFLAG_RW | CTLFLAG_TUN, &maxtsiz, 0,
127 "Maximum text size");
128 SYSCTL_ULONG(_kern, OID_AUTO, dfldsiz, CTLFLAG_RW | CTLFLAG_TUN, &dfldsiz, 0,
129 "Initial data size limit");
130 SYSCTL_ULONG(_kern, OID_AUTO, maxdsiz, CTLFLAG_RW | CTLFLAG_TUN, &maxdsiz, 0,
131 "Maximum data size");
132 SYSCTL_ULONG(_kern, OID_AUTO, dflssiz, CTLFLAG_RW | CTLFLAG_TUN, &dflssiz, 0,
133 "Initial stack size limit");
134 SYSCTL_ULONG(_kern, OID_AUTO, maxssiz, CTLFLAG_RW | CTLFLAG_TUN, &maxssiz, 0,
135 "Maximum stack size");
136 SYSCTL_ULONG(_kern, OID_AUTO, sgrowsiz, CTLFLAG_RW | CTLFLAG_TUN, &sgrowsiz, 0,
137 "Amount to grow stack on a stack fault");
138 SYSCTL_PROC(_kern, OID_AUTO, vm_guest, CTLFLAG_RD | CTLTYPE_STRING,
139 NULL, 0, sysctl_kern_vm_guest, "A",
140 "Virtual machine guest detected? (none|generic|xen)");
143 * These have to be allocated somewhere; allocating
144 * them here forces loader errors if this file is omitted
145 * (if they've been externed everywhere else; hah!).
150 * The elements of this array are ordered based upon the values of the
151 * corresponding enum VM_GUEST members.
153 static const char *const vm_guest_sysctl_names[] = {
161 static const char *const vm_bnames[] = {
163 "Plex86", /* Plex86 */
171 static const char *const vm_pnames[] = {
172 "VMware Virtual Platform", /* VMWare VM */
173 "Virtual Machine", /* Microsoft VirtualPC */
174 "VirtualBox", /* Sun xVM VirtualBox */
175 "Parallels Virtual Platform", /* Parallels VM */
182 * Detect known Virtual Machine hosts by inspecting the emulated BIOS.
190 sysenv = getenv("smbios.bios.vendor");
191 if (sysenv != NULL) {
192 for (i = 0; vm_bnames[i] != NULL; i++)
193 if (strcmp(sysenv, vm_bnames[i]) == 0) {
195 return (VM_GUEST_VM);
199 sysenv = getenv("smbios.system.product");
200 if (sysenv != NULL) {
201 for (i = 0; vm_pnames[i] != NULL; i++)
202 if (strcmp(sysenv, vm_pnames[i]) == 0) {
204 return (VM_GUEST_VM);
208 return (VM_GUEST_NO);
213 * Boot time overrides that are not scaled against main memory
219 vm_guest = detect_virtual();
221 vm_guest = VM_GUEST_XEN;
224 TUNABLE_INT_FETCH("kern.hz", &hz);
226 hz = vm_guest > VM_GUEST_NO ? HZ_VM : HZ;
229 #ifdef VM_SWZONE_SIZE_MAX
230 maxswzone = VM_SWZONE_SIZE_MAX;
232 TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone);
233 #ifdef VM_BCACHE_SIZE_MAX
234 maxbcache = VM_BCACHE_SIZE_MAX;
236 TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache);
237 msgbufsize = MSGBUF_SIZE;
238 TUNABLE_INT_FETCH("kern.msgbufsize", &msgbufsize);
241 TUNABLE_ULONG_FETCH("kern.maxtsiz", &maxtsiz);
243 TUNABLE_ULONG_FETCH("kern.dfldsiz", &dfldsiz);
245 TUNABLE_ULONG_FETCH("kern.maxdsiz", &maxdsiz);
247 TUNABLE_ULONG_FETCH("kern.dflssiz", &dflssiz);
249 TUNABLE_ULONG_FETCH("kern.maxssiz", &maxssiz);
251 TUNABLE_ULONG_FETCH("kern.sgrowsiz", &sgrowsiz);
254 * Let the administrator set {NGROUPS_MAX}, but disallow values
255 * less than NGROUPS_MAX which would violate POSIX.1-2008 or
256 * greater than INT_MAX-1 which would result in overflow.
258 ngroups_max = NGROUPS_MAX;
259 TUNABLE_INT_FETCH("kern.ngroups", &ngroups_max);
260 if (ngroups_max < NGROUPS_MAX)
261 ngroups_max = NGROUPS_MAX;
264 * Only allow to lower the maximal pid.
265 * Prevent setting up a non-bootable system if pid_max is too low.
267 TUNABLE_INT_FETCH("kern.pid_max", &pid_max);
268 if (pid_max > PID_MAX)
270 else if (pid_max < 300)
273 TUNABLE_INT_FETCH("vfs.unmapped_buf_allowed", &unmapped_buf_allowed);
277 * Boot time overrides that are scaled against main memory
280 init_param2(long physpages)
283 /* Base parameters */
285 TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
287 maxusers = physpages / (2 * 1024 * 1024 / PAGE_SIZE);
295 * The following can be overridden after boot via sysctl. Note:
296 * unless overriden, these macros are ultimately based on maxusers.
299 TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
301 * Limit maxproc so that kmap entries cannot be exhausted by
304 if (maxproc > (physpages / 12))
305 maxproc = physpages / 12;
307 TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
308 maxprocperuid = (maxproc * 9) / 10;
309 maxfilesperproc = (maxfiles * 9) / 10;
312 * Cannot be changed after boot.
315 TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
316 TUNABLE_INT_FETCH("kern.bio_transient_maxcnt", &bio_transient_maxcnt);
318 ncallout = 16 + maxproc + maxfiles;
319 TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
322 * The default for maxpipekva is min(1/64 of the kernel address space,
323 * max(1/64 of main memory, 512KB)). See sys_pipe.c for more details.
325 maxpipekva = (physpages / 64) * PAGE_SIZE;
326 if (maxpipekva < 512 * 1024)
327 maxpipekva = 512 * 1024;
328 if (maxpipekva > (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / 64)
329 maxpipekva = (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) /
331 TUNABLE_LONG_FETCH("kern.ipc.maxpipekva", &maxpipekva);
335 * Sysctl stringiying handler for kern.vm_guest.
338 sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)
340 return (SYSCTL_OUT(req, vm_guest_sysctl_names[vm_guest],
341 strlen(vm_guest_sysctl_names[vm_guest])));