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38 * @(#)param.c 8.3 (Berkeley) 8/20/94
39 * $FreeBSD: src/sys/kern/subr_param.c,v 1.42.2.10 2002/03/09 21:05:47 silby Exp $
40 * $DragonFly: src/sys/kern/subr_param.c,v 1.7 2005/06/26 22:03:22 dillon Exp $
43 #include "opt_param.h"
44 #include "opt_maxusers.h"
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/kernel.h>
50 #include <machine/vmparam.h>
53 * System parameter formulae.
59 #define NPROC (20 + 16 * maxusers)
64 #define MAXFILES (maxproc * 16)
66 #ifndef MAXPOSIXLOCKSPERUID
67 #define MAXPOSIXLOCKSPERUID (maxusers * 64) /* Should be a safe value */
73 int ustick
; /* tick interval in microseconds */
74 int nstick
; /* tick interval in nanoseconds */
75 int maxusers
; /* base tunable */
76 int maxproc
; /* maximum # of processes */
77 int maxprocperuid
; /* max # of procs per user */
78 int maxfiles
; /* system wide open files limit */
79 int maxfilesrootres
; /* descriptors reserved for root use */
80 int minfilesperproc
; /* per-proc min open files (safety) */
81 int maxfilesperproc
; /* per-proc open files limit */
82 int maxfilesperuser
; /* per-user open files limit */
83 int maxposixlocksperuid
; /* max # POSIX locks per uid */
84 int ncallout
; /* maximum # of timer events */
85 int mbuf_wait
= 32; /* mbuf sleep time in ticks */
88 long maxswzone
; /* max swmeta KVA storage */
89 long maxbcache
; /* max buffer cache KVA storage */
90 u_quad_t maxtsiz
; /* max text size */
91 u_quad_t dfldsiz
; /* initial data size limit */
92 u_quad_t maxdsiz
; /* max data size */
93 u_quad_t dflssiz
; /* initial stack size limit */
94 u_quad_t maxssiz
; /* max stack size */
95 u_quad_t sgrowsiz
; /* amount to grow stack */
98 * These have to be allocated somewhere; allocating
99 * them here forces loader errors if this file is omitted
100 * (if they've been externed everywhere else; hah!).
105 * Boot time overrides that are not scaled against main memory
111 TUNABLE_INT_FETCH("kern.hz", &hz
);
112 stathz
= hz
* 128 / 100;
114 ustick
= 1000000 / hz
;
115 nstick
= 1000000000 / hz
;
116 /* can adjust 30ms in 60s */
117 ntp_default_tick_delta
= howmany(30000000, 60 * hz
);
119 #ifdef VM_SWZONE_SIZE_MAX
120 maxswzone
= VM_SWZONE_SIZE_MAX
;
122 TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone
);
123 #ifdef VM_BCACHE_SIZE_MAX
124 maxbcache
= VM_BCACHE_SIZE_MAX
;
126 TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache
);
128 TUNABLE_QUAD_FETCH("kern.maxtsiz", &maxtsiz
);
130 TUNABLE_QUAD_FETCH("kern.dfldsiz", &dfldsiz
);
132 TUNABLE_QUAD_FETCH("kern.maxdsiz", &maxdsiz
);
134 TUNABLE_QUAD_FETCH("kern.dflssiz", &dflssiz
);
136 TUNABLE_QUAD_FETCH("kern.maxssiz", &maxssiz
);
138 TUNABLE_QUAD_FETCH("kern.sgrowsiz", &sgrowsiz
);
142 * Boot time overrides that are scaled against main memory
145 init_param2(int physpages
)
148 /* Base parameters */
150 TUNABLE_INT_FETCH("kern.maxusers", &maxusers
);
152 maxusers
= physpages
/ (2 * 1024 * 1024 / PAGE_SIZE
);
160 * The following can be overridden after boot via sysctl. Note:
161 * unless overriden, these macros are ultimately based on maxusers.
164 TUNABLE_INT_FETCH("kern.maxproc", &maxproc
);
167 * Limit maxproc so that kmap entries cannot be exhausted by
170 if (maxproc
> (physpages
/ 12))
171 maxproc
= physpages
/ 12;
173 TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles
);
178 * Limit file descriptors so no single user can exhaust the
181 * WARNING: Do not set minfilesperproc too high or the user
182 * can exhaust the system with a combination of fork()
183 * and open(). Actual worst case is:
185 * (minfilesperproc * maxprocperuid) + maxfilesperuser
187 maxprocperuid
= maxproc
/ 4;
188 if (maxprocperuid
< 128)
189 maxprocperuid
= maxproc
/ 2;
191 maxfilesperproc
= maxfiles
/ 4;
192 maxfilesperuser
= maxfilesperproc
* 2;
193 maxfilesrootres
= maxfiles
/ 20;
196 * Severe hack to try to prevent pipe() descriptors from
197 * blowing away kernel memory.
199 if (KvaSize
<= (vm_offset_t
)(1536LL * 1024 * 1024) &&
200 maxfilesperuser
> 20000) {
201 maxfilesperuser
= 20000;
204 maxposixlocksperuid
= MAXPOSIXLOCKSPERUID
;
205 TUNABLE_INT_FETCH("kern.maxposixlocksperuid", &maxposixlocksperuid
);
208 * Unless overriden, NBUF is typically 0 (auto-sized later).
211 TUNABLE_INT_FETCH("kern.nbuf", &nbuf
);
213 ncallout
= 16 + maxproc
+ maxfiles
;
214 TUNABLE_INT_FETCH("kern.ncallout", &ncallout
);