FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_param.c

     /*
      * Copyright (c) 1980, 1986, 1989, 1993
      *      The Regents of the University of California.  All rights reserved.
      * (c) UNIX System Laboratories, Inc.
      * All or some portions of this file are derived from material licensed
      * to the University of California by American Telephone and Telegraph
      * Co. or Unix System Laboratories, Inc. and are reproduced herein with
      * the permission of UNIX System Laboratories, Inc.
      *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)param.c     8.3 (Berkeley) 8/20/94
     * $FreeBSD: src/sys/kern/subr_param.c,v 1.42.2.10 2002/03/09 21:05:47 silby Exp $
     * $DragonFly: src/sys/kern/subr_param.c,v 1.7 2005/06/26 22:03:22 dillon Exp $
     */
    
    #include "opt_param.h"
    #include "opt_maxusers.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <vm/pmap.h>
    #include <machine/vmparam.h>
    
    /*
     * System parameter formulae.
     */
    
    #ifndef HZ
    #define HZ 100
    #endif
    #define NPROC (20 + 16 * maxusers)
    #ifndef NBUF
    #define NBUF 0
    #endif
    #ifndef MAXFILES
    #define MAXFILES (maxproc * 16)
    #endif
    #ifndef MAXPOSIXLOCKSPERUID
    #define MAXPOSIXLOCKSPERUID (maxusers * 64) /* Should be a safe value */
    #endif
    
    int     hz;
    int     stathz;
    int     profhz;
    int     ustick;                         /* tick interval in microseconds */
    int     nstick;                         /* tick interval in nanoseconds */
    int     maxusers;                       /* base tunable */
    int     maxproc;                        /* maximum # of processes */
    int     maxprocperuid;                  /* max # of procs per user */
    int     maxfiles;                       /* system wide open files limit */
    int     maxfilesrootres;                /* descriptors reserved for root use */
    int     minfilesperproc;                /* per-proc min open files (safety) */
    int     maxfilesperproc;                /* per-proc open files limit */
    int     maxfilesperuser;                /* per-user open files limit */
    int     maxposixlocksperuid;            /* max # POSIX locks per uid */
    int     ncallout;                       /* maximum # of timer events */
    int     mbuf_wait = 32;                 /* mbuf sleep time in ticks */
    long    nbuf;
    long    nswbuf;
    long    maxswzone;                      /* max swmeta KVA storage */
    long    maxbcache;                      /* max buffer cache KVA storage */
    int     vmm_guest = 0;                  /* Running as virtual machine guest? */
    u_quad_t        maxtsiz;                        /* max text size */
    u_quad_t        dfldsiz;                        /* initial data size limit */
    u_quad_t        maxdsiz;                        /* max data size */
    u_quad_t        dflssiz;                        /* initial stack size limit */
    u_quad_t        maxssiz;                        /* max stack size */
    u_quad_t        sgrowsiz;                       /* amount to grow stack */
    
    /*
     * These have to be allocated somewhere; allocating
     * them here forces loader errors if this file is omitted
     * (if they've been externed everywhere else; hah!).
     */
   struct  buf *swbuf;
   
   /*
    * Boot time overrides that are not scaled against main memory
    */
   void
   init_param1(void)
   {
           hz = HZ;
           TUNABLE_INT_FETCH("kern.hz", &hz);
           stathz = hz * 128 / 100;
           profhz = stathz;
           ustick = 1000000 / hz;
           nstick = 1000000000 / hz;
           /* can adjust 30ms in 60s */
           ntp_default_tick_delta = howmany(30000000, 60 * hz);
   
   #ifdef VM_SWZONE_SIZE_MAX
           maxswzone = VM_SWZONE_SIZE_MAX;
   #endif
           TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone);
   #ifdef VM_BCACHE_SIZE_MAX
           maxbcache = VM_BCACHE_SIZE_MAX;
   #endif
           TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache);
           maxtsiz = MAXTSIZ;
           TUNABLE_QUAD_FETCH("kern.maxtsiz", &maxtsiz);
           dfldsiz = DFLDSIZ;
           TUNABLE_QUAD_FETCH("kern.dfldsiz", &dfldsiz);
           maxdsiz = MAXDSIZ;
           TUNABLE_QUAD_FETCH("kern.maxdsiz", &maxdsiz);
           dflssiz = DFLSSIZ;
           TUNABLE_QUAD_FETCH("kern.dflssiz", &dflssiz);
           maxssiz = MAXSSIZ;
           TUNABLE_QUAD_FETCH("kern.maxssiz", &maxssiz);
           sgrowsiz = SGROWSIZ;
           TUNABLE_QUAD_FETCH("kern.sgrowsiz", &sgrowsiz);
   }
   
   /*
    * Boot time overrides that are scaled against main memory
    */
   void
   init_param2(int physpages)
   {
           size_t limsize;
   
           /*
            * Calculate manually becaus the VM page queues / system is not set up yet
            */
           limsize = (size_t)physpages * PAGE_SIZE;
           if (limsize > KvaSize)
                   limsize = KvaSize;
           limsize /= 1024 * 1024;         /* smaller of KVM or physmem in MB */
   
           /* Base parameters */
           maxusers = MAXUSERS;
           TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
           if (maxusers == 0) {
                   maxusers = limsize / 8;         /* ~384 per 3G */
                   if (maxusers < 32)
                           maxusers = 32;
                   /* no upper limit */
           }
   
           /*
            * The following can be overridden after boot via sysctl.  Note:
            * unless overriden, these macros are ultimately based on maxusers.
            *
            * Limit maxproc so that kmap entries cannot be exhausted by
            * processes.
            */
           maxproc = NPROC;
           TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
           if (maxproc < 32)
                   maxproc = 32;
           if (maxproc > limsize * 21)
                   maxproc = limsize * 21;
   
           /*
            * Maximum number of open files
            */
           maxfiles = MAXFILES;
           TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
           if (maxfiles < 128)
                   maxfiles = 128;
   
           /*
            * Limit file descriptors so no single user can exhaust the
            * system.
            *
            * WARNING: Do not set minfilesperproc too high or the user
            *          can exhaust the system with a combination of fork()
            *          and open().  Actual worst case is:
            *
            *          (minfilesperproc * maxprocperuid) + maxfilesperuser
            */
           maxprocperuid = maxproc / 4;
           if (maxprocperuid < 128)
                   maxprocperuid = maxproc / 2;
           minfilesperproc = 8;
           maxfilesperproc = maxfiles / 4;
           maxfilesperuser = maxfilesperproc * 2;
           maxfilesrootres = maxfiles / 20;
   
           /*
            * Severe hack to try to prevent pipe() descriptors from
            * blowing away kernel memory.
            */
           if (KvaSize <= (vm_offset_t)(1536LL * 1024 * 1024) &&
               maxfilesperuser > 20000) {
                   maxfilesperuser = 20000;
           }
   
           maxposixlocksperuid = MAXPOSIXLOCKSPERUID;
           TUNABLE_INT_FETCH("kern.maxposixlocksperuid", &maxposixlocksperuid);
   
           /*
            * Unless overriden, NBUF is typically 0 (auto-sized later).
            */
           nbuf = NBUF;
           TUNABLE_LONG_FETCH("kern.nbuf", &nbuf);
   
           ncallout = 16 + maxproc + maxfiles;
           TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
   }
   

Cache object: 7eb777fd1b6494e95b4794c9a4a40feb