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. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. 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
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/5.2/sys/kern/subr_param.c 118764 2003-08-11 05:51:51Z silby $");
    
    #include "opt_param.h"
    #include "opt_maxusers.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.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 * 2)
    #endif
    
    int     hz;
    int     tick;
    int     maxusers;                       /* base tunable */
    int     maxproc;                        /* maximum # of processes */
    int     maxprocperuid;                  /* max # of procs per user */
    int     maxfiles;                       /* sys. wide open files limit */
    int     maxfilesperproc;                /* per-proc open files limit */
    int     ncallout;                       /* maximum # of timer events */
    int     nbuf;
    int     nswbuf;
    int     maxswzone;                      /* max swmeta KVA storage */
    int     maxbcache;                      /* max buffer cache KVA storage */
    int     maxpipekva;                     /* Limit on pipe KVA */
    int     maxpipekvawired;                /* Limit on wired pipe KVA */
    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);
           tick = 1000000 / hz;
   
   #ifdef VM_SWZONE_SIZE_MAX
           maxswzone = VM_SWZONE_SIZE_MAX;
   #endif
           TUNABLE_INT_FETCH("kern.maxswzone", &maxswzone);
   #ifdef VM_BCACHE_SIZE_MAX
           maxbcache = VM_BCACHE_SIZE_MAX;
   #endif
           TUNABLE_INT_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(long physpages)
   {
   
           /* Base parameters */
           maxusers = MAXUSERS;
           TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
           if (maxusers == 0) {
                   maxusers = physpages / (2 * 1024 * 1024 / PAGE_SIZE);
                   if (maxusers < 32)
                           maxusers = 32;
                   if (maxusers > 384)
                           maxusers = 384;
           }
   
           /*
            * The following can be overridden after boot via sysctl.  Note:
            * unless overriden, these macros are ultimately based on maxusers.
            */
           maxproc = NPROC;
           TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
           /*
            * Limit maxproc so that kmap entries cannot be exhausted by
            * processes.
            */
           if (maxproc > (physpages / 12))
                   maxproc = physpages / 12;
           maxfiles = MAXFILES;
           TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
           maxprocperuid = (maxproc * 9) / 10;
           maxfilesperproc = (maxfiles * 9) / 10;
           
           /*
            * Cannot be changed after boot.
            */
           nbuf = NBUF;
           TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
   
           ncallout = 16 + maxproc + maxfiles;
           TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
   }
   
   /*
    * Boot time overrides that are scaled against the kernel map
    */
   void
   init_param3(long kmempages)
   {
           /*
            * Limit pageable pipe memory usage to 5% of the kernel map
            * (via pipe_map), and nonpageable pipe memory usage to 2.5%
            * of the same.  Ensure that all have reasonable floors.
            * (See sys_pipe.c for more info.)
            */
           maxpipekva = (kmempages / 20) * PAGE_SIZE;
           maxpipekvawired = (kmempages / 40) * PAGE_SIZE;
   
           if (maxpipekva < 512 * 1024)
                   maxpipekva = 512 * 1024;
           if (maxpipekvawired < 512 * 1024)
                   maxpipekvawired = 512 * 1024;
   
           TUNABLE_INT_FETCH("kern.ipc.maxpipekva", &maxpipekva);
   }

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