freebsd-nq/sys/kern/subr_param.c
Hans Petter Selasky 35a33d14b5 time(3): Optimize tvtohz() function.
List of changes:
- Use integer multiplication instead of long multiplication, because the result is an integer.
- Remove multiple if-statements and predict new if-statements.
- Rename local variable name, "ticks" into "retval" to avoid shadowing
the system "ticks" global variable.

Reviewed by:	kib@ and imp@
MFC after:	1 week
Sponsored by:	NVIDIA Networking
Differential Revision:  https://reviews.freebsd.org/D36859
2022-10-23 10:04:50 +02:00

348 lines
11 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* 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
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_param.h"
#include "opt_msgbuf.h"
#include "opt_maxphys.h"
#include "opt_maxusers.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/msgbuf.h>
#include <sys/sysctl.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
/*
* System parameter formulae.
*/
#ifndef HZ
# define HZ 1000
# ifndef HZ_VM
# define HZ_VM 100
# endif
#else
# ifndef HZ_VM
# define HZ_VM HZ
# endif
#endif
#define NPROC (20 + 16 * maxusers)
#ifndef NBUF
#define NBUF 0
#endif
#ifndef MAXFILES
#define MAXFILES (40 + 32 * maxusers)
#endif
static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
int hz; /* system clock's frequency */
int tick; /* usec per tick (1000000 / hz) */
time_t tick_seconds_max; /* max hz * seconds an integer can hold */
struct bintime tick_bt; /* bintime per tick (1s / hz) */
sbintime_t tick_sbt;
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 msgbufsize; /* size of kernel message buffer */
int nbuf; /* number of bcache bufs */
int bio_transient_maxcnt;
int ngroups_max; /* max # groups per process */
int nswbuf;
pid_t pid_max = PID_MAX;
u_long maxswzone; /* max swmeta KVA storage */
u_long maxbcache; /* max buffer cache KVA storage */
u_long maxpipekva; /* Limit on pipe KVA */
u_long maxphys; /* max raw I/O transfer size */
int vm_guest = VM_GUEST_NO; /* Running as virtual machine guest? */
u_long maxtsiz; /* max text size */
u_long dfldsiz; /* initial data size limit */
u_long maxdsiz; /* max data size */
u_long dflssiz; /* initial stack size limit */
u_long maxssiz; /* max stack size */
u_long sgrowsiz; /* amount to grow stack */
SYSCTL_INT(_kern, OID_AUTO, hz, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &hz, 0,
"Number of clock ticks per second");
SYSCTL_INT(_kern, OID_AUTO, hz_max, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, HZ_MAXIMUM,
"Maximum hz value supported");
SYSCTL_INT(_kern, OID_AUTO, hz_min, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, HZ_MINIMUM,
"Minimum hz value supported");
SYSCTL_INT(_kern, OID_AUTO, nbuf, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &nbuf, 0,
"Number of buffers in the buffer cache");
SYSCTL_INT(_kern, OID_AUTO, nswbuf, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &nswbuf, 0,
"Number of swap buffers");
SYSCTL_INT(_kern, OID_AUTO, msgbufsize, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &msgbufsize, 0,
"Size of the kernel message buffer");
SYSCTL_LONG(_kern, OID_AUTO, maxswzone, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &maxswzone, 0,
"Maximum memory for swap metadata");
SYSCTL_LONG(_kern, OID_AUTO, maxbcache, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &maxbcache, 0,
"Maximum value of vfs.maxbufspace");
SYSCTL_INT(_kern, OID_AUTO, bio_transient_maxcnt, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
&bio_transient_maxcnt, 0,
"Maximum number of transient BIOs mappings");
SYSCTL_ULONG(_kern, OID_AUTO, maxtsiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &maxtsiz, 0,
"Maximum text size");
SYSCTL_ULONG(_kern, OID_AUTO, dfldsiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &dfldsiz, 0,
"Initial data size limit");
SYSCTL_ULONG(_kern, OID_AUTO, maxdsiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &maxdsiz, 0,
"Maximum data size");
SYSCTL_ULONG(_kern, OID_AUTO, dflssiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &dflssiz, 0,
"Initial stack size limit");
SYSCTL_ULONG(_kern, OID_AUTO, maxssiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &maxssiz, 0,
"Maximum stack size");
SYSCTL_ULONG(_kern, OID_AUTO, sgrowsiz, CTLFLAG_RWTUN | CTLFLAG_NOFETCH, &sgrowsiz, 0,
"Amount to grow stack on a stack fault");
SYSCTL_PROC(_kern, OID_AUTO, vm_guest,
CTLFLAG_RD | CTLTYPE_STRING | CTLFLAG_MPSAFE, NULL, 0,
sysctl_kern_vm_guest, "A",
"Virtual machine guest detected?");
/*
* The elements of this array are ordered based upon the values of the
* corresponding enum VM_GUEST members.
*/
static const char *const vm_guest_sysctl_names[] = {
[VM_GUEST_NO] = "none",
[VM_GUEST_VM] = "generic",
[VM_GUEST_XEN] = "xen",
[VM_GUEST_HV] = "hv",
[VM_GUEST_VMWARE] = "vmware",
[VM_GUEST_KVM] = "kvm",
[VM_GUEST_BHYVE] = "bhyve",
[VM_GUEST_VBOX] = "vbox",
[VM_GUEST_PARALLELS] = "parallels",
[VM_LAST] = NULL
};
CTASSERT(nitems(vm_guest_sysctl_names) - 1 == VM_LAST);
/*
* Boot time overrides that are not scaled against main memory
*/
void
init_param1(void)
{
#if !defined(__mips__) && !defined(__arm64__)
TUNABLE_INT_FETCH("kern.kstack_pages", &kstack_pages);
#endif
hz = -1;
TUNABLE_INT_FETCH("kern.hz", &hz);
if (hz == -1)
hz = vm_guest > VM_GUEST_NO ? HZ_VM : HZ;
/* range check the "hz" value */
if (__predict_false(hz < HZ_MINIMUM))
hz = HZ_MINIMUM;
else if (__predict_false(hz > HZ_MAXIMUM))
hz = HZ_MAXIMUM;
tick = 1000000 / hz;
tick_sbt = SBT_1S / hz;
tick_bt = sbttobt(tick_sbt);
tick_seconds_max = INT_MAX / hz;
/*
* Arrange for ticks to wrap 10 minutes after boot to help catch
* sign problems sooner.
*/
ticks = INT_MAX - (hz * 10 * 60);
vn_lock_pair_pause_max = hz / 100;
if (vn_lock_pair_pause_max == 0)
vn_lock_pair_pause_max = 1;
#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);
msgbufsize = MSGBUF_SIZE;
TUNABLE_INT_FETCH("kern.msgbufsize", &msgbufsize);
maxtsiz = MAXTSIZ;
TUNABLE_ULONG_FETCH("kern.maxtsiz", &maxtsiz);
dfldsiz = DFLDSIZ;
TUNABLE_ULONG_FETCH("kern.dfldsiz", &dfldsiz);
maxdsiz = MAXDSIZ;
TUNABLE_ULONG_FETCH("kern.maxdsiz", &maxdsiz);
dflssiz = DFLSSIZ;
TUNABLE_ULONG_FETCH("kern.dflssiz", &dflssiz);
maxssiz = MAXSSIZ;
TUNABLE_ULONG_FETCH("kern.maxssiz", &maxssiz);
sgrowsiz = SGROWSIZ;
TUNABLE_ULONG_FETCH("kern.sgrowsiz", &sgrowsiz);
/*
* Let the administrator set {NGROUPS_MAX}, but disallow values
* less than NGROUPS_MAX which would violate POSIX.1-2008 or
* greater than INT_MAX-1 which would result in overflow.
*/
ngroups_max = NGROUPS_MAX;
TUNABLE_INT_FETCH("kern.ngroups", &ngroups_max);
if (ngroups_max < NGROUPS_MAX)
ngroups_max = NGROUPS_MAX;
/*
* Only allow to lower the maximal pid.
* Prevent setting up a non-bootable system if pid_max is too low.
*/
TUNABLE_INT_FETCH("kern.pid_max", &pid_max);
if (pid_max > PID_MAX)
pid_max = PID_MAX;
else if (pid_max < 300)
pid_max = 300;
TUNABLE_INT_FETCH("vfs.unmapped_buf_allowed", &unmapped_buf_allowed);
}
/*
* 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;
#ifdef VM_MAX_AUTOTUNE_MAXUSERS
if (maxusers > VM_MAX_AUTOTUNE_MAXUSERS)
maxusers = VM_MAX_AUTOTUNE_MAXUSERS;
#endif
/*
* Scales down the function in which maxusers grows once
* we hit 384.
*/
if (maxusers > 384)
maxusers = 384 + ((maxusers - 384) / 8);
}
/*
* The following can be overridden after boot via sysctl. Note:
* unless overridden, 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 > (physpages / 12))
maxproc = physpages / 12;
if (maxproc > pid_max)
maxproc = pid_max;
maxprocperuid = (maxproc * 9) / 10;
/*
* The default limit for maxfiles is 1/12 of the number of
* physical page but not less than 16 times maxusers.
* At most it can be 1/6 the number of physical pages.
*/
maxfiles = imax(MAXFILES, physpages / 8);
TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
if (maxfiles > (physpages / 4))
maxfiles = physpages / 4;
maxfilesperproc = (maxfiles / 10) * 9;
TUNABLE_INT_FETCH("kern.maxfilesperproc", &maxfilesperproc);
/*
* Cannot be changed after boot.
*/
nbuf = NBUF;
TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
TUNABLE_INT_FETCH("kern.bio_transient_maxcnt", &bio_transient_maxcnt);
maxphys = MAXPHYS;
TUNABLE_ULONG_FETCH("kern.maxphys", &maxphys);
if (maxphys == 0) {
maxphys = MAXPHYS;
} else if (__bitcountl(maxphys) != 1) { /* power of two */
if (flsl(maxphys) == NBBY * sizeof(maxphys))
maxphys = MAXPHYS;
else
maxphys = 1UL << flsl(maxphys);
}
if (maxphys < PAGE_SIZE)
maxphys = MAXPHYS;
/*
* Physical buffers are pre-allocated buffers (struct buf) that
* are used as temporary holders for I/O, such as paging I/O.
*/
TUNABLE_INT_FETCH("kern.nswbuf", &nswbuf);
/*
* The default for maxpipekva is min(1/64 of the kernel address space,
* max(1/64 of main memory, 512KB)). See sys_pipe.c for more details.
*/
maxpipekva = ptoa(physpages / 64);
TUNABLE_LONG_FETCH("kern.ipc.maxpipekva", &maxpipekva);
if (maxpipekva < 512 * 1024)
maxpipekva = 512 * 1024;
if (maxpipekva > (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / 64)
maxpipekva = (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) /
64;
}
/*
* Sysctl stringifying handler for kern.vm_guest.
*/
static int
sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)
{
return (SYSCTL_OUT_STR(req, vm_guest_sysctl_names[vm_guest]));
}