freebsd-skq/sys/vm/vm_glue.c
David Greenman 5afce28270 Add a "NO_SWAPPING" option to disable swapping. This was originally done
to help diagnose a problem on wcarchive (where the kernel stack was
sometimes not present), but is useful in its own right since swapping
actually reduces performance on some systems (such as wcarchive).
Note: swapping in this context means making the U pages pageable and has
nothing to do with generic VM paging, which is unaffected by this option.

Reviewed by:	 <dyson>
1996-02-22 10:57:37 +00:00

637 lines
16 KiB
C

/*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* 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.
*
* from: @(#)vm_glue.c 8.6 (Berkeley) 1/5/94
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $Id: vm_glue.c,v 1.38 1996/01/29 12:10:30 davidg Exp $
*/
#include "opt_sysvipc.h"
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/buf.h>
#include <sys/shm.h>
#include <sys/vmmeter.h>
#include <sys/kernel.h>
#include <sys/dkstat.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_inherit.h>
#include <vm/vm_prot.h>
#include <vm/lock.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <sys/user.h>
#include <machine/stdarg.h>
#include <machine/cpu.h>
/*
* System initialization
*
* Note: proc0 from proc.h
*/
static void vm_init_limits __P((void *));
SYSINIT(vm_limits, SI_SUB_VM_CONF, SI_ORDER_FIRST, vm_init_limits, &proc0)
/*
* THIS MUST BE THE LAST INITIALIZATION ITEM!!!
*
* Note: run scheduling should be divorced from the vm system.
*/
static void scheduler __P((void *));
SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL)
static void swapout __P((struct proc *));
extern char kstack[];
/* vm_map_t upages_map; */
int
kernacc(addr, len, rw)
caddr_t addr;
int len, rw;
{
boolean_t rv;
vm_offset_t saddr, eaddr;
vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE;
saddr = trunc_page(addr);
eaddr = round_page(addr + len);
rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
return (rv == TRUE);
}
int
useracc(addr, len, rw)
caddr_t addr;
int len, rw;
{
boolean_t rv;
vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE;
/*
* XXX - check separately to disallow access to user area and user
* page tables - they are in the map.
*
* XXX - VM_MAXUSER_ADDRESS is an end address, not a max. It was once
* only used (as an end address) in trap.c. Use it as an end address
* here too. This bogusness has spread. I just fixed where it was
* used as a max in vm_mmap.c.
*/
if ((vm_offset_t) addr + len > /* XXX */ VM_MAXUSER_ADDRESS
|| (vm_offset_t) addr + len < (vm_offset_t) addr) {
return (FALSE);
}
rv = vm_map_check_protection(&curproc->p_vmspace->vm_map,
trunc_page(addr), round_page(addr + len), prot);
return (rv == TRUE);
}
#ifdef KGDB
/*
* Change protections on kernel pages from addr to addr+len
* (presumably so debugger can plant a breakpoint).
* All addresses are assumed to reside in the Sysmap,
*/
chgkprot(addr, len, rw)
register caddr_t addr;
int len, rw;
{
vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE;
vm_map_protect(kernel_map, trunc_page(addr),
round_page(addr + len), prot, FALSE);
}
#endif
void
vslock(addr, len)
caddr_t addr;
u_int len;
{
vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page(addr),
round_page(addr + len), FALSE);
}
void
vsunlock(addr, len, dirtied)
caddr_t addr;
u_int len;
int dirtied;
{
#ifdef lint
dirtied++;
#endif /* lint */
vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page(addr),
round_page(addr + len), TRUE);
}
/*
* Implement fork's actions on an address space.
* Here we arrange for the address space to be copied or referenced,
* allocate a user struct (pcb and kernel stack), then call the
* machine-dependent layer to fill those in and make the new process
* ready to run.
* NOTE: the kernel stack may be at a different location in the child
* process, and thus addresses of automatic variables may be invalid
* after cpu_fork returns in the child process. We do nothing here
* after cpu_fork returns.
*/
int
vm_fork(p1, p2, isvfork)
register struct proc *p1, *p2;
int isvfork;
{
register struct user *up;
vm_offset_t addr, ptaddr, ptpa;
int error, i;
vm_map_t map;
pmap_t pvp;
vm_page_t stkm;
while ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) {
VM_WAIT;
}
/*
* avoid copying any of the parent's pagetables or other per-process
* objects that reside in the map by marking all of them
* non-inheritable
*/
(void) vm_map_inherit(&p1->p_vmspace->vm_map,
UPT_MIN_ADDRESS - UPAGES * PAGE_SIZE, VM_MAX_ADDRESS, VM_INHERIT_NONE);
p2->p_vmspace = vmspace_fork(p1->p_vmspace);
#ifdef SYSVSHM
if (p1->p_vmspace->vm_shm)
shmfork(p1, p2, isvfork);
#endif
/*
* Allocate a wired-down (for now) pcb and kernel stack for the
* process
*/
addr = (vm_offset_t) kstack;
map = &p2->p_vmspace->vm_map;
pvp = &p2->p_vmspace->vm_pmap;
/* get new pagetables and kernel stack */
error = vm_map_find(map, NULL, 0, &addr, UPT_MAX_ADDRESS - addr, FALSE,
VM_PROT_ALL, VM_PROT_ALL, 0);
if (error != KERN_SUCCESS)
panic("vm_fork: vm_map_find failed, addr=0x%x, error=%d", addr, error);
/* get a kernel virtual address for the UPAGES for this proc */
up = (struct user *) kmem_alloc_pageable(u_map, UPAGES * PAGE_SIZE);
if (up == NULL)
panic("vm_fork: u_map allocation failed");
p2->p_vmspace->vm_upages_obj = vm_object_allocate( OBJT_DEFAULT,
UPAGES);
ptaddr = trunc_page((u_int) vtopte(kstack));
(void) vm_fault(map, ptaddr, VM_PROT_READ|VM_PROT_WRITE, FALSE);
ptpa = pmap_extract(pvp, ptaddr);
if (ptpa == 0) {
panic("vm_fork: no pte for UPAGES");
}
stkm = PHYS_TO_VM_PAGE(ptpa);
vm_page_hold(stkm);
for(i=0;i<UPAGES;i++) {
vm_page_t m;
while ((m = vm_page_alloc(p2->p_vmspace->vm_upages_obj, i, VM_ALLOC_ZERO)) == NULL) {
VM_WAIT;
}
vm_page_wire(m);
m->flags &= ~PG_BUSY;
pmap_enter( pvp, (vm_offset_t) kstack + i * PAGE_SIZE,
VM_PAGE_TO_PHYS(m), VM_PROT_READ|VM_PROT_WRITE, 1);
pmap_kenter(((vm_offset_t) up) + i * PAGE_SIZE,
VM_PAGE_TO_PHYS(m));
if ((m->flags & PG_ZERO) == 0)
bzero(((caddr_t) up) + i * PAGE_SIZE, PAGE_SIZE);
m->flags &= ~PG_ZERO;
m->valid = VM_PAGE_BITS_ALL;
}
vm_page_unhold(stkm);
p2->p_addr = up;
/*
* p_stats and p_sigacts currently point at fields in the user struct
* but not at &u, instead at p_addr. Copy p_sigacts and parts of
* p_stats; zero the rest of p_stats (statistics).
*/
p2->p_stats = &up->u_stats;
p2->p_sigacts = &up->u_sigacts;
up->u_sigacts = *p1->p_sigacts;
bzero(&up->u_stats.pstat_startzero,
(unsigned) ((caddr_t) &up->u_stats.pstat_endzero -
(caddr_t) &up->u_stats.pstat_startzero));
bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy,
((caddr_t) &up->u_stats.pstat_endcopy -
(caddr_t) &up->u_stats.pstat_startcopy));
/*
* cpu_fork will copy and update the kernel stack and pcb, and make
* the child ready to run. It marks the child so that it can return
* differently than the parent. It returns twice, once in the parent
* process and once in the child.
*/
return (cpu_fork(p1, p2));
}
/*
* Set default limits for VM system.
* Called for proc 0, and then inherited by all others.
*
* XXX should probably act directly on proc0.
*/
static void
vm_init_limits(udata)
void *udata;
{
register struct proc *p = udata;
int rss_limit;
/*
* Set up the initial limits on process VM. Set the maximum resident
* set size to be half of (reasonably) available memory. Since this
* is a soft limit, it comes into effect only when the system is out
* of memory - half of main memory helps to favor smaller processes,
* and reduces thrashing of the object cache.
*/
p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ;
p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ;
p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ;
p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ;
/* limit the limit to no less than 2MB */
rss_limit = max(cnt.v_free_count, 512);
p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit);
p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY;
}
void
faultin(p)
struct proc *p;
{
vm_offset_t i;
vm_offset_t ptaddr;
int s;
if ((p->p_flag & P_INMEM) == 0) {
vm_map_t map = &p->p_vmspace->vm_map;
pmap_t pmap = &p->p_vmspace->vm_pmap;
vm_page_t stkm, m;
vm_offset_t ptpa;
int error;
++p->p_lock;
ptaddr = trunc_page((u_int) vtopte(kstack));
(void) vm_fault(map, ptaddr, VM_PROT_READ|VM_PROT_WRITE, FALSE);
ptpa = pmap_extract(&p->p_vmspace->vm_pmap, ptaddr);
if (ptpa == 0) {
panic("vm_fork: no pte for UPAGES");
}
stkm = PHYS_TO_VM_PAGE(ptpa);
vm_page_hold(stkm);
for(i=0;i<UPAGES;i++) {
int s;
s = splhigh();
retry:
if ((m = vm_page_lookup(p->p_vmspace->vm_upages_obj, i)) == NULL) {
if ((m = vm_page_alloc(p->p_vmspace->vm_upages_obj, i, VM_ALLOC_NORMAL)) == NULL) {
VM_WAIT;
goto retry;
}
} else {
if ((m->flags & PG_BUSY) || m->busy) {
m->flags |= PG_WANTED;
tsleep(m, PVM, "swinuw",0);
goto retry;
}
}
vm_page_wire(m);
if (m->valid == VM_PAGE_BITS_ALL)
m->flags &= ~PG_BUSY;
splx(s);
pmap_enter( pmap, (vm_offset_t) kstack + i * PAGE_SIZE,
VM_PAGE_TO_PHYS(m), VM_PROT_READ|VM_PROT_WRITE, TRUE);
pmap_kenter(((vm_offset_t) p->p_addr) + i * PAGE_SIZE,
VM_PAGE_TO_PHYS(m));
if (m->valid != VM_PAGE_BITS_ALL) {
int rv;
rv = vm_pager_get_pages(p->p_vmspace->vm_upages_obj,
&m, 1, 0);
if (rv != VM_PAGER_OK)
panic("faultin: cannot get upages for proc: %d\n", p->p_pid);
m->valid = VM_PAGE_BITS_ALL;
m->flags &= ~PG_BUSY;
}
}
vm_page_unhold(stkm);
s = splhigh();
if (p->p_stat == SRUN)
setrunqueue(p);
p->p_flag |= P_INMEM;
/* undo the effect of setting SLOCK above */
--p->p_lock;
splx(s);
}
}
/*
* This swapin algorithm attempts to swap-in processes only if there
* is enough space for them. Of course, if a process waits for a long
* time, it will be swapped in anyway.
*/
/* ARGSUSED*/
static void
scheduler(dummy)
void *dummy;
{
register struct proc *p;
register int pri;
struct proc *pp;
int ppri;
loop:
while ((cnt.v_free_count + cnt.v_cache_count) < (cnt.v_free_reserved + UPAGES + 2)) {
VM_WAIT;
}
pp = NULL;
ppri = INT_MIN;
for (p = (struct proc *) allproc; p != NULL; p = p->p_next) {
if (p->p_stat == SRUN &&
(p->p_flag & (P_INMEM | P_SWAPPING)) == 0) {
int mempri;
pri = p->p_swtime + p->p_slptime - p->p_nice * 8;
mempri = pri > 0 ? pri : 0;
/*
* if this process is higher priority and there is
* enough space, then select this process instead of
* the previous selection.
*/
if (pri > ppri) {
pp = p;
ppri = pri;
}
}
}
/*
* Nothing to do, back to sleep
*/
if ((p = pp) == NULL) {
tsleep(&proc0, PVM, "sched", 0);
goto loop;
}
/*
* We would like to bring someone in. (only if there is space).
*/
faultin(p);
p->p_swtime = 0;
goto loop;
}
#ifndef NO_SWAPPING
#define swappable(p) \
(((p)->p_lock == 0) && \
((p)->p_flag & (P_TRACED|P_NOSWAP|P_SYSTEM|P_INMEM|P_WEXIT|P_PHYSIO|P_SWAPPING)) == P_INMEM)
/*
* Swapout is driven by the pageout daemon. Very simple, we find eligible
* procs and unwire their u-areas. We try to always "swap" at least one
* process in case we need the room for a swapin.
* If any procs have been sleeping/stopped for at least maxslp seconds,
* they are swapped. Else, we swap the longest-sleeping or stopped process,
* if any, otherwise the longest-resident process.
*/
void
swapout_procs()
{
register struct proc *p;
struct proc *outp, *outp2;
int outpri, outpri2;
int didswap = 0;
outp = outp2 = NULL;
outpri = outpri2 = INT_MIN;
retry:
for (p = (struct proc *) allproc; p != NULL; p = p->p_next) {
if (!swappable(p))
continue;
switch (p->p_stat) {
default:
continue;
case SSLEEP:
case SSTOP:
/*
* do not swapout a realtime process
*/
if (p->p_rtprio.type == RTP_PRIO_REALTIME)
continue;
/*
* do not swapout a process waiting on a critical
* event of some kind
*/
if (((p->p_priority & 0x7f) < PSOCK) ||
(p->p_slptime <= 4))
continue;
vm_map_reference(&p->p_vmspace->vm_map);
/*
* do not swapout a process that is waiting for VM
* datastructures there is a possible deadlock.
*/
if (!lock_try_write(&p->p_vmspace->vm_map.lock)) {
vm_map_deallocate(&p->p_vmspace->vm_map);
continue;
}
vm_map_unlock(&p->p_vmspace->vm_map);
/*
* If the process has been asleep for awhile and had
* most of its pages taken away already, swap it out.
*/
swapout(p);
vm_map_deallocate(&p->p_vmspace->vm_map);
didswap++;
goto retry;
}
}
/*
* If we swapped something out, and another process needed memory,
* then wakeup the sched process.
*/
if (didswap)
wakeup(&proc0);
}
static void
swapout(p)
register struct proc *p;
{
vm_map_t map = &p->p_vmspace->vm_map;
pmap_t pmap = &p->p_vmspace->vm_pmap;
vm_offset_t ptaddr;
int i;
++p->p_stats->p_ru.ru_nswap;
/*
* remember the process resident count
*/
p->p_vmspace->vm_swrss =
p->p_vmspace->vm_pmap.pm_stats.resident_count;
(void) splhigh();
p->p_flag &= ~P_INMEM;
p->p_flag |= P_SWAPPING;
if (p->p_stat == SRUN)
remrq(p);
(void) spl0();
/*
* let the upages be paged
*/
for(i=0;i<UPAGES;i++) {
vm_page_t m;
if ((m = vm_page_lookup(p->p_vmspace->vm_upages_obj, i)) == NULL)
panic("swapout: upage already missing???");
m->dirty = VM_PAGE_BITS_ALL;
vm_page_unwire(m);
pmap_kremove( (vm_offset_t) p->p_addr + PAGE_SIZE * i);
}
pmap_remove(pmap, (vm_offset_t) kstack,
(vm_offset_t) kstack + PAGE_SIZE * UPAGES);
p->p_flag &= ~P_SWAPPING;
p->p_swtime = 0;
}
#endif /* !NO_SWAPPING */
#ifdef DDB
/*
* DEBUG stuff
*/
int indent;
#include <machine/stdarg.h> /* see subr_prf.c */
/*ARGSUSED2*/
void
#if __STDC__
iprintf(const char *fmt,...)
#else
iprintf(fmt /* , va_alist */ )
char *fmt;
/* va_dcl */
#endif
{
register int i;
va_list ap;
for (i = indent; i >= 8; i -= 8)
printf("\t");
while (--i >= 0)
printf(" ");
va_start(ap, fmt);
vprintf(fmt, ap);
va_end(ap);
}
#endif /* DDB */