4.4BSD/usr/src/sys/vm/vm_glue.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.
*
* @(#)vm_glue.c 8.1 (Berkeley) 7/15/93
*
*
* 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.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/buf.h>
#include <sys/user.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_kern.h>
int avefree = 0; /* XXX */
unsigned maxdmap = MAXDSIZ; /* XXX */
int readbuffers = 0; /* XXX allow kgdb to read kernel buffer pool */
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);
/*
* XXX there are still some things (e.g. the buffer cache) that
* are managed behind the VM system's back so even though an
* address is accessible in the mind of the VM system, there may
* not be physical pages where the VM thinks there is. This can
* lead to bogus allocation of pages in the kernel address space
* or worse, inconsistencies at the pmap level. We only worry
* about the buffer cache for now.
*/
if (!readbuffers && rv && (eaddr > (vm_offset_t)buffers &&
saddr < (vm_offset_t)buffers + MAXBSIZE * nbuf))
rv = FALSE;
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;
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).
*
* We force the protection change at the pmap level. If we were
* to use vm_map_protect a change to allow writing would be lazily-
* applied meaning we would still take a protection fault, something
* we really don't want to do. It would also fragment the kernel
* map unnecessarily. We cannot use pmap_protect since it also won't
* enforce a write-enable request. Using pmap_enter is the only way
* we can ensure the change takes place properly.
*/
void
chgkprot(addr, len, rw)
register caddr_t addr;
int len, rw;
{
vm_prot_t prot;
vm_offset_t pa, sva, eva;
prot = rw == B_READ ? VM_PROT_READ : VM_PROT_READ|VM_PROT_WRITE;
eva = round_page(addr + len);
for (sva = trunc_page(addr); sva < eva; sva += PAGE_SIZE) {
/*
* Extract physical address for the page.
* We use a cheezy hack to differentiate physical
* page 0 from an invalid mapping, not that it
* really matters...
*/
pa = pmap_extract(kernel_pmap, sva|1);
if (pa == 0)
panic("chgkprot: invalid page");
pmap_enter(kernel_pmap, sva, pa&~1, prot, TRUE);
}
}
#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
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;
#ifdef i386
/*
* 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*NBPG, VM_MAX_ADDRESS, VM_INHERIT_NONE);
#endif
p2->p_vmspace = vmspace_fork(p1->p_vmspace);
#ifdef SYSVSHM
if (p1->p_vmspace->vm_shm)
shmfork(p1, p2, isvfork);
#endif
#ifndef i386
/*
* Allocate a wired-down (for now) pcb and kernel stack for the process
*/
addr = kmem_alloc_pageable(kernel_map, ctob(UPAGES));
if (addr == 0)
panic("vm_fork: no more kernel virtual memory");
vm_map_pageable(kernel_map, addr, addr + ctob(UPAGES), FALSE);
#else
/* XXX somehow, on 386, ocassionally pageout removes active, wired down kstack,
and pagetables, WITHOUT going thru vm_page_unwire! Why this appears to work is
not yet clear, yet it does... */
addr = kmem_alloc(kernel_map, ctob(UPAGES));
if (addr == 0)
panic("vm_fork: no more kernel virtual memory");
#endif
up = (struct user *)addr;
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));
#ifdef i386
{ u_int addr = UPT_MIN_ADDRESS - UPAGES*NBPG; struct vm_map *vp;
vp = &p2->p_vmspace->vm_map;
(void)vm_deallocate(vp, addr, UPT_MAX_ADDRESS - addr);
(void)vm_allocate(vp, &addr, UPT_MAX_ADDRESS - addr, FALSE);
(void)vm_map_inherit(vp, addr, UPT_MAX_ADDRESS, VM_INHERIT_NONE);
}
#endif
/*
* 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.
*/
void
vm_init_limits(p)
register struct proc *p;
{
/*
* Set up the initial limits on process VM.
* Set the maximum resident set size to be all
* of (reasonably) available memory. This causes
* any single, large process to start random page
* replacement once it fills memory.
*/
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;
p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(cnt.v_free_count);
}
#include <vm/vm_pageout.h>
#ifdef DEBUG
int enableswap = 1;
int swapdebug = 0;
#define SDB_FOLLOW 1
#define SDB_SWAPIN 2
#define SDB_SWAPOUT 4
#endif
/*
* Brutally simple:
* 1. Attempt to swapin every swaped-out, runnable process in
* order of priority.
* 2. If not enough memory, wake the pageout daemon and let it
* clear some space.
*/
void
sched()
{
register struct proc *p;
register int pri;
struct proc *pp;
int ppri;
vm_offset_t addr;
vm_size_t size;
loop:
#ifdef DEBUG
while (!enableswap)
sleep((caddr_t)&proc0, PVM);
#endif
pp = NULL;
ppri = INT_MIN;
for (p = (struct proc *)allproc; p != NULL; p = p->p_nxt) {
if (p->p_stat == SRUN && (p->p_flag & SLOAD) == 0) {
pri = p->p_time + p->p_slptime - p->p_nice * 8;
if (pri > ppri) {
pp = p;
ppri = pri;
}
}
}
#ifdef DEBUG
if (swapdebug & SDB_FOLLOW)
printf("sched: running, procp %x pri %d\n", pp, ppri);
#endif
/*
* Nothing to do, back to sleep
*/
if ((p = pp) == NULL) {
sleep((caddr_t)&proc0, PVM);
goto loop;
}
/*
* We would like to bring someone in.
* This part is really bogus cuz we could deadlock on memory
* despite our feeble check.
*/
size = round_page(ctob(UPAGES));
addr = (vm_offset_t) p->p_addr;
if (cnt.v_free_count > atop(size)) {
#ifdef DEBUG
if (swapdebug & SDB_SWAPIN)
printf("swapin: pid %d(%s)@%x, pri %d free %d\n",
p->p_pid, p->p_comm, p->p_addr,
ppri, cnt.v_free_count);
#endif
vm_map_pageable(kernel_map, addr, addr+size, FALSE);
(void) splstatclock();
if (p->p_stat == SRUN)
setrq(p);
p->p_flag |= SLOAD;
(void) spl0();
p->p_time = 0;
goto loop;
}
/*
* Not enough memory, jab the pageout daemon and wait til the
* coast is clear.
*/
#ifdef DEBUG
if (swapdebug & SDB_FOLLOW)
printf("sched: no room for pid %d(%s), free %d\n",
p->p_pid, p->p_comm, cnt.v_free_count);
#endif
(void) splhigh();
VM_WAIT;
(void) spl0();
#ifdef DEBUG
if (swapdebug & SDB_FOLLOW)
printf("sched: room again, free %d\n", cnt.v_free_count);
#endif
goto loop;
}
#define swappable(p) \
(((p)->p_flag & (SSYS|SLOAD|SKEEP|SWEXIT|SPHYSIO)) == SLOAD)
/*
* 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_threads()
{
register struct proc *p;
struct proc *outp, *outp2;
int outpri, outpri2;
int didswap = 0;
extern int maxslp;
#ifdef DEBUG
if (!enableswap)
return;
#endif
outp = outp2 = NULL;
outpri = outpri2 = 0;
for (p = (struct proc *)allproc; p != NULL; p = p->p_nxt) {
if (!swappable(p))
continue;
switch (p->p_stat) {
case SRUN:
if (p->p_time > outpri2) {
outp2 = p;
outpri2 = p->p_time;
}
continue;
case SSLEEP:
case SSTOP:
if (p->p_slptime >= maxslp) {
swapout(p);
didswap++;
} else if (p->p_slptime > outpri) {
outp = p;
outpri = p->p_slptime;
}
continue;
}
}
/*
* If we didn't get rid of any real duds, toss out the next most
* likely sleeping/stopped or running candidate. We only do this
* if we are real low on memory since we don't gain much by doing
* it (UPAGES pages).
*/
if (didswap == 0 &&
cnt.v_free_count <= atop(round_page(ctob(UPAGES)))) {
if ((p = outp) == 0)
p = outp2;
#ifdef DEBUG
if (swapdebug & SDB_SWAPOUT)
printf("swapout_threads: no duds, try procp %x\n", p);
#endif
if (p)
swapout(p);
}
}
void
swapout(p)
register struct proc *p;
{
vm_offset_t addr;
vm_size_t size;
#ifdef DEBUG
if (swapdebug & SDB_SWAPOUT)
printf("swapout: pid %d(%s)@%x, stat %x pri %d free %d\n",
p->p_pid, p->p_comm, p->p_addr, p->p_stat,
p->p_slptime, cnt.v_free_count);
#endif
size = round_page(ctob(UPAGES));
addr = (vm_offset_t) p->p_addr;
#if defined(hp300) || defined(luna68k)
/*
* Ugh! u-area is double mapped to a fixed address behind the
* back of the VM system and accesses are usually through that
* address rather than the per-process address. Hence reference
* and modify information are recorded at the fixed address and
* lost at context switch time. We assume the u-struct and
* kernel stack are always accessed/modified and force it to be so.
*/
{
register int i;
volatile long tmp;
for (i = 0; i < UPAGES; i++) {
tmp = *(long *)addr; *(long *)addr = tmp;
addr += NBPG;
}
addr = (vm_offset_t) p->p_addr;
}
#endif
#ifdef mips
/*
* Be sure to save the floating point coprocessor state before
* paging out the u-struct.
*/
{
extern struct proc *machFPCurProcPtr;
if (p == machFPCurProcPtr) {
MachSaveCurFPState(p);
machFPCurProcPtr = (struct proc *)0;
}
}
#endif
#ifndef i386 /* temporary measure till we find spontaineous unwire of kstack */
vm_map_pageable(kernel_map, addr, addr+size, TRUE);
pmap_collect(vm_map_pmap(&p->p_vmspace->vm_map));
#endif
(void) splhigh();
p->p_flag &= ~SLOAD;
if (p->p_stat == SRUN)
remrq(p);
(void) spl0();
p->p_time = 0;
}
/*
* The rest of these routines fake thread handling
*/
void
assert_wait(event, ruptible)
int event;
boolean_t ruptible;
{
#ifdef lint
ruptible++;
#endif
curproc->p_thread = event;
}
void
thread_block()
{
int s = splhigh();
if (curproc->p_thread)
sleep((caddr_t)curproc->p_thread, PVM);
splx(s);
}
void
thread_sleep(event, lock, ruptible)
int event;
simple_lock_t lock;
boolean_t ruptible;
{
#ifdef lint
ruptible++;
#endif
int s = splhigh();
curproc->p_thread = event;
simple_unlock(lock);
if (curproc->p_thread)
sleep((caddr_t)event, PVM);
splx(s);
}
void
thread_wakeup(event)
int event;
{
int s = splhigh();
wakeup((caddr_t)event);
splx(s);
}
/*
* DEBUG stuff
*/
int indent = 0;
#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);
printf("%r", fmt, ap);
va_end(ap);
}