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NetBSD/sys/vm/vm_glue.c

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/* $NetBSD: vm_glue.c,v 1.72 1998/03/01 02:24:00 fvdl Exp $ */
/*
* 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 8.9 (Berkeley) 3/4/95
*
*
* 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>
#ifdef SYSVSHM
#include <sys/shm.h>
#endif
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_kern.h>
#include <machine/cpu.h>
int avefree = 0; /* XXX */
unsigned maxdmap = MAXDSIZ; /* XXX */
unsigned maxsmap = MAXSSIZ; /* 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;
#if defined(i386) || defined(pc532)
/*
* XXX - specially disallow access to user page tables - they are
* in the map. This is here until i386 & pc532 pmaps are fixed...
*/
if ((vm_offset_t) addr >= VM_MAXUSER_ADDRESS
|| (vm_offset_t) addr + len > VM_MAXUSER_ADDRESS
|| (vm_offset_t) addr + len <= (vm_offset_t) addr)
return (FALSE);
#endif
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(pmap_kernel(), sva|1);
if (pa == 0)
panic("chgkprot: invalid page");
pmap_enter(pmap_kernel(), 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)
caddr_t addr;
u_int len;
{
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.
*/
void
vm_fork(p1, p2, shared)
register struct proc *p1, *p2;
boolean_t shared;
{
register struct user *up;
vm_offset_t addr;
/*
* Share the address space if we've been directed to.
*/
if (shared == TRUE)
vmspace_share(p1, p2);
else
p2->p_vmspace = vmspace_fork(p1->p_vmspace);
#if !defined(vax)
/*
* Allocate a wired-down (for now) pcb and kernel stack for the process
*/
addr = kmem_alloc_pageable(kernel_map, USPACE);
if (addr == 0)
panic("vm_fork: no more kernel virtual memory");
vm_map_pageable(kernel_map, addr, addr + USPACE, 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, USPACE);
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));
/*
* cpu_fork will copy and update the kernel stack and pcb,
* and make the child ready to run. The child will exit
* directly to user mode on its first time slice, and will
* not return here.
*/
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
/*
* Swap in a process's u-area.
*/
void
swapin(p)
struct proc *p;
{
vm_offset_t addr;
int s;
addr = (vm_offset_t)p->p_addr;
vm_map_pageable(kernel_map, addr, addr + USPACE, FALSE);
/*
* Some architectures need to be notified when the
* user area has moved to new physical page(s) (e.g.
* see pmax/pmax/vm_machdep.c).
*/
cpu_swapin(p);
s = splstatclock();
if (p->p_stat == SRUN)
setrunqueue(p);
p->p_flag |= P_INMEM;
splx(s);
p->p_swtime = 0;
++cnt.v_swpin;
}
/*
* 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
scheduler()
{
register struct proc *p;
register int pri;
struct proc *pp;
int ppri;
loop:
#ifdef DEBUG
while (!enableswap)
tsleep((caddr_t)&proc0, PVM, "noswap", 0);
#endif
pp = NULL;
ppri = INT_MIN;
for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
if (p->p_stat == SRUN && (p->p_flag & P_INMEM) == 0) {
/* XXX should also penalize based on vm_swrss */
pri = p->p_swtime + p->p_slptime
- (p->p_nice - NZERO) * 8;
if (pri > ppri) {
pp = p;
ppri = pri;
}
}
}
#ifdef DEBUG
if (swapdebug & SDB_FOLLOW)
printf("scheduler: running, procp %p pri %d\n", pp, ppri);
#endif
/*
* Nothing to do, back to sleep
*/
if ((p = pp) == NULL) {
tsleep((caddr_t)&proc0, PVM, "scheduler", 0);
goto loop;
}
/*
* We would like to bring someone in.
* This part is really bogus cuz we could deadlock on memory
* despite our feeble check.
* XXX should require at least vm_swrss / 2
*/
if (cnt.v_free_count > atop(USPACE)) {
#ifdef DEBUG
if (swapdebug & SDB_SWAPIN)
printf("swapin: pid %d(%s)@%p, pri %d free %d\n",
p->p_pid, p->p_comm, p->p_addr,
ppri, cnt.v_free_count);
#endif
swapin(p);
goto loop;
}
/*
* Not enough memory, jab the pageout daemon and wait til the
* coast is clear.
*/
#ifdef DEBUG
if (swapdebug & SDB_FOLLOW)
printf("scheduler: no room for pid %d(%s), free %d\n",
p->p_pid, p->p_comm, cnt.v_free_count);
#endif
(void) splhigh();
vm_wait("fLowmem");
(void) spl0();
#ifdef DEBUG
if (swapdebug & SDB_FOLLOW)
printf("scheduler: room again, free %d\n", cnt.v_free_count);
#endif
goto loop;
}
#define swappable(p) \
(((p)->p_flag & (P_SYSTEM | P_INMEM | P_WEXIT)) == P_INMEM && \
(p)->p_holdcnt == 0)
/*
* 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 = allproc.lh_first; p != 0; p = p->p_list.le_next) {
if (!swappable(p))
continue;
switch (p->p_stat) {
case SRUN:
if (p->p_swtime > outpri2) {
outp2 = p;
outpri2 = p->p_swtime;
}
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 (USPACE bytes).
*/
if (didswap == 0 &&
cnt.v_free_count <= atop(round_page(USPACE))) {
if ((p = outp) == 0)
p = outp2;
#ifdef DEBUG
if (swapdebug & SDB_SWAPOUT)
printf("swapout_threads: no duds, try procp %p\n", p);
#endif
if (p)
swapout(p);
}
}
void
swapout(p)
register struct proc *p;
{
vm_offset_t addr;
int s;
#ifdef DEBUG
if (swapdebug & SDB_SWAPOUT)
printf("swapout: pid %d(%s)@%p, 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
/*
* Do any machine-specific actions necessary before swapout.
* This can include saving floating point state, etc.
*/
cpu_swapout(p);
/*
* Unwire the to-be-swapped process's user struct and kernel stack.
*/
addr = (vm_offset_t)p->p_addr;
vm_map_pageable(kernel_map, addr, addr + USPACE, TRUE);
pmap_collect(vm_map_pmap(&p->p_vmspace->vm_map));
/*
* Mark it as (potentially) swapped out.
*/
s = splstatclock();
p->p_flag &= ~P_INMEM;
if (p->p_stat == SRUN)
remrunqueue(p);
splx(s);
p->p_swtime = 0;
++cnt.v_swpout;
}
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