518 lines
14 KiB
C
518 lines
14 KiB
C
/* $NetBSD: vm_glue.c,v 1.79 1998/09/13 13:21:37 christos Exp $ */
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/*
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* The Mach Operating System project at Carnegie-Mellon University.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)vm_glue.c 8.9 (Berkeley) 3/4/95
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*
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*
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* Copyright (c) 1987, 1990 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/buf.h>
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#include <sys/user.h>
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#ifdef SYSVSHM
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#include <sys/shm.h>
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#endif
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#include <vm/vm.h>
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#include <vm/vm_page.h>
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#include <vm/vm_kern.h>
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#include <machine/cpu.h>
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int avefree = 0; /* XXX */
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unsigned maxdmap = MAXDSIZ; /* XXX */
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unsigned maxsmap = MAXSSIZ; /* XXX */
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int readbuffers = 0; /* XXX allow kgdb to read kernel buffer pool */
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int
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kernacc(addr, len, rw)
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caddr_t addr;
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size_t len;
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int rw;
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{
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boolean_t rv;
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vaddr_t saddr, eaddr;
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vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE;
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saddr = trunc_page(addr);
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eaddr = round_page(addr+len);
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rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
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/*
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* XXX there are still some things (e.g. the buffer cache) that
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* are managed behind the VM system's back so even though an
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* address is accessible in the mind of the VM system, there may
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* not be physical pages where the VM thinks there is. This can
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* lead to bogus allocation of pages in the kernel address space
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* or worse, inconsistencies at the pmap level. We only worry
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* about the buffer cache for now.
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*/
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if (!readbuffers && rv && (eaddr > (vaddr_t)buffers &&
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saddr < (vaddr_t)buffers + MAXBSIZE * nbuf))
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rv = FALSE;
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return(rv == TRUE);
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}
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int
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useracc(addr, len, rw)
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caddr_t addr;
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size_t len;
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int rw;
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{
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boolean_t rv;
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vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE;
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#if defined(i386) || defined(pc532)
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/*
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* XXX - specially disallow access to user page tables - they are
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* in the map. This is here until i386 & pc532 pmaps are fixed...
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*/
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if ((vaddr_t) addr >= VM_MAXUSER_ADDRESS
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|| (vaddr_t) addr + len > VM_MAXUSER_ADDRESS
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|| (vaddr_t) addr + len <= (vaddr_t) addr)
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return (FALSE);
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#endif
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rv = vm_map_check_protection(&curproc->p_vmspace->vm_map,
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trunc_page(addr), round_page(addr+len), prot);
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return(rv == TRUE);
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}
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#ifdef KGDB
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/*
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* Change protections on kernel pages from addr to addr+len
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* (presumably so debugger can plant a breakpoint).
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*
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* We force the protection change at the pmap level. If we were
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* to use vm_map_protect a change to allow writing would be lazily-
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* applied meaning we would still take a protection fault, something
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* we really don't want to do. It would also fragment the kernel
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* map unnecessarily. We cannot use pmap_protect since it also won't
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* enforce a write-enable request. Using pmap_enter is the only way
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* we can ensure the change takes place properly.
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*/
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void
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chgkprot(addr, len, rw)
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register caddr_t addr;
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size_t len;
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int rw;
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{
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vm_prot_t prot;
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vaddr_t pa;
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vaddr_t sva, eva;
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prot = rw == B_READ ? VM_PROT_READ : VM_PROT_READ|VM_PROT_WRITE;
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eva = round_page(addr + len);
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for (sva = trunc_page(addr); sva < eva; sva += PAGE_SIZE) {
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/*
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* Extract physical address for the page.
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* We use a cheezy hack to differentiate physical
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* page 0 from an invalid mapping, not that it
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* really matters...
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*/
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pa = pmap_extract(pmap_kernel(), sva|1);
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if (pa == 0)
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panic("chgkprot: invalid page");
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pmap_enter(pmap_kernel(), sva, pa&~1, prot, TRUE);
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}
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}
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#endif
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void
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vslock(p, addr, len)
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struct proc *p;
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caddr_t addr;
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size_t len;
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{
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vm_map_pageable(&p->p_vmspace->vm_map, trunc_page(addr),
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round_page(addr+len), FALSE);
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}
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void
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vsunlock(p, addr, len)
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struct proc *p;
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caddr_t addr;
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size_t len;
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{
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vm_map_pageable(&p->p_vmspace->vm_map, trunc_page(addr),
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round_page(addr+len), TRUE);
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}
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/*
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* Implement fork's actions on an address space.
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* Here we arrange for the address space to be copied or referenced,
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* allocate a user struct (pcb and kernel stack), then call the
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* machine-dependent layer to fill those in and make the new process
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* ready to run.
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* NOTE: the kernel stack may be at a different location in the child
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* process, and thus addresses of automatic variables may be invalid
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* after cpu_fork returns in the child process. We do nothing here
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* after cpu_fork returns.
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*/
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void
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vm_fork(p1, p2, shared)
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register struct proc *p1, *p2;
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boolean_t shared;
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{
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struct user *up = p2->p_addr;
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/*
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* Share the address space if we've been directed to.
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*/
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if (shared == TRUE)
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vmspace_share(p1, p2);
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else
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p2->p_vmspace = vmspace_fork(p1->p_vmspace);
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/*
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* Wire down the U-area for the process, which contains the PCB
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* and the kernel stack.
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*/
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vm_map_pageable(kernel_map, (vaddr_t)up,
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(vaddr_t)up + USPACE, FALSE);
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/*
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* p_stats and p_sigacts currently point at fields
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* in the user struct but not at &u, instead at p_addr.
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* Copy p_sigacts and parts of p_stats; zero the rest
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* of p_stats (statistics).
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*/
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p2->p_stats = &up->u_stats;
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p2->p_sigacts = &up->u_sigacts;
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up->u_sigacts = *p1->p_sigacts;
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memset(&up->u_stats.pstat_startzero, 0,
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(unsigned) ((caddr_t)&up->u_stats.pstat_endzero -
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(caddr_t)&up->u_stats.pstat_startzero));
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memcpy(&up->u_stats.pstat_startcopy, &p1->p_stats->pstat_startcopy,
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((caddr_t)&up->u_stats.pstat_endcopy -
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(caddr_t)&up->u_stats.pstat_startcopy));
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/*
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* cpu_fork will copy and update the kernel stack and pcb,
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* and make the child ready to run. The child will exit
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* directly to user mode on its first time slice, and will
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* not return here.
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*/
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cpu_fork(p1, p2);
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}
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/*
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* Free the VM resources held by a dead (pre-zombie) process; we
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* are running on the reaper thread when we come here. We must
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* run on a valid context because freeing these resources may block.
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*/
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void
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vm_exit(p)
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struct proc *p;
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{
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vmspace_free(p->p_vmspace);
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kmem_free(kernel_map, (vaddr_t)p->p_addr, USPACE);
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}
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/*
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* Set default limits for VM system.
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* Called for proc 0, and then inherited by all others.
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*/
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void
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vm_init_limits(p)
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register struct proc *p;
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{
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/*
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* Set up the initial limits on process VM.
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* Set the maximum resident set size to be all
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* of (reasonably) available memory. This causes
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* any single, large process to start random page
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* replacement once it fills memory.
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*/
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p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ;
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p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ;
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p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ;
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p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ;
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p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(cnt.v_free_count);
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}
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#include <vm/vm_pageout.h>
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#ifdef DEBUG
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int enableswap = 1;
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int swapdebug = 0;
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#define SDB_FOLLOW 1
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#define SDB_SWAPIN 2
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#define SDB_SWAPOUT 4
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#endif
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/*
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* Swap in a process's u-area.
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*/
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void
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swapin(p)
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struct proc *p;
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{
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vaddr_t addr;
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int s;
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addr = (vaddr_t)p->p_addr;
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vm_map_pageable(kernel_map, addr, addr + USPACE, FALSE);
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/*
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* Some architectures need to be notified when the
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* user area has moved to new physical page(s) (e.g.
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* see pmax/pmax/vm_machdep.c).
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*/
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cpu_swapin(p);
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s = splstatclock();
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if (p->p_stat == SRUN)
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setrunqueue(p);
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p->p_flag |= P_INMEM;
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splx(s);
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p->p_swtime = 0;
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++cnt.v_swpin;
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}
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/*
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* Brutally simple:
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* 1. Attempt to swapin every swaped-out, runnable process in
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* order of priority.
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* 2. If not enough memory, wake the pageout daemon and let it
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* clear some space.
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*/
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void
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scheduler()
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{
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register struct proc *p;
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register int pri;
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struct proc *pp;
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int ppri;
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loop:
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#ifdef DEBUG
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while (!enableswap)
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tsleep((caddr_t)&proc0, PVM, "noswap", 0);
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#endif
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pp = NULL;
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ppri = INT_MIN;
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for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
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if (p->p_stat == SRUN && (p->p_flag & P_INMEM) == 0) {
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/* XXX should also penalize based on vm_swrss */
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pri = p->p_swtime + p->p_slptime
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- (p->p_nice - NZERO) * 8;
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if (pri > ppri) {
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pp = p;
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ppri = pri;
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}
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}
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}
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#ifdef DEBUG
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if (swapdebug & SDB_FOLLOW)
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printf("scheduler: running, procp %p pri %d\n", pp, ppri);
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#endif
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/*
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* Nothing to do, back to sleep
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*/
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if ((p = pp) == NULL) {
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tsleep((caddr_t)&proc0, PVM, "scheduler", 0);
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goto loop;
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}
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/*
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* We would like to bring someone in.
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* This part is really bogus cuz we could deadlock on memory
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* despite our feeble check.
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* XXX should require at least vm_swrss / 2
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*/
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if (cnt.v_free_count > atop(USPACE)) {
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#ifdef DEBUG
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if (swapdebug & SDB_SWAPIN)
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printf("swapin: pid %d(%s)@%p, pri %d free %d\n",
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p->p_pid, p->p_comm, p->p_addr,
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ppri, cnt.v_free_count);
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#endif
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swapin(p);
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goto loop;
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}
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/*
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* Not enough memory, jab the pageout daemon and wait til the
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* coast is clear.
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*/
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#ifdef DEBUG
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if (swapdebug & SDB_FOLLOW)
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printf("scheduler: no room for pid %d(%s), free %d\n",
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p->p_pid, p->p_comm, cnt.v_free_count);
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#endif
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(void) splhigh();
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vm_wait("fLowmem");
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(void) spl0();
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#ifdef DEBUG
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if (swapdebug & SDB_FOLLOW)
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printf("scheduler: room again, free %d\n", cnt.v_free_count);
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#endif
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goto loop;
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}
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#define swappable(p) \
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(((p)->p_flag & (P_SYSTEM | P_INMEM | P_WEXIT)) == P_INMEM && \
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(p)->p_holdcnt == 0)
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/*
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* Swapout is driven by the pageout daemon. Very simple, we find eligible
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* procs and unwire their u-areas. We try to always "swap" at least one
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* process in case we need the room for a swapin.
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* If any procs have been sleeping/stopped for at least maxslp seconds,
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* they are swapped. Else, we swap the longest-sleeping or stopped process,
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* if any, otherwise the longest-resident process.
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*/
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void
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swapout_threads()
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{
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register struct proc *p;
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struct proc *outp, *outp2;
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int outpri, outpri2;
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int didswap = 0;
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extern int maxslp;
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#ifdef DEBUG
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if (!enableswap)
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return;
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#endif
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outp = outp2 = NULL;
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outpri = outpri2 = 0;
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for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
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if (!swappable(p))
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continue;
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switch (p->p_stat) {
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case SRUN:
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if (p->p_swtime > outpri2) {
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outp2 = p;
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outpri2 = p->p_swtime;
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}
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continue;
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case SSLEEP:
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case SSTOP:
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if (p->p_slptime >= maxslp) {
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swapout(p);
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didswap++;
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} else if (p->p_slptime > outpri) {
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outp = p;
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outpri = p->p_slptime;
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}
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continue;
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}
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}
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/*
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* If we didn't get rid of any real duds, toss out the next most
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* likely sleeping/stopped or running candidate. We only do this
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* if we are real low on memory since we don't gain much by doing
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* it (USPACE bytes).
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*/
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if (didswap == 0 &&
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cnt.v_free_count <= atop(round_page(USPACE))) {
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if ((p = outp) == 0)
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p = outp2;
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#ifdef DEBUG
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if (swapdebug & SDB_SWAPOUT)
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printf("swapout_threads: no duds, try procp %p\n", p);
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#endif
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if (p)
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swapout(p);
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}
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}
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void
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swapout(p)
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register struct proc *p;
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{
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vaddr_t addr;
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int s;
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#ifdef DEBUG
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if (swapdebug & SDB_SWAPOUT)
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printf("swapout: pid %d(%s)@%p, stat %x pri %d free %d\n",
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p->p_pid, p->p_comm, p->p_addr, p->p_stat,
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p->p_slptime, cnt.v_free_count);
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#endif
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/*
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* Do any machine-specific actions necessary before swapout.
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* This can include saving floating point state, etc.
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*/
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cpu_swapout(p);
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/*
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* Unwire the to-be-swapped process's user struct and kernel stack.
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*/
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addr = (vaddr_t)p->p_addr;
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vm_map_pageable(kernel_map, addr, addr + USPACE, TRUE);
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pmap_collect(vm_map_pmap(&p->p_vmspace->vm_map));
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/*
|
|
* 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;
|
|
}
|