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NetBSD/sys/uvm/uvm_glue.c

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/* $NetBSD: uvm_glue.c,v 1.41 2000/09/23 00:43:10 enami Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
* 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 Charles D. Cranor,
* Washington University, 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 8.6 (Berkeley) 1/5/94
* from: Id: uvm_glue.c,v 1.1.2.8 1998/02/07 01:16:54 chs Exp
*
*
* 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 "opt_uvmhist.h"
#include "opt_sysv.h"
/*
* uvm_glue.c: glue functions
*/
#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 <uvm/uvm.h>
#include <machine/cpu.h>
/*
* local prototypes
*/
static void uvm_swapout __P((struct proc *));
/*
* XXXCDC: do these really belong here?
*/
unsigned maxdmap = MAXDSIZ; /* kern_resource.c: RLIMIT_DATA max */
unsigned maxsmap = MAXSSIZ; /* kern_resource.c: RLIMIT_STACK max */
int readbuffers = 0; /* allow KGDB to read kern buffer pool */
/* XXX: see uvm_kernacc */
/*
* uvm_kernacc: can the kernel access a region of memory
*
* - called from malloc [DIAGNOSTIC], and /dev/kmem driver (mem.c)
*/
boolean_t
uvm_kernacc(addr, len, rw)
caddr_t addr;
size_t len;
int rw;
{
boolean_t rv;
vaddr_t saddr, eaddr;
vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE;
saddr = trunc_page((vaddr_t)addr);
eaddr = round_page((vaddr_t)addr+len);
vm_map_lock_read(kernel_map);
rv = uvm_map_checkprot(kernel_map, saddr, eaddr, prot);
vm_map_unlock_read(kernel_map);
/*
* 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 > (vaddr_t)buffers &&
saddr < (vaddr_t)buffers + MAXBSIZE * nbuf))
rv = FALSE;
return(rv);
}
/*
* uvm_useracc: can the user access it?
*
* - called from physio() and sys___sysctl().
*/
boolean_t
uvm_useracc(addr, len, rw)
caddr_t addr;
size_t len;
int rw;
{
vm_map_t map;
boolean_t rv;
vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE;
/* XXX curproc */
map = &curproc->p_vmspace->vm_map;
vm_map_lock_read(map);
rv = uvm_map_checkprot(map, trunc_page((vaddr_t)addr),
round_page((vaddr_t)addr+len), prot);
vm_map_unlock_read(map);
return(rv);
}
#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
uvm_chgkprot(addr, len, rw)
caddr_t addr;
size_t len;
int rw;
{
vm_prot_t prot;
paddr_t pa;
vaddr_t sva, eva;
prot = rw == B_READ ? VM_PROT_READ : VM_PROT_READ|VM_PROT_WRITE;
eva = round_page((vaddr_t)addr + len);
for (sva = trunc_page((vaddr_t)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...
*/
if (pmap_extract(pmap_kernel(), sva, &pa) == FALSE)
panic("chgkprot: invalid page");
pmap_enter(pmap_kernel(), sva, pa, prot, PMAP_WIRED);
}
}
#endif
/*
* vslock: wire user memory for I/O
*
* - called from physio and sys___sysctl
* - XXXCDC: consider nuking this (or making it a macro?)
*/
int
uvm_vslock(p, addr, len, access_type)
struct proc *p;
caddr_t addr;
size_t len;
vm_prot_t access_type;
{
vm_map_t map;
vaddr_t start, end;
int rv;
map = &p->p_vmspace->vm_map;
start = trunc_page((vaddr_t)addr);
end = round_page((vaddr_t)addr + len);
rv = uvm_fault_wire(map, start, end, access_type);
return (rv);
}
/*
* vslock: wire user memory for I/O
*
* - called from physio and sys___sysctl
* - XXXCDC: consider nuking this (or making it a macro?)
*/
void
uvm_vsunlock(p, addr, len)
struct proc *p;
caddr_t addr;
size_t len;
{
uvm_fault_unwire(&p->p_vmspace->vm_map, trunc_page((vaddr_t)addr),
round_page((vaddr_t)addr+len));
}
/*
* uvm_fork: fork a virtual address space
*
* - the address space is copied as per parent map's inherit values
* - a new "user" structure is allocated for the child process
* [filled in by MD layer...]
* - if specified, the child gets a new user stack described by
* stack and stacksize
* - 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.
* - XXXCDC: we need a way for this to return a failure value rather
* than just hang
*/
void
uvm_fork(p1, p2, shared, stack, stacksize, func, arg)
struct proc *p1, *p2;
boolean_t shared;
void *stack;
size_t stacksize;
void (*func) __P((void *));
void *arg;
{
struct user *up = p2->p_addr;
int rv;
if (shared == TRUE)
uvmspace_share(p1, p2); /* share vmspace */
else
p2->p_vmspace = uvmspace_fork(p1->p_vmspace); /* fork vmspace */
/*
* Wire down the U-area for the process, which contains the PCB
* and the kernel stack. Wired state is stored in p->p_flag's
* P_INMEM bit rather than in the vm_map_entry's wired count
* to prevent kernel_map fragmentation.
*
* Note the kernel stack gets read/write accesses right off
* the bat.
*/
rv = uvm_fault_wire(kernel_map, (vaddr_t)up,
(vaddr_t)up + USPACE, VM_PROT_READ | VM_PROT_WRITE);
if (rv != KERN_SUCCESS)
panic("uvm_fork: uvm_fault_wire failed: %d", rv);
/*
* p_stats currently points at a field in the user struct. Copy
* parts of p_stats, and zero out the rest.
*/
p2->p_stats = &up->u_stats;
memset(&up->u_stats.pstat_startzero, 0,
(unsigned) ((caddr_t)&up->u_stats.pstat_endzero -
(caddr_t)&up->u_stats.pstat_startzero));
memcpy(&up->u_stats.pstat_startcopy, &p1->p_stats->pstat_startcopy,
((caddr_t)&up->u_stats.pstat_endcopy -
(caddr_t)&up->u_stats.pstat_startcopy));
/*
* cpu_fork() copy and update the pcb, and make the child ready
* to run. If this is a normal user fork, the child will exit
* directly to user mode via child_return() on its first time
* slice and will not return here. If this is a kernel thread,
* the specified entry point will be executed.
*/
cpu_fork(p1, p2, stack, stacksize, func, arg);
}
/*
* uvm_exit: exit a virtual address space
*
* - the process passed to us is a dead (pre-zombie) process; we
* are running on a different context now (the reaper).
* - we must run in a separate thread because freeing the vmspace
* of the dead process may block.
*/
void
uvm_exit(p)
struct proc *p;
{
uvmspace_free(p->p_vmspace);
uvm_km_free(kernel_map, (vaddr_t)p->p_addr, USPACE);
p->p_addr = NULL;
}
/*
* uvm_init_limit: init per-process VM limits
*
* - called for process 0 and then inherited by all others.
*/
void
uvm_init_limits(p)
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(uvmexp.free);
}
#ifdef DEBUG
int enableswap = 1;
int swapdebug = 0;
#define SDB_FOLLOW 1
#define SDB_SWAPIN 2
#define SDB_SWAPOUT 4
#endif
/*
* uvm_swapin: swap in a process's u-area.
*/
void
uvm_swapin(p)
struct proc *p;
{
vaddr_t addr;
int s;
addr = (vaddr_t)p->p_addr;
/* make P_INMEM true */
uvm_fault_wire(kernel_map, addr, addr + USPACE,
VM_PROT_READ | VM_PROT_WRITE);
/*
* Some architectures need to be notified when the user area has
* moved to new physical page(s) (e.g. see mips/mips/vm_machdep.c).
*/
cpu_swapin(p);
SCHED_LOCK(s);
if (p->p_stat == SRUN)
setrunqueue(p);
p->p_flag |= P_INMEM;
SCHED_UNLOCK(s);
p->p_swtime = 0;
++uvmexp.swapins;
}
/*
* uvm_scheduler: process zero main loop
*
* - attempt to swapin every swaped-out, runnable process in order of
* priority.
* - if not enough memory, wake the pagedaemon and let it clear space.
*/
void
uvm_scheduler()
{
struct proc *p;
int pri;
struct proc *pp;
int ppri;
UVMHIST_FUNC("uvm_scheduler"); UVMHIST_CALLED(maphist);
loop:
#ifdef DEBUG
while (!enableswap)
tsleep((caddr_t)&proc0, PVM, "noswap", 0);
#endif
pp = NULL; /* process to choose */
ppri = INT_MIN; /* its priority */
proclist_lock_read();
for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
/* is it a runnable swapped out process? */
if (p->p_stat == SRUN && (p->p_flag & P_INMEM) == 0) {
pri = p->p_swtime + p->p_slptime -
(p->p_nice - NZERO) * 8;
if (pri > ppri) { /* higher priority? remember it. */
pp = p;
ppri = pri;
}
}
}
/*
* XXXSMP: possible unlock/sleep race between here and the
* "scheduler" tsleep below..
*/
proclist_unlock_read();
#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 have found swapped out process which we would like to bring
* back in.
*
* XXX: this part is really bogus cuz we could deadlock on memory
* despite our feeble check
*/
if (uvmexp.free > 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, uvmexp.free);
#endif
uvm_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, uvmexp.free);
#endif
uvm_wait("schedpwait");
#ifdef DEBUG
if (swapdebug & SDB_FOLLOW)
printf("scheduler: room again, free %d\n", uvmexp.free);
#endif
goto loop;
}
/*
* swappable: is process "p" swappable?
*/
#define swappable(p) \
(((p)->p_flag & (P_SYSTEM | P_INMEM | P_WEXIT)) == P_INMEM && \
(p)->p_holdcnt == 0)
/*
* swapout_threads: find threads that can be swapped and unwire their
* u-areas.
*
* - called by the pagedaemon
* - try and swap at least one processs
* - processes that are sleeping or stopped for maxslp or more seconds
* are swapped... otherwise the longest-sleeping or stopped process
* is swapped, otherwise the longest resident process...
*/
void
uvm_swapout_threads()
{
struct proc *p;
struct proc *outp, *outp2;
int outpri, outpri2;
int didswap = 0;
extern int maxslp;
/* XXXCDC: should move off to uvmexp. or uvm., also in uvm_meter */
#ifdef DEBUG
if (!enableswap)
return;
#endif
/*
* outp/outpri : stop/sleep process with largest sleeptime < maxslp
* outp2/outpri2: the longest resident process (its swap time)
*/
outp = outp2 = NULL;
outpri = outpri2 = 0;
proclist_lock_read();
for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
if (!swappable(p))
continue;
switch (p->p_stat) {
case SRUN:
case SONPROC:
if (p->p_swtime > outpri2) {
outp2 = p;
outpri2 = p->p_swtime;
}
continue;
case SSLEEP:
case SSTOP:
if (p->p_slptime >= maxslp) {
uvm_swapout(p); /* zap! */
didswap++;
} else if (p->p_slptime > outpri) {
outp = p;
outpri = p->p_slptime;
}
continue;
}
}
proclist_unlock_read();
/*
* 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 && uvmexp.free <= atop(round_page(USPACE))) {
if ((p = outp) == NULL)
p = outp2;
#ifdef DEBUG
if (swapdebug & SDB_SWAPOUT)
printf("swapout_threads: no duds, try procp %p\n", p);
#endif
if (p)
uvm_swapout(p);
}
}
/*
* uvm_swapout: swap out process "p"
*
* - currently "swapout" means "unwire U-area" and "pmap_collect()"
* the pmap.
* - XXXCDC: should deactivate all process' private anonymous memory
*/
static void
uvm_swapout(p)
struct proc *p;
{
vaddr_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, uvmexp.free);
#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 = (vaddr_t)p->p_addr;
uvm_fault_unwire(kernel_map, addr, addr + USPACE); /* !P_INMEM */
pmap_collect(vm_map_pmap(&p->p_vmspace->vm_map));
/*
* Mark it as (potentially) swapped out.
*/
SCHED_LOCK(s);
p->p_flag &= ~P_INMEM;
if (p->p_stat == SRUN)
remrunqueue(p);
SCHED_UNLOCK(s);
p->p_swtime = 0;
++uvmexp.swapouts;
}
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