1
0
mirror of https://git.FreeBSD.org/src.git synced 2024-12-24 11:29:10 +00:00
freebsd/sys/vm/vm_glue.c
Alan Cox d974f03c69 o Introduce and use vm_map_trylock() to replace several direct uses
of lockmgr().
 o Add missing synchronization to vmspace_swap_count(): Obtain a read lock
   on the vm_map before traversing it.
2002-04-28 06:07:54 +00:00

632 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.
*
* $FreeBSD$
*/
#include "opt_vm.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/shm.h>
#include <sys/vmmeter.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/unistd.h>
#include <machine/limits.h>
#include <vm/vm.h>
#include <vm/vm_param.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 <sys/user.h>
extern int maxslp;
/*
* System initialization
*
* Note: proc0 from proc.h
*/
static void vm_init_limits(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(void *);
SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL)
#ifndef NO_SWAPPING
static void swapout(struct proc *);
#endif
int
kernacc(addr, len, rw)
caddr_t addr;
int len, rw;
{
boolean_t rv;
vm_offset_t saddr, eaddr;
vm_prot_t prot;
KASSERT((rw & ~VM_PROT_ALL) == 0,
("illegal ``rw'' argument to kernacc (%x)\n", rw));
prot = rw;
saddr = trunc_page((vm_offset_t)addr);
eaddr = round_page((vm_offset_t)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;
GIANT_REQUIRED;
KASSERT((rw & ~VM_PROT_ALL) == 0,
("illegal ``rw'' argument to useracc (%x)\n", rw));
prot = rw;
/*
* 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((vm_offset_t)addr), round_page((vm_offset_t)addr + len),
prot);
return (rv == TRUE);
}
void
vslock(addr, len)
caddr_t addr;
u_int len;
{
GIANT_REQUIRED;
vm_map_pageable(&curproc->p_vmspace->vm_map,
trunc_page((vm_offset_t)addr),
round_page((vm_offset_t)addr + len), FALSE);
}
void
vsunlock(addr, len)
caddr_t addr;
u_int len;
{
GIANT_REQUIRED;
vm_map_pageable(&curproc->p_vmspace->vm_map,
trunc_page((vm_offset_t)addr),
round_page((vm_offset_t)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. The new process is set up so that it returns directly
* to user mode to avoid stack copying and relocation problems.
*/
void
vm_forkproc(td, p2, td2, flags)
struct thread *td;
struct proc *p2;
struct thread *td2;
int flags;
{
struct proc *p1 = td->td_proc;
struct user *up;
GIANT_REQUIRED;
if ((flags & RFPROC) == 0) {
/*
* Divorce the memory, if it is shared, essentially
* this changes shared memory amongst threads, into
* COW locally.
*/
if ((flags & RFMEM) == 0) {
if (p1->p_vmspace->vm_refcnt > 1) {
vmspace_unshare(p1);
}
}
cpu_fork(td, p2, td2, flags);
return;
}
if (flags & RFMEM) {
p2->p_vmspace = p1->p_vmspace;
p1->p_vmspace->vm_refcnt++;
}
while (vm_page_count_severe()) {
VM_WAIT;
}
if ((flags & RFMEM) == 0) {
p2->p_vmspace = vmspace_fork(p1->p_vmspace);
pmap_pinit2(vmspace_pmap(p2->p_vmspace));
if (p1->p_vmspace->vm_shm)
shmfork(p1, p2);
}
pmap_new_proc(p2);
pmap_new_thread(td2); /* Initial thread */
/* XXXKSE this is unsatisfactory but should be adequate */
up = p2->p_uarea;
/*
* p_stats currently points at fields in the user struct
* but not at &u, instead at p_addr. Copy parts of
* p_stats; zero the rest of p_stats (statistics).
*
* If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need
* to share sigacts, so we use the up->u_sigacts.
*/
p2->p_stats = &up->u_stats;
if (p2->p_sigacts == NULL) {
if (p2->p_procsig->ps_refcnt != 1)
printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid);
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 pcb, set up the kernel stack,
* and make the child ready to run.
*/
cpu_fork(td, p2, td2, flags);
}
/*
* Called after process has been wait(2)'ed apon and is being reaped.
* The idea is to reclaim resources that we could not reclaim while
* the process was still executing.
*/
void
vm_waitproc(p)
struct proc *p;
{
struct thread *td;
GIANT_REQUIRED;
cpu_wait(p);
pmap_dispose_proc(p); /* drop per-process resources */
FOREACH_THREAD_IN_PROC(p, td)
pmap_dispose_thread(td);
vmspace_exitfree(p); /* and clean-out the vmspace */
}
/*
* 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;
{
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;
{
struct thread *td;
GIANT_REQUIRED;
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_lock_spin(&sched_lock);
if ((p->p_sflag & PS_INMEM) == 0) {
++p->p_lock;
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
pmap_swapin_proc(p);
FOREACH_THREAD_IN_PROC (p, td)
pmap_swapin_thread(td);
PROC_LOCK(p);
mtx_lock_spin(&sched_lock);
FOREACH_THREAD_IN_PROC (p, td)
if (td->td_proc->p_stat == SRUN) /* XXXKSE */
setrunqueue(td);
p->p_sflag |= PS_INMEM;
/* undo the effect of setting SLOCK above */
--p->p_lock;
}
mtx_unlock_spin(&sched_lock);
}
/*
* 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.
*
* XXXKSE - KSEGRP with highest priority counts..
*
* Giant is still held at this point, to be released in tsleep.
*/
/* ARGSUSED*/
static void
scheduler(dummy)
void *dummy;
{
struct proc *p;
int pri;
struct proc *pp;
int ppri;
mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED);
/* GIANT_REQUIRED */
loop:
if (vm_page_count_min()) {
VM_WAIT;
goto loop;
}
pp = NULL;
ppri = INT_MIN;
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
struct ksegrp *kg;
mtx_lock_spin(&sched_lock);
if (p->p_stat == SRUN
&& (p->p_sflag & (PS_INMEM | PS_SWAPPING)) == 0) {
/* Find the minimum sleeptime for the process */
FOREACH_KSEGRP_IN_PROC(p, kg) {
pri = p->p_swtime + kg->kg_slptime;
if ((p->p_sflag & PS_SWAPINREQ) == 0) {
pri -= kg->kg_nice * 8;
}
/*
* if this ksegrp is higher priority
* and there is enough space, then select
* this process instead of the previous
* selection.
*/
if (pri > ppri) {
pp = p;
ppri = pri;
}
}
}
mtx_unlock_spin(&sched_lock);
}
sx_sunlock(&allproc_lock);
/*
* Nothing to do, back to sleep.
*/
if ((p = pp) == NULL) {
tsleep(&proc0, PVM, "sched", maxslp * hz / 2);
goto loop;
}
mtx_lock_spin(&sched_lock);
p->p_sflag &= ~PS_SWAPINREQ;
mtx_unlock_spin(&sched_lock);
/*
* We would like to bring someone in. (only if there is space).
*/
PROC_LOCK(p);
faultin(p);
PROC_UNLOCK(p);
mtx_lock_spin(&sched_lock);
p->p_swtime = 0;
mtx_unlock_spin(&sched_lock);
goto loop;
}
#ifndef NO_SWAPPING
/*
* Swap_idle_threshold1 is the guaranteed swapped in time for a process
*/
static int swap_idle_threshold1 = 2;
SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1,
CTLFLAG_RW, &swap_idle_threshold1, 0, "");
/*
* Swap_idle_threshold2 is the time that a process can be idle before
* it will be swapped out, if idle swapping is enabled.
*/
static int swap_idle_threshold2 = 10;
SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2,
CTLFLAG_RW, &swap_idle_threshold2, 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_procs(action)
int action;
{
struct proc *p;
struct ksegrp *kg;
struct proc *outp, *outp2;
int outpri, outpri2;
int didswap = 0;
GIANT_REQUIRED;
outp = outp2 = NULL;
outpri = outpri2 = INT_MIN;
retry:
sx_slock(&allproc_lock);
LIST_FOREACH(p, &allproc, p_list) {
struct vmspace *vm;
int minslptime = 100000;
PROC_LOCK(p);
if (p->p_lock != 0 ||
(p->p_flag & (P_TRACED|P_SYSTEM|P_WEXIT)) != 0) {
PROC_UNLOCK(p);
continue;
}
/*
* only aiod changes vmspace, however it will be
* skipped because of the if statement above checking
* for P_SYSTEM
*/
vm = p->p_vmspace;
mtx_lock_spin(&sched_lock);
if ((p->p_sflag & (PS_INMEM|PS_SWAPPING)) != PS_INMEM) {
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
continue;
}
switch (p->p_stat) {
default:
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
continue;
case SSLEEP:
case SSTOP:
/*
* do not swapout a realtime process
* Check all the thread groups..
*/
FOREACH_KSEGRP_IN_PROC(p, kg) {
if (PRI_IS_REALTIME(kg->kg_pri_class)) {
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
goto nextproc;
}
/*
* Do not swapout a process waiting
* on a critical event of some kind.
* Also guarantee swap_idle_threshold1
* time in memory.
*/
if (((FIRST_THREAD_IN_PROC(p)->td_priority) < PSOCK) ||
(kg->kg_slptime < swap_idle_threshold1)) {
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
goto nextproc;
}
/*
* If the system is under memory stress,
* or if we are swapping
* idle processes >= swap_idle_threshold2,
* then swap the process out.
*/
if (((action & VM_SWAP_NORMAL) == 0) &&
(((action & VM_SWAP_IDLE) == 0) ||
(kg->kg_slptime < swap_idle_threshold2))) {
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
goto nextproc;
}
if (minslptime > kg->kg_slptime)
minslptime = kg->kg_slptime;
}
mtx_unlock_spin(&sched_lock);
++vm->vm_refcnt;
/*
* do not swapout a process that
* is waiting for VM
* data structures there is a
* possible deadlock.
*/
if (!vm_map_trylock(&vm->vm_map)) {
vmspace_free(vm);
PROC_UNLOCK(p);
goto nextproc;
}
vm_map_unlock(&vm->vm_map);
/*
* If the process has been asleep for awhile and had
* most of its pages taken away already, swap it out.
*/
if ((action & VM_SWAP_NORMAL) ||
((action & VM_SWAP_IDLE) &&
(minslptime > swap_idle_threshold2))) {
sx_sunlock(&allproc_lock);
swapout(p);
vmspace_free(vm);
didswap++;
goto retry;
}
PROC_UNLOCK(p);
vmspace_free(vm);
}
nextproc:
continue;
}
sx_sunlock(&allproc_lock);
/*
* If we swapped something out, and another process needed memory,
* then wakeup the sched process.
*/
if (didswap)
wakeup(&proc0);
}
static void
swapout(p)
struct proc *p;
{
struct thread *td;
PROC_LOCK_ASSERT(p, MA_OWNED);
#if defined(SWAP_DEBUG)
printf("swapping out %d\n", p->p_pid);
#endif
++p->p_stats->p_ru.ru_nswap;
/*
* remember the process resident count
*/
p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace);
mtx_lock_spin(&sched_lock);
p->p_sflag &= ~PS_INMEM;
p->p_sflag |= PS_SWAPPING;
PROC_UNLOCK(p);
FOREACH_THREAD_IN_PROC (p, td)
if (td->td_proc->p_stat == SRUN) /* XXXKSE */
remrunqueue(td); /* XXXKSE */
mtx_unlock_spin(&sched_lock);
pmap_swapout_proc(p);
FOREACH_THREAD_IN_PROC(p, td)
pmap_swapout_thread(td);
mtx_lock_spin(&sched_lock);
p->p_sflag &= ~PS_SWAPPING;
p->p_swtime = 0;
mtx_unlock_spin(&sched_lock);
}
#endif /* !NO_SWAPPING */