[dragonfly.git] / 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.
 *
 *      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: src/sys/vm/vm_glue.c,v 1.94.2.4 2003/01/13 22:51:17 dillon Exp $
 * $DragonFly: src/sys/vm/vm_glue.c,v 1.25 2004/07/24 20:21:35 dillon Exp $
 */

#include "opt_vm.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/buf.h>
#include <sys/shm.h>
#include <sys/vmmeter.h>
#include <sys/sysctl.h>

#include <sys/kernel.h>
#include <sys/unistd.h>

#include <machine/limits.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <sys/lock.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>
#include <vm/vm_page2.h>

/*
 * 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)


static void swapout (struct proc *);

int
kernacc(caddr_t addr, int len, int 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);
        vm_map_lock_read(kernel_map);
        rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
        vm_map_unlock_read(kernel_map);
        return (rv == TRUE);
}

int
useracc(caddr_t addr, int len, int rw)
{
        boolean_t rv;
        vm_prot_t prot;
        vm_map_t map;
        vm_map_entry_t save_hint;

        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);
        }
        map = &curproc->p_vmspace->vm_map;
        vm_map_lock_read(map);
        /*
         * We save the map hint, and restore it.  Useracc appears to distort
         * the map hint unnecessarily.
         */
        save_hint = map->hint;
        rv = vm_map_check_protection(map,
            trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), prot);
        map->hint = save_hint;
        vm_map_unlock_read(map);
        
        return (rv == TRUE);
}

void
vslock(caddr_t addr, u_int len)
{
        vm_map_wire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr),
            round_page((vm_offset_t)addr + len), 0);
}

void
vsunlock(caddr_t addr, u_int len)
{
        vm_map_wire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr),
            round_page((vm_offset_t)addr + len), KM_PAGEABLE);
}

/*
 * 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_fork(struct proc *p1, struct proc *p2, int flags)
{
        struct user *up;
        struct thread *td2;

        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(p1, p2, 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);
        }

        td2 = lwkt_alloc_thread(NULL, -1);
        pmap_init_proc(p2, td2);
        lwkt_setpri(td2, TDPRI_KERN_USER);
        lwkt_set_comm(td2, "%s", p1->p_comm);

        up = p2->p_addr;

        /*
         * 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, sizeof(struct pstats));
        bcopy(&p1->p_stats->p_prof, &up->u_stats.p_prof,
                sizeof(struct uprof));
        bcopy(&p1->p_thread->td_start, &p2->p_thread->td_start,
                sizeof(struct timeval));


        /*
         * cpu_fork will copy and update the pcb, set up the kernel stack,
         * and make the child ready to run.
         */
        cpu_fork(p1, p2, 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(struct proc *p)
{
        cpu_proc_wait(p);
        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(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(vmstats.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(struct proc *p)
{
        int s;

        if ((p->p_flag & P_INMEM) == 0) {

                ++p->p_lock;

                pmap_swapin_proc(p);

                s = splhigh();

                /*
                 * The process is in the kernel and controlled by LWKT,
                 * so we just schedule it rather then call setrunqueue().
                 */
                if (p->p_stat == SRUN)
                        lwkt_schedule(p->p_thread);

                p->p_flag |= P_INMEM;

                /* undo the effect of setting SLOCK above */
                --p->p_lock;
                splx(s);

        }
}

/*
 * Kernel initialization eventually falls through to this function,
 * which is process 0.
 *
 * 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.
 */
/* ARGSUSED*/
static void
scheduler(void *dummy)
{
        struct proc *p;
        int pri;
        struct proc *pp;
        int ppri;

        KKASSERT(!IN_CRITICAL_SECT(curthread));
loop:
        if (vm_page_count_min()) {
                vm_wait();
                goto loop;
        }

        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 | P_SWAPPING)) == 0) {

                        pri = p->p_swtime + p->p_slptime;
                        if ((p->p_flag & P_SWAPINREQ) == 0) {
                                pri -= p->p_nice * 8;
                        }

                        /*
                         * if this process is higher priority and there is
                         * enough space, then select this process instead of
                         * the previous selection.
                         */
                        if (pri > ppri) {
                                pp = p;
                                ppri = pri;
                        }
                }
        }

        /*
         * Nothing to do, back to sleep.
         */
        if ((p = pp) == NULL) {
                tsleep(&proc0, 0, "sched", 0);
                goto loop;
        }
        p->p_flag &= ~P_SWAPINREQ;

        /*
         * We would like to bring someone in. (only if there is space).
         */
        faultin(p);
        p->p_swtime = 0;
        goto loop;
}

#ifndef NO_SWAPPING

#define swappable(p) \
        (((p)->p_lock == 0) && \
                ((p)->p_flag & (P_TRACED|P_SYSTEM|P_INMEM|P_WEXIT|P_SWAPPING)) == P_INMEM)


/*
 * 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(int action)
{
        struct proc *p;
        struct proc *outp, *outp2;
        int outpri, outpri2;
        int didswap = 0;

        outp = outp2 = NULL;
        outpri = outpri2 = INT_MIN;
retry:
        for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
                struct vmspace *vm;
                if (!swappable(p))
                        continue;

                vm = p->p_vmspace;

                switch (p->p_stat) {
                default:
                        continue;

                case SSLEEP:
                case SSTOP:
                        /*
                         * do not swapout a realtime process
                         */
                        if (RTP_PRIO_IS_REALTIME(p->p_rtprio.type))
                                continue;

                        /*
                         * YYY do not swapout a proc waiting on a critical
                         * event.
                         *
                         * Guarentee swap_idle_threshold time in memory
                         */
                        if (p->p_slptime < swap_idle_threshold1)
                                continue;

                        /*
                         * 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) ||
                                  (p->p_slptime < swap_idle_threshold2)))
                                continue;

                        ++vm->vm_refcnt;
                        /*
                         * do not swapout a process that is waiting for VM
                         * data structures there is a possible deadlock.
                         */
                        if (lockmgr(&vm->vm_map.lock,
                                        LK_EXCLUSIVE | LK_NOWAIT,
                                        NULL, curthread)) {
                                vmspace_free(vm);
                                continue;
                        }
                        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) &&
                                 (p->p_slptime > swap_idle_threshold2))) {
                                swapout(p);
                                vmspace_free(vm);
                                didswap++;
                                goto retry;
                        }

                        /*
                         * cleanup our reference
                         */
                        vmspace_free(vm);
                }
        }
        /*
         * If we swapped something out, and another process needed memory,
         * then wakeup the sched process.
         */
        if (didswap)
                wakeup(&proc0);
}

static void
swapout(struct proc *p)
{

#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);

        (void) splhigh();
        p->p_flag &= ~P_INMEM;
        p->p_flag |= P_SWAPPING;
        if (p->p_flag & P_ONRUNQ)
                remrunqueue(p);
        (void) spl0();

        pmap_swapout_proc(p);

        p->p_flag &= ~P_SWAPPING;
        p->p_swtime = 0;
}
#endif /* !NO_SWAPPING */