.ref-BSD-4_4_Lite1/usr/src/sys/vm/vm_pager.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.
 *
 *      @(#)vm_pager.c  8.6 (Berkeley) 1/12/94
 *
 *
 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
 * All rights reserved.
 *
 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
 *
 * 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.
 */

/*
 *      Paging space routine stubs.  Emulates a matchmaker-like interface
 *      for builtin pagers.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>

#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_kern.h>

#ifdef SWAPPAGER
extern struct pagerops swappagerops;
#endif

#ifdef VNODEPAGER
extern struct pagerops vnodepagerops;
#endif

#ifdef DEVPAGER
extern struct pagerops devicepagerops;
#endif

struct pagerops *pagertab[] = {
#ifdef SWAPPAGER
        &swappagerops,          /* PG_SWAP */
#else
        NULL,
#endif
#ifdef VNODEPAGER
        &vnodepagerops,         /* PG_VNODE */
#else
        NULL,
#endif
#ifdef DEVPAGER
        &devicepagerops,        /* PG_DEV */
#else
        NULL,
#endif
};
int npagers = sizeof (pagertab) / sizeof (pagertab[0]);

struct pagerops *dfltpagerops = NULL;   /* default pager */

/*
 * Kernel address space for mapping pages.
 * Used by pagers where KVAs are needed for IO.
 *
 * XXX needs to be large enough to support the number of pending async
 * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size
 * (MAXPHYS == 64k) if you want to get the most efficiency.
 */
#define PAGER_MAP_SIZE  (4 * 1024 * 1024)

vm_map_t pager_map;
boolean_t pager_map_wanted;
vm_offset_t pager_sva, pager_eva;

void
vm_pager_init()
{
        struct pagerops **pgops;

        /*
         * Allocate a kernel submap for tracking get/put page mappings
         */
        pager_map = kmem_suballoc(kernel_map, &pager_sva, &pager_eva,
                                  PAGER_MAP_SIZE, FALSE);
        /*
         * Initialize known pagers
         */
        for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
                if (pgops)
                        (*(*pgops)->pgo_init)();
        if (dfltpagerops == NULL)
                panic("no default pager");
}

/*
 * Allocate an instance of a pager of the given type.
 * Size, protection and offset parameters are passed in for pagers that
 * need to perform page-level validation (e.g. the device pager).
 */
vm_pager_t
vm_pager_allocate(type, handle, size, prot, off)
        int type;
        caddr_t handle;
        vm_size_t size;
        vm_prot_t prot;
        vm_offset_t off;
{
        struct pagerops *ops;

        ops = (type == PG_DFLT) ? dfltpagerops : pagertab[type];
        if (ops)
                return ((*ops->pgo_alloc)(handle, size, prot, off));
        return (NULL);
}

void
vm_pager_deallocate(pager)
        vm_pager_t      pager;
{
        if (pager == NULL)
                panic("vm_pager_deallocate: null pager");

        (*pager->pg_ops->pgo_dealloc)(pager);
}

int
vm_pager_get_pages(pager, mlist, npages, sync)
        vm_pager_t      pager;
        vm_page_t       *mlist;
        int             npages;
        boolean_t       sync;
{
        int rv;

        if (pager == NULL) {
                rv = VM_PAGER_OK;
                while (npages--)
                        if (!vm_page_zero_fill(*mlist)) {
                                rv = VM_PAGER_FAIL;
                                break;
                        } else
                                mlist++;
                return (rv);
        }
        return ((*pager->pg_ops->pgo_getpages)(pager, mlist, npages, sync));
}

int
vm_pager_put_pages(pager, mlist, npages, sync)
        vm_pager_t      pager;
        vm_page_t       *mlist;
        int             npages;
        boolean_t       sync;
{
        if (pager == NULL)
                panic("vm_pager_put_pages: null pager");
        return ((*pager->pg_ops->pgo_putpages)(pager, mlist, npages, sync));
}

boolean_t
vm_pager_has_page(pager, offset)
        vm_pager_t      pager;
        vm_offset_t     offset;
{
        if (pager == NULL)
                panic("vm_pager_has_page: null pager");
        return ((*pager->pg_ops->pgo_haspage)(pager, offset));
}

/*
 * Called by pageout daemon before going back to sleep.
 * Gives pagers a chance to clean up any completed async pageing operations.
 */
void
vm_pager_sync()
{
        struct pagerops **pgops;

        for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
                if (pgops)
                        (*(*pgops)->pgo_putpages)(NULL, NULL, 0, FALSE);
}

void
vm_pager_cluster(pager, offset, loff, hoff)
        vm_pager_t      pager;
        vm_offset_t     offset;
        vm_offset_t     *loff;
        vm_offset_t     *hoff;
{
        if (pager == NULL)
                panic("vm_pager_cluster: null pager");
        return ((*pager->pg_ops->pgo_cluster)(pager, offset, loff, hoff));
}

void
vm_pager_clusternull(pager, offset, loff, hoff)
        vm_pager_t      pager;
        vm_offset_t     offset;
        vm_offset_t     *loff;
        vm_offset_t     *hoff;
{
        panic("vm_pager_nullcluster called");
}

vm_offset_t
vm_pager_map_pages(mlist, npages, canwait)
        vm_page_t       *mlist;
        int             npages;
        boolean_t       canwait;
{
        vm_offset_t kva, va;
        vm_size_t size;
        vm_page_t m;

        /*
         * Allocate space in the pager map, if none available return 0.
         * This is basically an expansion of kmem_alloc_wait with optional
         * blocking on no space.
         */
        size = npages * PAGE_SIZE;
        vm_map_lock(pager_map);
        while (vm_map_findspace(pager_map, 0, size, &kva)) {
                if (!canwait) {
                        vm_map_unlock(pager_map);
                        return (0);
                }
                pager_map_wanted = TRUE;
                vm_map_unlock(pager_map);
                (void) tsleep(pager_map, PVM, "pager_map", 0);
                vm_map_lock(pager_map);
        }
        vm_map_insert(pager_map, NULL, 0, kva, kva + size);
        vm_map_unlock(pager_map);

        for (va = kva; npages--; va += PAGE_SIZE) {
                m = *mlist++;
#ifdef DEBUG
                if ((m->flags & PG_BUSY) == 0)
                        panic("vm_pager_map_pages: page not busy");
                if (m->flags & PG_PAGEROWNED)
                        panic("vm_pager_map_pages: page already in pager");
#endif
#ifdef DEBUG
                m->flags |= PG_PAGEROWNED;
#endif
                pmap_enter(vm_map_pmap(pager_map), va, VM_PAGE_TO_PHYS(m),
                           VM_PROT_DEFAULT, TRUE);
        }
        return (kva);
}

void
vm_pager_unmap_pages(kva, npages)
        vm_offset_t     kva;
        int             npages;
{
        vm_size_t size = npages * PAGE_SIZE;

#ifdef DEBUG
        vm_offset_t va;
        vm_page_t m;
        int np = npages;

        for (va = kva; np--; va += PAGE_SIZE) {
                m = vm_pager_atop(va);
                if (m->flags & PG_PAGEROWNED)
                        m->flags &= ~PG_PAGEROWNED;
                else
                        printf("vm_pager_unmap_pages: %x(%x/%x) not owned\n",
                               m, va, VM_PAGE_TO_PHYS(m));
        }
#endif
        pmap_remove(vm_map_pmap(pager_map), kva, kva + size);
        vm_map_lock(pager_map);
        (void) vm_map_delete(pager_map, kva, kva + size);
        if (pager_map_wanted)
                wakeup(pager_map);
        vm_map_unlock(pager_map);
}

vm_page_t
vm_pager_atop(kva)
        vm_offset_t     kva;
{
        vm_offset_t pa;

        pa = pmap_extract(vm_map_pmap(pager_map), kva);
        if (pa == 0)
                panic("vm_pager_atop");
        return (PHYS_TO_VM_PAGE(pa));
}

vm_pager_t
vm_pager_lookup(pglist, handle)
        register struct pagerlst *pglist;
        caddr_t handle;
{
        register vm_pager_t pager;

        for (pager = pglist->tqh_first; pager; pager = pager->pg_list.tqe_next)
                if (pager->pg_handle == handle)
                        return (pager);
        return (NULL);
}

/*
 * This routine gains a reference to the object.
 * Explicit deallocation is necessary.
 */
int
pager_cache(object, should_cache)
        vm_object_t     object;
        boolean_t       should_cache;
{
        if (object == NULL)
                return (KERN_INVALID_ARGUMENT);

        vm_object_cache_lock();
        vm_object_lock(object);
        if (should_cache)
                object->flags |= OBJ_CANPERSIST;
        else
                object->flags &= ~OBJ_CANPERSIST;
        vm_object_unlock(object);
        vm_object_cache_unlock();

        vm_object_deallocate(object);

        return (KERN_SUCCESS);
}