4.4BSD/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 8.1 (Berkeley) 6/11/93
*
*
* 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 */
#endif
#ifdef VNODEPAGER
&vnodepagerops, /* PG_VNODE */
#endif
#ifdef DEVPAGER
&devicepagerops, /* PG_DEV */
#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.
*/
#define PAGER_MAP_SIZE (256 * PAGE_SIZE)
vm_map_t pager_map;
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++)
(*(*pgops)->pgo_init)();
if (dfltpagerops == NULL)
panic("no default pager");
}
/*
* Allocate an instance of a pager of the given type.
*/
vm_pager_t
vm_pager_allocate(type, handle, size, prot)
int type;
caddr_t handle;
vm_size_t size;
vm_prot_t prot;
{
vm_pager_t pager;
struct pagerops *ops;
ops = (type == PG_DFLT) ? dfltpagerops : pagertab[type];
return((*ops->pgo_alloc)(handle, size, prot));
}
void
vm_pager_deallocate(pager)
vm_pager_t pager;
{
if (pager == NULL)
panic("vm_pager_deallocate: null pager");
VM_PAGER_DEALLOC(pager);
}
int
vm_pager_get(pager, m, sync)
vm_pager_t pager;
vm_page_t m;
boolean_t sync;
{
extern boolean_t vm_page_zero_fill();
if (pager == NULL)
return(vm_page_zero_fill(m) ? VM_PAGER_OK : VM_PAGER_FAIL);
return(VM_PAGER_GET(pager, m, sync));
}
int
vm_pager_put(pager, m, sync)
vm_pager_t pager;
vm_page_t m;
boolean_t sync;
{
if (pager == NULL)
panic("vm_pager_put: null pager");
return(VM_PAGER_PUT(pager, m, 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");
return(VM_PAGER_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++)
(*(*pgops)->pgo_putpage)(NULL, NULL, FALSE);
}
vm_offset_t
vm_pager_map_page(m)
vm_page_t m;
{
vm_offset_t kva;
#ifdef DEBUG
if ((m->flags & PG_BUSY) == 0)
panic("vm_pager_map_page: page not busy");
if (m->flags & PG_PAGEROWNED)
printf("vm_pager_map_page: page %x already in pager\n", m);
#endif
kva = kmem_alloc_wait(pager_map, PAGE_SIZE);
#ifdef DEBUG
m->flags |= PG_PAGEROWNED;
#endif
pmap_enter(vm_map_pmap(pager_map), kva, VM_PAGE_TO_PHYS(m),
VM_PROT_DEFAULT, TRUE);
return(kva);
}
void
vm_pager_unmap_page(kva)
vm_offset_t kva;
{
#ifdef DEBUG
vm_page_t m;
m = PHYS_TO_VM_PAGE(pmap_extract(vm_map_pmap(pager_map), kva));
#endif
pmap_remove(vm_map_pmap(pager_map), kva, kva + PAGE_SIZE);
kmem_free_wakeup(pager_map, kva, PAGE_SIZE);
#ifdef DEBUG
if (m->flags & PG_PAGEROWNED)
m->flags &= ~PG_PAGEROWNED;
else
printf("vm_pager_unmap_page: page %x(%x/%x) not owned\n",
m, kva, VM_PAGE_TO_PHYS(m));
#endif
}
vm_pager_t
vm_pager_lookup(list, handle)
register queue_head_t *list;
caddr_t handle;
{
register vm_pager_t pager;
pager = (vm_pager_t) queue_first(list);
while (!queue_end(list, (queue_entry_t)pager)) {
if (pager->pg_handle == handle)
return(pager);
pager = (vm_pager_t) queue_next(&pager->pg_list);
}
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);
}