d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
8bdc42c0a1
freebsd-skq/sys/vm/vm_object.c

1761 lines
42 KiB
C
Raw Blame History

/*
* 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_object.c 8.5 (Berkeley) 3/22/94
*
*
* 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.
*
* $Id: vm_object.c,v 1.146 1999/02/07 21:48:22 dillon Exp $
*/
/*
* Virtual memory object module.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h> /* for curproc, pageproc */
#include <sys/vnode.h>
#include <sys/vmmeter.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_prot.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_pager.h>
#include <vm/swap_pager.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/vm_zone.h>
static void vm_object_qcollapse __P((vm_object_t object));
/*
* Virtual memory objects maintain the actual data
* associated with allocated virtual memory. A given
* page of memory exists within exactly one object.
*
* An object is only deallocated when all "references"
* are given up. Only one "reference" to a given
* region of an object should be writeable.
*
* Associated with each object is a list of all resident
* memory pages belonging to that object; this list is
* maintained by the "vm_page" module, and locked by the object's
* lock.
*
* Each object also records a "pager" routine which is
* used to retrieve (and store) pages to the proper backing
* storage. In addition, objects may be backed by other
* objects from which they were virtual-copied.
*
* The only items within the object structure which are
* modified after time of creation are:
* reference count locked by object's lock
* pager routine locked by object's lock
*
*/
struct object_q vm_object_list;
#ifndef NULL_SIMPLELOCKS
static struct simplelock vm_object_list_lock;
#endif
static long vm_object_count; /* count of all objects */
vm_object_t kernel_object;
vm_object_t kmem_object;
static struct vm_object kernel_object_store;
static struct vm_object kmem_object_store;
extern int vm_pageout_page_count;
static long object_collapses;
static long object_bypasses;
static int next_index;
static vm_zone_t obj_zone;
static struct vm_zone obj_zone_store;
static int object_hash_rand;
#define VM_OBJECTS_INIT 256
static struct vm_object vm_objects_init[VM_OBJECTS_INIT];
void
_vm_object_allocate(type, size, object)
objtype_t type;
vm_size_t size;
vm_object_t object;
{
int incr;
TAILQ_INIT(&object->memq);
TAILQ_INIT(&object->shadow_head);
object->type = type;
object->size = size;
object->ref_count = 1;
object->flags = 0;
if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP))
vm_object_set_flag(object, OBJ_ONEMAPPING);
object->behavior = OBJ_NORMAL;
object->paging_in_progress = 0;
object->resident_page_count = 0;
object->cache_count = 0;
object->wire_count = 0;
object->shadow_count = 0;
object->pg_color = next_index;
if ( size > (PQ_L2_SIZE / 3 + PQ_PRIME1))
incr = PQ_L2_SIZE / 3 + PQ_PRIME1;
else
incr = size;
next_index = (next_index + incr) & PQ_L2_MASK;
object->handle = NULL;
object->backing_object = NULL;
object->backing_object_offset = (vm_ooffset_t) 0;
/*
* Try to generate a number that will spread objects out in the
* hash table. We 'wipe' new objects across the hash in 128 page
* increments plus 1 more to offset it a little more by the time
* it wraps around.
*/
object->hash_rand = object_hash_rand - 129;
object->last_read = 0;
object->generation++;
TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
vm_object_count++;
object_hash_rand = object->hash_rand;
}
/*
* vm_object_init:
*
* Initialize the VM objects module.
*/
void
vm_object_init()
{
TAILQ_INIT(&vm_object_list);
simple_lock_init(&vm_object_list_lock);
vm_object_count = 0;
kernel_object = &kernel_object_store;
_vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
kernel_object);
kmem_object = &kmem_object_store;
_vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
kmem_object);
obj_zone = &obj_zone_store;
zbootinit(obj_zone, "VM OBJECT", sizeof (struct vm_object),
vm_objects_init, VM_OBJECTS_INIT);
}
void
vm_object_init2() {
zinitna(obj_zone, NULL, NULL, 0, 0, 0, 1);
}
/*
* vm_object_allocate:
*
* Returns a new object with the given size.
*/
vm_object_t
vm_object_allocate(type, size)
objtype_t type;
vm_size_t size;
{
vm_object_t result;
result = (vm_object_t) zalloc(obj_zone);
_vm_object_allocate(type, size, result);
return (result);
}
/*
* vm_object_reference:
*
* Gets another reference to the given object.
*/
void
vm_object_reference(object)
vm_object_t object;
{
if (object == NULL)
return;
KASSERT(!(object->flags & OBJ_DEAD),
("vm_object_reference: attempting to reference dead obj"));
object->ref_count++;
if (object->type == OBJT_VNODE) {
while (vget((struct vnode *) object->handle, LK_RETRY|LK_NOOBJ, curproc)) {
#if !defined(MAX_PERF)
printf("vm_object_reference: delay in getting object\n");
#endif
}
}
}
void
vm_object_vndeallocate(object)
vm_object_t object;
{
struct vnode *vp = (struct vnode *) object->handle;
KASSERT(object->type == OBJT_VNODE,
("vm_object_vndeallocate: not a vnode object"));
KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
#ifdef INVARIANTS
if (object->ref_count == 0) {
vprint("vm_object_vndeallocate", vp);
panic("vm_object_vndeallocate: bad object reference count");
}
#endif
object->ref_count--;
if (object->ref_count == 0) {
vp->v_flag &= ~VTEXT;
vm_object_clear_flag(object, OBJ_OPT);
}
vrele(vp);
}
/*
* vm_object_deallocate:
*
* Release a reference to the specified object,
* gained either through a vm_object_allocate
* or a vm_object_reference call. When all references
* are gone, storage associated with this object
* may be relinquished.
*
* No object may be locked.
*/
void
vm_object_deallocate(object)
vm_object_t object;
{
vm_object_t temp;
while (object != NULL) {
if (object->type == OBJT_VNODE) {
vm_object_vndeallocate(object);
return;
}
if (object->ref_count == 0) {
panic("vm_object_deallocate: object deallocated too many times: %d", object->type);
} else if (object->ref_count > 2) {
object->ref_count--;
return;
}
/*
* Here on ref_count of one or two, which are special cases for
* objects.
*/
if ((object->ref_count == 2) && (object->shadow_count == 0)) {
vm_object_set_flag(object, OBJ_ONEMAPPING);
object->ref_count--;
return;
} else if ((object->ref_count == 2) && (object->shadow_count == 1)) {
object->ref_count--;
if ((object->handle == NULL) &&
(object->type == OBJT_DEFAULT ||
object->type == OBJT_SWAP)) {
vm_object_t robject;
robject = TAILQ_FIRST(&object->shadow_head);
KASSERT(robject != NULL,
("vm_object_deallocate: ref_count: %d, shadow_count: %d",
object->ref_count,
object->shadow_count));
if ((robject->handle == NULL) &&
(robject->type == OBJT_DEFAULT ||
robject->type == OBJT_SWAP)) {
robject->ref_count++;
while (
robject->paging_in_progress ||
object->paging_in_progress
) {
vm_object_pip_sleep(robject, "objde1");
vm_object_pip_sleep(object, "objde2");
}
if (robject->ref_count == 1) {
robject->ref_count--;
object = robject;
goto doterm;
}
object = robject;
vm_object_collapse(object);
continue;
}
}
return;
} else {
object->ref_count--;
if (object->ref_count != 0)
return;
}
doterm:
temp = object->backing_object;
if (temp) {
TAILQ_REMOVE(&temp->shadow_head, object, shadow_list);
temp->shadow_count--;
if (temp->ref_count == 0)
vm_object_clear_flag(temp, OBJ_OPT);
temp->generation++;
object->backing_object = NULL;
}
vm_object_terminate(object);
/* unlocks and deallocates object */
object = temp;
}
}
/*
* vm_object_terminate actually destroys the specified object, freeing
* up all previously used resources.
*
* The object must be locked.
* This routine may block.
*/
void
vm_object_terminate(object)
vm_object_t object;
{
vm_page_t p;
int s;
/*
* Make sure no one uses us.
*/
vm_object_set_flag(object, OBJ_DEAD);
/*
* wait for the pageout daemon to be done with the object
*/
vm_object_pip_wait(object, "objtrm");
KASSERT(!object->paging_in_progress,
("vm_object_terminate: pageout in progress"));
/*
* Clean and free the pages, as appropriate. All references to the
* object are gone, so we don't need to lock it.
*/
if (object->type == OBJT_VNODE) {
struct vnode *vp;
/*
* Freeze optimized copies.
*/
vm_freeze_copyopts(object, 0, object->size);
/*
* Clean pages and flush buffers.
*/
vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
vp = (struct vnode *) object->handle;
vinvalbuf(vp, V_SAVE, NOCRED, NULL, 0, 0);
}
if (object->ref_count != 0)
panic("vm_object_terminate: object with references, ref_count=%d", object->ref_count);
/*
* Now free any remaining pages. For internal objects, this also
* removes them from paging queues. Don't free wired pages, just
* remove them from the object.
*/
s = splvm();
while ((p = TAILQ_FIRST(&object->memq)) != NULL) {
#if !defined(MAX_PERF)
if (p->busy || (p->flags & PG_BUSY))
panic("vm_object_terminate: freeing busy page %p\n", p);
#endif
if (p->wire_count == 0) {
vm_page_busy(p);
vm_page_free(p);
cnt.v_pfree++;
} else {
vm_page_busy(p);
vm_page_remove(p);
}
}
splx(s);
/*
* Let the pager know object is dead.
*/
vm_pager_deallocate(object);
/*
* Remove the object from the global object list.
*/
simple_lock(&vm_object_list_lock);
TAILQ_REMOVE(&vm_object_list, object, object_list);
simple_unlock(&vm_object_list_lock);
wakeup(object);
/*
* Free the space for the object.
*/
zfree(obj_zone, object);
}
/*
* vm_object_page_clean
*
* Clean all dirty pages in the specified range of object.
* Leaves page on whatever queue it is currently on.
*
* Odd semantics: if start == end, we clean everything.
*
* The object must be locked.
*/
void
vm_object_page_clean(object, start, end, flags)
vm_object_t object;
vm_pindex_t start;
vm_pindex_t end;
int flags;
{
vm_page_t p, np, tp;
vm_offset_t tstart, tend;
vm_pindex_t pi;
int s;
struct vnode *vp;
int runlen;
int maxf;
int chkb;
int maxb;
int i;
int pagerflags;
vm_page_t maf[vm_pageout_page_count];
vm_page_t mab[vm_pageout_page_count];
vm_page_t ma[vm_pageout_page_count];
int curgeneration;
if (object->type != OBJT_VNODE ||
(object->flags & OBJ_MIGHTBEDIRTY) == 0)
return;
pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : 0;
pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0;
vp = object->handle;
vm_object_set_flag(object, OBJ_CLEANING);
tstart = start;
if (end == 0) {
tend = object->size;
} else {
tend = end;
}
for(p = TAILQ_FIRST(&object->memq); p; p = TAILQ_NEXT(p, listq)) {
vm_page_flag_set(p, PG_CLEANCHK);
vm_page_protect(p, VM_PROT_READ);
}
if ((tstart == 0) && (tend == object->size)) {
vm_object_clear_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
}
rescan:
curgeneration = object->generation;
for(p = TAILQ_FIRST(&object->memq); p; p = np) {
np = TAILQ_NEXT(p, listq);
pi = p->pindex;
if (((p->flags & PG_CLEANCHK) == 0) ||
(pi < tstart) || (pi >= tend) ||
(p->valid == 0) ||
((p->queue - p->pc) == PQ_CACHE)) {
vm_page_flag_clear(p, PG_CLEANCHK);
continue;
}
vm_page_test_dirty(p);
if ((p->dirty & p->valid) == 0) {
vm_page_flag_clear(p, PG_CLEANCHK);
continue;
}
s = splvm();
while (vm_page_sleep_busy(p, TRUE, "vpcwai")) {
if (object->generation != curgeneration) {
splx(s);
goto rescan;
}
}
maxf = 0;
for(i=1;i<vm_pageout_page_count;i++) {
if ((tp = vm_page_lookup(object, pi + i)) != NULL) {
if ((tp->flags & PG_BUSY) ||
(tp->flags & PG_CLEANCHK) == 0 ||
(tp->busy != 0))
break;
if((tp->queue - tp->pc) == PQ_CACHE) {
vm_page_flag_clear(tp, PG_CLEANCHK);
break;
}
vm_page_test_dirty(tp);
if ((tp->dirty & tp->valid) == 0) {
vm_page_flag_clear(tp, PG_CLEANCHK);
break;
}
maf[ i - 1 ] = tp;
maxf++;
continue;
}
break;
}
maxb = 0;
chkb = vm_pageout_page_count - maxf;
if (chkb) {
for(i = 1; i < chkb;i++) {
if ((tp = vm_page_lookup(object, pi - i)) != NULL) {
if ((tp->flags & PG_BUSY) ||
(tp->flags & PG_CLEANCHK) == 0 ||
(tp->busy != 0))
break;
if((tp->queue - tp->pc) == PQ_CACHE) {
vm_page_flag_clear(tp, PG_CLEANCHK);
break;
}
vm_page_test_dirty(tp);
if ((tp->dirty & tp->valid) == 0) {
vm_page_flag_clear(tp, PG_CLEANCHK);
break;
}
mab[ i - 1 ] = tp;
maxb++;
continue;
}
break;
}
}
for(i=0;i<maxb;i++) {
int index = (maxb - i) - 1;
ma[index] = mab[i];
vm_page_flag_clear(ma[index], PG_CLEANCHK);
}
vm_page_flag_clear(p, PG_CLEANCHK);
ma[maxb] = p;
for(i=0;i<maxf;i++) {
int index = (maxb + i) + 1;
ma[index] = maf[i];
vm_page_flag_clear(ma[index], PG_CLEANCHK);
}
runlen = maxb + maxf + 1;
splx(s);
vm_pageout_flush(ma, runlen, pagerflags);
for (i = 0; i<runlen; i++) {
if (ma[i]->valid & ma[i]->dirty) {
vm_page_protect(ma[i], VM_PROT_READ);
vm_page_flag_set(ma[i], PG_CLEANCHK);
}
}
if (object->generation != curgeneration)
goto rescan;
}
VOP_FSYNC(vp, NULL, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc);
vm_object_clear_flag(object, OBJ_CLEANING);
return;
}
#ifdef not_used
/* XXX I cannot tell if this should be an exported symbol */
/*
* vm_object_deactivate_pages
*
* Deactivate all pages in the specified object. (Keep its pages
* in memory even though it is no longer referenced.)
*
* The object must be locked.
*/
static void
vm_object_deactivate_pages(object)
vm_object_t object;
{
vm_page_t p, next;
for (p = TAILQ_FIRST(&object->memq); p != NULL; p = next) {
next = TAILQ_NEXT(p, listq);
vm_page_deactivate(p);
}
}
#endif
/*
* Same as vm_object_pmap_copy, except range checking really
* works, and is meant for small sections of an object.
*
* This code protects resident pages by making them read-only
* and is typically called on a fork or split when a page
* is converted to copy-on-write.
*
* NOTE: If the page is already at VM_PROT_NONE, calling
* vm_page_protect will have no effect.
*/
void
vm_object_pmap_copy_1(object, start, end)
vm_object_t object;
vm_pindex_t start;
vm_pindex_t end;
{
vm_pindex_t idx;
vm_page_t p;
if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0)
return;
for (idx = start; idx < end; idx++) {
p = vm_page_lookup(object, idx);
if (p == NULL)
continue;
vm_page_protect(p, VM_PROT_READ);
}
}
/*
* vm_object_pmap_remove:
*
* Removes all physical pages in the specified
* object range from all physical maps.
*
* The object must *not* be locked.
*/
void
vm_object_pmap_remove(object, start, end)
vm_object_t object;
vm_pindex_t start;
vm_pindex_t end;
{
vm_page_t p;
if (object == NULL)
return;
for (p = TAILQ_FIRST(&object->memq);
p != NULL;
p = TAILQ_NEXT(p, listq)) {
if (p->pindex >= start && p->pindex < end)
vm_page_protect(p, VM_PROT_NONE);
}
if ((start == 0) && (object->size == end))
vm_object_clear_flag(object, OBJ_WRITEABLE);
}
/*
* vm_object_madvise:
*
* Implements the madvise function at the object/page level.
*
* Currently, madvise() functions are limited to the default and
* swap object types only, and also limited to only the unshared portions
* of a process's address space. MADV_FREE, certainly, could never be
* run on anything else. The others are more flexible and the code could
* be adjusted in the future to handle expanded cases for them.
*/
void
vm_object_madvise(object, pindex, count, advise)
vm_object_t object;
vm_pindex_t pindex;
int count;
int advise;
{
vm_pindex_t end, tpindex;
vm_object_t tobject;
vm_page_t m;
if (object == NULL)
return;
end = pindex + count;
/*
* MADV_FREE special case - free any swap backing store (as well
* as resident pages later on).
*/
if (advise == MADV_FREE) {
tobject = object;
tpindex = pindex;
while (
(tobject->type == OBJT_DEFAULT ||
tobject->type == OBJT_SWAP) &&
(tobject->flags & OBJ_ONEMAPPING)
) {
if (tobject->type == OBJT_SWAP) {
swap_pager_freespace(tobject, tpindex, count);
}
if ((tobject = tobject->backing_object) == NULL)
break;
tpindex += OFF_TO_IDX(tobject->backing_object_offset);
}
}
/*
* Locate and adjust resident pages
*/
for (; pindex < end; pindex += 1) {
relookup:
tobject = object;
tpindex = pindex;
shadowlookup:
if (tobject->type != OBJT_DEFAULT &&
tobject->type != OBJT_SWAP
) {
continue;
}
if ((tobject->flags & OBJ_ONEMAPPING) == 0)
continue;
m = vm_page_lookup(tobject, tpindex);
if (m == NULL) {
tobject = tobject->backing_object;
if (tobject == NULL)
continue;
tpindex += OFF_TO_IDX(tobject->backing_object_offset);
goto shadowlookup;
}
/*
* If the page is busy or not in a normal active state,
* we skip it. Things can break if we mess with pages
* in any of the below states.
*/
if (
m->hold_count ||
m->wire_count ||
m->valid != VM_PAGE_BITS_ALL
) {
continue;
}
if (vm_page_sleep_busy(m, TRUE, "madvpo"))
goto relookup;
if (advise == MADV_WILLNEED) {
vm_page_activate(m);
} else if (advise == MADV_DONTNEED) {
vm_page_deactivate(m);
} else if (advise == MADV_FREE) {
/*
* If MADV_FREE_FORCE_FREE is defined, we attempt to
* immediately free the page. Otherwise we just
* destroy any swap backing store, mark it clean,
* and stuff it into the cache.
*/
pmap_clear_modify(VM_PAGE_TO_PHYS(m));
m->dirty = 0;
#ifdef MADV_FREE_FORCE_FREE
if (tobject->resident_page_count > 1) {
vm_page_busy(m);
vm_page_protect(m, VM_PROT_NONE);
vm_page_free(m);
} else
#endif
{
vm_page_cache(m);
}
}
}
}
/*
* vm_object_shadow:
*
* Create a new object which is backed by the
* specified existing object range. The source
* object reference is deallocated.
*
* The new object and offset into that object
* are returned in the source parameters.
*/
void
vm_object_shadow(object, offset, length)
vm_object_t *object; /* IN/OUT */
vm_ooffset_t *offset; /* IN/OUT */
vm_size_t length;
{
vm_object_t source;
vm_object_t result;
source = *object;
/*
* Allocate a new object with the given length
*/
if ((result = vm_object_allocate(OBJT_DEFAULT, length)) == NULL)
panic("vm_object_shadow: no object for shadowing");
/*
* The new object shadows the source object, adding a reference to it.
* Our caller changes his reference to point to the new object,
* removing a reference to the source object. Net result: no change
* of reference count.
*
* Try to optimize the result object's page color when shadowing
* in order to maintain page coloring consistancy in the combined
* shadowed object.
*/
result->backing_object = source;
if (source) {
TAILQ_INSERT_TAIL(&source->shadow_head, result, shadow_list);
vm_object_clear_flag(source, OBJ_ONEMAPPING);
source->shadow_count++;
source->generation++;
result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & PQ_L2_MASK;
}
/*
* Store the offset into the source object, and fix up the offset into
* the new object.
*/
result->backing_object_offset = *offset;
/*
* Return the new things
*/
*offset = 0;
*object = result;
}
/*
* this version of collapse allows the operation to occur earlier and
* when paging_in_progress is true for an object... This is not a complete
* operation, but should plug 99.9% of the rest of the leaks.
*/
static void
vm_object_qcollapse(object)
vm_object_t object;
{
vm_object_t backing_object;
vm_pindex_t backing_offset_index;
vm_page_t p, pp;
vm_size_t size;
int s;
backing_object = object->backing_object;
if (backing_object->ref_count != 1)
return;
backing_object->ref_count += 2;
backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
size = object->size;
/*
* Since paging is in progress, we have to run at splbio() to
* avoid busied pages from getting ripped out from under us
* and screwing up the list sequencing.
*/
s = splbio();
p = TAILQ_FIRST(&backing_object->memq);
while (p) {
vm_page_t next;
vm_pindex_t new_pindex;
vm_pindex_t old_pindex;
/*
* setup for loop.
* loop if the page isn't trivial.
*/
next = TAILQ_NEXT(p, listq);
if ((p->flags & (PG_BUSY | PG_FICTITIOUS)) ||
!p->valid || p->hold_count || p->wire_count || p->busy) {
p = next;
continue;
}
/*
* busy the page and move it from the backing store to the
* parent object.
*/
vm_page_busy(p);
KASSERT(p->object == backing_object, ("vm_object_qcollapse(): object mismatch"));
old_pindex = p->pindex;
new_pindex = old_pindex - backing_offset_index;
if (old_pindex < backing_offset_index || new_pindex >= size) {
/*
* Page is out of the parent object's range, we
* can simply destroy it.
*/
vm_page_protect(p, VM_PROT_NONE);
vm_page_free(p);
} else {
pp = vm_page_lookup(object, new_pindex);
if (pp != NULL ||
(object->type == OBJT_SWAP && vm_pager_has_page(object,
new_pindex, NULL, NULL))) {
/*
* page already exists in parent OR swap exists
* for this location in the parent. Destroy
* the original page from the backing object.
*/
vm_page_protect(p, VM_PROT_NONE);
vm_page_free(p);
} else {
/*
* Page does not exist in parent, rename the
* page.
*/
if ((p->queue - p->pc) == PQ_CACHE)
vm_page_deactivate(p);
else
vm_page_protect(p, VM_PROT_NONE);
vm_page_rename(p, object, new_pindex);
/* page automatically made dirty by rename */
}
}
/*
* Destroy any swap assigned to the backing object at this
* location. This is an optimization.
*/
if (backing_object->type == OBJT_SWAP) {
swap_pager_freespace(backing_object, old_pindex, 1);
}
p = next;
}
backing_object->ref_count -= 2;
splx(s);
}
/*
* vm_object_collapse:
*
* Collapse an object with the object backing it.
* Pages in the backing object are moved into the
* parent, and the backing object is deallocated.
*/
void
vm_object_collapse(object)
vm_object_t object;
{
vm_object_t backing_object;
vm_ooffset_t backing_offset;
vm_size_t size;
vm_pindex_t new_pindex, backing_offset_index;
vm_page_t p, pp;
while (TRUE) {
/*
* Verify that the conditions are right for collapse:
*
* The object exists and no pages in it are currently being paged
* out.
*/
if (object == NULL)
return;
/*
* Make sure there is a backing object.
*/
if ((backing_object = object->backing_object) == NULL)
return;
/*
* we check the backing object first, because it is most likely
* not collapsable.
*/
if (backing_object->handle != NULL ||
(backing_object->type != OBJT_DEFAULT &&
backing_object->type != OBJT_SWAP) ||
(backing_object->flags & OBJ_DEAD) ||
object->handle != NULL ||
(object->type != OBJT_DEFAULT &&
object->type != OBJT_SWAP) ||
(object->flags & OBJ_DEAD)) {
return;
}
if (object->paging_in_progress != 0 ||
backing_object->paging_in_progress != 0) {
vm_object_qcollapse(object);
return;
}
/*
* We know that we can either collapse the backing object (if
* the parent is the only reference to it) or (perhaps) remove
* the parent's reference to it.
*/
backing_offset = object->backing_object_offset;
backing_offset_index = OFF_TO_IDX(backing_offset);
size = object->size;
/*
* If there is exactly one reference to the backing object, we
* can collapse it into the parent.
*/
if (backing_object->ref_count == 1) {
vm_object_set_flag(backing_object, OBJ_DEAD);
/*
* We can collapse the backing object.
*
* Move all in-memory pages from backing_object to the
* parent. Pages that have been paged out will be
* overwritten by any of the parent's pages that
* shadow them.
*/
while ((p = TAILQ_FIRST(&backing_object->memq)) != 0) {
if (vm_page_sleep_busy(p, TRUE, "vmocol"))
continue;
vm_page_busy(p);
new_pindex = p->pindex - backing_offset_index;
/*
* If the parent has a page here, or if this
* page falls outside the parent, dispose of
* it.
*
* Otherwise, move it as planned.
*/
if (p->pindex < backing_offset_index ||
new_pindex >= size) {
vm_page_protect(p, VM_PROT_NONE);
vm_page_free(p);
} else {
pp = vm_page_lookup(object, new_pindex);
if (pp != NULL || (object->type == OBJT_SWAP && vm_pager_has_page(object,
new_pindex, NULL, NULL))) {
vm_page_protect(p, VM_PROT_NONE);
vm_page_free(p);
} else {
if ((p->queue - p->pc) == PQ_CACHE)
vm_page_deactivate(p);
else
vm_page_protect(p, VM_PROT_NONE);
vm_page_rename(p, object, new_pindex);
/* page automatically made dirty by rename */
}
}
}
/*
* Move the pager from backing_object to object.
*/
if (backing_object->type == OBJT_SWAP) {
vm_object_pip_add(backing_object, 1);
/*
* scrap the paging_offset junk and do a
* discrete copy. This also removes major
* assumptions about how the swap-pager
* works from where it doesn't belong. The
* new swapper is able to optimize the
* destroy-source case.
*/
vm_object_pip_add(object, 1);
swap_pager_copy(
backing_object,
object,
OFF_TO_IDX(object->backing_object_offset), TRUE);
vm_object_pip_wakeup(object);
vm_object_pip_wakeup(backing_object);
}
/*
* Object now shadows whatever backing_object did.
* Note that the reference to backing_object->backing_object
* moves from within backing_object to within object.
*/
TAILQ_REMOVE(&object->backing_object->shadow_head, object,
shadow_list);
object->backing_object->shadow_count--;
object->backing_object->generation++;
if (backing_object->backing_object) {
TAILQ_REMOVE(&backing_object->backing_object->shadow_head,
backing_object, shadow_list);
backing_object->backing_object->shadow_count--;
backing_object->backing_object->generation++;
}
object->backing_object = backing_object->backing_object;
if (object->backing_object) {
TAILQ_INSERT_TAIL(&object->backing_object->shadow_head,
object, shadow_list);
object->backing_object->shadow_count++;
object->backing_object->generation++;
}
object->backing_object_offset += backing_object->backing_object_offset;
/*
* Discard backing_object.
*
* Since the backing object has no pages, no pager left,
* and no object references within it, all that is
* necessary is to dispose of it.
*/
TAILQ_REMOVE(&vm_object_list, backing_object,
object_list);
vm_object_count--;
zfree(obj_zone, backing_object);
object_collapses++;
} else {
vm_object_t new_backing_object;
/*
* If all of the pages in the backing object are
* shadowed by the parent object, the parent object no
* longer has to shadow the backing object; it can
* shadow the next one in the chain.
*
* The backing object must not be paged out - we'd have
* to check all of the paged-out pages, as well.
*/
if (backing_object->type != OBJT_DEFAULT) {
return;
}
/*
* Should have a check for a 'small' number of pages
* here.
*/
for (p = TAILQ_FIRST(&backing_object->memq); p;
p = TAILQ_NEXT(p, listq)) {
new_pindex = p->pindex - backing_offset_index;
vm_page_busy(p);
/*
* If the parent has a page here, or if this
* page falls outside the parent, keep going.
*
* Otherwise, the backing_object must be left in
* the chain.
*/
if (p->pindex >= backing_offset_index &&
new_pindex <= size) {
pp = vm_page_lookup(object, new_pindex);
if ((pp == NULL) || (pp->flags & PG_BUSY) || pp->busy) {
vm_page_wakeup(p);
return;
}
vm_page_busy(pp);
if ((pp->valid == 0) &&
!vm_pager_has_page(object, new_pindex, NULL, NULL)) {
/*
* Page still needed. Can't go any
* further.
*/
vm_page_wakeup(pp);
vm_page_wakeup(p);
return;
}
vm_page_wakeup(pp);
}
vm_page_wakeup(p);
}
/*
* Make the parent shadow the next object in the
* chain. Deallocating backing_object will not remove
* it, since its reference count is at least 2.
*/
TAILQ_REMOVE(&backing_object->shadow_head,
object, shadow_list);
backing_object->shadow_count--;
backing_object->generation++;
new_backing_object = backing_object->backing_object;
if ((object->backing_object = new_backing_object) != NULL) {
vm_object_reference(new_backing_object);
TAILQ_INSERT_TAIL(&new_backing_object->shadow_head,
object, shadow_list);
new_backing_object->shadow_count++;
new_backing_object->generation++;
object->backing_object_offset +=
backing_object->backing_object_offset;
}
/*
* Drop the reference count on backing_object. Since
* its ref_count was at least 2, it will not vanish;
* so we don't need to call vm_object_deallocate, but
* we do anyway.
*/
vm_object_deallocate(backing_object);
object_bypasses++;
}
/*
* Try again with this object's new backing object.
*/
}
}
/*
* vm_object_page_remove: [internal]
*
* Removes all physical pages in the specified
* object range from the object's list of pages.
*
* The object must be locked.
*/
void
vm_object_page_remove(object, start, end, clean_only)
vm_object_t object;
vm_pindex_t start;
vm_pindex_t end;
boolean_t clean_only;
{
vm_page_t p, next;
unsigned int size;
int all;
if (object == NULL)
return;
all = ((end == 0) && (start == 0));
vm_object_pip_add(object, 1);
again:
size = end - start;
if (all || size > 4 || size >= object->size / 4) {
for (p = TAILQ_FIRST(&object->memq); p != NULL; p = next) {
next = TAILQ_NEXT(p, listq);
if (all || ((start <= p->pindex) && (p->pindex < end))) {
if (p->wire_count != 0) {
vm_page_protect(p, VM_PROT_NONE);
if (!clean_only)
p->valid = 0;
continue;
}
/*
* The busy flags are only cleared at
* interrupt -- minimize the spl transitions
*/
if (vm_page_sleep_busy(p, TRUE, "vmopar"))
goto again;
if (clean_only && p->valid) {
vm_page_test_dirty(p);
if (p->valid & p->dirty)
continue;
}
vm_page_busy(p);
vm_page_protect(p, VM_PROT_NONE);
vm_page_free(p);
}
}
} else {
while (size > 0) {
if ((p = vm_page_lookup(object, start)) != 0) {
if (p->wire_count != 0) {
vm_page_protect(p, VM_PROT_NONE);
if (!clean_only)
p->valid = 0;
start += 1;
size -= 1;
continue;
}
/*
* The busy flags are only cleared at
* interrupt -- minimize the spl transitions
*/
if (vm_page_sleep_busy(p, TRUE, "vmopar"))
goto again;
if (clean_only && p->valid) {
vm_page_test_dirty(p);
if (p->valid & p->dirty) {
start += 1;
size -= 1;
continue;
}
}
vm_page_busy(p);
vm_page_protect(p, VM_PROT_NONE);
vm_page_free(p);
}
start += 1;
size -= 1;
}
}
vm_object_pip_wakeup(object);
}
/*
* Routine: vm_object_coalesce
* Function: Coalesces two objects backing up adjoining
* regions of memory into a single object.
*
* returns TRUE if objects were combined.
*
* NOTE: Only works at the moment if the second object is NULL -
* if it's not, which object do we lock first?
*
* Parameters:
* prev_object First object to coalesce
* prev_offset Offset into prev_object
* next_object Second object into coalesce
* next_offset Offset into next_object
*
* prev_size Size of reference to prev_object
* next_size Size of reference to next_object
*
* Conditions:
* The object must *not* be locked.
*/
boolean_t
vm_object_coalesce(prev_object, prev_pindex, prev_size, next_size)
vm_object_t prev_object;
vm_pindex_t prev_pindex;
vm_size_t prev_size, next_size;
{
vm_size_t newsize;
if (prev_object == NULL) {
return (TRUE);
}
if (prev_object->type != OBJT_DEFAULT &&
prev_object->type != OBJT_SWAP) {
return (FALSE);
}
/*
* Try to collapse the object first
*/
vm_object_collapse(prev_object);
/*
* Can't coalesce if: . more than one reference . paged out . shadows
* another object . has a copy elsewhere (any of which mean that the
* pages not mapped to prev_entry may be in use anyway)
*/
if (prev_object->backing_object != NULL) {
return (FALSE);
}
prev_size >>= PAGE_SHIFT;
next_size >>= PAGE_SHIFT;
if ((prev_object->ref_count > 1) &&
(prev_object->size != prev_pindex + prev_size)) {
return (FALSE);
}
/*
* Remove any pages that may still be in the object from a previous
* deallocation.
*/
vm_object_page_remove(prev_object,
prev_pindex + prev_size,
prev_pindex + prev_size + next_size, FALSE);
/*
* Extend the object if necessary.
*/
newsize = prev_pindex + prev_size + next_size;
if (newsize > prev_object->size)
prev_object->size = newsize;
return (TRUE);
}
#include "opt_ddb.h"
#ifdef DDB
#include <sys/kernel.h>
#include <machine/cons.h>
#include <ddb/ddb.h>
static int _vm_object_in_map __P((vm_map_t map, vm_object_t object,
vm_map_entry_t entry));
static int vm_object_in_map __P((vm_object_t object));
static int
_vm_object_in_map(map, object, entry)
vm_map_t map;
vm_object_t object;
vm_map_entry_t entry;
{
vm_map_t tmpm;
vm_map_entry_t tmpe;
vm_object_t obj;
int entcount;
if (map == 0)
return 0;
if (entry == 0) {
tmpe = map->header.next;
entcount = map->nentries;
while (entcount-- && (tmpe != &map->header)) {
if( _vm_object_in_map(map, object, tmpe)) {
return 1;
}
tmpe = tmpe->next;
}
} else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
tmpm = entry->object.sub_map;
tmpe = tmpm->header.next;
entcount = tmpm->nentries;
while (entcount-- && tmpe != &tmpm->header) {
if( _vm_object_in_map(tmpm, object, tmpe)) {
return 1;
}
tmpe = tmpe->next;
}
} else if ((obj = entry->object.vm_object) != NULL) {
for(; obj; obj=obj->backing_object)
if( obj == object) {
return 1;
}
}
return 0;
}
static int
vm_object_in_map( object)
vm_object_t object;
{
struct proc *p;
for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
if( !p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
continue;
if( _vm_object_in_map(&p->p_vmspace->vm_map, object, 0))
return 1;
}
if( _vm_object_in_map( kernel_map, object, 0))
return 1;
if( _vm_object_in_map( kmem_map, object, 0))
return 1;
if( _vm_object_in_map( pager_map, object, 0))
return 1;
if( _vm_object_in_map( buffer_map, object, 0))
return 1;
if( _vm_object_in_map( io_map, object, 0))
return 1;
if( _vm_object_in_map( phys_map, object, 0))
return 1;
if( _vm_object_in_map( mb_map, object, 0))
return 1;
if( _vm_object_in_map( u_map, object, 0))
return 1;
return 0;
}
DB_SHOW_COMMAND(vmochk, vm_object_check)
{
vm_object_t object;
/*
* make sure that internal objs are in a map somewhere
* and none have zero ref counts.
*/
for (object = TAILQ_FIRST(&vm_object_list);
object != NULL;
object = TAILQ_NEXT(object, object_list)) {
if (object->handle == NULL &&
(object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
if (object->ref_count == 0) {
db_printf("vmochk: internal obj has zero ref count: %d\n",
object->size);
}
if (!vm_object_in_map(object)) {
db_printf(
"vmochk: internal obj is not in a map: "
"ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
object->ref_count, (u_long)object->size,
(u_long)object->size,
(void *)object->backing_object);
}
}
}
}
/*
* vm_object_print: [ debug ]
*/
DB_SHOW_COMMAND(object, vm_object_print_static)
{
/* XXX convert args. */
vm_object_t object = (vm_object_t)addr;
boolean_t full = have_addr;
vm_page_t p;
/* XXX count is an (unused) arg. Avoid shadowing it. */
#define count was_count
int count;
if (object == NULL)
return;
db_iprintf(
"Object %p: type=%d, size=0x%lx, res=%d, ref=%d, flags=0x%x\n",
object, (int)object->type, (u_long)object->size,
object->resident_page_count, object->ref_count, object->flags);
/*
* XXX no %qd in kernel. Truncate object->backing_object_offset.
*/
db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%lx\n",
object->shadow_count,
object->backing_object ? object->backing_object->ref_count : 0,
object->backing_object, (long)object->backing_object_offset);
if (!full)
return;
db_indent += 2;
count = 0;
for (p = TAILQ_FIRST(&object->memq); p != NULL; p = TAILQ_NEXT(p, listq)) {
if (count == 0)
db_iprintf("memory:=");
else if (count == 6) {
db_printf("\n");
db_iprintf(" ...");
count = 0;
} else
db_printf(",");
count++;
db_printf("(off=0x%lx,page=0x%lx)",
(u_long) p->pindex, (u_long) VM_PAGE_TO_PHYS(p));
}
if (count != 0)
db_printf("\n");
db_indent -= 2;
}
/* XXX. */
#undef count
/* XXX need this non-static entry for calling from vm_map_print. */
void
vm_object_print(addr, have_addr, count, modif)
/* db_expr_t */ long addr;
boolean_t have_addr;
/* db_expr_t */ long count;
char *modif;
{
vm_object_print_static(addr, have_addr, count, modif);
}
DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
{
vm_object_t object;
int nl = 0;
int c;
for (object = TAILQ_FIRST(&vm_object_list);
object != NULL;
object = TAILQ_NEXT(object, object_list)) {
vm_pindex_t idx, fidx;
vm_pindex_t osize;
vm_offset_t pa = -1, padiff;
int rcount;
vm_page_t m;
db_printf("new object: %p\n", (void *)object);
if ( nl > 18) {
c = cngetc();
if (c != ' ')
return;
nl = 0;
}
nl++;
rcount = 0;
fidx = 0;
osize = object->size;
if (osize > 128)
osize = 128;
for(idx=0;idx<osize;idx++) {
m = vm_page_lookup(object, idx);
if (m == NULL) {
if (rcount) {
db_printf(" index(%d)run(%d)pa(0x%x)\n",
fidx, rcount, pa);
if ( nl > 18) {
c = cngetc();
if (c != ' ')
return;
nl = 0;
}
nl++;
rcount = 0;
}
continue;
}
if (rcount &&
(VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
++rcount;
continue;
}
if (rcount) {
padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m);
padiff >>= PAGE_SHIFT;
padiff &= PQ_L2_MASK;
if (padiff == 0) {
pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE;
++rcount;
continue;
}
db_printf(" index(%d)run(%d)pa(0x%x)", fidx, rcount, pa);
db_printf("pd(%d)\n", padiff);
if ( nl > 18) {
c = cngetc();
if (c != ' ')
return;
nl = 0;
}
nl++;
}
fidx = idx;
pa = VM_PAGE_TO_PHYS(m);
rcount = 1;
}
if (rcount) {
db_printf(" index(%d)run(%d)pa(0x%x)\n", fidx, rcount, pa);
if ( nl > 18) {
c = cngetc();
if (c != ' ')
return;
nl = 0;
}
nl++;
}
}
}
#endif /* DDB */
Reference in New Issue View Git Blame Copy Permalink