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freebsd-skq/sys/vm/vm_object.c
dyson 6e92f5716b Some VM improvements, including elimination of alot of Sig-11 
problems.  Tor Egge and others have helped with various VM bugs
lately, but don't blame him -- blame me!!!

pmap.c:
1)	Create an object for kernel page table allocations.  This
	fixes a bogus allocation method previously used for such, by
	grabbing pages from the kernel object, using bogus pindexes.
	(This was a code cleanup, and perhaps a minor system stability
	 issue.)

pmap.c:
2)	Pre-set the modify and accessed bits when prudent.  This will
	decrease bus traffic under certain circumstances.

vfs_bio.c, vfs_cluster.c:
3)	Rather than calculating the beginning virtual byte offset
	multiple times, stick the offset into the buffer header, so
	that the calculated offset can be reused.  (Long long multiplies
	are often expensive, and this is a probably unmeasurable performance
	improvement, and code cleanup.)

vfs_bio.c:
4)	Handle write recursion more intelligently (but not perfectly) so
	that it is less likely to cause a system panic, and is also
	much more robust.

vfs_bio.c:
5)	getblk incorrectly wrote out blocks that are incorrectly sized.
	The problem is fixed, and writes blocks out ONLY when B_DELWRI
	is true.

vfs_bio.c:
6)	Check that already constituted buffers have fully valid pages.  If
	not, then make sure that the B_CACHE bit is not set. (This was
	a major source of Sig-11 type problems.)

vfs_bio.c:
7)	Fix a potential system deadlock due to an incorrectly specified
	sleep priority while waiting for a buffer write operation.  The
	change that I made opens the system up to serious problems, and
	we need to examine the issue of process sleep priorities.

vfs_cluster.c, vfs_bio.c:
8)	Make clustered reads work more correctly (and more completely)
	when buffers are already constituted, but not fully valid.
	(This was another system reliability issue.)

vfs_subr.c, ffs_inode.c:
9)	Create a vtruncbuf function, which is used by filesystems that
	can truncate files.  The vinvalbuf forced a file sync type operation,
	while vtruncbuf only invalidates the buffers past the new end of file,
	and also invalidates the appropriate pages.  (This was a system reliabiliy
	and performance issue.)

10)	Modify FFS to use vtruncbuf.

vm_object.c:
11)	Make the object rundown mechanism for OBJT_VNODE type objects work
	more correctly.  Included in that fix, create pager entries for
	the OBJT_DEAD pager type, so that paging requests that might slip
	in during race conditions are properly handled.  (This was a system
	reliability issue.)

vm_page.c:
12)	Make some of the page validation routines be a little less picky
	about arguments passed to them.  Also, support page invalidation
	change the object generation count so that we handle generation
	counts a little more robustly.

vm_pageout.c:
13)	Further reduce pageout daemon activity when the system doesn't
	need help from it.  There should be no additional performance
	decrease even when the pageout daemon is running.  (This was
	a significant performance issue.)

vnode_pager.c:
14)	Teach the vnode pager to handle race conditions during vnode
	deallocations.
1998-03-16 01:56:03 +00:00

1720 lines
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/*
* 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 1.118 1998/03/08 18:05:59 dyson 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 <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_prot.h>
#include <sys/lock.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));
static void vm_object_dispose __P((vm_object_t));
/*
* 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;
static struct simplelock vm_object_list_lock;
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;
#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;
register 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;
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->paging_offset = (vm_ooffset_t) 0;
object->backing_object = NULL;
object->backing_object_offset = (vm_ooffset_t) 0;
object->page_hint = NULL;
object->last_read = 0;
object->generation++;
TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
vm_object_count++;
}
/*
* 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;
{
register 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)
register vm_object_t object;
{
if (object == NULL)
return;
#if defined(DIAGNOSTIC)
if (object->flags & OBJ_DEAD)
panic("vm_object_reference: attempting to reference dead obj");
#endif
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;
#if defined(DIAGNOSTIC)
if (object->type != OBJT_VNODE)
panic("vm_object_vndeallocate: not a vnode object");
if (vp == NULL)
panic("vm_object_vndeallocate: missing vp");
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;
object->flags &= ~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;
{
int s;
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 == 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);
#if defined(DIAGNOSTIC)
if (robject == NULL)
panic("vm_object_deallocate: ref_count: %d,"
" shadow_count: %d",
object->ref_count, object->shadow_count);
#endif
if ((robject->handle == NULL) &&
(robject->type == OBJT_DEFAULT ||
robject->type == OBJT_SWAP)) {
robject->ref_count++;
retry:
if (robject->paging_in_progress ||
object->paging_in_progress) {
vm_object_pip_sleep(robject, "objde1");
if (robject->paging_in_progress &&
robject->type == OBJT_SWAP) {
swap_pager_sync();
goto retry;
}
vm_object_pip_sleep(object, "objde2");
if (object->paging_in_progress &&
object->type == OBJT_SWAP) {
swap_pager_sync();
}
goto retry;
}
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)
temp->flags &= ~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.
*/
void
vm_object_terminate(object)
register vm_object_t object;
{
register vm_page_t p;
int s;
/*
* Make sure no one uses us.
*/
object->flags |= OBJ_DEAD;
/*
* wait for the pageout daemon to be done with the object
*/
vm_object_pip_wait(object, "objtrm");
#if defined(DIAGNOSTIC)
if (object->paging_in_progress != 0)
panic("vm_object_terminate: pageout in progress");
#endif
/*
* 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);
/*
* Let the pager know object is dead.
*/
vm_pager_deallocate(object);
}
if ((object->type != OBJT_VNODE) && (object->ref_count == 0)) {
/*
* Now free the pages. For internal objects, this also removes them
* from paging queues.
*/
while ((p = TAILQ_FIRST(&object->memq)) != NULL) {
#if !defined(MAX_PERF)
if (p->busy || (p->flags & PG_BUSY))
printf("vm_object_terminate: freeing busy page\n");
#endif
p->flags |= PG_BUSY;
vm_page_free(p);
cnt.v_pfree++;
}
/*
* Let the pager know object is dead.
*/
vm_pager_deallocate(object);
}
if ((object->ref_count == 0) && (object->resident_page_count == 0))
vm_object_dispose(object);
}
/*
* vm_object_dispose
*
* Dispose the object.
*/
static void
vm_object_dispose(object)
vm_object_t object;
{
simple_lock(&vm_object_list_lock);
TAILQ_REMOVE(&vm_object_list, object, object_list);
vm_object_count--;
simple_unlock(&vm_object_list_lock);
/*
* Free the space for the object.
*/
zfree(obj_zone, object);
wakeup(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;
{
register vm_page_t p, np, tp;
register 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;
struct proc *pproc = curproc; /* XXX */
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;
object->flags |= 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)) {
p->flags |= PG_CLEANCHK;
vm_page_protect(p, VM_PROT_READ);
}
if ((tstart == 0) && (tend == object->size)) {
object->flags &= ~(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)) {
p->flags &= ~PG_CLEANCHK;
continue;
}
vm_page_test_dirty(p);
if ((p->dirty & p->valid) == 0) {
p->flags &= ~PG_CLEANCHK;
continue;
}
s = splvm();
while ((p->flags & PG_BUSY) || p->busy) {
p->flags |= PG_WANTED | PG_REFERENCED;
tsleep(p, PVM, "vpcwai", 0);
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)) {
if ((tp->flags & PG_BUSY) ||
(tp->flags & PG_CLEANCHK) == 0 ||
(tp->busy != 0))
break;
if((tp->queue - tp->pc) == PQ_CACHE) {
tp->flags &= ~PG_CLEANCHK;
break;
}
vm_page_test_dirty(tp);
if ((tp->dirty & tp->valid) == 0) {
tp->flags &= ~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)) {
if ((tp->flags & PG_BUSY) ||
(tp->flags & PG_CLEANCHK) == 0 ||
(tp->busy != 0))
break;
if((tp->queue - tp->pc) == PQ_CACHE) {
tp->flags &= ~PG_CLEANCHK;
break;
}
vm_page_test_dirty(tp);
if ((tp->dirty & tp->valid) == 0) {
tp->flags &= ~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];
ma[index]->flags &= ~PG_CLEANCHK;
}
p->flags &= ~PG_CLEANCHK;
ma[maxb] = p;
for(i=0;i<maxf;i++) {
int index = (maxb + i) + 1;
ma[index] = maf[i];
ma[index]->flags &= ~PG_CLEANCHK;
}
runlen = maxb + maxf + 1;
splx(s);
vm_pageout_flush(ma, runlen, pagerflags);
if (object->generation != curgeneration)
goto rescan;
}
VOP_FSYNC(vp, NULL, (pagerflags & VM_PAGER_PUT_SYNC)?1:0, curproc);
object->flags &= ~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)
register vm_object_t object;
{
register 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
/*
* vm_object_pmap_copy:
*
* Makes all physical pages in the specified
* object range copy-on-write. No writeable
* references to these pages should remain.
*
* The object must *not* be locked.
*/
void
vm_object_pmap_copy(object, start, end)
register vm_object_t object;
register vm_pindex_t start;
register vm_pindex_t end;
{
register vm_page_t p;
if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0)
return;
for (p = TAILQ_FIRST(&object->memq);
p != NULL;
p = TAILQ_NEXT(p, listq)) {
vm_page_protect(p, VM_PROT_READ);
}
object->flags &= ~OBJ_WRITEABLE;
}
/*
* Same as vm_object_pmap_copy_1, except range checking really
* works, and is meant for small sections of an object.
*/
void
vm_object_pmap_copy_1(object, start, end)
register vm_object_t object;
register vm_pindex_t start;
register vm_pindex_t end;
{
vm_pindex_t idx;
register 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)
register vm_object_t object;
register vm_pindex_t start;
register vm_pindex_t end;
{
register 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))
object->flags &= ~OBJ_WRITEABLE;
}
/*
* vm_object_madvise:
*
* Implements the madvise function at the object/page level.
*/
void
vm_object_madvise(object, pindex, count, advise)
vm_object_t object;
vm_pindex_t pindex;
int count;
int advise;
{
int s;
vm_pindex_t end, tpindex;
vm_object_t tobject;
vm_page_t m;
if (object == NULL)
return;
end = pindex + count;
for (; pindex < end; pindex += 1) {
relookup:
tobject = object;
tpindex = pindex;
shadowlookup:
m = vm_page_lookup(tobject, tpindex);
if (m == NULL) {
if (tobject->type != OBJT_DEFAULT) {
continue;
}
tobject = tobject->backing_object;
if ((tobject == NULL) || (tobject->ref_count != 1)) {
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(m, "madvpo", &m->busy))
goto relookup;
if (advise == MADV_WILLNEED) {
vm_page_activate(m);
} else if (advise == MADV_DONTNEED) {
vm_page_deactivate(m);
} else if (advise == MADV_FREE) {
pmap_clear_modify(VM_PAGE_TO_PHYS(m));
m->dirty = 0;
/*
* Force a demand zero if attempt to read from swap.
* We currently don't handle vnode files correctly,
* and will reread stale contents unnecessarily.
*/
if (object->type == OBJT_SWAP)
swap_pager_dmzspace(tobject, m->pindex, 1);
}
}
}
/*
* 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;
{
register vm_object_t source;
register 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.
*/
result->backing_object = source;
if (source) {
TAILQ_INSERT_TAIL(&source->shadow_head, result, shadow_list);
source->shadow_count++;
source->generation++;
}
/*
* 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)
register vm_object_t object;
{
register vm_object_t backing_object;
register vm_pindex_t backing_offset_index, paging_offset_index;
vm_pindex_t backing_object_paging_offset_index;
vm_pindex_t new_pindex;
register vm_page_t p, pp;
register vm_size_t size;
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);
backing_object_paging_offset_index = OFF_TO_IDX(backing_object->paging_offset);
paging_offset_index = OFF_TO_IDX(object->paging_offset);
size = object->size;
p = TAILQ_FIRST(&backing_object->memq);
while (p) {
vm_page_t next;
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;
}
p->flags |= PG_BUSY;
new_pindex = p->pindex - backing_offset_index;
if (p->pindex < backing_offset_index ||
new_pindex >= size) {
if (backing_object->type == OBJT_SWAP)
swap_pager_freespace(backing_object,
backing_object_paging_offset_index+p->pindex,
1);
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,
paging_offset_index + new_pindex, NULL, NULL))) {
if (backing_object->type == OBJT_SWAP)
swap_pager_freespace(backing_object,
backing_object_paging_offset_index + p->pindex, 1);
vm_page_protect(p, VM_PROT_NONE);
vm_page_free(p);
} else {
if (backing_object->type == OBJT_SWAP)
swap_pager_freespace(backing_object,
backing_object_paging_offset_index + p->pindex, 1);
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);
p->dirty = VM_PAGE_BITS_ALL;
}
}
p = next;
}
backing_object->ref_count -= 2;
}
/*
* 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) {
backing_object->flags |= 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) {
new_pindex = p->pindex - backing_offset_index;
p->flags |= PG_BUSY;
/*
* 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,
OFF_TO_IDX(object->paging_offset) + 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);
p->dirty = VM_PAGE_BITS_ALL;
}
}
}
/*
* Move the pager from backing_object to object.
*/
if (backing_object->type == OBJT_SWAP) {
backing_object->paging_in_progress++;
if (object->type == OBJT_SWAP) {
object->paging_in_progress++;
/*
* copy shadow object pages into ours
* and destroy unneeded pages in
* shadow object.
*/
swap_pager_copy(
backing_object,
OFF_TO_IDX(backing_object->paging_offset),
object,
OFF_TO_IDX(object->paging_offset),
OFF_TO_IDX(object->backing_object_offset));
vm_object_pip_wakeup(object);
} else {
object->paging_in_progress++;
/*
* move the shadow backing_object's pager data to
* "object" and convert "object" type to OBJT_SWAP.
*/
object->type = OBJT_SWAP;
object->un_pager.swp.swp_nblocks =
backing_object->un_pager.swp.swp_nblocks;
object->un_pager.swp.swp_allocsize =
backing_object->un_pager.swp.swp_allocsize;
object->un_pager.swp.swp_blocks =
backing_object->un_pager.swp.swp_blocks;
object->un_pager.swp.swp_poip = /* XXX */
backing_object->un_pager.swp.swp_poip;
object->paging_offset = backing_object->paging_offset + backing_offset;
TAILQ_INSERT_TAIL(&swap_pager_un_object_list, object, pager_object_list);
/*
* Convert backing object from OBJT_SWAP to
* OBJT_DEFAULT. XXX - only the TAILQ_REMOVE is
* actually necessary.
*/
backing_object->type = OBJT_DEFAULT;
TAILQ_REMOVE(&swap_pager_un_object_list, backing_object, pager_object_list);
/*
* free unnecessary blocks
*/
swap_pager_freespace(object, 0,
OFF_TO_IDX(object->paging_offset));
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;
p->flags |= PG_BUSY;
/*
* 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) {
PAGE_WAKEUP(p);
return;
}
pp->flags |= PG_BUSY;
if ((pp->valid == 0) &&
!vm_pager_has_page(object, OFF_TO_IDX(object->paging_offset) + new_pindex, NULL, NULL)) {
/*
* Page still needed. Can't go any
* further.
*/
PAGE_WAKEUP(pp);
PAGE_WAKEUP(p);
return;
}
PAGE_WAKEUP(pp);
}
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) {
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)
register vm_object_t object;
register vm_pindex_t start;
register vm_pindex_t end;
boolean_t clean_only;
{
register vm_page_t p, next;
unsigned int size;
int s, all;
if (object == NULL)
return;
all = ((end == 0) && (start == 0));
object->paging_in_progress++;
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);
p->valid = 0;
continue;
}
/*
* The busy flags are only cleared at
* interrupt -- minimize the spl transitions
*/
if (vm_page_sleep(p, "vmopar", &p->busy))
goto again;
if (clean_only && p->valid) {
vm_page_test_dirty(p);
if (p->valid & p->dirty)
continue;
}
p->flags |= PG_BUSY;
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) {
p->valid = 0;
vm_page_protect(p, VM_PROT_NONE);
start += 1;
size -= 1;
continue;
}
/*
* The busy flags are only cleared at
* interrupt -- minimize the spl transitions
*/
if (vm_page_sleep(p, "vmopar", &p->busy))
goto again;
if (clean_only && p->valid) {
vm_page_test_dirty(p);
if (p->valid & p->dirty) {
start += 1;
size -= 1;
continue;
}
}
p->flags |= PG_BUSY;
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)
register 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) {
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_A_MAP|MAP_ENTRY_IS_SUB_MAP)) {
tmpm = entry->object.share_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) {
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: %d: 0x%x, backing_object: 0x%x\n",
object->ref_count, object->size,
object->size, 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;
register vm_page_t p;
/* XXX count is an (unused) arg. Avoid shadowing it. */
#define count was_count
register int count;
if (object == NULL)
return;
db_iprintf("Object 0x%x: type=%d, size=0x%x, res=%d, ref=%d, flags=0x%x\n",
(int) object, (int) object->type, (int) object->size,
object->resident_page_count,
object->ref_count,
object->flags);
db_iprintf(" sref=%d, offset=0x%x, backing_object(%d)=(0x%x)+0x%x\n",
object->shadow_count,
(int) object->paging_offset,
(((int)object->backing_object)?object->backing_object->ref_count:0),
(int) object->backing_object,
(int) 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 addr;
boolean_t have_addr;
db_expr_t 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: 0x%x\n", 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 */
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