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o Migrate vm_map_split() from vm_map.c to vm_object.c, renaming it

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to vm_object_split().  Its interface should still be changed
   to resemble vm_object_shadow().
This commit is contained in:
Alan Cox 2002-06-02 23:54:09 +00:00
parent ce7be04eae
commit c5aaa06ded
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=97753
3 changed files with 93 additions and 90 deletions
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91
sys/vm/vm_map.c
View File

@ -2177,95 +2177,6 @@ vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end,
return (TRUE);
}
/*
* Split the pages in a map entry into a new object. This affords
* easier removal of unused pages, and keeps object inheritance from
* being a negative impact on memory usage.
*/
static void
vm_map_split(vm_map_entry_t entry)
{
vm_page_t m;
vm_object_t orig_object, new_object, source;
vm_offset_t s, e;
vm_pindex_t offidxstart, offidxend, idx;
vm_size_t size;
vm_ooffset_t offset;
GIANT_REQUIRED;
orig_object = entry->object.vm_object;
if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP)
return;
if (orig_object->ref_count <= 1)
return;
offset = entry->offset;
s = entry->start;
e = entry->end;
offidxstart = OFF_TO_IDX(offset);
offidxend = offidxstart + OFF_TO_IDX(e - s);
size = offidxend - offidxstart;
new_object = vm_pager_allocate(orig_object->type,
NULL, IDX_TO_OFF(size), VM_PROT_ALL, 0LL);
if (new_object == NULL)
return;
source = orig_object->backing_object;
if (source != NULL) {
vm_object_reference(source); /* Referenced by new_object */
TAILQ_INSERT_TAIL(&source->shadow_head,
new_object, shadow_list);
vm_object_clear_flag(source, OBJ_ONEMAPPING);
new_object->backing_object_offset =
orig_object->backing_object_offset + IDX_TO_OFF(offidxstart);
new_object->backing_object = source;
source->shadow_count++;
source->generation++;
}
for (idx = 0; idx < size; idx++) {
retry:
m = vm_page_lookup(orig_object, offidxstart + idx);
if (m == NULL)
continue;
/*
* We must wait for pending I/O to complete before we can
* rename the page.
*
* We do not have to VM_PROT_NONE the page as mappings should
* not be changed by this operation.
*/
if (vm_page_sleep_busy(m, TRUE, "spltwt"))
goto retry;
vm_page_busy(m);
vm_page_rename(m, new_object, idx);
/* page automatically made dirty by rename and cache handled */
vm_page_busy(m);
}
if (orig_object->type == OBJT_SWAP) {
vm_object_pip_add(orig_object, 1);
/*
* copy orig_object pages into new_object
* and destroy unneeded pages in
* shadow object.
*/
swap_pager_copy(orig_object, new_object, offidxstart, 0);
vm_object_pip_wakeup(orig_object);
}
for (idx = 0; idx < size; idx++) {
m = vm_page_lookup(new_object, idx);
if (m != NULL)
vm_page_wakeup(m);
}
entry->object.vm_object = new_object;
entry->offset = 0LL;
vm_object_deallocate(orig_object);
}
/*
* vm_map_copy_entry:
*
@ -2307,7 +2218,7 @@ vm_map_copy_entry(
src_object->type == OBJT_SWAP)) {
vm_object_collapse(src_object);
if ((src_object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING) {
vm_map_split(src_entry);
vm_object_split(src_entry);
src_object = src_entry->object.vm_object;
}
}

91
sys/vm/vm_object.c
View File

@ -1180,6 +1180,97 @@ vm_object_shadow(
mtx_unlock(&Giant);
}
/*
* vm_object_split:
*
* Split the pages in a map entry into a new object. This affords
* easier removal of unused pages, and keeps object inheritance from
* being a negative impact on memory usage.
*/
void
vm_object_split(vm_map_entry_t entry)
{
vm_page_t m;
vm_object_t orig_object, new_object, source;
vm_offset_t s, e;
vm_pindex_t offidxstart, offidxend, idx;
vm_size_t size;
vm_ooffset_t offset;
GIANT_REQUIRED;
orig_object = entry->object.vm_object;
if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP)
return;
if (orig_object->ref_count <= 1)
return;
offset = entry->offset;
s = entry->start;
e = entry->end;
offidxstart = OFF_TO_IDX(offset);
offidxend = offidxstart + OFF_TO_IDX(e - s);
size = offidxend - offidxstart;
new_object = vm_pager_allocate(orig_object->type,
NULL, IDX_TO_OFF(size), VM_PROT_ALL, 0LL);
if (new_object == NULL)
return;
source = orig_object->backing_object;
if (source != NULL) {
vm_object_reference(source); /* Referenced by new_object */
TAILQ_INSERT_TAIL(&source->shadow_head,
new_object, shadow_list);
vm_object_clear_flag(source, OBJ_ONEMAPPING);
new_object->backing_object_offset =
orig_object->backing_object_offset + IDX_TO_OFF(offidxstart);
new_object->backing_object = source;
source->shadow_count++;
source->generation++;
}
for (idx = 0; idx < size; idx++) {
retry:
m = vm_page_lookup(orig_object, offidxstart + idx);
if (m == NULL)
continue;
/*
* We must wait for pending I/O to complete before we can
* rename the page.
*
* We do not have to VM_PROT_NONE the page as mappings should
* not be changed by this operation.
*/
if (vm_page_sleep_busy(m, TRUE, "spltwt"))
goto retry;
vm_page_busy(m);
vm_page_rename(m, new_object, idx);
/* page automatically made dirty by rename and cache handled */
vm_page_busy(m);
}
if (orig_object->type == OBJT_SWAP) {
vm_object_pip_add(orig_object, 1);
/*
* copy orig_object pages into new_object
* and destroy unneeded pages in
* shadow object.
*/
swap_pager_copy(orig_object, new_object, offidxstart, 0);
vm_object_pip_wakeup(orig_object);
}
for (idx = 0; idx < size; idx++) {
m = vm_page_lookup(new_object, idx);
if (m != NULL)
vm_page_wakeup(m);
}
entry->object.vm_object = new_object;
entry->offset = 0LL;
vm_object_deallocate(orig_object);
}
#define OBSC_TEST_ALL_SHADOWED 0x0001
#define OBSC_COLLAPSE_NOWAIT 0x0002
#define OBSC_COLLAPSE_WAIT 0x0004

1
sys/vm/vm_object.h
View File

@ -198,6 +198,7 @@ void vm_object_pmap_copy_1 (vm_object_t, vm_pindex_t, vm_pindex_t);
void vm_object_pmap_remove (vm_object_t, vm_pindex_t, vm_pindex_t);
void vm_object_reference (vm_object_t);
void vm_object_shadow (vm_object_t *, vm_ooffset_t *, vm_size_t);
void vm_object_split(vm_map_entry_t);
void vm_object_madvise (vm_object_t, vm_pindex_t, int, int);
void vm_object_init2 (void);
#endif /* _KERNEL */