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Create a function for creating objects to back map entries, and one

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for giving cred to a map entry backed by an object, and use them
instead of the code duplicated inline now.

Approved by: kib (mentor)
Differential Revision: https://reviews.freebsd.org/D20370
This commit is contained in:
Doug Moore 2019-06-13 20:09:07 +00:00
parent 4f7c3b7be5
commit af1d6d6a11
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=349023
1 changed files with 58 additions and 72 deletions
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130
sys/vm/vm_map.c
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@ -2108,6 +2108,60 @@ vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry)
}
}
/*
* vm_map_entry_back:
*
* Allocate an object to back a map entry.
*/
static inline void
vm_map_entry_back(vm_map_entry_t entry)
{
vm_object_t object;
KASSERT(entry->object.vm_object == NULL,
("map entry %p has backing object", entry));
KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
("map entry %p is a submap", entry));
object = vm_object_allocate(OBJT_DEFAULT,
atop(entry->end - entry->start));
entry->object.vm_object = object;
entry->offset = 0;
if (entry->cred != NULL) {
object->cred = entry->cred;
object->charge = entry->end - entry->start;
entry->cred = NULL;
}
}
/*
* vm_map_entry_charge_object
*
* If there is no object backing this entry, create one. Otherwise, if
* the entry has cred, give it to the backing object.
*/
static inline void
vm_map_entry_charge_object(vm_map_t map, vm_map_entry_t entry)
{
VM_MAP_ASSERT_LOCKED(map);
KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
("map entry %p is a submap", entry));
if (entry->object.vm_object == NULL && !map->system_map &&
(entry->eflags & MAP_ENTRY_GUARD) == 0)
vm_map_entry_back(entry);
else if (entry->object.vm_object != NULL &&
((entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) &&
entry->cred != NULL) {
VM_OBJECT_WLOCK(entry->object.vm_object);
KASSERT(entry->object.vm_object->cred == NULL,
("OVERCOMMIT: %s: both cred e %p", __func__, entry));
entry->object.vm_object->cred = entry->cred;
entry->object.vm_object->charge = entry->end - entry->start;
VM_OBJECT_WUNLOCK(entry->object.vm_object);
entry->cred = NULL;
}
}
/*
* vm_map_clip_start: [ internal use only ]
*
@ -2140,38 +2194,7 @@ _vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t start)
* starting address.
*/
vm_map_simplify_entry(map, entry);
/*
* If there is no object backing this entry, we might as well create
* one now. If we defer it, an object can get created after the map
* is clipped, and individual objects will be created for the split-up
* map. This is a bit of a hack, but is also about the best place to
* put this improvement.
*/
if (entry->object.vm_object == NULL && !map->system_map &&
(entry->eflags & MAP_ENTRY_GUARD) == 0) {
vm_object_t object;
object = vm_object_allocate(OBJT_DEFAULT,
atop(entry->end - entry->start));
entry->object.vm_object = object;
entry->offset = 0;
if (entry->cred != NULL) {
object->cred = entry->cred;
object->charge = entry->end - entry->start;
entry->cred = NULL;
}
} else if (entry->object.vm_object != NULL &&
((entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) &&
entry->cred != NULL) {
VM_OBJECT_WLOCK(entry->object.vm_object);
KASSERT(entry->object.vm_object->cred == NULL,
("OVERCOMMIT: vm_entry_clip_start: both cred e %p", entry));
entry->object.vm_object->cred = entry->cred;
entry->object.vm_object->charge = entry->end - entry->start;
VM_OBJECT_WUNLOCK(entry->object.vm_object);
entry->cred = NULL;
}
vm_map_entry_charge_object(map, entry);
new_entry = vm_map_entry_create(map);
*new_entry = *entry;
@ -2222,40 +2245,11 @@ _vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t end)
KASSERT(entry->start < end && entry->end > end,
("_vm_map_clip_end: invalid clip of entry %p", entry));
/*
* If there is no object backing this entry, we might as well create
* one now. If we defer it, an object can get created after the map
* is clipped, and individual objects will be created for the split-up
* map. This is a bit of a hack, but is also about the best place to
* put this improvement.
*/
if (entry->object.vm_object == NULL && !map->system_map &&
(entry->eflags & MAP_ENTRY_GUARD) == 0) {
vm_object_t object;
object = vm_object_allocate(OBJT_DEFAULT,
atop(entry->end - entry->start));
entry->object.vm_object = object;
entry->offset = 0;
if (entry->cred != NULL) {
object->cred = entry->cred;
object->charge = entry->end - entry->start;
entry->cred = NULL;
}
} else if (entry->object.vm_object != NULL &&
((entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) &&
entry->cred != NULL) {
VM_OBJECT_WLOCK(entry->object.vm_object);
KASSERT(entry->object.vm_object->cred == NULL,
("OVERCOMMIT: vm_entry_clip_end: both cred e %p", entry));
entry->object.vm_object->cred = entry->cred;
entry->object.vm_object->charge = entry->end - entry->start;
VM_OBJECT_WUNLOCK(entry->object.vm_object);
entry->cred = NULL;
}
/*
* Create a new entry and insert it AFTER the specified entry
*/
vm_map_entry_charge_object(map, entry);
new_entry = vm_map_entry_create(map);
*new_entry = *entry;
@ -3935,16 +3929,8 @@ vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge)
*/
object = old_entry->object.vm_object;
if (object == NULL) {
object = vm_object_allocate(OBJT_DEFAULT,
atop(old_entry->end - old_entry->start));
old_entry->object.vm_object = object;
old_entry->offset = 0;
if (old_entry->cred != NULL) {
object->cred = old_entry->cred;
object->charge = old_entry->end -
old_entry->start;
old_entry->cred = NULL;
}
vm_map_entry_back(old_entry);
object = old_entry->object.vm_object;
}
/*