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Bugfixes, enhancements

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- Fixed an important bug with shadow object handling.
  When a shadow is dropped, if there are references left
  to it, both the object in front and dropped object becomes
  a shadow of the original object underneath. We had thought
  of this case but had not increase the shadow count.

- Added a test mechanism that tests the number of objects,
  vmfiles, shadows etc. by first counting them and trying to
  reach the same number by other means, i.e. per-object-shadow counts.
  It discovered a plethora of bugs.

- Added new set of functions to register objects, files and tasks
  globally with the pager, these functions introduce a refcount as
  well as adding structures to linked lists.

- fork/exit now seems to work stably i.e. no negative shadow counts etc.
This commit is contained in:
Bahadir Balban
2008-10-24 13:45:39 +03:00
parent b3693de21b
commit 651901d8b9
13 changed files with 384 additions and 146 deletions
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73
tasks/mm0/src/vm_object.c
View File

@@ -8,6 +8,52 @@
#include <l4/macros.h>
#include <l4/api/errno.h>
#include <kmalloc/kmalloc.h>
#include <globals.h>
/* Global list of all in-memory files on the system */
struct global_list global_vm_files = {
.list = { &global_vm_files.list, &global_vm_files.list },
.total = 0,
};
/* Global list of in-memory vm objects in the system */
struct global_list global_vm_objects = {
.list = { &global_vm_objects.list, &global_vm_objects.list },
.total = 0,
};
void global_add_vm_object(struct vm_object *obj)
{
BUG_ON(!list_empty(&obj->list));
list_add(&obj->list, &global_vm_objects.list);
global_vm_objects.total++;
}
void global_remove_vm_object(struct vm_object *obj)
{
BUG_ON(list_empty(&obj->list));
list_del_init(&obj->list);
BUG_ON(--global_vm_objects.total < 0);
}
void global_add_vm_file(struct vm_file *f)
{
BUG_ON(!list_empty(&f->list));
list_add(&f->list, &global_vm_files.list);
global_vm_files.total++;
global_add_vm_object(&f->vm_obj);
}
void global_remove_vm_file(struct vm_file *f)
{
BUG_ON(list_empty(&f->list));
list_del_init(&f->list);
BUG_ON(--global_vm_files.total < 0);
global_remove_vm_object(&f->vm_obj);
}
void print_cache_pages(struct vm_object *vmo)
{
@@ -51,8 +97,21 @@ void vm_object_print(struct vm_object *vmo)
// printf("\n");
}
/* Global list of in-memory vm objects. */
LIST_HEAD(vm_object_list);
void vm_print_files(struct list_head *files)
{
struct vm_file *f;
list_for_each_entry(f, files, list)
vm_object_print(&f->vm_obj);
}
void vm_print_objects(struct list_head *objects)
{
struct vm_object *vmo;
list_for_each_entry(vmo, objects, list)
vm_object_print(vmo);
}
struct vm_object *vm_object_init(struct vm_object *obj)
{
@@ -118,7 +177,11 @@ int vm_object_delete(struct vm_object *vmo)
vmo->pager->ops.release_pages(vmo);
/* Remove from global list */
list_del(&vmo->list);
if (vmo->flags & VM_OBJ_FILE)
global_remove_vm_file(vm_object_to_file(vmo));
else if (vmo->flags & VM_OBJ_SHADOW)
global_remove_vm_object(vmo);
else BUG();
/* Check any references */
BUG_ON(vmo->nlinks);
@@ -126,6 +189,7 @@ int vm_object_delete(struct vm_object *vmo)
BUG_ON(!list_empty(&vmo->shdw_list));
BUG_ON(!list_empty(&vmo->link_list));
BUG_ON(!list_empty(&vmo->page_cache));
BUG_ON(!list_empty(&vmo->shref));
/* Obtain and free via the base object */
if (vmo->flags & VM_OBJ_FILE) {
@@ -147,9 +211,6 @@ int vm_object_delete(struct vm_object *vmo)
int vm_file_delete(struct vm_file *f)
{
/* Delete it from global file list */
list_del_init(&f->list);
/* Delete file via base object */
return vm_object_delete(&f->vm_obj);
}