mirror of
https://github.com/drasko/codezero.git
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63e9d059c8
Added a list of links for vm objects so they can follow the links that point at them. More succinct handling of the case where a vm object is dropped. Now depending on the object's number of link references and shadow references, upon a drop it could either be merged, deleted or kept. Added opener reference count for vm files. Now files have opener count, objects have shadow and link count. Link count is also meaningful for how many tasks have mmap'ed that object.
144 lines
2.9 KiB
C
144 lines
2.9 KiB
C
/*
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* vm objects.
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*
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* Copyright (C) 2008 Bahadir Balban
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*/
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#include <file.h>
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#include <vm_area.h>
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#include <l4/macros.h>
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#include <l4/api/errno.h>
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#include <kmalloc/kmalloc.h>
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#if defined(DEBUG_FAULT_HANDLING)
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void print_cache_pages(struct vm_object *vmo)
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{
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struct page *p;
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if (!list_empty(&vmo->page_cache))
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printf("Pages:\n======\n");
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list_for_each_entry(p, &vmo->page_cache, list) {
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dprintf("Page offset: 0x%x, virtual: 0x%x, refcnt: %d\n", p->offset,
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p->virtual, p->refcnt);
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}
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}
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void vm_object_print(struct vm_object *vmo)
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{
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struct vm_file *f;
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printf("Object type: %s %s. links: %d, shadows: %d, Pages in cache: %d.\n",
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vmo->flags & VM_WRITE ? "writeable" : "read-only",
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vmo->flags & VM_OBJ_FILE ? "file" : "shadow", vmo->nlinks, vmo->shadows,
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vmo->npages);
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if (vmo->flags & VM_OBJ_FILE) {
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f = vm_object_to_file(vmo);
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char *ftype;
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if (f->type == VM_FILE_DEVZERO)
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ftype = "devzero";
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else if (f->type == VM_FILE_BOOTFILE)
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ftype = "bootfile";
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else if (f->type == VM_FILE_SHM)
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ftype = "shm file";
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else if (f->type == VM_FILE_VFS)
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ftype = "regular";
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else
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BUG();
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printf("File type: %s\n", ftype);
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}
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print_cache_pages(vmo);
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printf("\n");
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}
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#else
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void print_cache_pages(struct vm_object *vmo) { }
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void vm_object_print(struct vm_object *vmo) { }
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#endif
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/* Global list of in-memory vm objects. */
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LIST_HEAD(vm_object_list);
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struct vm_object *vm_object_init(struct vm_object *obj)
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{
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INIT_LIST_HEAD(&obj->list);
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INIT_LIST_HEAD(&obj->shref);
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INIT_LIST_HEAD(&obj->shdw_list);
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INIT_LIST_HEAD(&obj->page_cache);
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INIT_LIST_HEAD(&obj->link_list);
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return obj;
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}
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/* Allocate and initialise a vmfile, and return it */
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struct vm_object *vm_object_create(void)
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{
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struct vm_object *obj;
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if (!(obj = kzalloc(sizeof(*obj))))
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return 0;
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return vm_object_init(obj);
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}
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struct vm_file *vm_file_create(void)
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{
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struct vm_file *f;
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if (!(f = kzalloc(sizeof(*f))))
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return PTR_ERR(-ENOMEM);
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INIT_LIST_HEAD(&f->list);
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vm_object_init(&f->vm_obj);
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f->vm_obj.flags = VM_OBJ_FILE;
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return f;
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}
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/*
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* Populates the priv_data with vfs-file-specific
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* information.
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*/
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struct vm_file *vfs_file_create(void)
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{
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struct vm_file *f = vm_file_create();
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if (IS_ERR(f))
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return f;
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f->priv_data = kzalloc(sizeof(struct vfs_file_data));
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f->type = VM_FILE_VFS;
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return f;
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}
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/* Deletes the object via its base, along with all its pages */
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int vm_object_delete(struct vm_object *vmo)
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{
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struct vm_file *f;
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/* Release all pages */
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vmo->pager->ops.release_pages(vmo);
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/* Remove from global list */
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list_del(&vmo->list);
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/* Check any references */
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BUG_ON(vmo->nlinks);
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BUG_ON(vmo->shadows);
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BUG_ON(!list_empty(&vmo->shdw_list));
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BUG_ON(!list_empty(&vmo->link_list));
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BUG_ON(!list_empty(&vmo->page_cache));
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/* Obtain and free via the base object */
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if (vmo->flags & VM_OBJ_FILE) {
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f = vm_object_to_file(vmo);
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kfree(f);
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} else if (vmo->flags & VM_OBJ_SHADOW)
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kfree(vmo);
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else BUG();
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return 0;
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}
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