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Diffstat (limited to 'mm/prio_tree.c')
| -rw-r--r-- | mm/prio_tree.c | 208 |
1 files changed, 0 insertions, 208 deletions
diff --git a/mm/prio_tree.c b/mm/prio_tree.c deleted file mode 100644 index 799dcfd7cd8..00000000000 --- a/mm/prio_tree.c +++ /dev/null @@ -1,208 +0,0 @@ -/* - * mm/prio_tree.c - priority search tree for mapping->i_mmap - * - * Copyright (C) 2004, Rajesh Venkatasubramanian <vrajesh@umich.edu> - * - * This file is released under the GPL v2. - * - * Based on the radix priority search tree proposed by Edward M. McCreight - * SIAM Journal of Computing, vol. 14, no.2, pages 257-276, May 1985 - * - * 02Feb2004 Initial version - */ - -#include <linux/mm.h> -#include <linux/prio_tree.h> -#include <linux/prefetch.h> - -/* - * See lib/prio_tree.c for details on the general radix priority search tree - * code. - */ - -/* - * The following #defines are mirrored from lib/prio_tree.c. They're only used - * for debugging, and should be removed (along with the debugging code using - * them) when switching also VMAs to the regular prio_tree code. - */ - -#define RADIX_INDEX(vma) ((vma)->vm_pgoff) -#define VMA_SIZE(vma) (((vma)->vm_end - (vma)->vm_start) >> PAGE_SHIFT) -/* avoid overflow */ -#define HEAP_INDEX(vma) ((vma)->vm_pgoff + (VMA_SIZE(vma) - 1)) - -/* - * Radix priority search tree for address_space->i_mmap - * - * For each vma that map a unique set of file pages i.e., unique [radix_index, - * heap_index] value, we have a corresponding priority search tree node. If - * multiple vmas have identical [radix_index, heap_index] value, then one of - * them is used as a tree node and others are stored in a vm_set list. The tree - * node points to the first vma (head) of the list using vm_set.head. - * - * prio_tree_root - * | - * A vm_set.head - * / \ / - * L R -> H-I-J-K-M-N-O-P-Q-S - * ^ ^ <-- vm_set.list --> - * tree nodes - * - * We need some way to identify whether a vma is a tree node, head of a vm_set - * list, or just a member of a vm_set list. We cannot use vm_flags to store - * such information. The reason is, in the above figure, it is possible that - * vm_flags' of R and H are covered by the different mmap_sems. When R is - * removed under R->mmap_sem, H replaces R as a tree node. Since we do not hold - * H->mmap_sem, we cannot use H->vm_flags for marking that H is a tree node now. - * That's why some trick involving shared.vm_set.parent is used for identifying - * tree nodes and list head nodes. - * - * vma radix priority search tree node rules: - * - * vma->shared.vm_set.parent != NULL ==> a tree node - * vma->shared.vm_set.head != NULL ==> list of others mapping same range - * vma->shared.vm_set.head == NULL ==> no others map the same range - * - * vma->shared.vm_set.parent == NULL - * vma->shared.vm_set.head != NULL ==> list head of vmas mapping same range - * vma->shared.vm_set.head == NULL ==> a list node - */ - -/* - * Add a new vma known to map the same set of pages as the old vma: - * useful for fork's dup_mmap as well as vma_prio_tree_insert below. - * Note that it just happens to work correctly on i_mmap_nonlinear too. - */ -void vma_prio_tree_add(struct vm_area_struct *vma, struct vm_area_struct *old) -{ - /* Leave these BUG_ONs till prio_tree patch stabilizes */ - BUG_ON(RADIX_INDEX(vma) != RADIX_INDEX(old)); - BUG_ON(HEAP_INDEX(vma) != HEAP_INDEX(old)); - - vma->shared.vm_set.head = NULL; - vma->shared.vm_set.parent = NULL; - - if (!old->shared.vm_set.parent) - list_add(&vma->shared.vm_set.list, - &old->shared.vm_set.list); - else if (old->shared.vm_set.head) - list_add_tail(&vma->shared.vm_set.list, - &old->shared.vm_set.head->shared.vm_set.list); - else { - INIT_LIST_HEAD(&vma->shared.vm_set.list); - vma->shared.vm_set.head = old; - old->shared.vm_set.head = vma; - } -} - -void vma_prio_tree_insert(struct vm_area_struct *vma, - struct prio_tree_root *root) -{ - struct prio_tree_node *ptr; - struct vm_area_struct *old; - - vma->shared.vm_set.head = NULL; - - ptr = raw_prio_tree_insert(root, &vma->shared.prio_tree_node); - if (ptr != (struct prio_tree_node *) &vma->shared.prio_tree_node) { - old = prio_tree_entry(ptr, struct vm_area_struct, - shared.prio_tree_node); - vma_prio_tree_add(vma, old); - } -} - -void vma_prio_tree_remove(struct vm_area_struct *vma, - struct prio_tree_root *root) -{ - struct vm_area_struct *node, *head, *new_head; - - if (!vma->shared.vm_set.head) { - if (!vma->shared.vm_set.parent) - list_del_init(&vma->shared.vm_set.list); - else - raw_prio_tree_remove(root, &vma->shared.prio_tree_node); - } else { - /* Leave this BUG_ON till prio_tree patch stabilizes */ - BUG_ON(vma->shared.vm_set.head->shared.vm_set.head != vma); - if (vma->shared.vm_set.parent) { - head = vma->shared.vm_set.head; - if (!list_empty(&head->shared.vm_set.list)) { - new_head = list_entry( - head->shared.vm_set.list.next, - struct vm_area_struct, - shared.vm_set.list); - list_del_init(&head->shared.vm_set.list); - } else - new_head = NULL; - - raw_prio_tree_replace(root, &vma->shared.prio_tree_node, - &head->shared.prio_tree_node); - head->shared.vm_set.head = new_head; - if (new_head) - new_head->shared.vm_set.head = head; - - } else { - node = vma->shared.vm_set.head; - if (!list_empty(&vma->shared.vm_set.list)) { - new_head = list_entry( - vma->shared.vm_set.list.next, - struct vm_area_struct, - shared.vm_set.list); - list_del_init(&vma->shared.vm_set.list); - node->shared.vm_set.head = new_head; - new_head->shared.vm_set.head = node; - } else - node->shared.vm_set.head = NULL; - } - } -} - -/* - * Helper function to enumerate vmas that map a given file page or a set of - * contiguous file pages. The function returns vmas that at least map a single - * page in the given range of contiguous file pages. - */ -struct vm_area_struct *vma_prio_tree_next(struct vm_area_struct *vma, - struct prio_tree_iter *iter) -{ - struct prio_tree_node *ptr; - struct vm_area_struct *next; - - if (!vma) { - /* - * First call is with NULL vma - */ - ptr = prio_tree_next(iter); - if (ptr) { - next = prio_tree_entry(ptr, struct vm_area_struct, - shared.prio_tree_node); - prefetch(next->shared.vm_set.head); - return next; - } else - return NULL; - } - - if (vma->shared.vm_set.parent) { - if (vma->shared.vm_set.head) { - next = vma->shared.vm_set.head; - prefetch(next->shared.vm_set.list.next); - return next; - } - } else { - next = list_entry(vma->shared.vm_set.list.next, - struct vm_area_struct, shared.vm_set.list); - if (!next->shared.vm_set.head) { - prefetch(next->shared.vm_set.list.next); - return next; - } - } - - ptr = prio_tree_next(iter); - if (ptr) { - next = prio_tree_entry(ptr, struct vm_area_struct, - shared.prio_tree_node); - prefetch(next->shared.vm_set.head); - return next; - } else - return NULL; -} |