Re: [PATCH -mm 1/7] mm: track free size between VMAs in VMA rbtree

From: Peter Zijlstra
Date: Thu Jun 21 2012 - 07:07:54 EST


On Mon, 2012-06-18 at 18:05 -0400, Rik van Riel wrote:
> @@ -473,11 +524,17 @@ __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
> struct vm_area_struct *prev)
> {
> struct vm_area_struct *next = vma->vm_next;
> + struct rb_node *deepest;
>
> prev->vm_next = next;
> - if (next)
> + if (next) {
> next->vm_prev = prev;
> + adjust_free_gap(next);
> + }
> + deepest = rb_augment_erase_begin(&vma->vm_rb);
> rb_erase(&vma->vm_rb, &mm->mm_rb);
> + rb_augment_erase_end(deepest, vma_rb_augment_cb, NULL);
> +
> if (mm->mmap_cache == vma)
> mm->mmap_cache = prev;
> }


> @@ -1933,7 +2002,10 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
> insertion_point = (prev ? &prev->vm_next : &mm->mmap);
> vma->vm_prev = NULL;
> do {
> + struct rb_node *deepest;
> + deepest = rb_augment_erase_begin(&vma->vm_rb);
> rb_erase(&vma->vm_rb, &mm->mm_rb);
> + rb_augment_erase_end(deepest, vma_rb_augment_cb, NULL);


---
include/linux/rbtree.h | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index 033b507..07c5843 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -155,6 +155,14 @@ extern struct rb_node *rb_augment_erase_begin(struct rb_node *node);
extern void rb_augment_erase_end(struct rb_node *node,
rb_augment_f func, void *data);

+static inline void rb_augment_erase(struct rb_node *node, struct rb_root *root,
+ rb_augment_f func, void *data)
+{
+ struct rb_node *deepest = rb_augment_erase_begin(node);
+ rb_erase(node, root);
+ rb_augment_erase_end(deepest, func, data);
+}
+
/* Find logical next and previous nodes in a tree */
extern struct rb_node *rb_next(const struct rb_node *);
extern struct rb_node *rb_prev(const struct rb_node *);

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