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mm: replace vma prio_tree with an interval tree

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Implement an interval tree as a replacement for the VMA prio_tree.  The
algorithms are similar to lib/interval_tree.c; however that code can't be
directly reused as the interval endpoints are not explicitly stored in the
VMA.  So instead, the common algorithm is moved into a template and the
details (node type, how to get interval endpoints from the node, etc) are
filled in using the C preprocessor.

Once the interval tree functions are available, using them as a
replacement to the VMA prio tree is a relatively simple, mechanical job.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michel Lespinasse
2012-10-08 16:31:25 -07:00
committed by Linus Torvalds
parent fff3fd8a12
commit 6b2dbba8b6
25 changed files with 355 additions and 464 deletions
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61
mm/interval_tree.c Normal file
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/*
* mm/interval_tree.c - interval tree for mapping->i_mmap
*
* Copyright (C) 2012, Michel Lespinasse <walken@google.com>
*
* This file is released under the GPL v2.
*/
#include <linux/mm.h>
#include <linux/fs.h>
#define ITSTRUCT struct vm_area_struct
#define ITRB shared.linear.rb
#define ITTYPE unsigned long
#define ITSUBTREE shared.linear.rb_subtree_last
#define ITSTART(n) ((n)->vm_pgoff)
#define ITLAST(n) ((n)->vm_pgoff + \
(((n)->vm_end - (n)->vm_start) >> PAGE_SHIFT) - 1)
#define ITSTATIC
#define ITPREFIX vma_interval_tree
#include <linux/interval_tree_tmpl.h>
/* Insert old immediately after vma in the interval tree */
void vma_interval_tree_add(struct vm_area_struct *vma,
struct vm_area_struct *old,
struct address_space *mapping)
{
struct rb_node **link;
struct vm_area_struct *parent;
unsigned long last;
if (unlikely(vma->vm_flags & VM_NONLINEAR)) {
list_add(&vma->shared.nonlinear, &old->shared.nonlinear);
return;
}
last = ITLAST(vma);
if (!old->shared.linear.rb.rb_right) {
parent = old;
link = &old->shared.linear.rb.rb_right;
} else {
parent = rb_entry(old->shared.linear.rb.rb_right,
struct vm_area_struct, shared.linear.rb);
if (parent->shared.linear.rb_subtree_last < last)
parent->shared.linear.rb_subtree_last = last;
while (parent->shared.linear.rb.rb_left) {
parent = rb_entry(parent->shared.linear.rb.rb_left,
struct vm_area_struct, shared.linear.rb);
if (parent->shared.linear.rb_subtree_last < last)
parent->shared.linear.rb_subtree_last = last;
}
link = &parent->shared.linear.rb.rb_left;
}
vma->shared.linear.rb_subtree_last = last;
rb_link_node(&vma->shared.linear.rb, &parent->shared.linear.rb, link);
rb_insert_augmented(&vma->shared.linear.rb, &mapping->i_mmap,
&vma_interval_tree_augment_callbacks);
}