From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
This rather specialised walk can use the VMA iterator. If this proves
to be too slow, we can write a custom routine to find the two largest
gaps, but it will be somewhat complicated, so let's see if we need it
first.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
mm/damon/vaddr.c | 53 ++++++++++++++++++++++++------------------------
1 file changed, 27 insertions(+), 26 deletions(-)
diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 35fe49080ee9..906eb8d0c640 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -120,37 +120,38 @@ static void swap_ranges(struct damon_addr_range *r1,
*
* Returns 0 if success, or negative error code otherwise.
*/
-static int __damon_va_three_regions(struct vm_area_struct *vma,
+static int __damon_va_three_regions(struct mm_struct *mm,
struct damon_addr_range regions[3])
{
- struct damon_addr_range gap = {0}, first_gap = {0}, second_gap = {0};
- struct vm_area_struct *last_vma = NULL;
- unsigned long start = 0;
- struct rb_root rbroot;
-
- /* Find two biggest gaps so that first_gap > second_gap > others */
- for (; vma; vma = vma->vm_next) {
- if (!last_vma) {
- start = vma->vm_start;
- goto next;
- }
+ struct damon_addr_range first_gap = {0}, second_gap = {0};
+ VMA_ITERATOR(vmi, mm, 0);
+ struct vm_area_struct *vma, *prev = NULL;
+ unsigned long start;
- if (vma->rb_subtree_gap <= sz_range(&second_gap)) {
- rbroot.rb_node = &vma->vm_rb;
- vma = rb_entry(rb_last(&rbroot),
- struct vm_area_struct, vm_rb);
+ /*
+ * Find the two biggest gaps so that first_gap > second_gap > others.
+ * If this is too slow, it can be optimised to examine the maple
+ * tree gaps.
+ */
+ for_each_vma(vmi, vma) {
+ unsigned long gap;
+
+ if (!prev) {
+ start = vma->vm_start;
goto next;
}
-
- gap.start = last_vma->vm_end;
- gap.end = vma->vm_start;
- if (sz_range(&gap) > sz_range(&second_gap)) {
- swap_ranges(&gap, &second_gap);
- if (sz_range(&second_gap) > sz_range(&first_gap))
- swap_ranges(&second_gap, &first_gap);
+ gap = vma->vm_start - prev->vm_end;
+
+ if (gap > sz_range(&first_gap)) {
+ second_gap = first_gap;
+ first_gap.start = prev->vm_end;
+ first_gap.end = vma->vm_start;
+ } else if (gap > sz_range(&second_gap)) {
+ second_gap.start = prev->vm_end;
+ second_gap.end = vma->vm_start;
}
next:
- last_vma = vma;
+ prev = vma;
}
if (!sz_range(&second_gap) || !sz_range(&first_gap))
@@ -166,7 +167,7 @@ static int __damon_va_three_regions(struct vm_area_struct *vma,
regions[1].start = ALIGN(first_gap.end, DAMON_MIN_REGION);
regions[1].end = ALIGN(second_gap.start, DAMON_MIN_REGION);
regions[2].start = ALIGN(second_gap.end, DAMON_MIN_REGION);
- regions[2].end = ALIGN(last_vma->vm_end, DAMON_MIN_REGION);
+ regions[2].end = ALIGN(prev->vm_end, DAMON_MIN_REGION);
return 0;
}
@@ -187,7 +188,7 @@ static int damon_va_three_regions(struct damon_target *t,
return -EINVAL;
mmap_read_lock(mm);
- rc = __damon_va_three_regions(mm->mmap, regions);
+ rc = __damon_va_three_regions(mm, regions);
mmap_read_unlock(mm);
mmput(mm);
--
2.30.2
