The quilt patch titled
Subject: mmap: change zeroing of maple tree in __vma_adjust()
has been removed from the -mm tree. Its filename was
mmap-change-zeroing-of-maple-tree-in-__vma_adjust.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Subject: mmap: change zeroing of maple tree in __vma_adjust()
Date: Tue, 6 Sep 2022 19:48:49 +0000
Only write to the maple tree if we are not inserting or the insert isn't
going to overwrite the area to clear. This avoids spanning writes and
node coealescing when unnecessary.
The change requires a custom search for the linked list addition to find
the correct VMA for the prev link.
Link: https://lkml.kernel.org/r/20220906194824.2110408-19-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Tested-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Cc: SeongJae Park <sj@xxxxxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 30 ++++++++++++++++++++++--------
1 file changed, 22 insertions(+), 8 deletions(-)
--- a/mm/mmap.c~mmap-change-zeroing-of-maple-tree-in-__vma_adjust
+++ a/mm/mmap.c
@@ -567,11 +567,11 @@ static int vma_link(struct mm_struct *mm
* mm's list and the mm tree. It has already been inserted into the interval tree.
*/
static void __insert_vm_struct(struct mm_struct *mm, struct ma_state *mas,
- struct vm_area_struct *vma)
+ struct vm_area_struct *vma, unsigned long location)
{
struct vm_area_struct *prev;
- mas_set(mas, vma->vm_start);
+ mas_set(mas, location);
prev = mas_prev(mas, 0);
vma_mas_store(vma, mas);
__vma_link_list(mm, vma, prev);
@@ -601,6 +601,7 @@ int __vma_adjust(struct vm_area_struct *
int remove_next = 0;
MA_STATE(mas, &mm->mm_mt, 0, 0);
struct vm_area_struct *exporter = NULL, *importer = NULL;
+ unsigned long ll_prev = vma->vm_start; /* linked list prev. */
if (next && !insert) {
if (end >= next->vm_end) {
@@ -728,15 +729,27 @@ int __vma_adjust(struct vm_area_struct *
}
if (start != vma->vm_start) {
- if (vma->vm_start < start)
+ if ((vma->vm_start < start) &&
+ (!insert || (insert->vm_end != start))) {
vma_mas_szero(&mas, vma->vm_start, start);
- vma_changed = true;
+ VM_WARN_ON(insert && insert->vm_start > vma->vm_start);
+ } else {
+ vma_changed = true;
+ }
vma->vm_start = start;
}
if (end != vma->vm_end) {
- if (vma->vm_end > end)
- vma_mas_szero(&mas, end, vma->vm_end);
- vma_changed = true;
+ if (vma->vm_end > end) {
+ if (!insert || (insert->vm_start != end)) {
+ vma_mas_szero(&mas, end, vma->vm_end);
+ VM_WARN_ON(insert &&
+ insert->vm_end < vma->vm_end);
+ } else if (insert->vm_start == end) {
+ ll_prev = vma->vm_end;
+ }
+ } else {
+ vma_changed = true;
+ }
vma->vm_end = end;
if (!next)
mm->highest_vm_end = vm_end_gap(vma);
@@ -783,7 +796,7 @@ int __vma_adjust(struct vm_area_struct *
* us to insert it before dropping the locks
* (it may either follow vma or precede it).
*/
- __insert_vm_struct(mm, &mas, insert);
+ __insert_vm_struct(mm, &mas, insert, ll_prev);
}
if (anon_vma) {
@@ -870,6 +883,7 @@ again:
if (insert && file)
uprobe_mmap(insert);
+ mas_destroy(&mas);
validate_mm(mm);
return 0;
}
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
