The patch titled
Subject: mmap: change zeroing of maple tree in __vma_adjust()
has been added to the -mm mm-unstable branch. Its filename is
mmap-change-zeroing-of-maple-tree-in-__vma_adjust.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mmap-change-zeroing-of-maple-tree-in-__vma_adjust.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Subject: mmap: change zeroing of maple tree in __vma_adjust()
Date: Mon, 22 Aug 2022 15:04:26 +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/20220822150128.1562046-19-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
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>
Cc: Yu Zhao <yuzhao@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
maple-tree-add-new-data-structure.patch
radix-tree-test-suite-add-pr_err-define.patch
radix-tree-test-suite-add-kmem_cache_set_non_kernel.patch
radix-tree-test-suite-add-allocation-counts-and-size-to-kmem_cache.patch
radix-tree-test-suite-add-support-for-slab-bulk-apis.patch
radix-tree-test-suite-add-lockdep_is_held-to-header.patch
lib-test_maple_tree-add-testing-for-maple-tree.patch
mm-start-tracking-vmas-with-maple-tree.patch
mm-mmap-use-the-maple-tree-in-find_vma-instead-of-the-rbtree.patch
mm-mmap-use-the-maple-tree-for-find_vma_prev-instead-of-the-rbtree.patch
mm-mmap-use-maple-tree-for-unmapped_area_topdown.patch
kernel-fork-use-maple-tree-for-dup_mmap-during-forking.patch
damon-convert-__damon_va_three_regions-to-use-the-vma-iterator.patch
mm-remove-rb-tree.patch
mmap-change-zeroing-of-maple-tree-in-__vma_adjust.patch
xen-use-vma_lookup-in-privcmd_ioctl_mmap.patch
mm-optimize-find_exact_vma-to-use-vma_lookup.patch
mm-khugepaged-optimize-collapse_pte_mapped_thp-by-using-vma_lookup.patch
mm-mmap-change-do_brk_flags-to-expand-existing-vma-and-add-do_brk_munmap.patch
mm-use-maple-tree-operations-for-find_vma_intersection.patch
mm-mmap-use-advanced-maple-tree-api-for-mmap_region.patch
mm-remove-vmacache.patch
mm-convert-vma_lookup-to-use-mtree_load.patch
mm-mmap-move-mmap_region-below-do_munmap.patch
mm-mmap-reorganize-munmap-to-use-maple-states.patch
mm-mmap-change-do_brk_munmap-to-use-do_mas_align_munmap.patch
arm64-change-elfcore-for_each_mte_vma-to-use-vma-iterator.patch
fs-proc-base-use-maple-tree-iterators-in-place-of-linked-list.patch
userfaultfd-use-maple-tree-iterator-to-iterate-vmas.patch
ipc-shm-use-vma-iterator-instead-of-linked-list.patch
bpf-remove-vma-linked-list.patch
mm-gup-use-maple-tree-navigation-instead-of-linked-list.patch
mm-madvise-use-vma_find-instead-of-vma-linked-list.patch
mm-memcontrol-stop-using-mm-highest_vm_end.patch
mm-mempolicy-use-vma-iterator-maple-state-instead-of-vma-linked-list.patch
mm-mprotect-use-maple-tree-navigation-instead-of-vma-linked-list.patch
mm-mremap-use-vma_find_intersection-instead-of-vma-linked-list.patch
mm-msync-use-vma_find-instead-of-vma-linked-list.patch
mm-oom_kill-use-maple-tree-iterators-instead-of-vma-linked-list.patch
mm-swapfile-use-vma-iterator-instead-of-vma-linked-list.patch
riscv-use-vma-iterator-for-vdso.patch
mm-remove-the-vma-linked-list.patch
mm-mmap-drop-range_has_overlap-function.patch
mm-mmapc-pass-in-mapping-to-__vma_link_file.patch
