The patch titled
Subject: mm/mempolicy: use vma iterator & maple state instead of vma linked list
has been added to the -mm mm-unstable branch. Its filename is
mm-mempolicy-use-vma-iterator-maple-state-instead-of-vma-linked-list.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mempolicy-use-vma-iterator-maple-state-instead-of-vma-linked-list.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: mm/mempolicy: use vma iterator & maple state instead of vma linked list
Date: Mon, 22 Aug 2022 15:06:30 +0000
Reworked the way mbind_range() finds the first VMA to reuse the maple
state and limit the number of tree walks needed.
Note, this drops the VM_BUG_ON(!vma) call, which would catch a start
address higher than the last VMA. The code was written in a way that
allowed no VMA updates to occur and still return success. There should be
no functional change to this scenario with the new code.
Link: https://lkml.kernel.org/r/20220822150128.1562046-57-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
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/mempolicy.c | 56 ++++++++++++++++++++++++++---------------------
1 file changed, 32 insertions(+), 24 deletions(-)
--- a/mm/mempolicy.c~mm-mempolicy-use-vma-iterator-maple-state-instead-of-vma-linked-list
+++ a/mm/mempolicy.c
@@ -381,9 +381,10 @@ void mpol_rebind_task(struct task_struct
void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
{
struct vm_area_struct *vma;
+ VMA_ITERATOR(vmi, mm, 0);
mmap_write_lock(mm);
- for (vma = mm->mmap; vma; vma = vma->vm_next)
+ for_each_vma(vmi, vma)
mpol_rebind_policy(vma->vm_policy, new);
mmap_write_unlock(mm);
}
@@ -654,7 +655,7 @@ static unsigned long change_prot_numa(st
static int queue_pages_test_walk(unsigned long start, unsigned long end,
struct mm_walk *walk)
{
- struct vm_area_struct *vma = walk->vma;
+ struct vm_area_struct *next, *vma = walk->vma;
struct queue_pages *qp = walk->private;
unsigned long endvma = vma->vm_end;
unsigned long flags = qp->flags;
@@ -669,9 +670,10 @@ static int queue_pages_test_walk(unsigne
/* hole at head side of range */
return -EFAULT;
}
+ next = find_vma(vma->vm_mm, vma->vm_end);
if (!(flags & MPOL_MF_DISCONTIG_OK) &&
((vma->vm_end < qp->end) &&
- (!vma->vm_next || vma->vm_end < vma->vm_next->vm_start)))
+ (!next || vma->vm_end < next->vm_start)))
/* hole at middle or tail of range */
return -EFAULT;
@@ -785,26 +787,24 @@ static int vma_replace_policy(struct vm_
static int mbind_range(struct mm_struct *mm, unsigned long start,
unsigned long end, struct mempolicy *new_pol)
{
+ MA_STATE(mas, &mm->mm_mt, start - 1, start - 1);
struct vm_area_struct *prev;
struct vm_area_struct *vma;
int err = 0;
pgoff_t pgoff;
- unsigned long vmstart;
- unsigned long vmend;
-
- vma = find_vma(mm, start);
- VM_BUG_ON(!vma);
- prev = vma->vm_prev;
- if (start > vma->vm_start)
- prev = vma;
+ prev = mas_find_rev(&mas, 0);
+ if (prev && (start < prev->vm_end))
+ vma = prev;
+ else
+ vma = mas_next(&mas, end - 1);
- for (; vma && vma->vm_start < end; prev = vma, vma = vma->vm_next) {
- vmstart = max(start, vma->vm_start);
- vmend = min(end, vma->vm_end);
+ for (; vma; vma = mas_next(&mas, end - 1)) {
+ unsigned long vmstart = max(start, vma->vm_start);
+ unsigned long vmend = min(end, vma->vm_end);
if (mpol_equal(vma_policy(vma), new_pol))
- continue;
+ goto next;
pgoff = vma->vm_pgoff +
((vmstart - vma->vm_start) >> PAGE_SHIFT);
@@ -813,6 +813,8 @@ static int mbind_range(struct mm_struct
new_pol, vma->vm_userfaultfd_ctx,
anon_vma_name(vma));
if (prev) {
+ /* vma_merge() invalidated the mas */
+ mas_pause(&mas);
vma = prev;
goto replace;
}
@@ -820,19 +822,25 @@ static int mbind_range(struct mm_struct
err = split_vma(vma->vm_mm, vma, vmstart, 1);
if (err)
goto out;
+ /* split_vma() invalidated the mas */
+ mas_pause(&mas);
}
if (vma->vm_end != vmend) {
err = split_vma(vma->vm_mm, vma, vmend, 0);
if (err)
goto out;
+ /* split_vma() invalidated the mas */
+ mas_pause(&mas);
}
- replace:
+replace:
err = vma_replace_policy(vma, new_pol);
if (err)
goto out;
+next:
+ prev = vma;
}
- out:
+out:
return err;
}
@@ -1049,6 +1057,7 @@ static int migrate_to_node(struct mm_str
int flags)
{
nodemask_t nmask;
+ struct vm_area_struct *vma;
LIST_HEAD(pagelist);
int err = 0;
struct migration_target_control mtc = {
@@ -1064,8 +1073,9 @@ static int migrate_to_node(struct mm_str
* need migration. Between passing in the full user address
* space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
*/
+ vma = find_vma(mm, 0);
VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
- queue_pages_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
+ queue_pages_range(mm, vma->vm_start, mm->task_size, &nmask,
flags | MPOL_MF_DISCONTIG_OK, &pagelist);
if (!list_empty(&pagelist)) {
@@ -1195,14 +1205,13 @@ static struct page *new_page(struct page
struct folio *dst, *src = page_folio(page);
struct vm_area_struct *vma;
unsigned long address;
+ VMA_ITERATOR(vmi, current->mm, start);
gfp_t gfp = GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL;
- vma = find_vma(current->mm, start);
- while (vma) {
+ for_each_vma(vmi, vma) {
address = page_address_in_vma(page, vma);
if (address != -EFAULT)
break;
- vma = vma->vm_next;
}
if (folio_test_hugetlb(src))
@@ -1480,6 +1489,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node,
unsigned long vmend;
unsigned long end;
int err = -ENOENT;
+ VMA_ITERATOR(vmi, mm, start);
start = untagged_addr(start);
if (start & ~PAGE_MASK)
@@ -1505,9 +1515,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node,
if (end == start)
return 0;
mmap_write_lock(mm);
- vma = find_vma(mm, start);
- for (; vma && vma->vm_start < end; vma = vma->vm_next) {
-
+ for_each_vma_range(vmi, vma, end) {
vmstart = max(start, vma->vm_start);
vmend = min(end, vma->vm_end);
new = mpol_dup(vma_policy(vma));
_
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
