[PATCH 03/10] mm: abstract duplicated policy comparison

Lorenzo Stoakes
2024-08-05T12:14:35Z

Both can_vma_merge_before() and can_vma_merge_after() are invoked after
checking for compatible VMA NUMA policy, we can simply move this to
is_mergeable_vma() and abstract this altogether.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
mm/mmap.c | 8 +++-----
mm/vma.c | 9 ++++-----
2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index f931000c561f..721ced6e37b0 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1422,8 +1422,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,

/* Attempt to expand an old mapping */
/* Check next */
- if (next && next->vm_start == end && !vma_policy(next) &&
- can_vma_merge_before(&vmg)) {
+ if (next && next->vm_start == end && can_vma_merge_before(&vmg)) {
merge_end = next->vm_end;
vma = next;
vmg.pgoff = next->vm_pgoff - pglen;
@@ -1435,8 +1434,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
}

/* Check prev */
- if (prev && prev->vm_end == addr && !vma_policy(prev) &&
- can_vma_merge_after(&vmg)) {
+ if (prev && prev->vm_end == addr && can_vma_merge_after(&vmg)) {
merge_start = prev->vm_start;
vma = prev;
vmg.pgoff = prev->vm_pgoff;
@@ -1798,7 +1796,7 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
* Expand the existing vma if possible; Note that singular lists do not
* occur after forking, so the expand will only happen on new VMAs.
*/
- if (vma && vma->vm_end == addr && !vma_policy(vma)) {
+ if (vma && vma->vm_end == addr) {
struct vma_merge_struct vmg = {
.prev = vma,
.flags = flags,
diff --git a/mm/vma.c b/mm/vma.c
index 20c4ce7712c0..b452b472a085 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -19,6 +19,8 @@ static inline bool is_mergeable_vma(struct vma_merge_struct *vmg, bool merge_nex
*/
bool may_remove_vma = merge_next;

+ if (!mpol_equal(vmg->policy, vma_policy(vma)))
+ return false;
/*
* VM_SOFTDIRTY should not prevent from VMA merging, if we
* match the flags but dirty bit -- the caller should mark
@@ -971,17 +973,14 @@ static struct vm_area_struct *vma_merge(struct vma_merge_struct *vmg)
vma_pgoff = prev->vm_pgoff;

/* Can we merge the predecessor? */
- if (addr == prev->vm_end && mpol_equal(vma_policy(prev), vmg->policy)
- && can_vma_merge_after(vmg)) {
-
+ if (addr == prev->vm_end && can_vma_merge_after(vmg)) {
merge_prev = true;
vma_prev(vmg->vmi);
}
}

/* Can we merge the successor? */
- if (next && mpol_equal(vmg->policy, vma_policy(next)) &&
- can_vma_merge_before(vmg)) {
+ if (next && can_vma_merge_before(vmg)) {
merge_next = true;
}

--
2.45.2