Re: [RFC 1/3] mm/ksm: add anonymous check in find_mergeable_vma
From: David Hildenbrand
Date: Wed Jun 05 2024 - 05:56:31 EST
On 05.06.24 11:53, alexs@xxxxxxxxxx wrote:
From: "Alex Shi (tencent)" <alexs@xxxxxxxxxx>
We do vma_set_anonyous in do_mmap(), and then vma_is_anonymous()
checking workable, use it as a extra check since ksm only care anonymous
pages.
Signed-off-by: Alex Shi (tencent) <alexs@xxxxxxxxxx>
---
mm/ksm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/ksm.c b/mm/ksm.c
index f5138f43f0d2..088bce39cd33 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -742,7 +742,8 @@ static struct vm_area_struct *find_mergeable_vma(struct mm_struct *mm,
if (ksm_test_exit(mm))
return NULL;
vma = vma_lookup(mm, addr);
- if (!vma || !(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
+ if (!vma || !(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma ||
+ !vma_is_anonymous(vma))
Doesn't KSM also apply to COW'ed pages in !anon mappings? At least
that's what I recall.
--
Cheers,
David / dhildenb