linux-kernel - [RFC 1/3] mm/ksm: add anonymous check in find_mergeable

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Date: Wed,  5 Jun 2024 17:53:01 +0800
From: alexs@...nel.org
To: Andrew Morton <akpm@...ux-foundation.org>,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	izik.eidus@...ellosystems.com,
	willy@...radead.org,
	aarcange@...hat.com,
	chrisw@...s-sol.org,
	hughd@...gle.com,
	david@...hat.com
Cc: "Alex Shi (tencent)" <alexs@...nel.org>
Subject: [RFC 1/3] mm/ksm: add anonymous check in find_mergeable_vma

From: "Alex Shi (tencent)" <alexs@...nel.org>

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@...nel.org>
---
 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))
 		return NULL;
 	return vma;
 }
-- 
2.43.0