Re: [PATCH] Add a new test 'migrate.cow_after_fork' that verifies correct RMAP handling of Copy-On-Write pages after fork(). Before a write, parent and child share the same PFN; after a write, the child’s PFN differs, confirming proper COW duplication.

On Tue, 14 Oct 2025 22:49:44 +0300 Itamar-Dalal dalalitamar@gmail.com wrote:

Subject: [PATCH] Add a new test 'migrate.cow_after_fork' that verifies correct RMAP handling of Copy-On-Write pages after fork(). Before a write, parent and child share the same PFN; after a write, the child’s PFN differs, confirming proper COW duplication. Date: Tue, 14 Oct 2025 22:49:44 +0300 X-Mailer: git-send-email 2.34.1

Signed-off-by: Itamar-Dalal dalalitamar@gmail.com

tools/testing/selftests/mm/rmap.c | 45 ++++++++++++++++++++++++++++++- 1 file changed, 44 insertions(+), 1 deletion(-)

OK, somehow your changelog was pasted into the email Subject, so please resend.

Please prefix the Subject: with something which tells readers what part of the kernel is affected. eg,

: : Subject: selfstests/mm/rmap: verify correct RMAP handling of COW pages after fork() :

Then enter the details in the changelog body, eg:

: : Before a write, parent and child share the same PFN. After a write, the : child’s PFN differs. Check this to confirm proper COW duplication. :