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.

[Andrew Morton]

On Tue, 14 Oct 2025 22:49:44 +0300 Itamar-Dalal <dalalitamar@xxxxxxxxx> 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@xxxxxxxxx>
> ---
>  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.
: