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Date:   Fri, 1 Nov 2019 19:19:11 -0200
From:   Marcelo Tosatti <mtosatti@redhat.com>
To:     Zhenzhong Duan <zhenzhong.duan@oracle.com>
Cc:     linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        joao.m.martins@oracle.com, rafael.j.wysocki@intel.com,
        rkrcmar@redhat.com, pbonzini@redhat.com
Subject: Re: [PATCH 4/5] cpuidle-haltpoll: add a check to ensure grow start
 value is nonzero
Message-ID: <20191101211908.GA20672@amt.cnet>
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On Sat, Oct 26, 2019 at 11:23:58AM +0800, Zhenzhong Duan wrote:
> dev->poll_limit_ns could be zeroed in certain cases (e.g. by
> guest_halt_poll_shrink). If guest_halt_poll_grow_start is zero,
> dev->poll_limit_ns will never be larger than zero.
>=20
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
> ---
>  drivers/cpuidle/governors/haltpoll.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)

I would rather disallow setting grow_start to zero rather
than silently setting it to one on the back of the user.