Re: [PATCH 4/5] cpuidle-haltpoll: add a check to ensure grow start value is nonzero

From: Paolo Bonzini
Date: Mon Nov 11 2019 - 08:54:52 EST


On 04/11/19 03:56, Zhenzhong Duan wrote:
>
> On 2019/11/2 5:19, Marcelo Tosatti wrote:
>> 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.
>>>
>>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>
>>> ---
>>>   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.
>
> Ok, will do.

Similar to patch 2, I think disabling halt polling is a good behavior if
grow_start = 0.

Paolo