Re: [RFD] clear virtual machine memory when virtual machine is turned off

From: David Hildenbrand
Date: Fri Dec 03 2021 - 13:20:57 EST


On 02.12.21 18:27, Mike Kravetz wrote:
> On 12/2/21 04:47, David Hildenbrand wrote:
>> On 02.12.21 11:19, fei luo wrote:
>>>
>>> When reusing the page that has been cleared, there is no need to clear it
>>>
>>> again, which also speeds up the memory allocation of user-mode programs.
>>>
>>>
>>> Is this feature feasible?
>>
>> "init_on_free=1" for the system as a whole, which might sounds like what
>> might tackle part of your use case.
>>
>
> Certainly init_on_free will not make much difference if VMs are backed by
> hugetlb pages. We (Joao and myself) have thought about clearing hugetlb
> pages from user space in an attempt speed up launching of VMs backed by
> hugetlb pages.
>

I remember that discussion. And I also recall a discussion regarding
extending init_on_free semantics to hugetlbfs.

--
Thanks,

David / dhildenb