Fw: somthing new for shared memory???

Francesco Cipollone
2007-10-25T20:44:11Z

----- Original Message -----
From: "Francesco Cipollone" <francesco.cipo-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: "Izik Eidus" <izike-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
Sent: Thursday, October 25, 2007 10:43 PM
Subject: Re: [kvm-devel] somthing new for shared memory???

>
> ----- Original Message -----
> From: "Izik Eidus" <izike-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
> To: "Francesco Cipollone" <francesco.cipo-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Sent: Thursday, October 25, 2007 11:25 PM
> Subject: Re: [kvm-devel] somthing new for shared memory???
>
>
>> Francesco Cipollone wrote:
>>> can you gently explain more about the second option
>>>
>>> ----- Original Message ----- From: "Izik Eidus" <izike-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
>>> To: "Francesco Cipollone" <francesco.cipo-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>>> Cc: <kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
>>> Sent: Thursday, October 25, 2007 11:03 PM
>>> Subject: Re: [kvm-devel] somthing new for shared memory???
>>>
>>>
>>>> Francesco Cipollone wrote:
>>>>> Hy
>>>>> somthing new about the shared memory support between VMs? or VM and
>>>>> host?
>>>>> bye
>>>>>
>>>> beside moving the memory allocation to userspace (this is first step in
>>>> share memory between VMs using smart file system)
>>>> there is not much advance.
>>>>
>>>> about sharing memory between VM and host, we improved it by adding
>>>> partial swapping support,
>>>> so the host can take memory from the guest in demand.
>>>
>>> can you gently explain to me more abouth this option?
>>> thank you very much
>>> Francesco
>>
>> this option (guest swapping) run by default, it have two good effect:
>> 1.part of the unused memory of the guest can be swapped (the kernel treat
>> this area of memory as of normal process memory and swap it
>> on deamed) it allow you to allocate VMs with more ram than you have on
>> host.
>> 2.memory is allocated on deamed, this make VM load faster and dont steal
>> memory that it dont touch
>>
>> about the "partial swapping" to make it short:
>> there is as for now (we will fix this) amount of memory that is mapped
>> inside kvm that cant be swapped,
>> it is hard to tell how much would it be, but from tests that i made i saw
>> that most of times (infact i never saw case when this is not true) guests
>> give up about 90%+ of their ram when the host asked for.
>
> So if i want to share a part of memory (for example i allocate it in
> kernel-space, in guest, with a module)
> and tell the host an address, can this one see it?
> I want to make a sort of sharing memory between host and guest, an
> unidirection channel,with a signal channel or somthing like that
> to wake up the host when there is somthing new to read in the shared
> memory.
> I want to do somthing like this becouse this application is almost
> invisible...
> is for a security application
> can you help me do that?
> I don't undestand if i can share a part of the phisical memory of the
> guest with the host.
>
> thanks
> Francesco
>
>>
>>
>>>
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>>>>> _______________________________________________
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>>>>>
>>>>
>>>
>>
>

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