>>> > I agree it's either COW breaking or (similarly) locking pages that
>>> > the guest hasn't touched yet.
>>> >
>>> > You can use prealloc or "-rt mlock=on" to avoid this problem.
>>> >
>>> > Paolo
>> Or the new shared flag - IIRC shared VMAs don't do COW either.
>
>Only if the problem isn't lo
>> What if you detach and re-attach?
>> Is it fast then?
>> If yes this means the issue is COW breaking that occurs with
>> get_user_pages, not translation as such.
>> Try hugepages with prealloc - does it help?
>
>I agree it's either COW breaking or (similarly) locking pages that the guest
>hasn
On Tue, Feb 18, 2014 at 12:05:19PM +0100, Paolo Bonzini wrote:
> Il 18/02/2014 11:51, Michael S. Tsirkin ha scritto:
> >>> I agree it's either COW breaking or (similarly) locking pages that
> >>> the guest hasn't touched yet.
> >>>
> >>> You can use prealloc or "-rt mlock=on" to avoid this problem.
Il 18/02/2014 11:51, Michael S. Tsirkin ha scritto:
> I agree it's either COW breaking or (similarly) locking pages that
> the guest hasn't touched yet.
>
> You can use prealloc or "-rt mlock=on" to avoid this problem.
>
> Paolo
Or the new shared flag - IIRC shared VMAs don't do COW either.
On
>> Hi, all
>>
>> The VM will get stuck for a while(about 6s for a VM with 20GB memory) when
>> attaching a pass-through PCI card to the non-pass-through VM for the first
>> time.
>> The reason is that the host will build the whole VT-d GPA->HPA DMAR
>> page-table, which needs a lot of time, an
On Tue, Feb 18, 2014 at 11:42:19AM +0100, Paolo Bonzini wrote:
> Il 18/02/2014 11:38, Michael S. Tsirkin ha scritto:
> >What if you detach and re-attach?
> >Is it fast then?
> >If yes this means the issue is COW breaking that occurs
> >with get_user_pages, not translation as such.
> >Try hugepages
Il 18/02/2014 11:38, Michael S. Tsirkin ha scritto:
What if you detach and re-attach?
Is it fast then?
If yes this means the issue is COW breaking that occurs
with get_user_pages, not translation as such.
Try hugepages with prealloc - does it help?
I agree it's either COW breaking or (similarly
On Tue, Feb 18, 2014 at 02:38:40AM +, Zhanghaoyu (A) wrote:
> Hi, all
>
> The VM will get stuck for a while(about 6s for a VM with 20GB memory) when
> attaching a pass-through PCI card to the non-pass-through VM for the first
> time.
> The reason is that the host will build the whole VT-d G
Hi, all
The VM will get stuck for a while(about 6s for a VM with 20GB memory) when
attaching a pass-through PCI card to the non-pass-through VM for the first
time.
The reason is that the host will build the whole VT-d GPA->HPA DMAR page-table,
which needs a lot of time, and during this time, t
