From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Janosch Frank <frankja@linux.vnet.ibm.com>
Cc: KVM <kvm@vger.kernel.org>, "Cornelia Huck" <cohuck@redhat.com>,
"David Hildenbrand" <david@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>
Subject: Re: [PATCH v2 0/2] disabling halt polling for nested virtualization
Date: Wed, 17 Apr 2019 15:23:19 +0200 [thread overview]
Message-ID: <2d1feb9b-b796-48d8-4576-0cf5bdaa227a@de.ibm.com> (raw)
In-Reply-To: <9a80c2bc-18d8-322f-c182-06fe61f2993c@redhat.com>
On 17.04.19 15:20, Paolo Bonzini wrote:
> On 16/04/19 20:01, Christian Borntraeger wrote:
>> v1->v2:
>> - add kvm_vcpu parameter to kvm_arch_no_poll
>> - add kvm stat in the s390 implementation
>> - make the value tunable
>>
>> Folks,
>>
>> this is a very simple variant to disable halt polling when the KVM host
>> is already running virtualized. We could imagine more complex variants
>> (like tuning down the halt polling value) but this seems to do the trick
>> for some kvm deployment scenarios on s390x. (e.g. having multiple LPARS
>> with KVMs that are in itself already overcommitted).
>
> Ok to queue this for 5.2?
Yes, after review. I can queue that in the s390 tree if you want.
> (Stupid question, I thought LPARs are partitions and as such were never
> overcommitted. What is it that separates an LPAR from a zVM or KVM guest?)
LPAR can do CPU overcommitment as well (or dedicated whatever you configure). Its the
memory that is hard partitioned on LPAR.
next prev parent reply other threads:[~2019-04-17 13:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-16 18:01 [PATCH v2 0/2] disabling halt polling for nested virtualization Christian Borntraeger
2019-04-16 18:01 ` [PATCH v2 1/2] KVM: polling: add architecture backend to disable polling Christian Borntraeger
2019-04-18 14:44 ` Cornelia Huck
2019-04-16 18:01 ` [PATCH v2 2/2] KVM: s390: provide kvm_arch_no_poll function Christian Borntraeger
2019-04-16 18:02 ` Christian Borntraeger
2019-04-18 14:46 ` Cornelia Huck
2019-04-17 13:20 ` [PATCH v2 0/2] disabling halt polling for nested virtualization Paolo Bonzini
2019-04-17 13:23 ` Christian Borntraeger [this message]
2019-04-17 13:43 ` Paolo Bonzini
2019-04-26 7:09 ` Christian Borntraeger
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