From mboxrd@z Thu Jan  1 00:00:00 1970
From: Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 2/3] kvm hypervisor : Add hypercalls to
	support pv-ticketlock
Date: Fri, 21 Jan 2011 09:48:29 -0500
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Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
	Xen-devel <xen-devel@lists.xensource.com>,
	=?UTF-8?B?QW3DqXJpY28g?=, Nick Piggin <npiggin@kernel.dk>,
	kvm@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Jan Beulich <JBeulich@novell.com>, Eric Dumazet <dada1@cosmosbay.com>,
	Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>,
	suzuki@in.ibm.com, Avi Kivity <avi@redhat.com>,
	=?UTF-8?B?V2FuZw==?= <xiyou.wangcong@gmail.com>,
	Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
	Linux Virtualization <virtualization@lists.linux-foundation.org>
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On 01/21/2011 09:02 AM, Srivatsa Vaddagiri wrote:
> On Thu, Jan 20, 2011 at 09:56:27AM -0800, Jeremy Fitzhardinge wrote:
>>>   The key here is not to
>>> sleep when waiting for locks (as implemented by current patch-series, which can
>>> put other VMs at an advantage by giving them more time than they are entitled
>>> to)
>>
>> Why?  If a VCPU can't make progress because its waiting for some
>> resource, then why not schedule something else instead?
>
> In the process, "something else" can get more share of cpu resource than its
> entitled to and that's where I was bit concerned. I guess one could
> employ hard-limits to cap "something else's" bandwidth where it is of real
> concern (like clouds).

I'd like to think I fixed those things in my yield_task_fair +
yield_to + kvm_vcpu_on_spin patch series from yesterday.

https://lkml.org/lkml/2011/1/20/403

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