From mboxrd@z Thu Jan  1 00:00:00 1970
From: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Subject: Re: [PATCH 2/3] kvm hypervisor : Add hypercalls to support
 pv-ticketlock
Date: Thu, 20 Jan 2011 17:12:46 +0530
Message-ID: <20110120114246.GA11177@linux.vnet.ibm.com>
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Cc: Peter Zijlstra <peterz@infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Nick Piggin <npiggin@kernel.dk>,
	Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
	=?iso-8859-1?Q?Am=E9rico?= Wang <xiyou.wangcong@gmail.com>,
	Eric Dumazet <dada1@cosmosbay.com>,
	Jan Beulich <JBeulich@novell.com>, Avi Kivity <avi@redhat.com>,
	Xen-devel <xen-devel@lists.xensource.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Linux Virtualization <virtualization@lists.linux-foundation.org>,
	Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>,
	kvm@vger.kernel.org, suzuki@in.ibm.com
To: Jeremy Fitzhardinge <jeremy@goop.org>
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On Wed, Jan 19, 2011 at 10:53:52AM -0800, Jeremy Fitzhardinge wrote:
> > The reason for wanting this should be clear I guess, it allows PI.
> 
> Well, if we can expand the spinlock to include an owner, then all this
> becomes moot...

How so? Having an owner will not eliminate the need for pv-ticketlocks
afaict. We still need a mechanism to reduce latency in scheduling the next
thread-in-waiting, which is achieved by your patches. 

- vatsa