Re: [RFC][PATCH] Improving directed yield scalability for PLE handler

From: Rik van Riel
Date: Mon Sep 10 2012 - 16:31:57 EST

On 09/10/2012 04:19 PM, Peter Zijlstra wrote:
On Mon, 2012-09-10 at 15:12 -0500, Andrew Theurer wrote:
+ /*
+ * if the target task is not running, then only yield if the
+ * current task is in guest mode
+ */
+ if (!(p_rq->curr->flags & PF_VCPU))
+ goto out_irq;

This would make yield_to() only ever work on KVM, not that I mind this
too much, its a horrid thing and making it less useful for (ab)use is a
good thing, still this probably wants mention somewhere :-)

Also, it would not preempt a non-kvm task, even if we need
to do that to boost a VCPU. I think the lines above should
be dropped.

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