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Date: Tue, 7 Dec 2010 17:10:23 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Dmitry Torokhov <dtor@vmware.com>
Cc: linux-kernel@vger.kernel.org, pv-drivers@vmware.com
Subject: Re: [PATCH] VMware balloon: stop locking pages when hypervisor
 tells us enough
Message-Id: <20101207171023.d28e20ee.akpm@linux-foundation.org>
In-Reply-To: <20101203165226.GA16146@dtor-ws.eng.vmware.com>
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On Fri, 3 Dec 2010 08:52:26 -0800
Dmitry Torokhov <dtor@vmware.com> wrote:

> When hypervisor decides to decrease target balloon size while the
> balloon driver tries to lock pages hypervisor may respond with
> VMW_BALLOON_PPN_NOTNEEDED. Use this data and immediately stop reserving
> pages and wait for the next update cycle to fetch new target instead
> of continuing trying to lock pages until size of refused list grows
> above VMW_BALLOON_MAX_REFUSED (16) pages.

OK, but ... why?  What is the externally visible effect of this change?