RE: [PATCH] hv_balloon: Add the support of hibernation

[Dexuan Cui <decui@microsoft.com>]

> From: David Hildenbrand <david@redhat.com>
> Sent: Thursday, September 26, 2019 12:20 AM
> To: Dexuan Cui <decui@microsoft.com>; KY Srinivasan <kys@microsoft.com>;
> Haiyang Zhang <haiyangz@microsoft.com>; Stephen Hemminger
> <sthemmin@microsoft.com>; sashal@kernel.org;
> linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.org; Michael Kelley
> <mikelley@microsoft.com>
> Subject: Re: [PATCH] hv_balloon: Add the support of hibernation
> 
> On 25.09.19 22:03, Dexuan Cui wrote:
> >> From: linux-hyperv-owner@vger.kernel.org
> >>  [... snipped ...]
> >>> Anyhow, just some comments from my side :) I can see how Windows
> Server
> >>> worked around that issue right now by just XOR'ing both features.
> >>>
> >>> David / dhildenb
> >>
> >> Thanks for sharing your thoughts!
> >>
> >> -- Dexuan
> >
> > Hi David,
> > If my explanation sounds good to you, can I have an Acked-by from you?
> >
> 
> I do ACK the approach but not the patch in it's current state. I don't
> like the ifdefs - once you can get rid of the ifdefery - e.g., after the
> prerequisite is upstream - you can add my
> 
> Acked-by: David Hildenbrand <david@redhat.com>
> 
> David / dhildenb

Makes sense. I'll wait for the prerequisite patch (i.e. the patch that implements
hv_is_hibernation_supported(), https://lkml.org/lkml/2019/9/5/1160 ) to be 
in upstream first, then I'll be able to get rid of the below "if 0" and post a v2
with your Acked-by. Thanks, David!

+#if 0
+	/*
+	 * The patch to implement hv_is_hibernation_supported() is going
+	 * through the tip tree. For now, let's hardcode allow_hibernation
+	 * to false to keep the current behavior of hv_balloon. If people
+	 * want to test hibernation, please blacklist hv_balloon fow now
+	 * or do not enable Dynamid Memory and Memory Resizing.
+	 *
+	 * We'll remove the conditional compilation as soon as
+	 * hv_is_hibernation_supported() is available in the mainline tree.
+	 */
+	allow_hibernation = hv_is_hibernation_supported();
+#else
+	allow_hibernation = false;

Thanks,
-- Dexuan