Re: [PATCH v2 5/7] virtio-mem: s390 support

Christian Borntraeger
2024-10-21T06:34:04Z

Am 15.10.24 um 10:37 schrieb Heiko Carstens:
> On Mon, Oct 14, 2024 at 09:16:45PM +0200, David Hildenbrand wrote:
>> On 14.10.24 20:48, Heiko Carstens wrote:
>>> On Mon, Oct 14, 2024 at 04:46:17PM +0200, David Hildenbrand wrote:
>>>> to dump. Based on this, support for dumping virtio-mem memory can be
>>> Hm.. who will add this support? This looks like a showstopper to me.
>>
>> The cover letter is clearer on that: "One remaining work item is kdump
>> support for virtio-mem memory. This will be sent out separately once initial
>> support landed."
>>
>> I had a prototype, but need to spend some time to clean it up -- or find
>> someone to hand it over to clean it up.
>>
>> I have to chose wisely what I work on nowadays, and cannot spend that time
>> if the basic support won't get ACKed.
>>
>>> Who is supposed to debug crash dumps where memory parts are missing?
>>
>> For many production use cases it certainly needs to exist.
>>
>> But note that virtio-mem can be used with ZONE_MOVABLE, in which case mostly
>> only user data (e.g., pagecache,anon) ends up on hotplugged memory, that
>> would get excluded from makedumpfile in the default configs either way.
>>
>> It's not uncommon to let kdump support be added later (e.g., AMD SNP
>> variants).
>
> I'll leave it up to kvm folks to decide if we need kdump support from
> the beginning or if we are good with the current implementation.

If David confirms that he has a plan for this, I am fine with a staged approach
for upstream.