Re: [PATCH-for-9.1 v2 2/3] migration: Remove RDMA protocol handling

From: Fabiano Rosas <farosas@suse.de>
To: "Philippe Mathieu-Daudé" <philmd@linaro.org>, qemu-devel@nongnu.org
Cc: "Yuval Shaia" <yuval.shaia.ml@gmail.com>,
	"Kevin Wolf" <kwolf@redhat.com>,
	"Prasanna Kumar Kalever" <prasanna.kalever@redhat.com>,
	"Cornelia Huck" <cohuck@redhat.com>,
	"Michael Roth" <michael.roth@amd.com>,
	"Li Zhijian" <lizhijian@fujitsu.com>,
	"Prasanna Kumar Kalever" <prasanna4324@gmail.com>,
	"Peter Xu" <peterx@redhat.com>,
	integration@gluster.org, "Paolo Bonzini" <pbonzini@redhat.com>,
	qemu-block@nongnu.org, "Daniel P. Berrangé" <berrange@redhat.com>,
	devel@lists.libvirt.org, "Hanna Reitz" <hreitz@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Thomas Huth" <thuth@redhat.com>,
	"Eric Blake" <eblake@redhat.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>,
	"Song Gao" <gaosong@loongson.cn>,
	"Marc-André Lureau" <marcandre.lureau@redhat.com>,
	"Markus Armbruster" <armbru@redhat.com>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	"Wainer dos Santos Moschetta" <wainersm@redhat.com>,
	"Beraldo Leal" <bleal@redhat.com>,
	"Peter Maydell" <peter.maydell@linaro.org>
Subject: Re: [PATCH-for-9.1 v2 2/3] migration: Remove RDMA protocol handling
Date: Thu, 28 Mar 2024 11:18:04 -0300	[thread overview]
Message-ID: <87frwatp7n.fsf@suse.de> (raw)
In-Reply-To: <20240328130255.52257-3-philmd@linaro.org>

Philippe Mathieu-Daudé <philmd@linaro.org> writes:

> The whole RDMA subsystem was deprecated in commit e9a54265f5
> ("hw/rdma: Deprecate the pvrdma device and the rdma subsystem")
> released in v8.2.
>
> Remove:
>  - RDMA handling from migration
>  - dependencies on libibumad, libibverbs and librdmacm
>
> Keep the RAM_SAVE_FLAG_HOOK definition since it might appears
> in old migration streams.
>
> Cc: Peter Xu <peterx@redhat.com>
> Cc: Li Zhijian <lizhijian@fujitsu.com>
> Acked-by: Fabiano Rosas <farosas@suse.de>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Just to be clear, because people raised the point in the last version,
the first link in the deprecation commit links to a thread comprising
entirely of rdma migration patches. I don't see any ambiguity on whether
the deprecation was intended to include migration. There's even an ack
from Juan.

So on the basis of not reverting the previous maintainer's decision, my
Ack stands here.

We also had pretty obvious bugs ([1], [2]) in the past that would have
been caught if we had any kind of testing for the feature, so I can't
even say this thing works currently.

@Peter Xu, @Li Zhijian, what are your thoughts on this?

1- https://lore.kernel.org/r/20230920090412.726725-1-lizhijian@fujitsu.com
2- https://lore.kernel.org/r/CAHEcVy7HXSwn4Ow_Kog+Q+TN6f_kMeiCHevz1qGM-fbxBPp1hQ@mail.gmail.com