linux-kernel - Re: [PATCH v1 0/4] virtio-mem: memory unplug/offlining related cleanups

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Message-ID: <20230713110235-mutt-send-email-mst@kernel.org>
Date:   Thu, 13 Jul 2023 11:03:08 -0400
From:   "Michael S. Tsirkin" <mst@...hat.com>
To:     David Hildenbrand <david@...hat.com>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        virtualization@...ts.linux-foundation.org,
        Jason Wang <jasowang@...hat.com>,
        Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
Subject: Re: [PATCH v1 0/4] virtio-mem: memory unplug/offlining related
 cleanups

On Thu, Jul 13, 2023 at 04:55:47PM +0200, David Hildenbrand wrote:
> Some cleanups+optimizations primarily around offline_and_remove_memory().
> 
> Patch #1 drops the "unsafe unplug" feature where we might get stuck in
> offline_and_remove_memory() forever.
> 
> Patch #2 handles unexpected errors from offline_and_remove_memory() a bit
> nicer.
> 
> Patch #3 handles the case where offline_and_remove_memory() failed and
> we want to retry later to remove a completely unplugged Linux memory
> block, to not have them waste memory forever.
> 
> Patch #4 something I had lying around for longer, which reacts faster
> on config changes when unplugging memory.
> 
> Cc: "Michael S. Tsirkin" <mst@...hat.com>
> Cc: Jason Wang <jasowang@...hat.com>
> Cc: Xuan Zhuo <xuanzhuo@...ux.alibaba.com>

This looks like something that's reasonable to put in this linux, right?
These are fixes even though they are for theoretical issues.

> David Hildenbrand (4):
>   virtio-mem: remove unsafe unplug in Big Block Mode (BBM)
>   virtio-mem: convert most offline_and_remove_memory() errors to -EBUSY
>   virtio-mem: keep retrying on offline_and_remove_memory() errors in Sub
>     Block Mode (SBM)
>   virtio-mem: check if the config changed before fake offlining memory
> 
>  drivers/virtio/virtio_mem.c | 168 ++++++++++++++++++++++++------------
>  1 file changed, 112 insertions(+), 56 deletions(-)
> 
> 
> base-commit: 3f01e9fed8454dcd89727016c3e5b2fbb8f8e50c
> -- 
> 2.41.0