From: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
To: Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com>
Cc: svt-core@virtuozzo.com, den@openvz.org, andrey.drobyshev@virtuozzo.com
Subject: Re: [QEMU HCI-8.0 PATCH v4 5/5] vhost-blk: preserve the uevent socket across cpr-exec
Date: Tue, 08 Sep 2026 16:34:59 +0300 [thread overview]
Message-ID: <178887449993.896596.2496016285845222050.b4-review@b4> (raw)
In-Reply-To: <20260908125208.278402-6-andrey.zhadchenko@virtuozzo.com>
On Tue, 08 Sep 2026 15:52:08 +0300, Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com> wrote:
> qemu-update uses cpr-exec migration: QEMU re-execs itself in place.
> A plain monitor fdset descriptor like our uevent socket does not
> survive that (unlike the cpr_save_fd()'d tap/vhost fds), so without
> help the resized-device notifications would silently stop until the
> next full VM start.
>
> Preserve it the same way the other devices do: on cold boot
> cpr_save_fd() the socket under the "<proxy id>_ueventfd" key, and
> on the re-exec'd (incoming) side adopt it with cpr_find_fd()
> instead of reopening a command line fd that no longer resolves.
> The management layer passes a placeholder for the "ueventfd"
> property in that case. The restored socket is validated just like
> a cold-boot one.
>
> [...]
Reviewed-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
--
Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
next prev parent reply other threads:[~2026-09-08 13:35 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-08 12:52 [QEMU HCI-8.0 PATCH v4 0/5] vhost-blk change backend setup Andrey Zhadchenko
2026-09-08 12:52 ` [QEMU HCI-8.0 PATCH v4 1/5] vhost-blk: improve vhost_blk_device_realize cleanup Andrey Zhadchenko
2026-09-08 12:52 ` [QEMU HCI-8.0 PATCH v4 2/5] vhost-blk: change backend setup Andrey Zhadchenko
2026-09-08 13:34 ` Andrey Drobyshev
2026-09-08 12:52 ` [QEMU HCI-8.0 PATCH v4 3/5] vhost-blk: add read-only flag Andrey Zhadchenko
2026-09-08 12:52 ` [QEMU HCI-8.0 PATCH v4 4/5] vhost-blk: watch the device for resize events Andrey Zhadchenko
2026-09-08 12:52 ` [QEMU HCI-8.0 PATCH v4 5/5] vhost-blk: preserve the uevent socket across cpr-exec Andrey Zhadchenko
2026-09-08 13:34 ` Andrey Drobyshev [this message]
2026-09-08 13:34 ` [QEMU HCI-8.0 PATCH v4 0/5] vhost-blk change backend setup Andrey Drobyshev
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