Re: [PATCH 0/2] vhost-user: Remove the nested event loop to unbreak the DPDK use case

[Greg Kurz <groug@kaod.org>]

On Thu, 19 Jan 2023 18:24:22 +0100
Greg Kurz <groug@kaod.org> wrote:

> The nested event loop was introduced in QEMU 6.0 to allow servicing
> of requests coming from the slave channel while waiting for an ack
> from the back-end on the master socket. It turns out this is fragile
> and breaks if the servicing of the slave channel causes a new message
> to be sent on the master socket. This is exactly what happens when
> using DPDK as reported in [0].
> 
> The only identified user for the nested loop is DAX enablement that
> isn't upstream yet. Just drop the code for now. Some more clever
> solution should be designed when the need to service concurrent
> requests from both channels arises again.
> 
> Greg Kurz (2):
>   Revert "vhost-user: Monitor slave channel in vhost_user_read()"
>   Revert "vhost-user: Introduce nested event loop in vhost_user_read()"
> 
>  hw/virtio/vhost-user.c | 100 ++++-------------------------------------
>  1 file changed, 8 insertions(+), 92 deletions(-)
> 

Hi Michael,

Can you please merge this series as you kindly proposed in [0] ?
This will help to fix [1] which is currently blocking downstream
testing.

Cheers,

--
Greg

[0] https://lore.kernel.org/qemu-devel/20230118060102-mutt-send-email-mst@kernel.org/
[1] https://bugzilla.redhat.com/show_bug.cgi?id=2155173