[pve-devel] applied: [PATCH qemu-server] migration: fix downtime limit auto-increase

[Thomas Lamprecht]

On 4/2/20 3:20 PM, Stefan Reiter wrote:
> 485449e37 ("qmp: use migrate-set-parameters in favor of deprecated options")
> changed the initial "migrate_set_downtime" QMP call to the more recent
> "migrate-set-parameters", but forgot to do so for the auto-increase code
> further below.
> 
> Since the units of the two calls don't match, this would have caused the
> auto-increase to increase the limit to absurd levels as soon as it kicked
> in (ms treated as s).
> 
> Update the second call to the new version as well, and while at it remove
> the unnecessary "defined()" check for $migrate_downtime, which is always
> initialized from the defaults anyway.
> 
> Signed-off-by: Stefan Reiter <s.reiter at proxmox.com>
> ---
> 
> I am not sure when this code is used at all... I tried slowing the network down
> to 56k-modem levels, and migration still completed without triggering it (both
> with default migrate_downtime and migrate_downtime set to 1ms).
> 

Applied, thanks. You should see it by doing something like:

stress -m 4 --vm-keep 

Which spawns 4 workers, each allocating 256MB and touching a byte every 4096
bytes - which allows to trash much memory with less CPU.