Add a new migration capability 'fixed-ram'.
The core of the feature is to ensure that each ram page has a specific
offset in the resulting migration stream. The reason why we'd want
such behavior are two fold:
- When doing a 'fixed-ram' migration the resulting file will have a
bounded size, since pages which are dirtied multiple times will
always go to a fixed location in the file, rather than constantly
being added to a sequential stream. This eliminates cases where a vm
with, say, 1G of ram can result in a migration file that's 10s of
GBs, provided that the workload constantly redirties memory.
- It paves the way to implement DIRECT_IO-enabled save/restore of the
migration stream as the pages are ensured to be written at aligned
offsets.
For now, enabling the capability has no effect. The next couple of
patches implement the core funcionality.
Signed-off-by: Fabiano Rosas <farosas@suse.de>
d990744ca8