On Wed, Feb 28, 2024 at 12:21:11PM -0300, Fabiano Rosas wrote: > Add a new migration capability 'mapped-ram'. > > The core of the feature is to ensure that RAM pages are mapped > directly to offsets in the resulting migration file instead of being > streamed at arbitrary points. > > The reasons why we'd want such behavior are: > > - 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 O_DIRECT-enabled save/restore of the > migration stream as the pages are ensured to be written at aligned > offsets. > > - It allows the usage of multifd so we can write RAM pages to the > migration file in parallel. > > For now, enabling the capability has no effect. The next couple of > patches implement the core functionality. > > Acked-by: Markus Armbruster <[email protected]> > Signed-off-by: Fabiano Rosas <[email protected]>
Reviewed-by: Peter Xu <[email protected]> -- Peter Xu
