Agreed. Very useful for KSM.
Unmapped virtual addresses cannot be pinned for RDMA (the hardware will
break),
but there's no way to know they are unmapped without checking another
data structure.
- Michael
On 03/20/2013 04:31 PM, Michael S. Tsirkin wrote:
OK sure, this could be useful to detect pages deduplicated by KSM and only
transmit one copy. There's still the question of creating same
duplicate mappings on destination - do you just do data copy on destination?
Not sure why you talk about unmapped pages above though, it seems
not really relevant...
There's also the matter of KSM not touching pinned pages,
that's another good reason not to pin all pages on destination,
they won't be deduplicated.
