super page with live migration

["Zhai, Edwin" <edwin.zhai@intel.com>]

Keir,

As you know, we try to allocate super pages in xc_hvm_build for better 
performance in EPT case. But the same logic is missing in xc_domain_restore.

When try to add the logic, I found it is blocked by the lazy populate algorithm 
in restore -- only populating the pages received from source side rather than 
doing it at one time.

So the result is the EPT guest has performance drop after live migration:(

Do you have any plan to change the lazy populate algorithm? The purpose of it, I 
believe, is to make restore process work without guest memory layout knowledge.  

But different memory allocation process may cause some issues, such as perf drop 
after live migration.

Thanks,



-- 
best rgds,
edwin