Hi Michal,

After looking at your suggested memblock_virt_alloc_core() change again, 
I decided to keep what I have. I do not want to inline 
memblock_virt_alloc_internal(), because it is not a performance critical 
path, and by inlining it we will unnecessarily increase the text size on 
all platforms.

Also, because it will be very hard to make sure that no platform 
regresses by making memset() default in _memblock_virt_alloc_core() (as 
I already showed last week at least sun4v SPARC64 will require special 
changes in order for this to work), I decided to make it available only 
for "deferred struct page init" case. As, what is already in the patch.

I am working on testing to make sure we do not need to double zero in 
the two cases that you found: sparsemem, and mem hotplug. Please let me 
know if you have any more comments, or if I can send new patches out 
when they are ready.

Thank you,
Pasha