Re: [Qemu-devel] [PATCHv5 06/10] migration: search for zero instead of dup pages

[Paolo Bonzini]

Il 06/04/2013 00:06, Peter Lieven ha scritto:
>> > I think we should MADV_DONTNEED it.
> i have to correct myself, on Linux it seems that MADV_DONTNEED guarantees that
> subsequent reads will return a zero filled page.
> 
> If I am right with that we could MADV_DONTNEED the memory on startup and keep
> not sending zero pages in bulk stage if we are running under Linux. Am I 
> right with that?

Actually we can use mmap+munmap to allocate a well-aligned, always zero
block for the RAM.

Paolo