Answering ping requests make mirage allocate pages to the point it exhausts its memory.

[Vincent Bernardoff <vb@xxxxxxxxxxxxxx>]

I'm running mirage-www under Xen with 64M of memory. When ping flooding, 
I don't loose packets but I have messages such that:
mm.c: Cannot handle page request order 1!
memalign(4096, 4096) failed.

repeating in a tight loop.

Looking at the code, it seems that Mirage tries to allocate memory to 
the point when it exhausts its memory, at that point, Gc.compact () is 
called and improve the situation, so that the unikernel never crashes 
with Out_of_memory.
Answering ping requests should not lead to allocate pages to the point 
it exhausts available memory, should it ?

We should fix that.
Cheers,

Vincent