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

[Vincent Bernardoff <vb@xxxxxxxxxxxxxx>]

On 22/08/2013 11:37, Vincent Bernardoff wrote:
> 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
I submitted a PR that mitigates the problem concerning the partical case 
of ICMP but there is still a big problem in OS.Netif: A new page is 
allocated for every "buffer refill" for incoming packets.
I'm not very sure how we should fix that. I guess the answer is to 
implement an OCaml memory management instead of asking MiniOS to 
allocate memory for us. But what partical implementation of a MM, I 
don't know.
I think this problem should be addressed quickly. Is this a regression ?

Cheers,

Vincent