Re: [Qemu-devel] [RFC PATCH v1 07/11] memory.c: Add address_space_init_shareable()

[Peter Maydell]

On 3 June 2014 03:10, Peter Crosthwaite <address@hidden> wrote:
> This will either create a new AS or return a pointer to an
> already existing equivalent one. Both name and root mr must
> match.
>
> The motivation is to reuse address spaces as much as possible.
> Its going to be quite common that bus masters out in device land
> have pointers to the same memory region for their mastering yet
> each will need to create its own address space. Let the memory
> API implement sharing for them.
>
> Signed-off-by: Peter Crosthwaite <address@hidden>
> ---
> I know this leaks memory. I'll fix that post RFC. I think we need
> AS ref counters to do it properly if anyone has any input on how
> that should be done.
>
> We could change the equivalency test only match mr to support device
> specific naming of these shared ASes. The singleton AS can ultimately
> only have one name however. So perhaps some strcatting each time a new
> sharer is added to the share. That or first-in-best-dressed.

Is this here because it looked like it would be really easy
to do, or because you tried this series without shared ASes
and found it was too inefficient?

thanks
-- PMM