Re: [PATCH v3 15/15] exec: Ram blocks with resizeable anonymous allocations under POSIX

[Peter Xu]

On Thu, Feb 27, 2020 at 11:12:05AM +0100, David Hildenbrand wrote:

[...]

> +static void ram_block_alloc_ram(RAMBlock *rb)
> +{
> +    const bool shared = qemu_ram_is_shared(rb);
> +
> +    /*
> +     * If we can, try to allocate actually resizeable ram. Will also fail
> +     * if qemu_anon_ram_alloc_resizeable() is not implemented.
> +     */
> +    if (phys_mem_alloc == qemu_anon_ram_alloc &&
> +        qemu_ram_is_resizeable(rb) &&
> +        ram_block_notifiers_support_resize()) {
> +        rb->host = qemu_anon_ram_alloc_resizeable(rb->used_length,
> +                                                  rb->max_length,
> +                                                  &rb->mr->align, shared);
> +        if (rb->host) {
> +            rb->flags |= RAM_RESIZEABLE_ALLOC;

A trivial nit: If it should only be set automatically by the memory
code, shall we mark it our somewhere just in case someone passed this
in flag explicitly (which, iiuc, is a misuse)?  Maybe:

  assert(!(rb->flags | RAM_RESIZEABLE_ALLOC));

At the entry of this function?  Other than that it looks sane to me:

Reviewed-by: Peter Xu <address@hidden>

> +            return;
> +        }
> +    }
> +    rb->host = phys_mem_alloc(rb->max_length, &rb->mr->align, shared);
> +}

Thanks,

-- 
Peter Xu