Re: [PATCH v6 09/12] softmmu/physmem: Don't use atomic operations in ram_block_discard_(disable|require)

[Paolo Bonzini]

On 22/02/21 14:33, David Hildenbrand wrote:
> > Also, uncoordinated require is unused, and therefore uncoordinated
> > disable is also never going to block anything.  Does it make sense to
> > keep it in the API?
>
> Right, "ram_block_discard_require()" is not used yet. I am planning on 
> using it in virtio-balloon context at some point, but can remove it for 
> now to simplify.
>
> ram_block_uncoordinated_discard_disable(), however, will block 
> virtio-balloon already via ram_block_discard_is_disabled(). (yes, 
> virtio-balloon is ugly)

Oops, I missed that API.

Does it make sense to turn the API inside out, with the 
coordinated/uncoordinated choice as an argument and the start/finish 
choice in the name?

enum {
    RAM_DISCARD_ALLOW_COORDINATED = 1,
};

bool ram_discard_disable(int flags, Error **errp);
void ram_discard_enable(int flags);
int ram_discard_start(bool coordinated, Error **errp);
void ram_discard_finish(bool coordinated);

Paolo