Re: [Qemu-devel] [RFC 0/7] Safe watch and breakpoint manipulation

[Sergey Fedorov]

On 20/06/16 19:27, Alex Bennée wrote:
> The watchpoint contention is the biggest one. FWIW I like the RCU
> approach because it is low impact when running (and I'm hoping faster as
> well by not being a linked list).

When can we expect any contention? I generally find the idea of RCU
really great, but in this particular case, I'm afraid, it could give us
less profit (performance) than pain (complexity).

> It's not a major problem in system mode because generally the system is
> halted when changes are made to the list. However I'd like to solve it
> properly for both system and user-mode so I can then forgot about
> another special case.

Could you please explain a bit more about problems in user-mode?

Thanks,
Sergey