Re: [PATCH v3 5/5] evtchn: don't call Xen consumer callback with per-channel lock held

[Jan Beulich <jbeulich@xxxxxxxx>]

On 23.12.2020 14:33, Julien Grall wrote:
> On 23/12/2020 13:12, Jan Beulich wrote:
>> From the input by both of you I still can't
>> conclude whether this patch should remain as is in v4, or revert
>> back to its v2 version. Please can we get this settled so I can get
>> v4 out?
> 
> I haven't had time to investigate the rest of the VM event code to find 
> other cases where this may happen. I still think there is a bigger 
> problem in the VM event code, but the maintainer disagrees here.
> 
> At which point, I see limited reason to try to paper over in the common 
> code. So I would rather ack/merge v2 rather than v3.

Since I expect Tamas and/or the Bitdefender folks to be of the
opposite opinion, there's still no way out, at least if "rather
ack" implies a nak for v3. Personally, if this expectation of
mine is correct, I'd prefer to keep the accounting but make it
optional (as suggested in a post-commit-message remark).
That'll eliminate the overhead you appear to be concerned of,
but of course it'll further complicate the logic (albeit just
slightly).

Jan