Re: [PATCH v2] core, x86: Add user return notifiers

Avi Kivity
2009-10-01T15:21:41Z

On 09/22/2009 06:19 PM, H. Peter Anvin wrote:
> Ingo Molnar wrote:
>> * Avi Kivity <avi@redhat.com> wrote:
>>
>>> On 09/19/2009 09:40 AM, Avi Kivity wrote:
>>>> Add a general per-cpu notifier that is called whenever the kernel is
>>>> about to return to userspace. The notifier uses a thread_info flag
>>>> and existing checks, so there is no impact on user return or context
>>>> switch fast paths.
>>> Ingo/Peter?
>>
>> Would be nice to convert some existing open-coded
>> return-to-user-space logic to this facility. One such candidate would
>> be lockdep_sys_exit?
>>
>> Ingo
>
> Sorry, limited bandwidth due to LinuxCon, but I like the concept, and
> the previous (partial) patch was really clean. I agree with Ingo that
> arch support so we can use this as a general facility would be nice,
> but I don't consider that as a prerequisite for merging.

Re-ping?

If accepted, please merge just the core patch and I will carry all of
them in parallel. Once tip is merged I'll drop my copy of the first patch.

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.