[PATCH 0/7 um: IRQ handling cleanups

[Anton Ivanov]

On 24/11/2020 09:06, Anton Ivanov wrote:
>
>
> On 24/11/2020 08:58, Johannes Berg wrote:
>> On Tue, 2020-11-24 at 09:55 +0100, Johannes Berg wrote:
>>>
>>>> I have tried some of what you did when working on timers/epoll -
>>>> namely turning off the HZ-like nanosleep in time.c. I could not get it
>>>> to work at the time. So I dropped it from the final version of the
>>>> patches.
>>>
>>> That one's just weird ... and unnecessary. I can't see why it could
>>> possibly matter.
>>
>> Or actually ... wait? I thought you were referring to "um: simplify
>> os_idle_sleep() and sleep longer" but that's not in this set now...
>>
>> Anyway, if you were indeed referring to that patch, it's not strictly
>> needed - removing it would just mean I couldn't call os_idle_sleep() for
>> suspend but would have to add os_suspend() or something. OTOH, it didn't
>> break anything for me (neither time-travel nor normal mode), and I can't
>> see how it was necessary since if clock_nanosleep() (or now select())
>> was interrupted by a signal and returned, the signal handler ran too...
>
> The early version of the timer patches were fairly fragile.
>
> There is quite a bit of belt-n-braces leftovers from that, it will be good to clean it up.

I need to double-check the IRQ delete code. While I made most of it lockless and reentrant, I never finished cleaning all of it at the end.

That is where ->purge was coming from.

There were a couple of places in the serial code which could (and did) try to delete an IRQ out of the IRQ handler. I am not sure that is still the case as that also got rewritten to implement write IRQs instead of IRQ_NONE.

A.

>
>>
>> johannes
>>
>>
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>
-- 
Anton R. Ivanov
https://www.kot-begemot.co.uk/