[PATCH v5] um: Enable preemption in UML

[Johannes Berg]

On Fri, 2023-09-22 at 09:01 +0100, Anton Ivanov wrote:
> 
> My favorite test which I run on all changes is:
> 
> find /usr -type f -exec cat {} > /dev/null \;
> 
> On Debian this forks /bin/cat for each file and does IO on it. That test passes here every time :(

Oh, apart from the splat, it all _works_ fine.

> However, I did not have debug turned on. So, I would not be surprised if something in the debug

OK.

> portion of the config makes the crashes more likely.

It's just a debug warning for me, no real crash.

> Otherwise, each fork is a forced tlb_flush_all, so it is a massive tlb exercise. Any bugs, locking, etc are likely to show up.
> 

Yes, but when does the fork actually happen?

That part confuses me - the fork_handler() seems to be called at various
kind of random points in time after?

johannes