Re: [ANNOUNCE] v5.14-rc4-rt4

From: Jens Axboe
Date: Wed Aug 04 2021 - 12:05:56 EST


On 8/4/21 9:57 AM, Sebastian Andrzej Siewior wrote:
> On 2021-08-04 09:49:48 [-0600], Jens Axboe wrote:
>>
>> That'd work on non-RT as well, but it makes it worse on non-RT as well with
>> the irq enable/disable dance. While that's not the end of the world, would
>> be nice to have a solution that doesn't sacrifice anything, yet doesn't
>> make RT unhappy.
>
> There were plans to make local_irq_disable() mostly a nop (similar to
> what ppc64 does). But I have no idea what happened. I hope that work
> gets picked up.

So what do you propose in the interim? As far as io_uring is concerned,
it's not a _huge_ deal to do the IRQ dance, but it does bother me that
we're making things slightly worse for the mainline kernel just to make
the out-of-tree patches happy.

--
Jens Axboe