[PATCH] um: Enable preemption in UML

[Anton Ivanov]

On 21/09/2023 08:30, Richard Weinberger wrote:
> ----- Ursprüngliche Mail -----
>> Von: "anton ivanov" <anton.ivanov at cambridgegreys.com>
>> An: "Peter Lafreniere" <peter at n8pjl.ca>
>> CC: "Johannes Berg" <johannes at sipsolutions.net>, "linux-um" <linux-um at lists.infradead.org>, "richard" <richard at nod.at>
>> Gesendet: Donnerstag, 21. September 2023 09:12:33
>> Betreff: Re: [PATCH] um: Enable preemption in UML
>> On 20/09/2023 15:49, Peter Lafreniere wrote:
>>> On Wed, Sep 20, 2023 at 08:31, anton.ivanov at cambridgegreys.com wrote:
>>>> From: Anton Ivanov anton.ivanov at cambridgegreys.com
>>>>
>>>>
>>>> Preemption requires saving/restoring FPU state. This patch
>>>> adds support for it using GCC intrinsics.
>>>>
>>>> Signed-off-by: Anton Ivanov anton.ivanov at cambridgegreys.com
> I'm not so sure whether we should really directly start with CONFIG_PREEMPT.

I have managed to make it work except the IRQ return bit suggested by Peter. We are quite paranoid regarding locking and we are UP so nearly all of it worked out of the box.

> How about implementing CONFIG_PREEMPT_COUNT first?

Sure. Will try that today.

>
> Thanks,
> //richard
>
-- 
Anton R. Ivanov
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