Re: [PATCH] slab: Fix too strict alignment check in create_cache()

[Jens Axboe <axboe@kernel.dk>]

On 11/21/24 11:30 AM, Guenter Roeck wrote:
> On Thu, Nov 21, 2024 at 09:23:28AM -0800, Christoph Lameter (Ampere) wrote:
>> On Thu, 21 Nov 2024, Geert Uytterhoeven wrote:
>>
>>> Linux has supported m68k since last century.
>>
>> Yeah I fondly remember the 80s where 68K systems were always out of reach
>> for me to have. The dream system that I never could get my hands on. The
>> creme de la creme du jour. I just had to be content with the 6800 and
>> 6502 processors. Then IBM started the sick road down the 8088, 8086
>> that led from crap to more crap. Sigh.
>>
>>> Any new such assumptions are fixed quickly (at least in the kernel).
>>> If you need a specific alignment, make sure to use __aligned and/or
>>> appropriate padding in structures.
>>> And yes, the compiler knows, and provides __alignof__.
>>>
>>>> How do you deal with torn reads/writes in such a scenario? Is this UP
>>>> only?
>>>
>>> Linux does not support (rate) SMP m68k machines.
>>
>> Ah. Ok that explains it.
>>
>> Do we really need to maintain support for a platform that has been
>> obsolete for decade and does not even support SMP?

I asked that earlier in this thread too...

> Since this keeps coming up, I think there is a much more important
> question to ask:
> 
> Do we really need to continue supporting nommu machines ? Is anyone
> but me even boot testing those ?

Getting rid of nommu would be nice for sure in terms of maintenance,
it's one of those things that pop up as a build breaking thing because
nobody is using/testing them.

I'm all for axing relics from the codebase. Doesn't mean they can't be
maintained out-of-tree, but that is where they belong imho.

-- 
Jens Axboe