Re: [PATCH v6 2/9] x86/resctrl: Require 64-bit x86 for resctrl support

[Reinette Chatre]

On 8/20/26 10:12 AM, Dave Hansen wrote:
> On 8/20/26 10:01, Luck, Tony wrote:
>>> To be specific, my comment about RDT not being a "server" feature was made with Apollo
>>> Lake [1] in mind. That system showed up in scenarios where servers do not typically venture
>>> and per [1] its max memory size (8GB) is significantly less than what servers can support.
>> Even with just 8GB you should really use 64-bit.
> 
> Just in practice, 32-bit is very lightly tested. We're generally not
> even supporting new CPU features on 32-bit even if the hardware supports
> it. Think of shadow stacks, for instance.
> 
> It's actually increasingly hard to even find a modern 32-bit distro.
> 
> So it really has nothing to do with high memory. It just practically
> that the arch/x86 32-bit code is increasingly there for legacy reasons.
> Its testing goes down every day and the testing of *new* features is for
> all intents and purposes zero.
> 
> Honestly, the only people who complain about 32-bit support going away
> are folks who "test" it regularly. It's quite rare to see anyone
> actually "using" a 32-bit system.

I do support this change and clearly stated so in my original review [1].

My comments were only regarding accuracy of the motivation used in the
changelog.

Reinette

[1] https://lore.kernel.org/lkml/d97deaa1-f42c-4fce-8ca8-5ccf8d822cd2@xxxxxxxxx/