Re: [PATCH -next] arch_topology: Fix cache attributes detection in the CPU hotplug path

Sudeep Holla
2022-07-15T09:11:34Z

On Thu, Jul 14, 2022 at 04:10:36PM +0000, Conor.Dooley@microchip.com wrote:
> On 14/07/2022 17:00, Sudeep Holla wrote:
> > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> >
> > On Thu, Jul 14, 2022 at 03:27:09PM +0000, Conor.Dooley@microchip.com wrote:
> >> On 14/07/2022 16:01, Sudeep Holla wrote:
> >>>
> >>> Interesting, need to check if it is not in atomic context on arm64.
> >>> Wonder if some configs are disabled and making this bug hidden. Let me
> >>> check.
> >>>
> >
> > OK, it turns I didn't have necessary config options enabled. Enabling
> > them, I did see the BUG splat and changing allocation to GFP_ATOMIC
> > fixed the same. Can you try that please so that you can test if other
> > things are fine.
> >
> >>> One possible solution is to add GFP_ATOMIC to the allocation but I want
> >>> to make sure if it is legal to be in atomic context when calling
> >>> update_siblings_masks.
> >>>
> >
> > So I take is as legal and needs to be fixed to push my patch.
> >
>
> With the GFP_ATOMIC, behaviour is the same as before for me.
>

So you still get -ENOMEM failure on your platform. It is fine, just that
I am bit curious to know why as it succeeds at device_initcall later.
I was hoping this might fix your memory allocation failure.

> Therefore, with the following diff & for RISC-V/DT:
>
> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
>

Thanks !

--
Regards,
Sudeep