Re: [PATCH v9 03/10] x86,fs/resctrl: Detect io_alloc feature

[Moger, Babu]

Hi Reinette,

On 9/18/2025 12:15 AM, Reinette Chatre wrote:
> Hi Babu,
>
> On 9/2/25 3:41 PM, Babu Moger wrote:
> > Smart Data Cache Injection (SDCI) is a mechanism that enables direct
> > insertion of data from I/O devices into the L3 cache. It can reduce the
> > demands on DRAM bandwidth and reduces latency to the processor consuming
> > the I/O data.
>
> This copy&pasted text found in cover letter and patch 1 and now here seems to be the
> type of annoying repetitive text that Boris referred to [1]. Looking at this changelog
> again it may also be confusing to start with introduction of one feature (SDCI), but
> end with another SDCIAE.
>
> Here is a changelog that attempts to address issues, please feel free to improve:
>
> 	AMD's SDCIAE (SDCI Allocation Enforcement) PQE feature enables system software
> 	to control the portions of L3 cache used for direct insertion of data from
> 	I/O devices into the L3 cache.
>                                                                                  
> 	Introduce a generic resctrl cache resource property "io_alloc_capable" as the
> 	first part of the new "io_alloc" resctrl feature that will support AMD's
> 	SDCIAE.	Any architecture can set a cache resource as "io_alloc_capable" if a
> 	portion	of the cache can be allocated for I/O traffic.
>                                                                                  
> 	Set the "io_alloc_capable" property for the L3 cache resource on x86
> 	(AMD) systems that support SDCIAE.
>
>   

Looks good. thank you.

> > Introduce cache resource property "io_alloc_capable" that an architecture
> > can set if a portion of the cache can be allocated for I/O traffic.
> >
> > Set this property on x86 systems that support SDCIAE (L3 Smart Data Cache
> > Injection Allocation Enforcement). This property is set only for the L3
> > cache resource on systems that support SDCIAE.
> >
> > Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> > Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
> > ---
>
> Reinette
>
>
> [1] https://lore.kernel.org/lkml/20250911150850.GAaMLmAoi5fTIznQzY@fat_crate.local/