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Date: Fri, 5 Sep 2025 17:19:34 +0100
From: Dave Martin <Dave.Martin@arm.com>
To: James Morse <james.morse@arm.com>
Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
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Subject: Re: [PATCH 02/33] drivers: base: cacheinfo: Add helper to find the
 cache size from cpu+level
Message-ID: <aLsNljxM+DN7kmC7@e133380.arm.com>
References: <20250822153048.2287-1-james.morse@arm.com>
 <20250822153048.2287-3-james.morse@arm.com>
 <aK7iDey7LATOXIUb@e133380.arm.com>
 <2ac66605-ee6a-495b-a0fb-910926abd8b0@arm.com>
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In-Reply-To: <2ac66605-ee6a-495b-a0fb-910926abd8b0@arm.com>

Hi,

On Wed, Aug 27, 2025 at 06:11:43PM +0100, James Morse wrote:
> Hi Dave,
> 
> On 27/08/2025 11:46, Dave Martin wrote:
> > Hi,
> > 
> > On Fri, Aug 22, 2025 at 03:29:43PM +0000, James Morse wrote:
> >> MPAM needs to know the size of a cache associated with a particular CPU.
> >> The DT/ACPI agnostic way of doing this is to ask cacheinfo.
> >>
> >> Add a helper to do this.
> 
> >> diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h

[...]

> >> +static inline unsigned int get_cpu_cacheinfo_size(int cpu, int level)
> >> +{
> >> +	struct cacheinfo *ci = get_cpu_cacheinfo_level(cpu, level);
> >> +
> >> +	return ci ? ci->size : 0;
> >> +}
> >> +
> > 
> > Orphaned function?
> > 
> > Can fs/resctrl/rdtgroup.c:rdtgroup_cbm_to_size() be ported to use this?
> > If so, this wouldn't just be dead code in this series.
> 
> Ah - I thought the MPAM driver was pulling this value in, but its the resctrl glue code.
> I was trying to reduce the number of trees this touches - its probably best to kick this
> into the next series that adds the resctrl code as its pretty trivial.
> 
> 
> Thanks,
> 
> James
> 

Fair enough.

Cheers
---Dave