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Message-ID: <8d3b27d9-1a58-455d-aaa7-ff9a7e49a0b2@arm.com>
Date: Fri, 14 Jun 2024 14:58:08 +0100
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Subject: Re: [PATCH v2 22/35] x86/resctrl: Make resctrl_arch_pseudo_lock_fn()
 take a plr
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To: Dave Martin <Dave.Martin@arm.com>, x86@kernel.org,
 linux-kernel@vger.kernel.org
Cc: Fenghua Yu <fenghua.yu@intel.com>,
 Reinette Chatre <reinette.chatre@intel.com>,
 Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
 Borislav Petkov <bp@alien8.de>, H Peter Anvin <hpa@zytor.com>,
 Babu Moger <Babu.Moger@amd.com>, shameerali.kolothum.thodi@huawei.com,
 D Scott Phillips OS <scott@os.amperecomputing.com>,
 carl@os.amperecomputing.com, lcherian@marvell.com,
 bobo.shaobowang@huawei.com, "Shaopeng Tan (Fujitsu)"
 <tan.shaopeng@fujitsu.com>, baolin.wang@linux.alibaba.com,
 Jamie Iles <quic_jiles@quicinc.com>, Xin Hao <xhao@linux.alibaba.com>,
 Peter Newman <peternewman@google.com>, dfustini@baylibre.com,
 amitsinght@marvell.com, David Hildenbrand <david@redhat.com>,
 Rex Nie <rex.nie@jaguarmicro.com>
References: <20240426150537.8094-1-Dave.Martin@arm.com>
 <20240426150904.8854-1-Dave.Martin@arm.com>
 <20240426150904.8854-22-Dave.Martin@arm.com>
From: James Morse <james.morse@arm.com>
In-Reply-To: <20240426150904.8854-22-Dave.Martin@arm.com>
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Hi Dave,

On 26/04/2024 16:08, Dave Martin wrote:
> From: James Morse <james.morse@arm.com>
> 
> resctrl_arch_pseudo_lock_fn() has architecture specific behaviour,
> and takes a struct rdtgroup as an argument.
> 
> After the filesystem code moves to /fs/, the definition of struct
> rdtgroup will not be available to the architecture code.
> 
> The only reason resctrl_arch_pseudo_lock_fn() wants the rdtgroup is
> for the CLOSID. Embed that in the pseudo_lock_region as a closid,
> and move the definition of struct pseudo_lock_region to resctrl.h.

> FYI: James Morse:
> 
>  * Review the v2 change below, in case there was any functional reason
>    for distinguishing "hw" closids here.
> 
> Changes in v2:
> 
>  * [Commit message only] Typo fix:
>    s/hw_closid/closid/g
> 
>    (The name "closid" is used in the code.  If there is a distinction
>    between "hardware" closids and resctrl closids, it doesn't seem to
>    be explicit in the naming elsewhere.)

Heh, this is a blast from the past!

In 2018 I was trying to get resctrl to convert 'closid' to 'hw_closid' using some
architecture provided helpers. This was an alternative way of folding the CDP code to hide
the differences between x86/arm64. I decided the fs/resctrl code was cleaner without it -
and arm64 can just juggle the numbers instead.


Thanks,

James