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References: <20221021131204.5581-1-james.morse@arm.com> <20221021131204.5581-2-james.morse@arm.com>
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From:   Peter Newman <peternewman@google.com>
Date:   Mon, 31 Oct 2022 15:42:50 +0100
Message-ID: <CALPaoCgxPgJ2MjTu_FDXSouD=nV_5zej1sjebK0i7M7V5SY_=g@mail.gmail.com>
Subject: Re: [PATCH 01/18] x86/resctrl: Track the closid with the rmid
To:     James Morse <james.morse@arm.com>
Cc:     x86@kernel.org, linux-kernel@vger.kernel.org,
        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, tan.shaopeng@fujitsu.com,
        Jamie Iles <quic_jiles@quicinc.com>,
        Xin Hao <xhao@linux.alibaba.com>, xingxin.hx@openanolis.org,
        baolin.wang@linux.alibaba.com
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Hi James,

On Fri, Oct 21, 2022 at 3:12 PM James Morse <james.morse@arm.com> wrote:
>
> x86's RMID are independent of the CLOSID. An RMID can be allocated,
> used and freed without considering the CLOSID.
>
> MPAM's equivalent feature is PMG, which is not an independent number,
> it extends the CLOSID/PARTID space. For MPAM, only PMG-bits worth of
> 'RMID' can be allocated for a single CLOSID.
> i.e. if there is 1 bit of PMG space, then each CLOSID can have two
> monitor groups.
>
> To allow rescrl to disambiguate RMID values for different CLOSID,
> everything in resctrl that keeps an RMID value needs to know the CLOSID
> too. This will always be ignored on x86.

I recall that the allocation of RMIDs on MPAM was an open topic of
discussion on the other thread. Can we finish that discussion first?

https://lore.kernel.org/lkml/14df28f0-90b1-9c43-add5-08947165596d@intel.com/

Thanks!
-Peter