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Date:   Thu, 14 Dec 2023 11:38:08 +0000
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Subject: Re: [PATCH v7 16/24] x86/resctrl: Make resctrl_mounted checks
 explicit
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To:     babu.moger@amd.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>,
        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,
        baolin.wang@linux.alibaba.com, Jamie Iles <quic_jiles@quicinc.com>,
        Xin Hao <xhao@linux.alibaba.com>, peternewman@google.com,
        dfustini@baylibre.com, amitsinght@marvell.com
References: <20231025180345.28061-1-james.morse@arm.com>
 <20231025180345.28061-17-james.morse@arm.com>
 <7e611640-9e7a-42a1-b0d7-f8b76999e9b2@amd.com>
From:   James Morse <james.morse@arm.com>
In-Reply-To: <7e611640-9e7a-42a1-b0d7-f8b76999e9b2@amd.com>
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Hi Babu,

On 09/11/2023 20:47, Moger, Babu wrote:
> On 10/25/23 13:03, James Morse wrote:
>> The rdt_enable_key is switched when resctrl is mounted, and used to
>> prevent a second mount of the filesystem. It also enables the
>> architecture's context switch code.
>>
>> This requires another architecture to have the same set of static-keys,
>> as resctrl depends on them too. The existing users of these static-keys
>> are implicitly also checking if the filesystem is mounted.
>>
>> Make the resctrl_mounted checks explicit: resctrl can keep track of
>> whether it has been mounted once. This doesn't need to be combined with
>> whether the arch code is context switching the CLOSID.
>>
>> rdt_mon_enable_key is never used just to test that resctrl is mounted,
>> but does also have this implication. Add a resctrl_mounted to all uses
>> of rdt_mon_enable_key. This will allow rdt_mon_enable_key to be swapped
>> with a helper in a subsequent patch.
>>
>> This will allow the static-key changing to be moved behind resctrl_arch_
>> calls.

> Reviewed-by: Babu Moger <babu.moger@amd.com>

Thanks!


James