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Message-ID: <bda01f60-e6fc-1c30-ba54-45abcbbc8e0a@arm.com>
Date:   Thu, 27 Apr 2023 15:19:47 +0100
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Subject: Re: [PATCH v3 15/19] x86/resctrl: Add helpers for system wide
 mon/alloc capable
Content-Language: en-GB
To:     Reinette Chatre <reinette.chatre@intel.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Fenghua Yu <fenghua.yu@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,
        xingxin.hx@openanolis.org, baolin.wang@linux.alibaba.com,
        Jamie Iles <quic_jiles@quicinc.com>,
        Xin Hao <xhao@linux.alibaba.com>, peternewman@google.com
References: <20230320172620.18254-1-james.morse@arm.com>
 <20230320172620.18254-16-james.morse@arm.com>
 <80e2962e-0aa6-c939-8f69-8f0cda988cbe@intel.com>
From:   James Morse <james.morse@arm.com>
In-Reply-To: <80e2962e-0aa6-c939-8f69-8f0cda988cbe@intel.com>
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On 01/04/2023 00:29, Reinette Chatre wrote:
> Hi James,
> 
> On 3/20/2023 10:26 AM, James Morse wrote:
>> resctrl reads rdt_alloc_capable or rdt_mon_capable to determine
>> whether any of the resources support the corresponding features.
>> resctrl also uses the static-keys that affect the architecture's
>> context-switch code to determine the same thing.
> 
> hmmm ... they are not the same though since the static-keys
> in addition means that resctrl is mounted.

and all the paths where this matters were updated in patch 12 to have an explicit
resctrl_mounted check.


Thanks,

James