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Message-ID: <39cb8e29-2c04-a316-73d4-2878e98c3625@arm.com>
Date:   Thu, 24 Nov 2022 14:22:00 +0000
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Subject: Re: [PATCH 14/18] x86/resctrl: Add helpers for system wide mon/alloc
 capable
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To:     "Shaopeng Tan (Fujitsu)" <tan.shaopeng@fujitsu.com>,
        "x86@kernel.org" <x86@kernel.org>,
        "linux-kernel@vger.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" 
        <shameerali.kolothum.thodi@huawei.com>,
        D Scott Phillips OS <scott@os.amperecomputing.com>,
        "carl@os.amperecomputing.com" <carl@os.amperecomputing.com>,
        "lcherian@marvell.com" <lcherian@marvell.com>,
        "bobo.shaobowang@huawei.com" <bobo.shaobowang@huawei.com>,
        Jamie Iles <quic_jiles@quicinc.com>,
        Xin Hao <xhao@linux.alibaba.com>,
        "xingxin.hx@openanolis.org" <xingxin.hx@openanolis.org>,
        "baolin.wang@linux.alibaba.com" <baolin.wang@linux.alibaba.com>,
        "peternewman@google.com" <peternewman@google.com>
References: <20221021131204.5581-1-james.morse@arm.com>
 <20221021131204.5581-15-james.morse@arm.com>
 <TYAPR01MB633026AE84D35BCB92211C4B8B019@TYAPR01MB6330.jpnprd01.prod.outlook.com>
From:   James Morse <james.morse@arm.com>
In-Reply-To: <TYAPR01MB633026AE84D35BCB92211C4B8B019@TYAPR01MB6330.jpnprd01.prod.outlook.com>
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Hello!

On 10/11/2022 10:51, Shaopeng Tan (Fujitsu) 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.
>>
>> This forces another architecture to have the same static-keys.
>>
>> As the static-key is enabled based on the capable flag, and none of the
>> filesystem uses of these are in the scheduler path, move the capable flags
>> behind helpers, and use these in the filesystem code instead of the static-key.
>>
>> After this change, only the architecture code manages and uses the static-keys
>> to ensure __resctrl_sched_in() does not need runtime checks.
>>
>> This avoids multiple architectures having to define the same static-keys.

> arch/x86/kernel/cpu/resctrl/rdtgroup.c
>  static void mkdir_rdt_prepare_rmid_free(struct rdtgroup *rgrp)
>  {
>          if (rdt_mon_capable) 
>                  free_rmid(rgrp->closid, rgrp->mon.rmid);
>  }
> I think you forgot to fix rdt_mon_capable here.
> if (rdt_mon_capable) => if (resctrl_arch_mon_capable())

Yes - looks like I did.


Thanks!

James