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From: Reinette Chatre <reinette.chatre@intel.com>
To: "Moger, Babu" <bmoger@amd.com>, Babu Moger <babu.moger@amd.com>,
	<tony.luck@intel.com>, <bp@alien8.de>, <ben.horgan@arm.com>
Cc: <corbet@lwn.net>, <skhan@linuxfoundation.org>,
	<rdunlap@infradead.org>, <x86@kernel.org>, <Dave.Martin@arm.com>,
	<james.morse@arm.com>, <tglx@kernel.org>, <mingo@redhat.com>,
	<dave.hansen@linux.intel.com>, <hpa@zytor.com>,
	<fenghuay@nvidia.com>, <kas@kernel.org>,
	<rick.p.edgecombe@intel.com>, <akpm@linux-foundation.org>,
	<rppt@kernel.org>, <dapeng1.mi@linux.intel.com>,
	<elver@google.com>, <enelsonmoore@gmail.com>,
	<jlayton@kernel.org>, <kuba@kernel.org>, <ebiggers@kernel.org>,
	<seanjc@google.com>, <ewanhai-oc@zhaoxin.com>,
	<binbin.wu@linux.intel.com>, <peterz@infradead.org>,
	<ashish.kalra@amd.com>, <superm1@kernel.org>,
	<chang.seok.bae@intel.com>, <prathyushi.nangia@amd.com>,
	<kim.phillips@amd.com>, <ackerleytng@google.com>,
	<elena.reshetova@intel.com>, <naveen@kernel.org>,
	<darwi@linutronix.de>, <linux-doc@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <linux-coco@lists.linux.dev>,
	<kvm@vger.kernel.org>, <eranian@google.com>,
	<peternewman@google.com>
Subject: Re: [PATCH v6 10/18] fs/resctrl: Add support for hidden resource group files
Date: Mon, 19 Oct 2026 09:22:52 -0700	[thread overview]
Message-ID: <8b10c05f-eb3c-4ce3-8580-1cb034ad4e18@intel.com> (raw)
In-Reply-To: <89715865-895d-4771-a700-f1a8aaa385cc@amd.com>

Hi Babu,

On 10/16/26 1:53 PM, Moger, Babu wrote:
> On 10/15/2026 10:27 AM, Reinette Chatre wrote:
>> On 10/1/26 8:10 AM, Babu Moger wrote:
>>> Some per-group resctrl files are only meaningful once a resource group
>>> has an active kernel mode association.
>>
>> Could this elaborate more about how the files depend on the kernel mode
>> and why they may not always be meaningful?
>>
>>>
>>> Creating them only at activation would complicate group setup and
>>
>> Why would it complicate group setup and teardown? I think it would
>> rather complicate mode activation and de-activation but since there is
>> no detail about how this will complicate group setup it is difficult to
>> compare. It is difficult to reason about a patch when the motivation is
>> vague.
>>
>>> teardown, while exposing them on every group would show empty files
>>
>> "show empty files" - technically these files, as they are implemented,
>> will not be empty but return errors
>>
>>> with no clear purpose.
>>>
>>> Add a hidden property to struct rftype to hide files at creation.
>>
>> Missing a "why".
>> This can append to describe how this adds the foundational support in
>> preparation for features to restore visibility when the feature's files
>> need to be exposed to user space.
>>
> 
> Will rephrase the whole changelog:
> 
> "Some per-group resctrl files are only applicable to resource groups
> with an active kernel mode association. Accessing these files before a
> kernel mode association is established would result in errors and does
> not provide useful information.

What does "and does not provide useful information" refer to? Does this
mean that the errors are not useful?

> 
> Creating and removing these files when a kernel mode is activated or
> deactivated would add complexity to the mode management path. Add a
> hidden property to struct rftype so files can be created with the
> resource group and exposed only when they become applicable.

Please separate the problem and solution descriptions.

> 
> This provides the infrastructure needed to control file visibility for
> future kernel-mode-specific resctrl interfaces."
Reinette



  reply	other threads:[~2026-10-19 16:23 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-01 15:10 [PATCH v6 00/18] x86,fs/resctrl: Add kernel-mode (e.g., PLZA) support to the resctrl subsystem Babu Moger
2026-10-01 15:10 ` [PATCH v6 01/18] x86/cpufeatures: Support Privilege Level Zero Association (PLZA) Babu Moger
2026-10-15 14:16   ` Reinette Chatre
2026-10-15 23:02     ` Babu Moger
2026-10-01 15:10 ` [PATCH v6 02/18] x86/resctrl: Add PLZA support to command-line options Babu Moger
2026-10-15 14:17   ` Reinette Chatre
2026-10-15 23:03     ` Babu Moger
2026-10-01 15:10 ` [PATCH v6 03/18] x86/resctrl: Add PLZA configuration definitions and data structures Babu Moger
2026-10-15 14:22   ` Reinette Chatre
2026-10-15 23:07     ` Babu Moger
2026-10-19 16:16       ` Reinette Chatre
2026-10-01 15:10 ` [PATCH v6 04/18] fs/resctrl: Introduce kernel mode enum Babu Moger
2026-10-15 14:44   ` Reinette Chatre
2026-10-15 23:09     ` Babu Moger
2026-10-19 16:17       ` Reinette Chatre
2026-10-01 15:10 ` [PATCH v6 05/18] x86,arm,fs/resctrl: Introduce architecture hook to program global kernel mode Babu Moger
2026-10-15 14:30   ` Reinette Chatre
2026-10-15 23:12     ` Moger, Babu
2026-10-01 15:10 ` [PATCH v6 06/18] fs/resctrl: Introduce kernel mode states for resctrl Babu Moger
2026-10-15 14:37   ` Reinette Chatre
2026-10-16 15:10     ` Moger, Babu
2026-10-19 16:18       ` Reinette Chatre
2026-10-01 15:10 ` [PATCH v6 07/18] fs/resctrl: Introduce resctrl_set_kmode_support() to register supported modes Babu Moger
2026-10-15 14:40   ` Reinette Chatre
2026-10-16 15:27     ` Moger, Babu
2026-10-19 16:19       ` Reinette Chatre
2026-10-01 15:10 ` [PATCH v6 08/18] x86/resctrl: Register RESCTRL_GLOBAL_ENABLE_PER_CPU when PLZA is available Babu Moger
2026-10-15 14:46   ` Reinette Chatre
2026-10-16 15:50     ` Moger, Babu
2026-10-01 15:10 ` [PATCH v6 09/18] fs/resctrl: Add interface to display kernel mode status Babu Moger
2026-10-15 15:16   ` Reinette Chatre
2026-10-16 19:10     ` Moger, Babu
2026-10-19 16:20       ` Reinette Chatre
2026-10-01 15:10 ` [PATCH v6 10/18] fs/resctrl: Add support for hidden resource group files Babu Moger
2026-10-15 15:27   ` Reinette Chatre
2026-10-16 20:53     ` Moger, Babu
2026-10-19 16:22       ` Reinette Chatre [this message]
2026-10-01 15:10 ` [PATCH v6 11/18] fs/resctrl: Introduce kmode_cpus/kmode_cpus_list per rdtgroup Babu Moger
2026-10-15 15:31   ` Reinette Chatre
2026-10-16 21:33     ` Moger, Babu
2026-10-19 16:34       ` Reinette Chatre
2026-10-01 15:10 ` [PATCH v6 12/18] fs/resctrl: Add CPU hotplug support for kernel mode associations Babu Moger
2026-10-15 15:33   ` Reinette Chatre
2026-10-16 22:21     ` Moger, Babu
2026-10-01 15:10 ` [PATCH v6 13/18] fs/resctrl: Deactivate kernel mode associations when a group is removed Babu Moger
2026-10-15 15:43   ` Reinette Chatre
2026-10-19 15:47     ` Babu Moger
2026-10-19 16:37       ` Reinette Chatre
2026-10-01 15:10 ` [PATCH v6 14/18] fs/resctrl: Control visibility of global per-CPU kernel mode group files Babu Moger
2026-10-15 15:46   ` Reinette Chatre
2026-10-19 16:31     ` Babu Moger
2026-10-19 22:00       ` Reinette Chatre
2026-10-01 15:10 ` [PATCH v6 15/18] fs/resctrl: Reject mode changes for groups backing kernel mode Babu Moger
2026-10-15 15:49   ` Reinette Chatre
2026-10-19 17:43     ` Babu Moger
2026-10-19 22:01       ` Reinette Chatre
2026-10-01 15:10 ` [PATCH v6 16/18] fs/resctrl: Add interface to modify kernel mode via info/kernel_mode Babu Moger
2026-10-15 16:07   ` Reinette Chatre
2026-10-01 15:10 ` [PATCH v6 17/18] fs/resctrl: Allow user space to write kmode_cpus/kmode_cpus_list Babu Moger
2026-10-01 15:10 ` [PATCH v6 18/18] fs/resctrl: Add kernel mode documentation and examples Babu Moger
2026-10-17  0:13 ` [PATCH v6 00/18] x86,fs/resctrl: Add kernel-mode (e.g., PLZA) support to the resctrl subsystem Drew Fustini

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