From: Reinette Chatre <reinette.chatre@intel.com>
To: Tony Luck <tony.luck@intel.com>, Fenghua Yu <fenghuay@nvidia.com>,
"Maciej Wieczor-Retman" <maciej.wieczor-retman@intel.com>,
Peter Newman <peternewman@google.com>,
James Morse <james.morse@arm.com>,
Babu Moger <babu.moger@amd.com>,
Drew Fustini <dfustini@baylibre.com>,
Dave Martin <Dave.Martin@arm.com>, Chen Yu <yu.c.chen@intel.com>,
David E Box <david.e.box@intel.com>, <x86@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>,
<linux-kernel@vger.kernel.org>, <patches@lists.linux.dev>
Subject: Re: [PATCH v12 04/25] x86/resctrl: Apply Intel MBM quirk from rdt_get_l3_mon_config()
Date: Thu, 24 Sep 2026 08:17:54 -0700 [thread overview]
Message-ID: <7aaf83b3-03ea-47bf-809b-561beb6b3843@intel.com> (raw)
In-Reply-To: <20260916231320.14502-5-tony.luck@intel.com>
Hi Tony,
To not document code the subject could be something like:
x86/resctrl: Apply MBM quirk during feature enumeration
On 9/16/26 4:12 PM, Tony Luck wrote:
> The Intel quirk to adjust Memory Bandwidth Monitoring (MBM) values on
> certain CPUs is applied early, before discovering if MBM is supported.
>
> Move the call into rdt_get_l3_mon_config(), but keep the decision on
> whether it is needed in __check_quirks_intel() with all the other
> model specific tests.
Last paragraph just documents the code change without any explanation
*why* this change is needed. Consider something like below (just a draft,
and suggestion, please improve from here).
The Intel MBM correction factor quirk is applied during early CPU model
checks using the RMID count from cpuinfo_x86::x86_cache_max_rmid. It is
the last consumer of the resctrl fields in struct cpuinfo_x86 now that
monitoring feature enumeration is contained within resctrl.
This lone consumer prevents those fields from being removed, and applies
MBM specific setup before resctrl has established that MBM is supported.
Apply the quirk during monitoring feature enumeration in preparation
for removing the resctrl fields from struct cpuinfo_x86.
Keep the decision on whether the quirk is needed with the other model
specific tests to avoid scattering quirk handling.
No functional change intended.
Reinette
next prev parent reply other threads:[~2026-09-24 15:18 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-16 23:12 [PATCH v12 00/25] Allow AET to use PMT as loadable module Tony Luck
2026-09-16 23:12 ` [PATCH v12 01/25] x86/cpufeatures: Add missing CQM feature dependency Tony Luck
2026-09-24 15:12 ` Reinette Chatre
2026-09-16 23:12 ` [PATCH v12 02/25] x86/resctrl: Check if monitoring features are supported Tony Luck
2026-09-24 15:13 ` Reinette Chatre
2026-09-16 23:12 ` [PATCH v12 03/25] x86/resctrl: Enumerate monitor features in rdt_get_l3_mon_config() Tony Luck
2026-09-24 15:15 ` Reinette Chatre
2026-09-16 23:12 ` [PATCH v12 04/25] x86/resctrl: Apply Intel MBM quirk from rdt_get_l3_mon_config() Tony Luck
2026-09-21 17:45 ` Babu Moger
2026-09-22 20:46 ` Luck, Tony
2026-09-24 15:23 ` Reinette Chatre
2026-09-24 15:17 ` Reinette Chatre [this message]
2026-09-16 23:13 ` [PATCH v12 05/25] x86/resctrl: Delete resctrl_cpu_detect() Tony Luck
2026-09-24 15:21 ` Reinette Chatre
2026-09-16 23:13 ` [PATCH v12 06/25] arm,x86,fs/resctrl: Replace architecture resctrl_arch_{alloc,mon}_capable() Tony Luck
2026-09-24 15:22 ` Reinette Chatre
2026-09-16 23:13 ` [PATCH v12 07/25] x86/resctrl: Update special case for Intel Haswell enumeration Tony Luck
2026-09-24 15:27 ` Reinette Chatre
2026-09-16 23:13 ` [PATCH v12 08/25] x86/resctrl: Delete rdt_alloc_capable and rdt_mon_capable Tony Luck
2026-09-24 15:28 ` Reinette Chatre
2026-09-16 23:13 ` [PATCH v12 09/25] fs/resctrl: Remove redundant calls to resctrl_{alloc,mon}_capable() Tony Luck
2026-09-21 17:45 ` Babu Moger
2026-09-22 20:33 ` Luck, Tony
2026-09-24 15:30 ` Reinette Chatre
2026-09-16 23:13 ` [PATCH v12 10/25] x86/resctrl: Honor rdt=perf option to force enable AET perf events Tony Luck
2026-09-24 15:29 ` Reinette Chatre
2026-09-16 23:13 ` [PATCH v12 11/25] fs/resctrl: Add interface to disable a monitor event Tony Luck
2026-09-24 15:31 ` Reinette Chatre
2026-09-16 23:13 ` [PATCH v12 12/25] arm,x86,fs/resctrl: Allocate maximum needed rmid_ptrs[] Tony Luck
2026-09-21 17:45 ` Babu Moger
2026-09-22 0:30 ` Reinette Chatre
2026-09-22 13:09 ` Babu Moger
2026-09-24 15:37 ` Reinette Chatre
2026-09-16 23:13 ` [PATCH v12 13/25] arm,x86,fs/resctrl: Allocate right size for L3 monitor arrays Tony Luck
2026-09-16 23:13 ` [PATCH v12 14/25] fs/resctrl: Rebuild free RMID list on each mount Tony Luck
2026-09-21 17:45 ` Babu Moger
2026-09-22 20:30 ` Luck, Tony
2026-09-22 22:58 ` Moger, Babu
2026-09-22 23:07 ` Luck, Tony
2026-09-23 13:21 ` Moger, Babu
2026-09-16 23:13 ` [PATCH v12 15/25] x86,fs/resctrl: Handle systems where AET is the only resource Tony Luck
2026-09-16 23:13 ` [PATCH v12 16/25] x86/resctrl: Add PMT registration API for AET enumeration callbacks Tony Luck
2026-09-16 23:13 ` [PATCH v12 17/25] platform/x86/intel/pmt: Register enumeration functions with resctrl Tony Luck
2026-09-16 23:13 ` [PATCH v12 18/25] x86/resctrl: Use registered function pointers for AET enumeration Tony Luck
2026-09-16 23:13 ` [PATCH v12 19/25] arm,x86,fs/resctrl: Enumerate AET on every resctrl mount Tony Luck
2026-09-16 23:13 ` [PATCH v12 20/25] x86/resctrl: Enforce system RMID limit on AET Tony Luck
2026-09-16 23:13 ` [PATCH v12 21/25] x86/resctrl: Export interface to report telemetry unbind/remove Tony Luck
2026-09-16 23:13 ` [PATCH v12 22/25] platform/x86/intel/pmt: Inform resctrl when MMIO maps are being removed Tony Luck
2026-09-18 16:29 ` [PATCH 12 22/25 UPDATED] " Tony Luck
2026-09-16 23:13 ` [PATCH v12 23/25] x86/resctrl: Require 64-bit x86 for resctrl support Tony Luck
2026-09-16 23:13 ` [PATCH v12 24/25] x86/resctrl: Simplify Kconfig options for resctrl Tony Luck
2026-09-16 23:13 ` [PATCH v12 25/25] x86,fs/resctrl: Document telemetry mount timing caveat Tony Luck
2026-09-17 16:32 ` [PATCH v12 00/25] Allow AET to use PMT as loadable module Luck, Tony
2026-09-17 21:23 ` Luck, Tony
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