From: Borislav Petkov <bp@alien8.de>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: "Moger, Babu" <babu.moger@amd.com>,
"corbet@lwn.net" <corbet@lwn.net>,
"Chatre, Reinette" <reinette.chatre@intel.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"Yu, Fenghua" <fenghua.yu@intel.com>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"hpa@zytor.com" <hpa@zytor.com>,
"paulmck@kernel.org" <paulmck@kernel.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"quic_neeraju@quicinc.com" <quic_neeraju@quicinc.com>,
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<damien.lemoal@opensource.wdc.com>,
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"Bae, Chang Seok" <chang.seok.bae@intel.com>,
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<pawan.kumar.gupta@linux.intel.com>,
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"Eranian, Stephane" <eranian@google.com>,
"christophe.leroy@csgroup.eu" <christophe.leroy@csgroup.eu>,
"jarkko@kernel.org" <jarkko@kernel.org>,
"Hunter, Adrian" <adrian.hunter@intel.com>,
"quic_jiles@quicinc.com" <quic_jiles@quicinc.com>,
"peternewman@google.com" <peternewman@google.com>
Subject: Re: [PATCH v11 04/13] x86/cpufeatures: Add Bandwidth Monitoring Event Configuration feature flag
Date: Tue, 24 Jan 2023 12:28:51 +0100 [thread overview]
Message-ID: <Y8/A8yYcU0QXVRGG@zn.tnic> (raw)
In-Reply-To: <SJ1PR11MB60839FFE6A7769A1E15818DDFCFE9@SJ1PR11MB6083.namprd11.prod.outlook.com>
On Mon, Jan 09, 2023 at 09:50:20PM +0000, Luck, Tony wrote:
> But that allows for the flimsiest of reasons to used to justify making a
> flag visible.
How's that for starters?
c: The naming override can be "", which means it will not appear in /proc/cpuinfo.
----------------------------------------------------------------------------------
The feature shall be omitted from /proc/cpuinfo if there is no valid use case
for userspace to query this flag and cannot rely on other means for detecting
feature support. For example, toolchains do use CPUID directly instead of
relying on the kernel providing that info.
If unsure, that flag can always be omitted initially and, once a valid use case
presents itself, be shown later. Not the other way around.
Another example is X86_FEATURE_ALWAYS, defined in cpufeatures.h. That flag is an
internal kernel feature used in the alternative runtime patching functionality.
So, its name is overridden with "". Its flag will not appear in /proc/cpuinfo
because it absolutely does not make any sense to appear there.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2023-01-24 11:29 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-09 16:43 [PATCH v11 00/13] x86/resctrl: Support for AMD QoS new features Babu Moger
2023-01-09 16:43 ` [PATCH v11 01/13] x86/resctrl: Replace smp_call_function_many() with on_each_cpu_mask() Babu Moger
2023-01-09 23:26 ` Ashok Raj
2023-01-10 2:23 ` Moger, Babu
2023-01-10 20:58 ` Luck, Tony
2023-01-11 15:42 ` Ashok Raj
2023-01-11 19:05 ` Luck, Tony
2023-01-11 23:21 ` Ashok Raj
2023-01-09 16:43 ` [PATCH v11 02/13] x86/cpufeatures: Add Slow Memory Bandwidth Allocation feature flag Babu Moger
2023-01-09 16:43 ` [PATCH v11 03/13] x86/resctrl: Add a new resource type RDT_RESOURCE_SMBA Babu Moger
2023-01-09 16:43 ` [PATCH v11 04/13] x86/cpufeatures: Add Bandwidth Monitoring Event Configuration feature flag Babu Moger
2023-01-09 18:58 ` Borislav Petkov
2023-01-09 19:49 ` Moger, Babu
2023-01-09 21:07 ` Borislav Petkov
2023-01-09 21:25 ` Luck, Tony
2023-01-09 21:39 ` Borislav Petkov
2023-01-09 21:50 ` Luck, Tony
2023-01-24 11:28 ` Borislav Petkov [this message]
2023-01-09 23:43 ` Reinette Chatre
2023-01-24 11:32 ` Borislav Petkov
2023-01-09 21:44 ` Moger, Babu
2023-01-09 21:51 ` Borislav Petkov
2023-01-09 23:10 ` Moger, Babu
2023-01-24 11:34 ` Borislav Petkov
2023-01-24 14:11 ` Moger, Babu
2023-01-24 15:10 ` Borislav Petkov
2023-01-24 16:06 ` Moger, Babu
2023-01-24 16:59 ` Reinette Chatre
2023-01-24 17:30 ` Moger, Babu
2023-01-24 17:47 ` Reinette Chatre
2023-01-24 19:03 ` Moger, Babu
2023-01-24 19:11 ` Borislav Petkov
2023-01-24 19:23 ` Reinette Chatre
2023-01-24 20:12 ` Moger, Babu
2023-01-09 16:43 ` [PATCH v11 05/13] x86/resctrl: Include new features in command line options Babu Moger
2023-01-09 16:43 ` [PATCH v11 06/13] x86/resctrl: Detect and configure Slow Memory Bandwidth Allocation Babu Moger
2023-01-09 16:43 ` [PATCH v11 07/13] x86/resctrl: Add __init attribute to rdt_get_mon_l3_config() Babu Moger
2023-01-09 16:44 ` [PATCH v11 08/13] x86/resctrl: Support monitor configuration Babu Moger
2023-01-09 16:44 ` [PATCH v11 09/13] x86/resctrl: Add interface to read mbm_total_bytes_config Babu Moger
2023-01-09 16:44 ` [PATCH v11 10/13] x86/resctrl: Add interface to read mbm_local_bytes_config Babu Moger
2023-01-09 16:44 ` [PATCH v11 11/13] x86/resctrl: Add interface to write mbm_total_bytes_config Babu Moger
2023-01-11 22:04 ` Reinette Chatre
2023-01-09 16:44 ` [PATCH v11 12/13] x86/resctrl: Add interface to write mbm_local_bytes_config Babu Moger
2023-01-09 16:44 ` [PATCH v11 13/13] Documentation/x86: Update resctrl.rst for new features Babu Moger
2023-01-11 22:06 ` Reinette Chatre
2023-01-11 22:39 ` Moger, Babu
2023-01-11 22:56 ` Reinette Chatre
2023-01-12 0:39 ` Moger, Babu
2023-01-12 0:47 ` Moger, Babu
2023-01-12 17:30 ` Reinette Chatre
2023-01-12 19:06 ` Moger, Babu
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