From: Yazen Ghannam <yazen.ghannam@amd.com>
To: Michal Pecio <michal.pecio@gmail.com>
Cc: Shyam-sundar.S-k@amd.com, bhelgaas@google.com,
hdegoede@redhat.com, ilpo.jarvinen@linux.intel.com,
jdelvare@suse.com, linux-edac@vger.kernel.org,
linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, linux@roeck-us.net,
mario.limonciello@amd.com, naveenkrishna.chatradhi@amd.com,
platform-driver-x86@vger.kernel.org, suma.hegde@amd.com,
tony.luck@intel.com, x86@kernel.org
Subject: Re: [PATCH v3 06/12] x86/amd_nb: Use topology info to get AMD node count
Date: Thu, 23 Oct 2025 15:09:01 -0400 [thread overview]
Message-ID: <20251023190901.GA840389@yaz-khff2.amd.com> (raw)
In-Reply-To: <20251023190429.GB796848@yaz-khff2.amd.com>
On Thu, Oct 23, 2025 at 03:04:29PM -0400, Yazen Ghannam wrote:
> On Thu, Oct 23, 2025 at 08:25:03PM +0200, Michal Pecio wrote:
> > On Thu, 23 Oct 2025 12:09:06 -0400, Yazen Ghannam wrote:
> > > The kernel seems to think there are 6 CPUs on your system:
> > >
> > > [ 0.072059] CPU topo: Allowing 4 present CPUs plus 2 hotplug CPUs
> >
> > I wonder if this code doesn't break systems which actually support
> > hotplug, when some sockets aren't populated at boot?
>
> I don't know about other vendors, but we don't do physical CPU hotplug.
> CPU hotplug, in this case, is there are physical CPUs already in the
> system, but they are not enabled for whatever policy decision. They
> could be disabled in BIOS, and so the MADT entries will reflect that. Or
> they can be disabled by kernel parameters.
>
Sorry for the rapid emails. Here's another interesting commit:
f0551af02130 ("x86/topology: Ignore non-present APIC IDs in a present package")
Thanks,
Yazen
next prev parent reply other threads:[~2025-10-23 19:09 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-07 22:28 [PATCH v3 00/12] AMD NB and SMN rework Yazen Ghannam
2025-01-07 22:28 ` [PATCH v3 01/12] x86/amd_nb: Restrict init function to AMD-based systems Yazen Ghannam
2025-01-07 22:28 ` [PATCH v3 02/12] x86/amd_nb: Clean up early_is_amd_nb() Yazen Ghannam
2025-01-07 22:28 ` [PATCH v3 03/12] x86: Start moving AMD node functionality out of AMD_NB Yazen Ghannam
2025-01-07 22:28 ` [PATCH v3 04/12] x86/amd_nb: Simplify function 4 search Yazen Ghannam
2025-01-07 22:28 ` [PATCH v3 05/12] x86/amd_nb: Simplify root device search Yazen Ghannam
2025-01-07 22:28 ` [PATCH v3 06/12] x86/amd_nb: Use topology info to get AMD node count Yazen Ghannam
2025-01-09 9:15 ` [tip: x86/misc] " tip-bot2 for Yazen Ghannam
2025-10-21 23:16 ` [PATCH v3 06/12] " Michal Pecio
2025-10-22 13:39 ` Yazen Ghannam
2025-10-22 15:38 ` Michal Pecio
2025-10-22 16:04 ` Guenter Roeck
2025-10-22 16:09 ` Yazen Ghannam
2025-10-22 16:18 ` Michal Pecio
2025-10-23 13:59 ` Yazen Ghannam
2025-10-23 15:01 ` Michal Pecio
2025-10-23 16:09 ` Yazen Ghannam
2025-10-23 16:22 ` Mario Limonciello
2025-10-23 17:06 ` Michal Pecio
2025-10-23 17:12 ` Mario Limonciello
2025-10-23 18:25 ` Yazen Ghannam
2025-10-23 21:43 ` Mario Limonciello
2025-10-23 16:31 ` Michal Pecio
2025-10-23 18:15 ` Yazen Ghannam
2025-10-23 18:25 ` Michal Pecio
2025-10-23 19:04 ` Yazen Ghannam
2025-10-23 19:09 ` Yazen Ghannam [this message]
2025-10-24 8:48 ` Michal Pecio
2025-10-24 13:42 ` Yazen Ghannam
2025-01-07 22:28 ` [PATCH v3 07/12] x86/amd_nb: Simplify function 3 search Yazen Ghannam
2025-01-09 9:15 ` [tip: x86/misc] " tip-bot2 for Yazen Ghannam
2025-01-07 22:28 ` [PATCH v3 08/12] x86/amd_nb, hwmon: (k10temp): Simplify amd_pci_dev_to_node_id() Yazen Ghannam
2025-01-07 22:28 ` [PATCH v3 09/12] x86/amd_nb: Move SMN access code to a new amd_node driver Yazen Ghannam
2025-01-08 5:30 ` Shyam Sundar S K
2025-01-08 8:56 ` Borislav Petkov
2025-01-07 22:28 ` [PATCH v3 10/12] x86/amd_node: Update __amd_smn_rw() error paths Yazen Ghannam
2025-01-07 22:28 ` [PATCH v3 11/12] x86/amd_node: Remove dependency on AMD_NB Yazen Ghannam
2025-01-07 22:28 ` [PATCH v3 12/12] x86/amd_node: Use defines for SMN register offsets Yazen Ghannam
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