Re: [PATCH] arch/x86: Remove second call to topology_update_package_map()
From: Prarit Bhargava
Date: Wed Oct 12 2016 - 16:55:11 EST
On 10/12/2016 03:51 PM, Tim Chen wrote:
> On Wed, 2016-10-12 at 11:06 -0400, Prarit Bhargava wrote:
>> On 10/12/2016 10:36 AM, Prarit Bhargava wrote:
>>> This was noticed during the investigation of
>>> A note for reviewers on the cleanup in smp_init_package_map(): The
>>> per_cpu variable x86_bios_cpu_apicid is initialized to BAD_APICID, and the
>>> bitmaps are set to false by default so the code isn't necessary. The
>>> pr_warn() can also be dropped as generic_processor_info() will do a
>>> pr_warning() in the same situation.
>>> After commit 1f12e32f4cd5 ("x86/topology: Create logical package id"),
>>> topology_update_package_map() is called twice on a CPU. The first call is in
>>> generic_processor_info(), which is called on all present cpus (found in either
>>> mptable or ACPI MADT). The second call is in smp_init_package_map() which
>>> is called later on in the init sequence.
>>> Only a single call is necessary for the kernel to initialize the data
>>> structures properly. This patch drops the later call in smp_init_package_map()
>>> and moves smp_init_package_map() out of smp_store_boot_cpu_info().
>> This seems to not work on systems with an empty socket :/. Looking into this now.
> My single node workstation also failed to boot with the patch.
The patch is incorrect. I'm dropping it completely.