From: Prarit Bhargava <prarit@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: "Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, "Jean Delvare" <jdelvare@suse.com>,
"Borislav Petkov" <bp@suse.de>,
"Andy Lutomirski" <luto@kernel.org>,
"Tim Chen" <tim.c.chen@linux.intel.com>,
"Vitaly Kuznetsov" <vkuznets@redhat.com>,
"Michael Ellerman" <mpe@ellerman.id.au>,
"Ville Syrjälä" <ville.syrjala@linux.intel.com>
Subject: Re: [PATCH] x86/smpboot: Fix __max_logical_packages estimate
Date: Thu, 7 Sep 2017 17:18:23 -0400 [thread overview]
Message-ID: <ffcc96a9-253d-4e78-d2a2-0a30972a2d60@redhat.com> (raw)
In-Reply-To: <1504722964-9170-1-git-send-email-prarit@redhat.com>
On 09/06/2017 02:36 PM, Prarit Bhargava wrote:
> A system booted with a small number of cores enabled per package
> panics because the estimate of __max_logical_packages is too low.
> This occurs when the total number of active cores across all packages
> is less than the maximum core count for a single package.
>
> ie) On a 4 package system with 20 cores/package where only 4 cores
> are enabled on each package, the value of __max_logical_packages is
> calculated as DIV_ROUND_UP(16 / 20) = 1 and not 4.
>
> Improve the estimate of __max_logical_packages by comparing the current
> estimate to the number of SMBIOS type 4 Processor Information structures.
> If __max_logical_packages is still insufficient during boot use the largest
> possible value of Package ID.
If I move this calculation to native_smp_cpus_done() I can eliminate a chunk
of code and use boot_cpu_data.booted_cores to get a correct value.
I'll resubmit with a new patch.
P.
prev parent reply other threads:[~2017-09-07 21:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-06 18:36 Prarit Bhargava
2017-09-07 21:18 ` Prarit Bhargava [this message]
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