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x86/smpboot: Fix __max_logical_packages estimate

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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. e.g.:

  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.

Calculate __max_logical_packages after the cpu enumeration has completed.
Use the boot cpu's data to extrapolate the number of packages.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: He Chen <he.chen@linux.intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Piotr Luc <piotr.luc@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arvind Yadav <arvind.yadav.cs@gmail.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: https://lkml.kernel.org/r/20171114124257.22013-4-prarit@redhat.com
This commit is contained in:
Prarit Bhargava 2017-11-14 07:42:57 -05:00 committed by Thomas Gleixner
parent 30bb981185
commit b4c0a7326f
1 changed files with 10 additions and 45 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

55
arch/x86/kernel/smpboot.c
View file

@ -310,12 +310,6 @@ int topology_update_package_map(unsigned int pkg, unsigned int cpu)
if (new >= 0)
goto found;
if (logical_packages >= __max_logical_packages) {
pr_warn("Package %u of CPU %u exceeds BIOS package data %u.\n",
logical_packages, cpu, __max_logical_packages);
return -ENOSPC;
}
new = logical_packages++;
if (new != pkg) {
pr_info("CPU %u Converting physical %u to logical package %u\n",
@ -326,44 +320,6 @@ int topology_update_package_map(unsigned int pkg, unsigned int cpu)
return 0;
}
static void __init smp_init_package_map(struct cpuinfo_x86 *c, unsigned int cpu)
{
unsigned int ncpus;
/*
* Today neither Intel nor AMD support heterogenous systems. That
* might change in the future....
*
* While ideally we'd want '* smp_num_siblings' in the below @ncpus
* computation, this won't actually work since some Intel BIOSes
* report inconsistent HT data when they disable HT.
*
* In particular, they reduce the APIC-IDs to only include the cores,
* but leave the CPUID topology to say there are (2) siblings.
* This means we don't know how many threads there will be until
* after the APIC enumeration.
*
* By not including this we'll sometimes over-estimate the number of
* logical packages by the amount of !present siblings, but this is
* still better than MAX_LOCAL_APIC.
*
* We use total_cpus not nr_cpu_ids because nr_cpu_ids can be limited
* on the command line leading to a similar issue as the HT disable
* problem because the hyperthreads are usually enumerated after the
* primary cores.
*/
ncpus = boot_cpu_data.x86_max_cores;
if (!ncpus) {
pr_warn("x86_max_cores == zero !?!?");
ncpus = 1;
}
__max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus);
pr_info("Max logical packages: %u\n", __max_logical_packages);
topology_update_package_map(c->phys_proc_id, cpu);
}
void __init smp_store_boot_cpu_info(void)
{
int id = 0; /* CPU 0 */
@ -371,7 +327,7 @@ void __init smp_store_boot_cpu_info(void)
*c = boot_cpu_data;
c->cpu_index = id;
smp_init_package_map(c, id);
topology_update_package_map(c->phys_proc_id, id);
c->initialized = true;
}
@ -1341,7 +1297,16 @@ void __init native_smp_prepare_boot_cpu(void)
void __init native_smp_cpus_done(unsigned int max_cpus)
{
int ncpus;
pr_debug("Boot done\n");
/*
* Today neither Intel nor AMD support heterogenous systems so
* extrapolate the boot cpu's data to all packages.
*/
ncpus = cpu_data(0).booted_cores * smp_num_siblings;
__max_logical_packages = DIV_ROUND_UP(nr_cpu_ids, ncpus);
pr_info("Max logical packages: %u\n", __max_logical_packages);
if (x86_has_numa_in_package)
set_sched_topology(x86_numa_in_package_topology);