diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 64b669d..81e6a43 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -312,8 +312,21 @@ static void __init smp_init_package_map(void) /* * 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. */ - ncpus = boot_cpu_data.x86_max_cores * smp_num_siblings; + ncpus = boot_cpu_data.x86_max_cores; __max_logical_packages = DIV_ROUND_UP(nr_cpu_ids, ncpus); /* |
