Messages in this thread Patch in this message | | | From | Prarit Bhargava <> | Subject | [PATCH] arch/x86: Remove second call to topology_update_package_map() | Date | Wed, 12 Oct 2016 10:36:28 -0400 |
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This was noticed during the investigation of
http://git.kernel.org/tip/2a51fe083eba7f99cbda72f5ef90cdf2f4df882c
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.
P.
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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().
Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: x86@kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Len Brown <len.brown@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Jiri Olsa <jolsa@redhat.com> --- arch/x86/kernel/smpboot.c | 20 +++----------------- 1 file changed, 3 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 951f093a96fe..0ff74f8bb5e9 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -271,7 +271,7 @@ int topology_update_package_map(unsigned int apicid, unsigned int cpu) if (!physical_package_map) return 0; - if (pkg >= max_physical_pkg_id) + if (!apic->apic_id_valid(apicid) || pkg >= max_physical_pkg_id) return -EINVAL; /* Set the logical package id */ @@ -310,7 +310,7 @@ int topology_phys_to_logical_pkg(unsigned int phys_pkg) static void __init smp_init_package_map(void) { - unsigned int ncpus, cpu; + unsigned int ncpus; size_t size; /* @@ -342,7 +342,6 @@ static void __init smp_init_package_map(void) } __max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus); - logical_packages = 0; /* * Possibly larger than what we need as the number of apic ids per @@ -355,19 +354,6 @@ static void __init smp_init_package_map(void) size = BITS_TO_LONGS(max_physical_pkg_id) * sizeof(unsigned long); physical_package_map = kzalloc(size, GFP_KERNEL); - for_each_present_cpu(cpu) { - unsigned int apicid = apic->cpu_present_to_apicid(cpu); - - if (apicid == BAD_APICID || !apic->apic_id_valid(apicid)) - continue; - if (!topology_update_package_map(apicid, cpu)) - continue; - pr_warn("CPU %u APICId %x disabled\n", cpu, apicid); - per_cpu(x86_bios_cpu_apicid, cpu) = BAD_APICID; - set_cpu_possible(cpu, false); - set_cpu_present(cpu, false); - } - if (logical_packages > __max_logical_packages) { pr_warn("Detected more packages (%u), then computed by BIOS data (%u).\n", logical_packages, __max_logical_packages); @@ -385,7 +371,6 @@ void __init smp_store_boot_cpu_info(void) *c = boot_cpu_data; c->cpu_index = id; - smp_init_package_map(); } /* @@ -1285,6 +1270,7 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus) * Setup boot CPU information */ smp_store_boot_cpu_info(); /* Final full version of the data */ + smp_init_package_map(); cpumask_copy(cpu_callin_mask, cpumask_of(0)); mb(); -- 1.7.9.3
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