Re: [PATCH] x86/xen: Calculate __max_logical_packages on PV domains

From: Boris Ostrovsky
Date: Wed Feb 07 2018 - 20:00:12 EST




On 02/07/2018 06:49 PM, Prarit Bhargava wrote:
The kernel panics on PV domains because native_smp_cpus_done() is
only called for HVM domains.

Calculate __max_logical_packages for PV domains.

Fixes: b4c0a7326f5d ("x86/smpboot: Fix __max_logical_packages estimate")
Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx>
Tested-and-reported-by: Simon Gaiser <simon@xxxxxxxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>
Cc: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Kate Stewart <kstewart@xxxxxxxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx


Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>

(+ Simon)

---
arch/x86/include/asm/smp.h | 1 +
arch/x86/kernel/smpboot.c | 10 ++++++++--
arch/x86/xen/smp.c | 2 ++
3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 461f53d27708..a4189762b266 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -129,6 +129,7 @@ static inline void arch_send_call_function_ipi_mask(const struct cpumask *mask)
void cpu_disable_common(void);
void native_smp_prepare_boot_cpu(void);
void native_smp_prepare_cpus(unsigned int max_cpus);
+void calculate_max_logical_packages(void);
void native_smp_cpus_done(unsigned int max_cpus);
void common_cpu_up(unsigned int cpunum, struct task_struct *tidle);
int native_cpu_up(unsigned int cpunum, struct task_struct *tidle);
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 6f27facbaa9b..767573b7f2db 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1281,11 +1281,10 @@ void __init native_smp_prepare_boot_cpu(void)
cpu_set_state_online(me);
}
-void __init native_smp_cpus_done(unsigned int max_cpus)
+void __init calculate_max_logical_packages(void)
{
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.
@@ -1293,6 +1292,13 @@ void __init native_smp_cpus_done(unsigned int max_cpus)
ncpus = cpu_data(0).booted_cores * topology_max_smt_threads();
__max_logical_packages = DIV_ROUND_UP(nr_cpu_ids, ncpus);
pr_info("Max logical packages: %u\n", __max_logical_packages);
+}
+
+void __init native_smp_cpus_done(unsigned int max_cpus)
+{
+ pr_debug("Boot done\n");
+
+ calculate_max_logical_packages();
if (x86_has_numa_in_package)
set_sched_topology(x86_numa_in_package_topology);
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 77c959cf81e7..7a43b2ae19f1 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -122,6 +122,8 @@ void __init xen_smp_cpus_done(unsigned int max_cpus)
if (xen_hvm_domain())
native_smp_cpus_done(max_cpus);
+ else
+ calculate_max_logical_packages();
if (xen_have_vcpu_info_placement)
return;