On Tue, 31 May 2022, Helge Deller wrote:
> Hello Mikulas,
>
> On 5/31/22 12:43, Mikulas Patocka wrote:
> > The kernel 5.18 doesn't boot on my C8000 with two dual-core CPUs. It hangs
> > at this point:
> >
> > [ 0.000000] NR_IRQS: 80
> > [ 0.000002] sched_clock: 64 bits at 1000MHz, resolution 1ns, wraps every 4398046511103ns
> > [ 0.107049] Console: colour dummy device 160x64
> > [ 0.166791] Calibrating delay loop... 1991.60 BogoMIPS (lpj=3317760)
> > [ 0.270079] pid_max: default: 32768 minimum: 301
> > [ 0.330158] random: get_random_bytes called from net_ns_init+0x118/0x4c8 with crng_init=0
> > [ 0.330394] Mount-cache hash table entries: 16384 (order: 5, 131072 bytes, linear)
> > [ 0.536892] Mountpoint-cache hash table entries: 16384 (order: 5, 131072 bytes, linear)
> > [ 0.644729] cblist_init_generic: Setting adjustable number of callback queues.
> > [ 0.740083] cblist_init_generic: Setting shift to 2 and lim to 1.
> > [ 0.820179] TOC handler registered
> > [ 0.866852] rcu: Hierarchical SRCU implementation.
> > [ 0.930550] smp: Bringing up secondary CPUs ...
> > [ 0.990084] smp: Brought up 1 node, 1 CPU
> >
> > I bisected it and it is caused by the commit
> > 62773112acc55d29727465d075fc61ed08a0a532 ("parisc: Switch from
> > GENERIC_CPU_DEVICES to GENERIC_ARCH_TOPOLOGY")
> >
> > When I revert this patch on the kernel 5.18 (and resolve several
> > conflcits), the kernel boots.
>
> You are really sure that you test v5.18-final, right?
Yes.
> If not there were multiple hickups during the -rc phases of v5.18, and
> bisecting through the -rc versions won't help much because we had multiple
> issues which conflicted with each other and prevented a boot.
I hit some crashes when running userspace when bisecting, but I bisected
them as "good" and I only bisected the hang at "smp: Brought up 1 node, 1
CPU" as "bad". And bisect showed the faulty commit - reverting that commit
makes the kernel bool.
> But those should have been resolved with my "for-5.18/parisc-3" push, which e.g.
> partly re-enabled GENERIC_CPU_DEVICES:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f002488d80b557c7dc540457b176011449895fcb
> Esp. this commit ("Re-enable GENERIC_CPU_DEVICES for !SMP") fixed it for non-SMP:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1955c4f879a130c7822f483cf593338ad747aed4
These commits are already present in 5.18. They don't fix the hang.
> So, right now I'm somehow lost how I can help.
If you don't know what causes it, I can try to add some debug printks into
the kernel and analyze it when I have time.
> You could you send me your .config, then I'll check locally.
> Please also try a "make oldconfig" with your .config so that the options don't have any leftovers.
I uploaded my config here:
https://people.redhat.com/~mpatocka/testcases/parisc-config-5.18.txt
> Helge
This is quick-and-dirty revert of the patch
62773112acc55d29727465d075fc61ed08a0a532. When it is applied on 5.18, the
kernel boots fine. I don't intend to try to push this into the kernel, but
it may help with debugging the problem.
Mikulas
---
arch/parisc/Kconfig | 11 ++++-
arch/parisc/include/asm/topology.h | 23 ++++++++++-
arch/parisc/kernel/Makefile | 2 -
arch/parisc/kernel/processor.c | 5 --
arch/parisc/kernel/smp.c | 2 -
arch/parisc/kernel/topology.c | 72 +++++++++++++++++++++++++++++--------
6 files changed, 89 insertions(+), 26 deletions(-)
Index: linux-5.18.1/arch/parisc/Kconfig
===================================================================
--- linux-5.18.1.orig/arch/parisc/Kconfig 2022-05-31 12:12:11.000000000 +0200
+++ linux-5.18.1/arch/parisc/Kconfig 2022-05-31 12:12:11.000000000 +0200
@@ -37,7 +37,7 @@ config PARISC
select GENERIC_PCI_IOMAP
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select GENERIC_SMP_IDLE_THREAD
- select GENERIC_ARCH_TOPOLOGY if SMP
+ select GENERIC_CPU_DEVICES
select GENERIC_CPU_DEVICES if !SMP
select GENERIC_LIB_DEVMEM_IS_ALLOWED
select SYSCTL_ARCH_UNALIGN_ALLOW
@@ -281,9 +281,16 @@ config SMP
If you don't know what to do here, say N.
+config PARISC_CPU_TOPOLOGY
+ bool "Support cpu topology definition"
+ depends on SMP
+ default y
+ help
+ Support PARISC cpu topology definition.
+
config SCHED_MC
bool "Multi-core scheduler support"
- depends on GENERIC_ARCH_TOPOLOGY && PA8X00
+ depends on PARISC_CPU_TOPOLOGY && PA8X00
help
Multi-core scheduler support improves the CPU scheduler's decision
making when dealing with multi-core CPU chips at a cost of slightly
Index: linux-5.18.1/arch/parisc/include/asm/topology.h
===================================================================
--- linux-5.18.1.orig/arch/parisc/include/asm/topology.h 2022-05-31 12:12:11.000000000 +0200
+++ linux-5.18.1/arch/parisc/include/asm/topology.h 2022-05-31 12:12:11.000000000 +0200
@@ -1,16 +1,33 @@
#ifndef _ASM_PARISC_TOPOLOGY_H
#define _ASM_PARISC_TOPOLOGY_H
-#ifdef CONFIG_GENERIC_ARCH_TOPOLOGY
+#ifdef CONFIG_PARISC_CPU_TOPOLOGY
#include <linux/cpumask.h>
-#include <linux/arch_topology.h>
+
+struct cputopo_parisc {
+ int thread_id;
+ int core_id;
+ int socket_id;
+ cpumask_t thread_sibling;
+ cpumask_t core_sibling;
+};
+
+extern struct cputopo_parisc cpu_topology[NR_CPUS];
+
+#define topology_physical_package_id(cpu) (cpu_topology[cpu].socket_id)
+#define topology_core_id(cpu) (cpu_topology[cpu].core_id)
+#define topology_core_cpumask(cpu) (&cpu_topology[cpu].core_sibling)
+#define topology_sibling_cpumask(cpu) (&cpu_topology[cpu].thread_sibling)
+
+void init_cpu_topology(void);
+void store_cpu_topology(unsigned int cpuid);
+const struct cpumask *cpu_coregroup_mask(int cpu);
#else
static inline void init_cpu_topology(void) { }
static inline void store_cpu_topology(unsigned int cpuid) { }
-static inline void reset_cpu_topology(void) { }
#endif
Index: linux-5.18.1/arch/parisc/kernel/Makefile
===================================================================
--- linux-5.18.1.orig/arch/parisc/kernel/Makefile 2022-05-31 12:12:11.000000000 +0200
+++ linux-5.18.1/arch/parisc/kernel/Makefile 2022-05-31 12:12:11.000000000 +0200
@@ -31,7 +31,7 @@ obj-$(CONFIG_AUDIT) += audit.o
obj64-$(CONFIG_AUDIT) += compat_audit.o
# only supported for PCX-W/U in 64-bit mode at the moment
obj-$(CONFIG_64BIT) += perf.o perf_asm.o $(obj64-y)
-obj-$(CONFIG_GENERIC_ARCH_TOPOLOGY) += topology.o
+obj-$(CONFIG_PARISC_CPU_TOPOLOGY) += topology.o
obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
Index: linux-5.18.1/arch/parisc/kernel/processor.c
===================================================================
--- linux-5.18.1.orig/arch/parisc/kernel/processor.c 2022-05-31 12:12:11.000000000 +0200
+++ linux-5.18.1/arch/parisc/kernel/processor.c 2022-05-31 12:12:11.000000000 +0200
@@ -19,7 +19,6 @@
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/cpu.h>
-#include <asm/topology.h>
#include <asm/param.h>
#include <asm/cache.h>
#include <asm/hardware.h> /* for register_parisc_driver() stuff */
@@ -392,7 +391,7 @@ show_cpuinfo (struct seq_file *m, void *
boot_cpu_data.cpu_hz / 1000000,
boot_cpu_data.cpu_hz % 1000000 );
-#ifdef CONFIG_GENERIC_ARCH_TOPOLOGY
+#ifdef CONFIG_PARISC_CPU_TOPOLOGY
seq_printf(m, "physical id\t: %d\n",
topology_physical_package_id(cpu));
seq_printf(m, "siblings\t: %d\n",
@@ -463,8 +462,6 @@ void __init processor_init(void)
{
unsigned int cpu;
- reset_cpu_topology();
-
/* reset possible mask. We will mark those which are possible. */
for_each_possible_cpu(cpu)
set_cpu_possible(cpu, false);
Index: linux-5.18.1/arch/parisc/kernel/topology.c
===================================================================
--- linux-5.18.1.orig/arch/parisc/kernel/topology.c 2022-05-31 12:12:11.000000000 +0200
+++ linux-5.18.1/arch/parisc/kernel/topology.c 2022-05-31 12:12:11.000000000 +0200
@@ -13,12 +13,46 @@
#include <linux/percpu.h>
#include <linux/sched.h>
#include <linux/sched/topology.h>
-#include <linux/cpu.h>
#include <asm/topology.h>
#include <asm/sections.h>
-static DEFINE_PER_CPU(struct cpu, cpu_devices);
+ /*
+ * cpu topology table
+ */
+struct cputopo_parisc cpu_topology[NR_CPUS] __read_mostly;
+EXPORT_SYMBOL_GPL(cpu_topology);
+
+const struct cpumask *cpu_coregroup_mask(int cpu)
+{
+ return &cpu_topology[cpu].core_sibling;
+}
+
+static void update_siblings_masks(unsigned int cpuid)
+{
+ struct cputopo_parisc *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
+ int cpu;
+
+ /* update core and thread sibling masks */
+ for_each_possible_cpu(cpu) {
+ cpu_topo = &cpu_topology[cpu];
+
+ if (cpuid_topo->socket_id != cpu_topo->socket_id)
+ continue;
+
+ cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
+ if (cpu != cpuid)
+ cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);
+
+ if (cpuid_topo->core_id != cpu_topo->core_id)
+ continue;
+
+ cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
+ if (cpu != cpuid)
+ cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
+ }
+ smp_wmb();
+}
static int dualcores_found;
@@ -29,7 +63,7 @@ static int dualcores_found;
*/
void store_cpu_topology(unsigned int cpuid)
{
- struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
+ struct cputopo_parisc *cpuid_topo = &cpu_topology[cpuid];
struct cpuinfo_parisc *p;
int max_socket = -1;
unsigned long cpu;
@@ -38,12 +72,6 @@ void store_cpu_topology(unsigned int cpu
if (cpuid_topo->core_id != -1)
return;
-#ifdef CONFIG_HOTPLUG_CPU
- per_cpu(cpu_devices, cpuid).hotpluggable = 1;
-#endif
- if (register_cpu(&per_cpu(cpu_devices, cpuid), cpuid))
- pr_warn("Failed to register CPU%d device", cpuid);
-
/* create cpu topology mapping */
cpuid_topo->thread_id = -1;
cpuid_topo->core_id = 0;
@@ -59,25 +87,25 @@ void store_cpu_topology(unsigned int cpu
cpuid_topo->core_id = cpu_topology[cpu].core_id;
if (p->cpu_loc) {
cpuid_topo->core_id++;
- cpuid_topo->package_id = cpu_topology[cpu].package_id;
+ cpuid_topo->socket_id = cpu_topology[cpu].socket_id;
dualcores_found = 1;
continue;
}
}
- if (cpuid_topo->package_id == -1)
- max_socket = max(max_socket, cpu_topology[cpu].package_id);
+ if (cpuid_topo->socket_id == -1)
+ max_socket = max(max_socket, cpu_topology[cpu].socket_id);
}
- if (cpuid_topo->package_id == -1)
- cpuid_topo->package_id = max_socket + 1;
+ if (cpuid_topo->socket_id == -1)
+ cpuid_topo->socket_id = max_socket + 1;
update_siblings_masks(cpuid);
pr_info("CPU%u: cpu core %d of socket %d\n",
cpuid,
cpu_topology[cpuid].core_id,
- cpu_topology[cpuid].package_id);
+ cpu_topology[cpuid].socket_id);
}
static struct sched_domain_topology_level parisc_mc_topology[] = {
@@ -95,6 +123,20 @@ static struct sched_domain_topology_leve
*/
void __init init_cpu_topology(void)
{
+ unsigned int cpu;
+
+ /* init core mask and capacity */
+ for_each_possible_cpu(cpu) {
+ struct cputopo_parisc *cpu_topo = &(cpu_topology[cpu]);
+
+ cpu_topo->thread_id = -1;
+ cpu_topo->core_id = -1;
+ cpu_topo->socket_id = -1;
+ cpumask_clear(&cpu_topo->core_sibling);
+ cpumask_clear(&cpu_topo->thread_sibling);
+ }
+ smp_wmb();
+
/* Set scheduler topology descriptor */
if (dualcores_found)
set_sched_topology(parisc_mc_topology);
Index: linux-5.18.1/arch/parisc/kernel/smp.c
===================================================================
--- linux-5.18.1.orig/arch/parisc/kernel/smp.c 2022-05-31 12:12:11.000000000 +0200
+++ linux-5.18.1/arch/parisc/kernel/smp.c 2022-05-31 12:12:11.000000000 +0200
@@ -457,7 +457,7 @@ int __cpu_disable(void)
#ifdef CONFIG_HOTPLUG_CPU
unsigned int cpu = smp_processor_id();
- remove_cpu_topology(cpu);
+ /*remove_cpu_topology(cpu);*/
/*
* Take this CPU offline. Once we clear this, we can't return,
