On Thu, 25 Jan 2024 22:44:51 PST (-0800), shijie@xxxxxxxxxxxxxxxxxxxxxx wrote:
During the kernel booting, the generic cpu_to_node() is called too early in
arm64, powerpc and riscv when CONFIG_NUMA is enabled.
There are at least four places in the common code where
the generic cpu_to_node() is called before it is initialized:
1.) early_trace_init() in kernel/trace/trace.c
2.) sched_init() in kernel/sched/core.c
3.) init_sched_fair_class() in kernel/sched/fair.c
4.) workqueue_init_early() in kernel/workqueue.c
In order to fix the bug, the patch introduces early_numa_node_init()
which is called after smp_prepare_boot_cpu() in start_kernel.
early_numa_node_init will initialize the "numa_node" as soon as
the early_cpu_to_node() is ready, before the cpu_to_node() is called
at the first time.
Signed-off-by: Huang Shijie <shijie@xxxxxxxxxxxxxxxxxxxxxx>
---
v2 --> v3:
Do not change the cpu_to_node to function pointer.
Introduce early_numa_node_init() which initialize
the numa_node at an early stage.
v2: https://lore.kernel.org/all/20240123045843.75969-1-shijie@xxxxxxxxxxxxxxxxxxxxxx/
v1 --> v2:
In order to fix the x86 compiling error, move the cpu_to_node()
from driver/base/arch_numa.c to driver/base/node.c.
v1: http://lists.infradead.org/pipermail/linux-arm-kernel/2024-January/896160.html
An old different title patch:
http://lists.infradead.org/pipermail/linux-arm-kernel/2024-January/895963.html
---
init/main.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/init/main.c b/init/main.c
index e24b0780fdff..39efe5ed58a0 100644
--- a/init/main.c
+++ b/init/main.c
@@ -870,6 +870,19 @@ static void __init print_unknown_bootoptions(void)
memblock_free(unknown_options, len);
}
+static void __init early_numa_node_init(void)
+{
+#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
+#ifndef cpu_to_node
+ int cpu;
+
+ /* The early_cpu_to_node() should be ready here. */
+ for_each_possible_cpu(cpu)
+ set_cpu_numa_node(cpu, early_cpu_to_node(cpu));
+#endif
+#endif
+}
+
asmlinkage __visible __init __no_sanitize_address __noreturn __no_stack_protector
void start_kernel(void)
{
@@ -900,6 +913,7 @@ void start_kernel(void)
setup_nr_cpu_ids();
setup_per_cpu_areas();
smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
+ early_numa_node_init();
boot_cpu_hotplug_init();
pr_notice("Kernel command line: %s\n", saved_command_line);
Acked-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx> # RISC-V
I don't really understand the init/main.c stuff all that well, I'm
adding Andrew as it looks like he's been merging stuff here.
