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From: Huang Shijie <shijie@os.amperecomputing.com>
To: gregkh@linuxfoundation.org
Cc: patches@amperecomputing.com, rafael@kernel.org,
	paul.walmsley@sifive.com, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, yury.norov@gmail.com, kuba@kernel.org,
	vschneid@redhat.com, mingo@kernel.org, akpm@linux-foundation.org,
	vbabka@suse.cz, rppt@kernel.org, tglx@linutronix.de,
	jpoimboe@kernel.org, ndesaulniers@google.com,
	mikelley@microsoft.com, mhiramat@kernel.org, arnd@arndb.de,
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com,
	will@kernel.org, mark.rutland@arm.com, mpe@ellerman.id.au,
	linuxppc-dev@lists.ozlabs.org, chenhuacai@kernel.org,
	jiaxun.yang@flygoat.com, linux-mips@vger.kernel.org,
	cl@os.amperecomputing.com,
	Huang Shijie <shijie@os.amperecomputing.com>
Subject: [PATCH v3] NUMA: Early use of cpu_to_node() returns 0 instead of the correct node id
Date: Fri, 26 Jan 2024 14:44:51 +0800	[thread overview]
Message-ID: <20240126064451.5465-1-shijie@os.amperecomputing.com> (raw)

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@os.amperecomputing.com>
---
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@os.amperecomputing.com/
	
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);
-- 
2.40.1


             reply	other threads:[~2024-01-26  6:45 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-26  6:44 Huang Shijie [this message]
2024-03-27 14:36 ` [PATCH v3] NUMA: Early use of cpu_to_node() returns 0 instead of the correct node id Palmer Dabbelt
2024-03-27 18:17 ` Andrew Morton
2024-03-28  2:09   ` Shijie Huang
2024-04-08 17:06   ` Lameter, Christopher

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