Messages in this thread | | | Date | Wed, 24 Jan 2024 09:19:00 -0800 (PST) | From | "Lameter, Christopher" <> | Subject | Re: [PATCH v2] NUMA: Early use of cpu_to_node() returns 0 instead of the correct node id |
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On Tue, 23 Jan 2024, Huang Shijie wrote:
> During the kernel booting, the generic cpu_to_node() is called too early in > arm64, powerpc and riscv when CONFIG_NUMA is enabled. > > For arm64/powerpc/riscv, 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 changes generic cpu_to_node to > function pointer, and export it for kernel modules. > Introduce smp_prepare_boot_cpu_start() to wrap the original > smp_prepare_boot_cpu(), and set cpu_to_node with early_cpu_to_node. > Introduce smp_prepare_cpus_done() to wrap the original smp_prepare_cpus(), > and set the cpu_to_node to formal _cpu_to_node().
Would you please fix this cleanly without a function pointer?
What I think needs to be done is a patch series.
1. Instrument cpu_to_node so that some warning is issued if it is used too early. Preloading the array with NUMA_NO_NODE would allow us to do that.
2. Implement early_cpu_to_node on platforms that currently do not have it.
3. A series of patches that fix each place where cpu_to_node is used too early.
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