NUMA: early use of cpu_to_node() returns 0 instead of the correct node id

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

This will harm performance since there is an increase in off node
accesses.

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.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Huang Shijie <[email protected]>
Acked-by: Palmer Dabbelt <[email protected]>	[RISC-V]
Cc: Albert Ou <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Jiaxun Yang <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Michael Kelley (LINUX) <[email protected]>
Cc: "Mike Rapoport (IBM)" <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Valentin Schneider <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yury Norov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions