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SubjectRe: [RFC/RFT PATCH 1/6] numa: Move numa implementation to common code
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On 08/20/2020 12:48 AM, Atish Patra wrote:
> On Tue, Aug 18, 2020 at 8:19 PM Anshuman Khandual
> <anshuman.khandual@arm.com> wrote:
>>
>>
>>
>> On 08/15/2020 03:17 AM, Atish Patra wrote:
>>> ARM64 numa implementation is generic enough that RISC-V can reuse that
>>> implementation with very minor cosmetic changes. This will help both
>>> ARM64 and RISC-V in terms of maintanace and feature improvement
>>>
>>> Move the numa implementation code to common directory so that both ISAs
>>> can reuse this. This doesn't introduce any function changes for ARM64.
>>>
>>> Signed-off-by: Atish Patra <atish.patra@wdc.com>
>>> ---
>>> arch/arm64/Kconfig | 1 +
>>> arch/arm64/include/asm/numa.h | 45 +---------------
>>> arch/arm64/mm/Makefile | 1 -
>>> drivers/base/Kconfig | 6 +++
>>> drivers/base/Makefile | 1 +
>>> .../mm/numa.c => drivers/base/arch_numa.c | 0
>>> include/asm-generic/numa.h | 51 +++++++++++++++++++
>>> 7 files changed, 60 insertions(+), 45 deletions(-)
>>> rename arch/arm64/mm/numa.c => drivers/base/arch_numa.c (100%)
>>> create mode 100644 include/asm-generic/numa.h
>>>
>>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>>> index 6d232837cbee..955a0cf75b16 100644
>>> --- a/arch/arm64/Kconfig
>>> +++ b/arch/arm64/Kconfig
>>> @@ -960,6 +960,7 @@ config HOTPLUG_CPU
>>> # Common NUMA Features
>>> config NUMA
>>> bool "NUMA Memory Allocation and Scheduler Support"
>>> + select GENERIC_ARCH_NUMA
>>
>> So this introduces a generic NUMA framework selectable with GENERIC_ARCH_NUMA.
>>
>>> select ACPI_NUMA if ACPI
>>> select OF_NUMA
>>> help
>>> diff --git a/arch/arm64/include/asm/numa.h b/arch/arm64/include/asm/numa.h
>>> index 626ad01e83bf..8c8cf4297cc3 100644
>>> --- a/arch/arm64/include/asm/numa.h
>>> +++ b/arch/arm64/include/asm/numa.h
>>> @@ -3,49 +3,6 @@
>>> #define __ASM_NUMA_H
>>>
>>> #include <asm/topology.h>
>>> -
>>> -#ifdef CONFIG_NUMA
>>> -
>>> -#define NR_NODE_MEMBLKS (MAX_NUMNODES * 2)
>>> -
>>> -int __node_distance(int from, int to);
>>> -#define node_distance(a, b) __node_distance(a, b)
>>> -
>>> -extern nodemask_t numa_nodes_parsed __initdata;
>>> -
>>> -extern bool numa_off;
>>> -
>>> -/* Mappings between node number and cpus on that node. */
>>> -extern cpumask_var_t node_to_cpumask_map[MAX_NUMNODES];
>>> -void numa_clear_node(unsigned int cpu);
>>> -
>>> -#ifdef CONFIG_DEBUG_PER_CPU_MAPS
>>> -const struct cpumask *cpumask_of_node(int node);
>>> -#else
>>> -/* Returns a pointer to the cpumask of CPUs on Node 'node'. */
>>> -static inline const struct cpumask *cpumask_of_node(int node)
>>> -{
>>> - return node_to_cpumask_map[node];
>>> -}
>>> -#endif
>>> -
>>> -void __init arm64_numa_init(void);
>>> -int __init numa_add_memblk(int nodeid, u64 start, u64 end);
>>> -void __init numa_set_distance(int from, int to, int distance);
>>> -void __init numa_free_distance(void);
>>> -void __init early_map_cpu_to_node(unsigned int cpu, int nid);
>>> -void numa_store_cpu_info(unsigned int cpu);
>>> -void numa_add_cpu(unsigned int cpu);
>>> -void numa_remove_cpu(unsigned int cpu);
>>> -
>>> -#else /* CONFIG_NUMA */
>>> -
>>> -static inline void numa_store_cpu_info(unsigned int cpu) { }
>>> -static inline void numa_add_cpu(unsigned int cpu) { }
>>> -static inline void numa_remove_cpu(unsigned int cpu) { }
>>> -static inline void arm64_numa_init(void) { }
>>> -static inline void early_map_cpu_to_node(unsigned int cpu, int nid) { }
>>> -
>>> -#endif /* CONFIG_NUMA */
>>> +#include <asm-generic/numa.h>
>>>
>>> #endif /* __ASM_NUMA_H */
>>> diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile
>>> index d91030f0ffee..928c308b044b 100644
>>> --- a/arch/arm64/mm/Makefile
>>> +++ b/arch/arm64/mm/Makefile
>>> @@ -6,7 +6,6 @@ obj-y := dma-mapping.o extable.o fault.o init.o \
>>> obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
>>> obj-$(CONFIG_PTDUMP_CORE) += dump.o
>>> obj-$(CONFIG_PTDUMP_DEBUGFS) += ptdump_debugfs.o
>>> -obj-$(CONFIG_NUMA) += numa.o
>>> obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o
>>> KASAN_SANITIZE_physaddr.o += n
>>>
>>> diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
>>> index 8d7001712062..73c2151de194 100644
>>> --- a/drivers/base/Kconfig
>>> +++ b/drivers/base/Kconfig
>>> @@ -210,4 +210,10 @@ config GENERIC_ARCH_TOPOLOGY
>>> appropriate scaling, sysfs interface for reading capacity values at
>>> runtime.
>>>
>>> +config GENERIC_ARCH_NUMA
>>> + bool
>>> + help
>>> + Enable support for generic numa implementation. Currently, RISC-V
>>> + and ARM64 uses it.
>>> +
>>> endmenu
>>> diff --git a/drivers/base/Makefile b/drivers/base/Makefile
>>> index 157452080f3d..c3d02c644222 100644
>>> --- a/drivers/base/Makefile
>>> +++ b/drivers/base/Makefile
>>> @@ -23,6 +23,7 @@ obj-$(CONFIG_PINCTRL) += pinctrl.o
>>> obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o
>>> obj-$(CONFIG_GENERIC_MSI_IRQ_DOMAIN) += platform-msi.o
>>> obj-$(CONFIG_GENERIC_ARCH_TOPOLOGY) += arch_topology.o
>>> +obj-$(CONFIG_GENERIC_ARCH_NUMA) += arch_numa.o
>>>
>>> obj-y += test/
>>>
>>> diff --git a/arch/arm64/mm/numa.c b/drivers/base/arch_numa.c
>>> similarity index 100%
>>> rename from arch/arm64/mm/numa.c
>>> rename to drivers/base/arch_numa.c
>>
>> drivers/base/ does not seem right place to host generic NUMA code.
>
> I chose drivers/base because the common topology code is also present there.
> drivers/base/arch_topology.c under GENERIC_ARCH_TOPOLOGY
> The idea is to keep all common arch(at least between RISC-V & ARM64)
> related code at one place.
>
>> Probably it should be either mm/ or kernel/. The other question here
>
> I am fine with mm/arch_numa.c as well if that is preferred over driver/base.

GENERIC_ARCH_NUMA being near other shared code such as GENERIC_ARCH_TOPOLOGY
do make sense. That being said, its a small nit and can be figured out later.

>
>> would be if existing arm64 NUMA implementation is sufficient enough
>> for generic NUMA. I would expect any platform selecting this config
>> should get some NUMA enabled, will be that be true with present code ?
>
> It is for RISC-V. Here is the RISC-V support patch (last patch in the series)
>
> http://lists.infradead.org/pipermail/linux-riscv/2020-August/001659.html
>

+ Jonathan Cameron <Jonathan.Cameron@huawei.com>

There is another patch/discussion which is trying to unify ARM64 NUMA init
code with X86 (https://patchwork.kernel.org/patch/11651437/). I am wondering
if all three platforms could use GENERIC_ARCH_NUMA.

>> Otherwise it will be difficult to name it as GENERIC_ARCH_NUMA.
>>
>> _______________________________________________
>> linux-riscv mailing list
>> linux-riscv@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv
>
>
>

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