[PATCH v7 1/4] arm64, numa: adding numa support for arm64 platforms.
Ganapatrao Kulkarni
gpkulkarni at gmail.com
Tue Dec 1 00:45:20 PST 2015
On Fri, Nov 27, 2015 at 1:30 PM, Shannon Zhao <zhaoshenglong at huawei.com> wrote:
>
>
> On 2015/11/18 1:20, Ganapatrao Kulkarni wrote:
>> Adding numa support for arm64 based platforms.
>> This patch adds by default the dummy numa node and
>> maps all memory and cpus to node 0.
>> using this patch, numa can be simulated on single node arm64 platforms.
>>
>> Reviewed-by: Robert Richter <rrichter at cavium.com>
>> Signed-off-by: Ganapatrao Kulkarni <gkulkarni at caviumnetworks.com>
>
> I've tested this patch on QEMU VM.
>
> Tested-by: Shannon Zhao <shannon.zhao at linaro.org>
thanks a lot!
>> ---
>> arch/arm64/Kconfig | 25 +++
>> arch/arm64/include/asm/mmzone.h | 17 ++
>> arch/arm64/include/asm/numa.h | 47 +++++
>> arch/arm64/kernel/setup.c | 4 +
>> arch/arm64/kernel/smp.c | 2 +
>> arch/arm64/mm/Makefile | 1 +
>> arch/arm64/mm/init.c | 30 +++-
>> arch/arm64/mm/numa.c | 384 ++++++++++++++++++++++++++++++++++++++++
>> 8 files changed, 506 insertions(+), 4 deletions(-)
>> create mode 100644 arch/arm64/include/asm/mmzone.h
>> create mode 100644 arch/arm64/include/asm/numa.h
>> create mode 100644 arch/arm64/mm/numa.c
>>
>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> index 9ac16a4..7d8fb42 100644
>> --- a/arch/arm64/Kconfig
>> +++ b/arch/arm64/Kconfig
>> @@ -71,6 +71,7 @@ config ARM64
>> select HAVE_GENERIC_DMA_COHERENT
>> select HAVE_HW_BREAKPOINT if PERF_EVENTS
>> select HAVE_MEMBLOCK
>> + select HAVE_MEMBLOCK_NODE_MAP if NUMA
>> select HAVE_PATA_PLATFORM
>> select HAVE_PERF_EVENTS
>> select HAVE_PERF_REGS
>> @@ -482,6 +483,30 @@ config HOTPLUG_CPU
>> Say Y here to experiment with turning CPUs off and on. CPUs
>> can be controlled through /sys/devices/system/cpu.
>>
>> +# Common NUMA Features
>> +config NUMA
>> + bool "Numa Memory Allocation and Scheduler Support"
>> + depends on SMP
>> + help
>> + Enable NUMA (Non Uniform Memory Access) support.
>> +
>> + The kernel will try to allocate memory used by a CPU on the
>> + local memory controller of the CPU and add some more
>> + NUMA awareness to the kernel.
>> +
>> +config NODES_SHIFT
>> + int "Maximum NUMA Nodes (as a power of 2)"
>> + range 1 10
>> + default "2"
>> + depends on NEED_MULTIPLE_NODES
>> + help
>> + Specify the maximum number of NUMA Nodes available on the target
>> + system. Increases memory reserved to accommodate various tables.
>> +
>> +config USE_PERCPU_NUMA_NODE_ID
>> + def_bool y
>> + depends on NUMA
>> +
>> source kernel/Kconfig.preempt
>> source kernel/Kconfig.hz
>>
>> diff --git a/arch/arm64/include/asm/mmzone.h b/arch/arm64/include/asm/mmzone.h
>> new file mode 100644
>> index 0000000..6ddd468
>> --- /dev/null
>> +++ b/arch/arm64/include/asm/mmzone.h
>> @@ -0,0 +1,17 @@
>> +#ifndef __ASM_ARM64_MMZONE_H_
>> +#define __ASM_ARM64_MMZONE_H_
>> +
>> +#ifdef CONFIG_NUMA
>> +
>> +#include <linux/mmdebug.h>
>> +#include <linux/types.h>
>> +
>> +#include <asm/smp.h>
>> +#include <asm/numa.h>
>> +
>> +extern struct pglist_data *node_data[];
>> +
>> +#define NODE_DATA(nid) (node_data[(nid)])
>> +
>> +#endif /* CONFIG_NUMA */
>> +#endif /* __ASM_ARM64_MMZONE_H_ */
>> diff --git a/arch/arm64/include/asm/numa.h b/arch/arm64/include/asm/numa.h
>> new file mode 100644
>> index 0000000..c00f3a4
>> --- /dev/null
>> +++ b/arch/arm64/include/asm/numa.h
>> @@ -0,0 +1,47 @@
>> +#ifndef _ASM_NUMA_H
>> +#define _ASM_NUMA_H
>> +
>> +#include <linux/nodemask.h>
>> +#include <asm/topology.h>
>> +
>> +#ifdef CONFIG_NUMA
>> +
>> +#define NR_NODE_MEMBLKS (MAX_NUMNODES * 2)
>> +#define ZONE_ALIGN (1UL << (MAX_ORDER + PAGE_SHIFT))
>> +
>> +/* currently, arm64 implements flat NUMA topology */
>> +#define parent_node(node) (node)
>> +
>> +extern int __node_distance(int from, int to);
>> +#define node_distance(a, b) __node_distance(a, b)
>> +
>> +/* dummy definitions for pci functions */
>> +#define pcibus_to_node(node) 0
>> +#define cpumask_of_pcibus(bus) 0
>> +
>> +extern int cpu_to_node_map[NR_CPUS];
>> +extern nodemask_t numa_nodes_parsed __initdata;
>> +
>> +/* Mappings between node number and cpus on that node. */
>> +extern cpumask_var_t node_to_cpumask_map[MAX_NUMNODES];
>> +extern void numa_clear_node(unsigned int cpu);
>> +#ifdef CONFIG_DEBUG_PER_CPU_MAPS
>> +extern 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_reset_distance(void);
>> +void numa_store_cpu_info(unsigned int cpu);
>> +#else /* CONFIG_NUMA */
>> +static inline void numa_store_cpu_info(unsigned int cpu) { }
>> +static inline void arm64_numa_init(void) { }
>> +#endif /* CONFIG_NUMA */
>> +#endif /* _ASM_NUMA_H */
>> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
>> index 8119479..d9b9761 100644
>> --- a/arch/arm64/kernel/setup.c
>> +++ b/arch/arm64/kernel/setup.c
>> @@ -53,6 +53,7 @@
>> #include <asm/cpufeature.h>
>> #include <asm/cpu_ops.h>
>> #include <asm/kasan.h>
>> +#include <asm/numa.h>
>> #include <asm/sections.h>
>> #include <asm/setup.h>
>> #include <asm/smp_plat.h>
>> @@ -372,6 +373,9 @@ static int __init topology_init(void)
>> {
>> int i;
>>
>> + for_each_online_node(i)
>> + register_one_node(i);
>> +
>> for_each_possible_cpu(i) {
>> struct cpu *cpu = &per_cpu(cpu_data.cpu, i);
>> cpu->hotpluggable = 1;
>> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
>> index b1adc51..d6e7d6a 100644
>> --- a/arch/arm64/kernel/smp.c
>> +++ b/arch/arm64/kernel/smp.c
>> @@ -45,6 +45,7 @@
>> #include <asm/cputype.h>
>> #include <asm/cpu_ops.h>
>> #include <asm/mmu_context.h>
>> +#include <asm/numa.h>
>> #include <asm/pgtable.h>
>> #include <asm/pgalloc.h>
>> #include <asm/processor.h>
>> @@ -125,6 +126,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
>> static void smp_store_cpu_info(unsigned int cpuid)
>> {
>> store_cpu_topology(cpuid);
>> + numa_store_cpu_info(cpuid);
>> }
>>
>> /*
>> diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile
>> index 57f57fd..2e57922 100644
>> --- a/arch/arm64/mm/Makefile
>> +++ b/arch/arm64/mm/Makefile
>> @@ -6,4 +6,5 @@ obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
>> obj-$(CONFIG_ARM64_PTDUMP) += dump.o
>>
>> obj-$(CONFIG_KASAN) += kasan_init.o
>> +obj-$(CONFIG_NUMA) += numa.o
>> KASAN_SANITIZE_kasan_init.o := n
>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
>> index 17bf39a..8dc9c5d 100644
>> --- a/arch/arm64/mm/init.c
>> +++ b/arch/arm64/mm/init.c
>> @@ -37,6 +37,7 @@
>>
>> #include <asm/fixmap.h>
>> #include <asm/memory.h>
>> +#include <asm/numa.h>
>> #include <asm/sections.h>
>> #include <asm/setup.h>
>> #include <asm/sizes.h>
>> @@ -77,6 +78,19 @@ static phys_addr_t max_zone_dma_phys(void)
>> return min(offset + (1ULL << 32), memblock_end_of_DRAM());
>> }
>>
>> +#ifdef CONFIG_NUMA
>> +static void __init zone_sizes_init(unsigned long min, unsigned long max)
>> +{
>> + unsigned long max_zone_pfns[MAX_NR_ZONES] = {0};
>> +
>> + if (IS_ENABLED(CONFIG_ZONE_DMA))
>> + max_zone_pfns[ZONE_DMA] = PFN_DOWN(max_zone_dma_phys());
>> + max_zone_pfns[ZONE_NORMAL] = max;
>> +
>> + free_area_init_nodes(max_zone_pfns);
>> +}
>> +
>> +#else
>> static void __init zone_sizes_init(unsigned long min, unsigned long max)
>> {
>> struct memblock_region *reg;
>> @@ -116,6 +130,7 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
>>
>> free_area_init_node(0, zone_size, min, zhole_size);
>> }
>> +#endif /* CONFIG_NUMA */
>>
>> #ifdef CONFIG_HAVE_ARCH_PFN_VALID
>> int pfn_valid(unsigned long pfn)
>> @@ -133,10 +148,15 @@ static void arm64_memory_present(void)
>> static void arm64_memory_present(void)
>> {
>> struct memblock_region *reg;
>> + int nid = 0;
>>
>> - for_each_memblock(memory, reg)
>> - memory_present(0, memblock_region_memory_base_pfn(reg),
>> - memblock_region_memory_end_pfn(reg));
>> + for_each_memblock(memory, reg) {
>> +#ifdef CONFIG_NUMA
>> + nid = reg->nid;
>> +#endif
>> + memory_present(nid, memblock_region_memory_base_pfn(reg),
>> + memblock_region_memory_end_pfn(reg));
>> + }
>> }
>> #endif
>>
>> @@ -193,6 +213,9 @@ void __init bootmem_init(void)
>>
>> early_memtest(min << PAGE_SHIFT, max << PAGE_SHIFT);
>>
>> + max_pfn = max_low_pfn = max;
>> +
>> + arm64_numa_init();
>> /*
>> * Sparsemem tries to allocate bootmem in memory_present(), so must be
>> * done after the fixed reservations.
>> @@ -203,7 +226,6 @@ void __init bootmem_init(void)
>> zone_sizes_init(min, max);
>>
>> high_memory = __va((max << PAGE_SHIFT) - 1) + 1;
>> - max_pfn = max_low_pfn = max;
>> }
>>
>> #ifndef CONFIG_SPARSEMEM_VMEMMAP
>> diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c
>> new file mode 100644
>> index 0000000..e3afbf8
>> --- /dev/null
>> +++ b/arch/arm64/mm/numa.c
>> @@ -0,0 +1,384 @@
>> +/*
>> + * NUMA support, based on the x86 implementation.
>> + *
>> + * Copyright (C) 2015 Cavium Inc.
>> + * Author: Ganapatrao Kulkarni <gkulkarni at cavium.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#include <linux/bootmem.h>
>> +#include <linux/ctype.h>
>> +#include <linux/init.h>
>> +#include <linux/kernel.h>
>> +#include <linux/mm.h>
>> +#include <linux/memblock.h>
>> +#include <linux/module.h>
>> +#include <linux/mmzone.h>
>> +#include <linux/nodemask.h>
>> +#include <linux/sched.h>
>> +#include <linux/string.h>
>> +#include <linux/topology.h>
>> +
>> +#include <asm/smp_plat.h>
>> +
>> +struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
>> +EXPORT_SYMBOL(node_data);
>> +nodemask_t numa_nodes_parsed __initdata;
>> +int cpu_to_node_map[NR_CPUS] = { [0 ... NR_CPUS-1] = NUMA_NO_NODE };
>> +
>> +static int numa_off;
>> +static int numa_distance_cnt;
>> +static u8 *numa_distance;
>> +
>> +static __init int numa_parse_early_param(char *opt)
>> +{
>> + if (!opt)
>> + return -EINVAL;
>> + if (!strncmp(opt, "off", 3)) {
>> + pr_info("%s\n", "NUMA turned off");
>> + numa_off = 1;
>> + }
>> + return 0;
>> +}
>> +early_param("numa", numa_parse_early_param);
>> +
>> +cpumask_var_t node_to_cpumask_map[MAX_NUMNODES];
>> +EXPORT_SYMBOL(node_to_cpumask_map);
>> +
>> +#ifdef CONFIG_DEBUG_PER_CPU_MAPS
>> +/*
>> + * Returns a pointer to the bitmask of CPUs on Node 'node'.
>> + */
>> +const struct cpumask *cpumask_of_node(int node)
>> +{
>> +
>> + if (WARN_ON(node >= nr_node_ids))
>> + return cpu_none_mask;
>> +
>> + if (WARN_ON(node_to_cpumask_map[node] == NULL))
>> + return cpu_online_mask;
>> +
>> + return node_to_cpumask_map[node];
>> +}
>> +EXPORT_SYMBOL(cpumask_of_node);
>> +#endif
>> +
>> +static void map_cpu_to_node(unsigned int cpu, int nid)
>> +{
>> + set_cpu_numa_node(cpu, nid);
>> + if (nid >= 0)
>> + cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
>> +}
>> +
>> +static void unmap_cpu_to_node(unsigned int cpu)
>> +{
>> + int nid = cpu_to_node(cpu);
>> +
>> + if (nid >= 0)
>> + cpumask_clear_cpu(cpu, node_to_cpumask_map[nid]);
>> + set_cpu_numa_node(cpu, NUMA_NO_NODE);
>> +}
>> +
>> +void numa_clear_node(unsigned int cpu)
>> +{
>> + unmap_cpu_to_node(cpu);
>> +}
>> +
>> +/*
>> + * Allocate node_to_cpumask_map based on number of available nodes
>> + * Requires node_possible_map to be valid.
>> + *
>> + * Note: cpumask_of_node() is not valid until after this is done.
>> + * (Use CONFIG_DEBUG_PER_CPU_MAPS to check this.)
>> + */
>> +static void __init setup_node_to_cpumask_map(void)
>> +{
>> + unsigned int cpu;
>> + int node;
>> +
>> + /* setup nr_node_ids if not done yet */
>> + if (nr_node_ids == MAX_NUMNODES)
>> + setup_nr_node_ids();
>> +
>> + /* allocate and clear the mapping */
>> + for (node = 0; node < nr_node_ids; node++) {
>> + alloc_bootmem_cpumask_var(&node_to_cpumask_map[node]);
>> + cpumask_clear(node_to_cpumask_map[node]);
>> + }
>> +
>> + for_each_possible_cpu(cpu)
>> + set_cpu_numa_node(cpu, NUMA_NO_NODE);
>> +
>> + /* cpumask_of_node() will now work */
>> + pr_debug("Node to cpumask map for %d nodes\n", nr_node_ids);
>> +}
>> +
>> +/*
>> + * Set the cpu to node and mem mapping
>> + */
>> +void numa_store_cpu_info(unsigned int cpu)
>> +{
>> + map_cpu_to_node(cpu, numa_off ? 0 : cpu_to_node_map[cpu]);
>> +}
>> +
>> +/**
>> + * numa_add_memblk - Set node id to memblk
>> + * @nid: NUMA node ID of the new memblk
>> + * @start: Start address of the new memblk
>> + * @size: Size of the new memblk
>> + *
>> + * RETURNS:
>> + * 0 on success, -errno on failure.
>> + */
>> +int __init numa_add_memblk(int nid, u64 start, u64 size)
>> +{
>> + int ret;
>> +
>> + ret = memblock_set_node(start, size, &memblock.memory, nid);
>> + if (ret < 0) {
>> + pr_err("NUMA: memblock [0x%llx - 0x%llx] failed to add on node %d\n",
>> + start, (start + size - 1), nid);
>> + return ret;
>> + }
>> +
>> + node_set(nid, numa_nodes_parsed);
>> + pr_info("NUMA: Adding memblock [0x%llx - 0x%llx] on node %d\n",
>> + start, (start + size - 1), nid);
>> + return ret;
>> +}
>> +EXPORT_SYMBOL(numa_add_memblk);
>> +
>> +/* Initialize NODE_DATA for a node on the local memory */
>> +static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
>> +{
>> + const size_t nd_size = roundup(sizeof(pg_data_t), SMP_CACHE_BYTES);
>> + u64 nd_pa;
>> + void *nd;
>> + int tnid;
>> +
>> + pr_info("Initmem setup node %d [mem %#010Lx-%#010Lx]\n",
>> + nid, start_pfn << PAGE_SHIFT,
>> + (end_pfn << PAGE_SHIFT) - 1);
>> +
>> + nd_pa = memblock_alloc_try_nid(nd_size, SMP_CACHE_BYTES, nid);
>> + nd = __va(nd_pa);
>> +
>> + /* report and initialize */
>> + pr_info(" NODE_DATA [mem %#010Lx-%#010Lx]\n",
>> + nd_pa, nd_pa + nd_size - 1);
>> + tnid = early_pfn_to_nid(nd_pa >> PAGE_SHIFT);
>> + if (tnid != nid)
>> + pr_info(" NODE_DATA(%d) on node %d\n", nid, tnid);
>> +
>> + node_data[nid] = nd;
>> + memset(NODE_DATA(nid), 0, sizeof(pg_data_t));
>> + NODE_DATA(nid)->node_id = nid;
>> + NODE_DATA(nid)->node_start_pfn = start_pfn;
>> + NODE_DATA(nid)->node_spanned_pages = end_pfn - start_pfn;
>> +}
>> +
>> +/**
>> + * numa_reset_distance - Reset NUMA distance table
>> + *
>> + * The current table is freed.
>> + * The next numa_set_distance() call will create a new one.
>> + */
>> +void __init numa_reset_distance(void)
>> +{
>> + size_t size;
>> +
>> + if (!numa_distance)
>> + return;
>> +
>> + size = numa_distance_cnt * numa_distance_cnt *
>> + sizeof(numa_distance[0]);
>> +
>> + memblock_free(__pa(numa_distance), size);
>> + numa_distance_cnt = 0;
>> + numa_distance = NULL;
>> +}
>> +
>> +static int __init numa_alloc_distance(void)
>> +{
>> + size_t size;
>> + u64 phys;
>> + int i, j;
>> +
>> + size = nr_node_ids * nr_node_ids * sizeof(numa_distance[0]);
>> + phys = memblock_find_in_range(0, PFN_PHYS(max_pfn),
>> + size, PAGE_SIZE);
>> + if (WARN_ON(!phys))
>> + return -ENOMEM;
>> +
>> + memblock_reserve(phys, size);
>> +
>> + numa_distance = __va(phys);
>> + numa_distance_cnt = nr_node_ids;
>> +
>> + /* fill with the default distances */
>> + for (i = 0; i < numa_distance_cnt; i++)
>> + for (j = 0; j < numa_distance_cnt; j++)
>> + numa_distance[i * numa_distance_cnt + j] = i == j ?
>> + LOCAL_DISTANCE : REMOTE_DISTANCE;
>> +
>> + pr_debug("NUMA: Initialized distance table, cnt=%d\n",
>> + numa_distance_cnt);
>> +
>> + return 0;
>> +}
>> +
>> +/**
>> + * numa_set_distance - Set NUMA distance from one NUMA to another
>> + * @from: the 'from' node to set distance
>> + * @to: the 'to' node to set distance
>> + * @distance: NUMA distance
>> + *
>> + * Set the distance from node @from to @to to @distance. If distance table
>> + * doesn't exist, one which is large enough to accommodate all the currently
>> + * known nodes will be created.
>> + *
>> + * If such table cannot be allocated, a warning is printed and further
>> + * calls are ignored until the distance table is reset with
>> + * numa_reset_distance().
>> + *
>> + * If @from or @to is higher than the highest known node or lower than zero
>> + * at the time of table creation or @distance doesn't make sense, the call
>> + * is ignored.
>> + * This is to allow simplification of specific NUMA config implementations.
>> + */
>> +void __init numa_set_distance(int from, int to, int distance)
>> +{
>> + if (!numa_distance)
>> + return;
>> +
>> + if (from >= numa_distance_cnt || to >= numa_distance_cnt ||
>> + from < 0 || to < 0) {
>> + pr_warn_once("NUMA: Warning: node ids are out of bound, from=%d to=%d distance=%d\n",
>> + from, to, distance);
>> + return;
>> + }
>> +
>> + if ((u8)distance != distance ||
>> + (from == to && distance != LOCAL_DISTANCE)) {
>> + pr_warn_once("NUMA: Warning: invalid distance parameter, from=%d to=%d distance=%d\n",
>> + from, to, distance);
>> + return;
>> + }
>> +
>> + numa_distance[from * numa_distance_cnt + to] = distance;
>> +}
>> +EXPORT_SYMBOL(numa_set_distance);
>> +
>> +int __node_distance(int from, int to)
>> +{
>> + if (from >= numa_distance_cnt || to >= numa_distance_cnt)
>> + return from == to ? LOCAL_DISTANCE : REMOTE_DISTANCE;
>> + return numa_distance[from * numa_distance_cnt + to];
>> +}
>> +EXPORT_SYMBOL(__node_distance);
>> +
>> +static int __init numa_register_nodes(void)
>> +{
>> + int nid;
>> + struct memblock_region *mblk;
>> +
>> + /* Check that valid nid is set to memblks */
>> + for_each_memblock(memory, mblk)
>> + if (mblk->nid == NUMA_NO_NODE || mblk->nid >= MAX_NUMNODES)
>> + return -EINVAL;
>> +
>> + /* Finally register nodes. */
>> + for_each_node_mask(nid, numa_nodes_parsed) {
>> + unsigned long start_pfn, end_pfn;
>> +
>> + get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
>> + setup_node_data(nid, start_pfn, end_pfn);
>> + node_set_online(nid);
>> + }
>> +
>> + /* Setup online nodes to actual nodes*/
>> + node_possible_map = numa_nodes_parsed;
>> +
>> + /* Dump memblock with node info and return. */
>> + memblock_dump_all();
>> + return 0;
>> +}
>> +
>> +static int __init numa_init(int (*init_func)(void))
>> +{
>> + int ret;
>> +
>> + nodes_clear(numa_nodes_parsed);
>> + nodes_clear(node_possible_map);
>> + nodes_clear(node_online_map);
>> + numa_reset_distance();
>> +
>> + ret = init_func();
>> + if (ret < 0)
>> + return ret;
>> +
>> + if (nodes_empty(numa_nodes_parsed))
>> + return -EINVAL;
>> +
>> + ret = numa_register_nodes();
>> + if (ret < 0)
>> + return ret;
>> +
>> + ret = numa_alloc_distance();
>> + if (ret < 0)
>> + return ret;
>> +
>> + setup_node_to_cpumask_map();
>> +
>> + /* init boot processor */
>> + cpu_to_node_map[0] = 0;
>> + map_cpu_to_node(0, 0);
>> +
>> + return 0;
>> +}
>> +
>> +/**
>> + * dummy_numa_init - Fallback dummy NUMA init
>> + *
>> + * Used if there's no underlying NUMA architecture, NUMA initialization
>> + * fails, or NUMA is disabled on the command line.
>> + *
>> + * Must online at least one node and add memory blocks that cover all
>> + * allowed memory. This function must not fail.
>> + */
>> +static int __init dummy_numa_init(void)
>> +{
>> + struct memblock_region *mblk;
>> +
>> + pr_info("%s\n", "No NUMA configuration found");
>> + pr_info("Faking a node at [mem %#018Lx-%#018Lx]\n",
>> + 0LLU, PFN_PHYS(max_pfn) - 1);
>> + for_each_memblock(memory, mblk)
>> + numa_add_memblk(0, mblk->base, mblk->size);
>> + numa_off = 1;
>> +
>> + return 0;
>> +}
>> +
>> +/**
>> + * arm64_numa_init - Initialize NUMA
>> + *
>> + * Try each configured NUMA initialization method until one succeeds. The
>> + * last fallback is dummy single node config encomapssing whole memory and
>> + * never fails.
>> + */
>> +void __init arm64_numa_init(void)
>> +{
>> + numa_init(dummy_numa_init);
>> +}
>>
>
> --
> Shannon
>
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