Re: [PATCH v7 1/4] arm64, numa: adding numa support for arm64 platforms.

[Ganapatrao Kulkarni <gpkulkarni-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Fri, Nov 27, 2015 at 1:30 PM, Shannon Zhao <zhaoshenglong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> 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-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org>
>> Signed-off-by: Ganapatrao Kulkarni <gkulkarni-M3mlKVOIwJVv6pq1l3V1OdBPR1lH4CV8@public.gmane.org>
>
> I've tested this patch on QEMU VM.
>
> Tested-by: Shannon Zhao <shannon.zhao-QSEj5FYQhm4dnm+yROfE0A@public.gmane.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-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org>
>> + *
>> + * 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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