[RFC PATCH v2 4/4] riscv: Add numa support for riscv64 platform

From: Greentime Hu
Date: Fri Jan 10 2020 - 05:46:49 EST

This implementation is based on arm64 porting. It is tested with
qemu-system-riscv64, SiFive Unleashed board and OmniXtend FPGA platform.

There will be two nodes in /sys/devices/system/node if it is described in
dts and CONFIG_NUMA is enabled. We can use numastat/numactl/numademo to see
its status.

Changes in v2:
- split this patch to more patches to be more readable
- set cpu->hotplugable to 0 since it is not supported yet
- add more explanation for moving unflatten_device_tree() to paging_init()

Signed-off-by: Greentime Hu <greentime.hu@xxxxxxxxxx>
---
arch/riscv/Kconfig | 30 ++-
arch/riscv/include/asm/mmzone.h | 13 ++
arch/riscv/include/asm/numa.h | 46 ++++
arch/riscv/include/asm/pci.h | 10 +
arch/riscv/kernel/setup.c | 25 +++
arch/riscv/kernel/smpboot.c | 8 +
arch/riscv/mm/Makefile | 1 +
arch/riscv/mm/init.c | 2 +
arch/riscv/mm/numa.c | 372 ++++++++++++++++++++++++++++++++
9 files changed, 506 insertions(+), 1 deletion(-)
create mode 100644 arch/riscv/include/asm/mmzone.h
create mode 100644 arch/riscv/include/asm/numa.h
create mode 100644 arch/riscv/mm/numa.c

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index d8efbaa78d67..5531913edab2 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -22,7 +22,6 @@ config RISCV
select CLONE_BACKWARDS
select COMMON_CLK
select GENERIC_CLOCKEVENTS
- select GENERIC_CPU_DEVICES
select GENERIC_IRQ_SHOW
select GENERIC_PCI_IOMAP
select GENERIC_SCHED_CLOCK
@@ -253,6 +252,35 @@ config TUNE_GENERIC
bool "generic"

endchoice
+# Common NUMA Features
+config NUMA
+ bool "Numa Memory Allocation and Scheduler Support"
+ select OF_NUMA
+ select ARCH_SUPPORTS_NUMA_BALANCING
+ depends on SPARSEMEM
+ help
+ Enable NUMA (Non-Uniform Memory Access) support.
+
+ The kernel will try to allocate memory used by a CPU on the
+ local memory 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
+
+config NEED_PER_CPU_EMBED_FIRST_CHUNK
+ def_bool y
+ depends on NUMA

config RISCV_ISA_C
bool "Emit compressed instructions when building Linux"
diff --git a/arch/riscv/include/asm/mmzone.h b/arch/riscv/include/asm/mmzone.h
new file mode 100644
index 000000000000..fa17e01d9ab2
--- /dev/null
+++ b/arch/riscv/include/asm/mmzone.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_MMZONE_H
+#define __ASM_MMZONE_H
+
+#ifdef CONFIG_NUMA
+
+#include <asm/numa.h>
+
+extern struct pglist_data *node_data[];
+#define NODE_DATA(nid) (node_data[(nid)])
+
+#endif /* CONFIG_NUMA */
+#endif /* __ASM_MMZONE_H */
diff --git a/arch/riscv/include/asm/numa.h b/arch/riscv/include/asm/numa.h
new file mode 100644
index 000000000000..10a4513d078b
--- /dev/null
+++ b/arch/riscv/include/asm/numa.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_NUMA_H
+#define __ASM_NUMA_H
+
+#include <asm/topology.h>
+
+#ifdef CONFIG_NUMA
+
+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 riscv_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 riscv_numa_init(void) { }
+static inline void early_map_cpu_to_node(unsigned int cpu, int nid) { }
+
+#endif /* CONFIG_NUMA */
+
+#endif /* __ASM_NUMA_H */
diff --git a/arch/riscv/include/asm/pci.h b/arch/riscv/include/asm/pci.h
index 1c473a1bd986..d6a0e59638c0 100644
--- a/arch/riscv/include/asm/pci.h
+++ b/arch/riscv/include/asm/pci.h
@@ -32,6 +32,16 @@ static inline int pci_proc_domain(struct pci_bus *bus)
/* always show the domain in /proc */
return 1;
}
+
+#ifdef CONFIG_NUMA
+int pcibus_to_node(struct pci_bus *bus);
+#ifndef cpumask_of_pcibus
+#define cpumask_of_pcibus(bus) (pcibus_to_node(bus) == -1 ? \
+ cpu_all_mask : \
+ cpumask_of_node(pcibus_to_node(bus)))
+#endif
+#endif /* CONFIG_NUMA */
+
#endif /* CONFIG_PCI */

#endif /* _ASM_RISCV_PCI_H */
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index bcd85f502fb2..fd44eaf2051d 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -54,6 +54,31 @@ void __init parse_dtb(void)
#endif
}

+static DEFINE_PER_CPU(struct cpu, cpu_devices);
+
+static int __init topology_init(void)
+{
+ int i, ret;
+
+#ifdef CONFIG_NEED_MULTIPLE_NODES
+ for_each_online_node(i)
+ register_one_node(i);
+#endif
+
+ for_each_possible_cpu(i) {
+ struct cpu *cpu = &per_cpu(cpu_devices, i);
+
+ cpu->hotpluggable = 0;
+ ret = register_cpu(cpu, i);
+ if (unlikely(ret))
+ pr_warn("Warning: %s: register_cpu %d failed (%d)\n",
+ __func__, i, ret);
+ }
+
+ return 0;
+}
+subsys_initcall(topology_init);
+
void __init setup_arch(char **cmdline_p)
{
init_mm.start_code = (unsigned long) _stext;
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index ceef7c579aeb..9e911774f4b8 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -27,6 +27,7 @@
#include <asm/clint.h>
#include <asm/irq.h>
#include <asm/mmu_context.h>
+#include <asm/numa.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/sbi.h>
@@ -49,6 +50,8 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
unsigned int this_cpu;

this_cpu = smp_processor_id();
+ numa_store_cpu_info(this_cpu);
+ numa_add_cpu(this_cpu);

/* This covers non-smp usecase mandated by "nosmp" option */
if (max_cpus == 0)
@@ -58,6 +61,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
if (cpuid == smp_processor_id())
continue;
set_cpu_present(cpuid, true);
+ numa_store_cpu_info(cpuid);
}
}

@@ -76,6 +80,7 @@ void __init setup_smp(void)
if (hart == cpuid_to_hartid_map(0)) {
BUG_ON(found_boot_cpu);
found_boot_cpu = 1;
+ early_map_cpu_to_node(0, of_node_to_nid(dn));
continue;
}
if (cpuid >= NR_CPUS) {
@@ -85,6 +90,7 @@ void __init setup_smp(void)
}

cpuid_to_hartid_map(cpuid) = hart;
+ early_map_cpu_to_node(cpuid, of_node_to_nid(dn));
cpuid++;
}

@@ -153,6 +159,8 @@ asmlinkage __visible void __init smp_callin(void)

trap_init();
notify_cpu_starting(this_cpu);
+ numa_store_cpu_info(this_cpu);
+ numa_add_cpu(this_cpu);
update_siblings_masks(this_cpu);
set_cpu_online(this_cpu, true);
/*
diff --git a/arch/riscv/mm/Makefile b/arch/riscv/mm/Makefile
index a1bd95c8047a..bada5c6d1a45 100644
--- a/arch/riscv/mm/Makefile
+++ b/arch/riscv/mm/Makefile
@@ -15,3 +15,4 @@ ifeq ($(CONFIG_MMU),y)
obj-$(CONFIG_SMP) += tlbflush.o
endif
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
+obj-$(CONFIG_NUMA) += numa.o
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index fbe69fe47806..589f3ef505c7 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -18,6 +18,7 @@
#include <asm/sections.h>
#include <asm/pgtable.h>
#include <asm/io.h>
+#include <asm/numa.h>

#include "../kernel/head.h"

@@ -492,6 +493,7 @@ void __init paging_init(void)
{
setup_vm_final();
unflatten_device_tree();
+ riscv_numa_init();
memblocks_present();
sparse_init();
setup_zero_page();
diff --git a/arch/riscv/mm/numa.c b/arch/riscv/mm/numa.c
new file mode 100644
index 000000000000..b679b2831990
--- /dev/null
+++ b/arch/riscv/mm/numa.c
@@ -0,0 +1,372 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * NUMA support, based on the arm64 implementation.
+ *
+ * Copyright (C) 2015 Cavium Inc.
+ * Author: Ganapatrao Kulkarni <gkulkarni@xxxxxxxxxx>
+ * Copyright (C) 2019 SiFive, Inc
+ */
+
+#define pr_fmt(fmt) "NUMA: " fmt
+
+#include <linux/memblock.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/device.h>
+#include <linux/pci.h>
+
+struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
+EXPORT_SYMBOL(node_data);
+nodemask_t numa_nodes_parsed __initdata;
+static int cpu_to_node_map[NR_CPUS] = { [0 ... NR_CPUS-1] = NUMA_NO_NODE };
+
+static u8 *numa_distance;
+static int numa_distance_cnt;
+bool numa_off;
+
+static __init int numa_parse_early_param(char *opt)
+{
+ if (!opt)
+ return -EINVAL;
+ if (str_has_prefix(opt, "off"))
+ numa_off = true;
+
+ 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
+
+int pcibus_to_node(struct pci_bus *bus)
+{
+ return dev_to_node(&bus->dev);
+}
+EXPORT_SYMBOL(pcibus_to_node);
+
+static void numa_update_cpu(unsigned int cpu, bool remove)
+{
+ int nid = cpu_to_node(cpu);
+
+ if (nid == NUMA_NO_NODE)
+ return;
+
+ if (remove)
+ cpumask_clear_cpu(cpu, node_to_cpumask_map[nid]);
+ else
+ cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
+}
+
+void numa_add_cpu(unsigned int cpu)
+{
+ numa_update_cpu(cpu, false);
+}
+
+/*
+ * Set the cpu to node and mem mapping
+ */
+void numa_store_cpu_info(unsigned int cpu)
+{
+ set_cpu_numa_node(cpu, cpu_to_node_map[cpu]);
+}
+
+void __init early_map_cpu_to_node(unsigned int cpu, int nid)
+{
+ /* fallback to node 0 */
+ if (nid < 0 || nid >= MAX_NUMNODES || numa_off)
+ nid = 0;
+
+ cpu_to_node_map[cpu] = nid;
+
+ /*
+ * We should set the numa node of cpu0 as soon as possible, because it
+ * has already been set up online before. cpu_to_node(0) will soon be
+ * called.
+ */
+ if (!cpu)
+ set_cpu_numa_node(cpu, nid);
+}
+
+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("Initialized distance table, cnt=%d\n", numa_distance_cnt);
+
+ return 0;
+}
+
+/**
+ * numa_add_memblk() - Set node id to memblk
+ * @nid: NUMA node ID of the new memblk
+ * @start: Start address of the new memblk
+ * @end: End address of the new memblk
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int __init numa_add_memblk(int nid, u64 start, u64 end)
+{
+ int ret;
+
+ ret = memblock_set_node(start, (end - start), &memblock.memory, nid);
+ if (ret < 0) {
+ pr_err("memblock [0x%llx - 0x%llx] failed to add on node %d\n",
+ start, (end - 1), nid);
+ return ret;
+ }
+
+ node_set(nid, numa_nodes_parsed);
+ return ret;
+}
+
+/*
+ * 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;
+
+ if (start_pfn >= end_pfn)
+ pr_info("Initmem setup node %d [<memory-less node>]\n", nid);
+
+ nd_pa = memblock_phys_alloc_try_nid(nd_size, SMP_CACHE_BYTES, nid);
+ if (!nd_pa)
+ panic("Cannot allocate %zu bytes for node %d data\n",
+ nd_size, 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;
+}
+
+void __init numa_set_distance(int from, int to, int distance)
+{
+ if (!numa_distance) {
+ pr_warn_once("Warning: distance table not allocated yet\n");
+ return;
+ }
+
+ if (from >= numa_distance_cnt || to >= numa_distance_cnt ||
+ from < 0 || to < 0) {
+ pr_warn_once("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("Warning: invalid distance parameter, from=%d to=%d distance=%d\n",
+ from, to, distance);
+ return;
+ }
+
+ numa_distance[from * numa_distance_cnt + to] = distance;
+}
+
+/*
+ * Return NUMA distance @from to @to
+ */
+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) {
+ pr_warn("Warning: invalid memblk node %d [mem %#010Lx-%#010Lx]\n",
+ mblk->nid, mblk->base,
+ mblk->base + mblk->size - 1);
+ 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;
+
+ return 0;
+}
+static void __init setup_node_to_cpumask_map(void)
+{
+ 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]);
+ }
+
+ /* cpumask_of_node() will now work */
+ pr_debug("Node to cpumask map for %u nodes\n", nr_node_ids);
+}
+
+void __init numa_free_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_init(int (*init_func)(void))
+{
+ int ret;
+
+ nodes_clear(numa_nodes_parsed);
+ nodes_clear(node_possible_map);
+ nodes_clear(node_online_map);
+
+ ret = numa_alloc_distance();
+ if (ret < 0)
+ return ret;
+
+ ret = init_func();
+ if (ret < 0)
+ goto out_free_distance;
+
+ if (nodes_empty(numa_nodes_parsed)) {
+ pr_info("No NUMA configuration found\n");
+ ret = -EINVAL;
+ goto out_free_distance;
+ }
+
+ ret = numa_register_nodes();
+ if (ret < 0)
+ goto out_free_distance;
+
+ setup_node_to_cpumask_map();
+
+ return 0;
+out_free_distance:
+ numa_free_distance();
+ return ret;
+}
+
+/**
+ * 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 (node 0) and add memory blocks that cover all
+ * allowed memory. It is unlikely that this function fails.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+static int __init dummy_numa_init(void)
+{
+ int ret;
+ struct memblock_region *mblk;
+
+ if (numa_off)
+ pr_info("NUMA disabled\n"); /* Forced off on command line. */
+ pr_info("Faking a node at [mem %#018Lx-%#018Lx]\n",
+ memblock_start_of_DRAM(), memblock_end_of_DRAM() - 1);
+
+ for_each_memblock(memory, mblk) {
+ ret = numa_add_memblk(0, mblk->base, mblk->base + mblk->size);
+ if (!ret)
+ continue;
+
+ pr_err("NUMA init failed\n");
+ return ret;
+ }
+
+ numa_off = true;
+ return 0;
+}
+
+/**
+ * riscv_numa_init() - Initialize NUMA
+ *
+ * Try each configured NUMA initialization method until one succeeds. The
+ * last fallback is dummy single node config encomapssing whole memory.
+ */
+void __init riscv_numa_init(void)
+{
+ if (!numa_off) {
+ if (!numa_init(of_numa_init))
+ return;
+ }
+
+ numa_init(dummy_numa_init);
+}
--
2.17.1