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Message-ID: <CAAhV-H4anpgfiAnPgm9h-m9pKCW0KUio+E72r1Q3F_0vm+zMRg@mail.gmail.com>
Date: Mon, 21 Oct 2024 22:32:06 +0800
From: Huacai Chen <chenhuacai@...nel.org>
To: Bibo Mao <maobibo@...ngson.cn>
Cc: Jianmin Lv <lvjianmin@...ngson.cn>, loongarch@...ts.linux.dev,
linux-kernel@...r.kernel.org, lixianglai@...ngson.cn,
WANG Xuerui <kernel@...0n.name>
Subject: Re: [PATCH v2] LoongArch: Fix cpu hotplug issue
Hi, Bibo,
This version still doesn't touch the round-robin method, but it
doesn't matter, I think I misunderstood something since V1...
Please correct me if I'm wrong: For cpus without ACPI_MADT_ENABLED, in
smp_prepare_boot_cpu() the round-robin node ids only apply to
cpu_to_node(), but __cpuid_to_node[] still record the right node ids.
early_cpu_to_node() returns NUMA_NO_NODE not because
__cpuid_to_node[] records NUMA_NO_NODE, but because cpu_logical_map()
< 0.
If the above is correct, we don't need so complicated, because the
correct and simplest way is:
https://lore.kernel.org/loongarch/6b2b3e89-5a46-2d20-3dfb-7aae33839f49@loongson.cn/T/#m950eead5250e5992cc703bbe69622348cecfa465
Huacai
On Mon, Oct 21, 2024 at 4:04 PM Bibo Mao <maobibo@...ngson.cn> wrote:
>
> On LoongArch system, there are two places to set cpu numa node. One
> is in arch specified function smp_prepare_boot_cpu(), the other is
> in generic function early_numa_node_init(). The latter will overwrite
> the numa node information.
>
> With hot-added cpu without numa information, cpu_logical_map() fails
> to its physical cpuid at beginning since it is not enabled in ACPI
> MADT table. So function early_cpu_to_node() also fails to get its
> numa node for hot-added cpu, and generic function
> early_numa_node_init() will overwrite with incorrect numa node.
>
> APIs topo_get_cpu() and topo_add_cpu() is added here, like other
> architectures logic cpu is allocated when parsing MADT table. When
> parsing SRAT table or hot-add cpu, logic cpu is acquired by searching
> all allocated logical cpu with matched physical id. It solves such
> problems such as:
> 1. Boot cpu is not the first entry in MADT table, the first entry
> will be overwritten with later boot cpu.
> 2. Physical cpu id not presented in MADT table is invalid, in later
> SRAT/hot-add cpu parsing, invalid physical cpu detected is added
> 3. For hot-add cpu, its logic cpu is allocated in MADT table parsing,
> so early_cpu_to_node() can be used for hot-add cpu and cpu_to_node()
> is correct for hot-add cpu.
>
> Signed-off-by: Bibo Mao <maobibo@...ngson.cn>
> ---
> v1 ... v2:
> 1. Like other architectures, allocate logic cpu when parsing MADT table.
> 2. Add invalid or duplicated physical cpuid parsing with SRAT table or
> hot-add cpu DSDT information.
> ---
> arch/loongarch/include/asm/smp.h | 3 ++
> arch/loongarch/kernel/acpi.c | 24 ++++++++++------
> arch/loongarch/kernel/setup.c | 47 ++++++++++++++++++++++++++++++++
> arch/loongarch/kernel/smp.c | 9 +++---
> 4 files changed, 70 insertions(+), 13 deletions(-)
>
> diff --git a/arch/loongarch/include/asm/smp.h b/arch/loongarch/include/asm/smp.h
> index 3383c9d24e94..c61b75937a77 100644
> --- a/arch/loongarch/include/asm/smp.h
> +++ b/arch/loongarch/include/asm/smp.h
> @@ -119,4 +119,7 @@ static inline void __cpu_die(unsigned int cpu)
> #define cpu_logical_map(cpu) 0
> #endif /* CONFIG_SMP */
>
> +int topo_add_cpu(int physid);
> +int topo_get_cpu(int physid);
> +
> #endif /* __ASM_SMP_H */
> diff --git a/arch/loongarch/kernel/acpi.c b/arch/loongarch/kernel/acpi.c
> index f1a74b80f22c..84d9812d5f38 100644
> --- a/arch/loongarch/kernel/acpi.c
> +++ b/arch/loongarch/kernel/acpi.c
> @@ -78,10 +78,10 @@ static int set_processor_mask(u32 id, u32 flags)
> return -ENODEV;
>
> }
> - if (cpuid == loongson_sysconf.boot_cpu_id)
> - cpu = 0;
> - else
> - cpu = find_first_zero_bit(cpumask_bits(cpu_present_mask), NR_CPUS);
> +
> + cpu = topo_add_cpu(cpuid);
> + if (cpu < 0)
> + return -EEXIST;
>
> if (!cpu_enumerated)
> set_cpu_possible(cpu, true);
> @@ -203,8 +203,6 @@ void __init acpi_boot_table_init(void)
> goto fdt_earlycon;
> }
>
> - loongson_sysconf.boot_cpu_id = read_csr_cpuid();
> -
> /*
> * Process the Multiple APIC Description Table (MADT), if present
> */
> @@ -257,7 +255,7 @@ void __init numa_set_distance(int from, int to, int distance)
> void __init
> acpi_numa_processor_affinity_init(struct acpi_srat_cpu_affinity *pa)
> {
> - int pxm, node;
> + int pxm, node, cpu;
>
> if (srat_disabled())
> return;
> @@ -286,6 +284,11 @@ acpi_numa_processor_affinity_init(struct acpi_srat_cpu_affinity *pa)
> return;
> }
>
> + cpu = topo_get_cpu(pa->apic_id);
> + /* Check whether apic_id exists in MADT table */
> + if (cpu < 0)
> + return;
> +
> early_numa_add_cpu(pa->apic_id, node);
>
> set_cpuid_to_node(pa->apic_id, node);
> @@ -324,12 +327,17 @@ int acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, u32 acpi_id, int *pcpu
> {
> int cpu;
>
> - cpu = set_processor_mask(physid, ACPI_MADT_ENABLED);
> + cpu = topo_get_cpu(physid);
> + /* Check whether apic_id exists in MADT table */
> if (cpu < 0) {
> pr_info(PREFIX "Unable to map lapic to logical cpu number\n");
> return cpu;
> }
>
> + num_processors++;
> + set_cpu_present(cpu, true);
> + __cpu_number_map[physid] = cpu;
> + __cpu_logical_map[cpu] = physid;
> acpi_map_cpu2node(handle, cpu, physid);
>
> *pcpu = cpu;
> diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
> index 00e307203ddb..649e98640076 100644
> --- a/arch/loongarch/kernel/setup.c
> +++ b/arch/loongarch/kernel/setup.c
> @@ -65,6 +65,8 @@ EXPORT_SYMBOL(cpu_data);
>
> struct loongson_board_info b_info;
> static const char dmi_empty_string[] = " ";
> +static int possible_cpus;
> +static bool bsp_added;
>
> /*
> * Setup information
> @@ -346,10 +348,55 @@ static void __init bootcmdline_init(char **cmdline_p)
> *cmdline_p = boot_command_line;
> }
>
> +int topo_get_cpu(int physid)
> +{
> + int i;
> +
> + for (i = 0; i < possible_cpus; i++)
> + if (cpu_logical_map(i) == physid)
> + break;
> +
> + if (i == possible_cpus)
> + return -ENOENT;
> +
> + return i;
> +}
> +
> +int topo_add_cpu(int physid)
> +{
> + int cpu;
> +
> + if (!bsp_added && (physid == loongson_sysconf.boot_cpu_id)) {
> + bsp_added = true;
> + return 0;
> + }
> +
> + cpu = topo_get_cpu(physid);
> + if (cpu >= 0) {
> + pr_warn("Adding duplicated physical cpuid 0x%x\n", physid);
> + return -EEXIST;
> + }
> +
> + if (possible_cpus >= nr_cpu_ids)
> + return -ERANGE;
> +
> + __cpu_logical_map[possible_cpus] = physid;
> + cpu = possible_cpus++;
> + return cpu;
> +}
> +
> +static void __init topo_init(void)
> +{
> + loongson_sysconf.boot_cpu_id = read_csr_cpuid();
> + __cpu_logical_map[0] = loongson_sysconf.boot_cpu_id;
> + possible_cpus++;
> +}
> +
> void __init platform_init(void)
> {
> arch_reserve_vmcore();
> arch_reserve_crashkernel();
> + topo_init();
>
> #ifdef CONFIG_ACPI
> acpi_table_upgrade();
> diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c
> index 9afc2d8b3414..a3f466b89179 100644
> --- a/arch/loongarch/kernel/smp.c
> +++ b/arch/loongarch/kernel/smp.c
> @@ -291,10 +291,9 @@ static void __init fdt_smp_setup(void)
> if (cpuid >= nr_cpu_ids)
> continue;
>
> - if (cpuid == loongson_sysconf.boot_cpu_id)
> - cpu = 0;
> - else
> - cpu = find_first_zero_bit(cpumask_bits(cpu_present_mask), NR_CPUS);
> + cpu = topo_add_cpu(cpuid);
> + if (cpu < 0)
> + continue;
>
> num_processors++;
> set_cpu_possible(cpu, true);
> @@ -302,7 +301,7 @@ static void __init fdt_smp_setup(void)
> __cpu_number_map[cpuid] = cpu;
> __cpu_logical_map[cpu] = cpuid;
>
> - early_numa_add_cpu(cpu, 0);
> + early_numa_add_cpu(cpuid, 0);
> set_cpuid_to_node(cpuid, 0);
> }
>
>
> base-commit: 42f7652d3eb527d03665b09edac47f85fb600924
> --
> 2.39.3
>
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