From: Xiongfeng Wang <wangxiongfeng2@huawei.com>
To: Jia He <jiakernel2@gmail.com>, <rjw@rjwysocki.net>,
<catalin.marinas@arm.com>, <james.morse@arm.com>
Cc: xiexiuqi@huawei.com, jonathan.cameron@huawei.com,
john.garry@huawei.com, linux-kernel@vger.kernel.org,
linux-acpi@vger.kernel.org, huawei.libin@huawei.com,
guohanjun@huawei.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH v2 2/3] arm64: mark all the GICC nodes in MADT as possible cpu
Date: Thu, 4 Jul 2019 16:18:46 +0800 [thread overview]
Message-ID: <e3bcc250-240e-e2b0-c0d4-d882cf43d255@huawei.com> (raw)
In-Reply-To: <762be90e-7629-ab5e-4c2d-6566b100f2e5@gmail.com>
On 2019/7/4 14:46, Jia He wrote:
>
> On 2019/6/29 10:42, Xiongfeng Wang wrote:
>> We set 'cpu_possible_mask' based on the enabled GICC node in MADT. If
>> the GICC node is disabled, we will skip initializing the kernel data
>> structure for that CPU.
>>
>> To support CPU hotplug, we need to initialize some CPU related data
>> structure in advance. This patch mark all the GICC nodes as possible CPU
>> and only these enabled GICC nodes as present CPU.
>>
>> Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
>> ---
>> arch/arm64/kernel/setup.c | 2 +-
>> arch/arm64/kernel/smp.c | 11 +++++------
>> 2 files changed, 6 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
>> index 7e541f9..7f4d12a 100644
>> --- a/arch/arm64/kernel/setup.c
>> +++ b/arch/arm64/kernel/setup.c
>> @@ -359,7 +359,7 @@ static int __init topology_init(void)
>> for_each_online_node(i)
>> register_one_node(i);
>> - for_each_possible_cpu(i) {
>> + for_each_online_cpu(i) {
>
> Have you considered the case in non-acpi mode? and setting "maxcpus=n" in host kernel boot
>
> parameters?
Thanks for your mention. I haven't considered non-acpi mode. I should add ACPI check in
'smp_prepare_cpus()'.
'maxcpus' is check when we actually online the CPU, so I think it is not influenced.
Thanks,
Xiongfeng
>
> ---
> Cheers,
> Justin (Jia He)
>
>
>> struct cpu *cpu = &per_cpu(cpu_data.cpu, i);
>> cpu->hotpluggable = 1;
>> register_cpu(cpu, i);
>> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
>> index 6dcf960..6d9983c 100644
>> --- a/arch/arm64/kernel/smp.c
>> +++ b/arch/arm64/kernel/smp.c
>> @@ -525,16 +525,14 @@ struct acpi_madt_generic_interrupt *acpi_cpu_get_madt_gicc(int cpu)
>> {
>> u64 hwid = processor->arm_mpidr;
>> - if (!(processor->flags & ACPI_MADT_ENABLED)) {
>> - pr_debug("skipping disabled CPU entry with 0x%llx MPIDR\n", hwid);
>> - return;
>> - }
>> -
>> if (hwid & ~MPIDR_HWID_BITMASK || hwid == INVALID_HWID) {
>> pr_err("skipping CPU entry with invalid MPIDR 0x%llx\n", hwid);
>> return;
>> }
>> + if (!(processor->flags & ACPI_MADT_ENABLED))
>> + pr_debug("disabled CPU entry with 0x%llx MPIDR\n", hwid);
>> +
>> if (is_mpidr_duplicate(cpu_count, hwid)) {
>> pr_err("duplicate CPU MPIDR 0x%llx in MADT\n", hwid);
>> return;
>> @@ -755,7 +753,8 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
>> if (err)
>> continue;
>> - set_cpu_present(cpu, true);
>> + if ((cpu_madt_gicc[cpu].flags & ACPI_MADT_ENABLED))
>> + set_cpu_present(cpu, true);
>> numa_store_cpu_info(cpu);
>> }
>> }
>
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next prev parent reply other threads:[~2019-07-04 8:19 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-29 2:42 [RFC PATCH v2 0/3] Support CPU hotplug for ARM64 Xiongfeng Wang
2019-06-29 2:42 ` [RFC PATCH v2 1/3] ACPI / scan: evaluate _STA for processors declared via ASL Device statement Xiongfeng Wang
2019-06-29 2:42 ` [RFC PATCH v2 2/3] arm64: mark all the GICC nodes in MADT as possible cpu Xiongfeng Wang
2019-07-04 6:46 ` Jia He
2019-07-04 8:18 ` Xiongfeng Wang [this message]
2019-06-29 2:42 ` [RFC PATCH v2 3/3] arm64: Add CPU hotplug support Xiongfeng Wang
2019-07-05 10:12 ` [RFC PATCH v2 0/3] Support CPU hotplug for ARM64 James Morse
2019-07-09 19:06 ` Maran Wilson
2019-07-10 9:15 ` Marc Zyngier
2019-07-10 16:05 ` Maran Wilson
2019-07-15 13:43 ` James Morse
2019-07-16 7:59 ` Jia He
2019-07-16 8:32 ` Marc Zyngier
2019-07-16 7:52 ` Xiongfeng Wang
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