Messages in this thread | | | Date | Wed, 15 Jul 2015 11:33:57 +0800 | From | Tang Chen <> | Subject | Re: [PATCH 3/5] x86, acpi, cpu-hotplug: Introduce apicid_to_cpuid[] array to store persistent cpuid <-> apicid mapping. |
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Hi Mika,
On 07/07/2015 07:14 PM, Mika Penttilä wrote: > I think you forgot to reserve CPU 0 for BSP in cpuid mask.
Sorry for the late reply.
I'm not familiar with BSP. Do you mean in get_cpuid(), I should reserve 0 for physical cpu0 in BSP ?
Would you please share more detail ?
Thanks.
> > --Mika > > On Tue, Jul 7, 2015 at 12:30 PM, Tang Chen <tangchen@cn.fujitsu.com> wrote: >> From: Gu Zheng <guz.fnst@cn.fujitsu.com> >> >> In this patch, we introduce a new static array named apicid_to_cpuid[], >> which is large enough to store info for all possible cpus. >> >> And then, we modify the cpuid calculation. In generic_processor_info(), >> it simply finds the next unused cpuid. And it is also why the cpuid <-> nodeid >> mapping changes with node hotplug. >> >> After this patch, we find the next unused cpuid, map it to an apicid, >> and store the mapping in apicid_to_cpuid[], so that cpuid <-> apicid >> mapping will be persistent. >> >> And finally we will use this array to make cpuid <-> nodeid persistent. >> >> cpuid <-> apicid mapping is established at local apic registeration time. >> But non-present or disabled cpus are ignored. >> >> In this patch, we establish all possible cpuid <-> apicid mapping when >> registering local apic. >> >> >> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> >> Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com> >> --- >> arch/x86/include/asm/mpspec.h | 1 + >> arch/x86/kernel/acpi/boot.c | 6 ++---- >> arch/x86/kernel/apic/apic.c | 47 ++++++++++++++++++++++++++++++++++++++++--- >> 3 files changed, 47 insertions(+), 7 deletions(-) >> >> diff --git a/arch/x86/include/asm/mpspec.h b/arch/x86/include/asm/mpspec.h >> index b07233b..db902d8 100644 >> --- a/arch/x86/include/asm/mpspec.h >> +++ b/arch/x86/include/asm/mpspec.h >> @@ -86,6 +86,7 @@ static inline void early_reserve_e820_mpc_new(void) { } >> #endif >> >> int generic_processor_info(int apicid, int version); >> +int __generic_processor_info(int apicid, int version, bool enabled); >> >> #define PHYSID_ARRAY_SIZE BITS_TO_LONGS(MAX_LOCAL_APIC) >> >> diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c >> index e49ee24..bcc85b2 100644 >> --- a/arch/x86/kernel/acpi/boot.c >> +++ b/arch/x86/kernel/acpi/boot.c >> @@ -174,15 +174,13 @@ static int acpi_register_lapic(int id, u8 enabled) >> return -EINVAL; >> } >> >> - if (!enabled) { >> + if (!enabled) >> ++disabled_cpus; >> - return -EINVAL; >> - } >> >> if (boot_cpu_physical_apicid != -1U) >> ver = apic_version[boot_cpu_physical_apicid]; >> >> - return generic_processor_info(id, ver); >> + return __generic_processor_info(id, ver, enabled); >> } >> >> static int __init >> diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c >> index a9c9830..c744ffb 100644 >> --- a/arch/x86/kernel/apic/apic.c >> +++ b/arch/x86/kernel/apic/apic.c >> @@ -1977,7 +1977,38 @@ void disconnect_bsp_APIC(int virt_wire_setup) >> apic_write(APIC_LVT1, value); >> } >> >> -static int __generic_processor_info(int apicid, int version, bool enabled) >> +/* >> + * Logic cpu number(cpuid) to local APIC id persistent mappings. >> + * Do not clear the mapping even if cpu is hot-removed. >> + */ >> +static int apicid_to_cpuid[] = { >> + [0 ... NR_CPUS - 1] = -1, >> +}; >> + >> +/* >> + * Internal cpu id bits, set the bit once cpu present, and never clear it. >> + */ >> +static cpumask_t cpuid_mask = CPU_MASK_NONE; >> + >> +static int get_cpuid(int apicid) >> +{ >> + int free_id, i; >> + >> + free_id = cpumask_next_zero(-1, &cpuid_mask); >> + if (free_id >= nr_cpu_ids) >> + return -1; >> + >> + for (i = 0; i < free_id; i++) >> + if (apicid_to_cpuid[i] == apicid) >> + return i; >> + >> + apicid_to_cpuid[free_id] = apicid; >> + cpumask_set_cpu(free_id, &cpuid_mask); >> + >> + return free_id; >> +} >> + >> +int __generic_processor_info(int apicid, int version, bool enabled) >> { >> int cpu, max = nr_cpu_ids; >> bool boot_cpu_detected = physid_isset(boot_cpu_physical_apicid, >> @@ -2058,8 +2089,18 @@ static int __generic_processor_info(int apicid, int version, bool enabled) >> * for BSP. >> */ >> cpu = 0; >> - } else >> - cpu = cpumask_next_zero(-1, cpu_present_mask); >> + } else { >> + cpu = get_cpuid(apicid); >> + if (cpu < 0) { >> + int thiscpu = max + disabled_cpus; >> + >> + pr_warning(" Processor %d/0x%x ignored.\n", >> + thiscpu, apicid); >> + if (enabled) >> + disabled_cpus++; >> + return -EINVAL; >> + } >> + } >> >> /* >> * Validate version >> -- >> 1.9.3 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> Please read the FAQ at http://www.tux.org/lkml/ > . >
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