From 8f54969dc8d6704632b42cbb5e47730cd75cc713 Mon Sep 17 00:00:00 2001 From: Gu Zheng Date: Thu, 25 Aug 2016 16:35:16 +0800 Subject: [PATCH] x86/acpi: Introduce persistent storage for cpuid <-> apicid mapping The whole patch-set aims at making cpuid <-> nodeid mapping persistent. So that, when node online/offline happens, cache based on cpuid <-> nodeid mapping such as wq_numa_possible_cpumask will not cause any problem. It contains 4 steps: 1. Enable apic registeration flow to handle both enabled and disabled cpus. 2. Introduce a new array storing all possible cpuid <-> apicid mapping. 3. Enable _MAT and MADT relative apis to return non-present or disabled cpus' apicid. 4. Establish all possible cpuid <-> nodeid mapping. This patch finishes step 2. In this patch, we introduce a new static array named cpuid_to_apicid[], 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 cpuid_to_apicid[], 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 Signed-off-by: Tang Chen Signed-off-by: Zhu Guihua Signed-off-by: Dou Liyang Acked-by: Ingo Molnar Cc: mika.j.penttila@gmail.com Cc: len.brown@intel.com Cc: rafael@kernel.org Cc: rjw@rjwysocki.net Cc: yasu.isimatu@gmail.com Cc: linux-mm@kvack.org Cc: linux-acpi@vger.kernel.org Cc: isimatu.yasuaki@jp.fujitsu.com Cc: gongzhaogang@inspur.com Cc: tj@kernel.org Cc: izumi.taku@jp.fujitsu.com Cc: cl@linux.com Cc: chen.tang@easystack.cn Cc: akpm@linux-foundation.org Cc: kamezawa.hiroyu@jp.fujitsu.com Cc: lenb@kernel.org Link: http://lkml.kernel.org/r/1472114120-3281-4-git-send-email-douly.fnst@cn.fujitsu.com Signed-off-by: Thomas Gleixner --- arch/x86/include/asm/mpspec.h | 1 + arch/x86/kernel/acpi/boot.c | 7 +--- arch/x86/kernel/apic/apic.c | 60 +++++++++++++++++++++++++++++++++-- 3 files changed, 59 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/mpspec.h b/arch/x86/include/asm/mpspec.h index c2f94dcc92ce..32007041ef8c 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 0447e314e7f5..7d668d172fce 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -176,15 +176,10 @@ static int acpi_register_lapic(int id, u32 acpiid, u8 enabled) return -EINVAL; } - if (!enabled) { - ++disabled_cpus; - return -EINVAL; - } - if (boot_cpu_physical_apicid != -1U) ver = boot_cpu_apic_version; - cpu = generic_processor_info(id, ver); + cpu = __generic_processor_info(id, ver, enabled); if (cpu >= 0) early_per_cpu(x86_cpu_to_acpiid, cpu) = acpiid; diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index a8c94bb6b528..2dc01c38ad8e 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2021,7 +2021,53 @@ void disconnect_bsp_APIC(int virt_wire_setup) apic_write(APIC_LVT1, value); } -static int __generic_processor_info(int apicid, int version, bool enabled) +/* + * The number of allocated logical CPU IDs. Since logical CPU IDs are allocated + * contiguously, it equals to current allocated max logical CPU ID plus 1. + * All allocated CPU ID should be in [0, nr_logical_cpuidi), so the maximum of + * nr_logical_cpuids is nr_cpu_ids. + * + * NOTE: Reserve 0 for BSP. + */ +static int nr_logical_cpuids = 1; + +/* + * Used to store mapping between logical CPU IDs and APIC IDs. + */ +static int cpuid_to_apicid[] = { + [0 ... NR_CPUS - 1] = -1, +}; + +/* + * Should use this API to allocate logical CPU IDs to keep nr_logical_cpuids + * and cpuid_to_apicid[] synchronized. + */ +static int allocate_logical_cpuid(int apicid) +{ + int i; + + /* + * cpuid <-> apicid mapping is persistent, so when a cpu is up, + * check if the kernel has allocated a cpuid for it. + */ + for (i = 0; i < nr_logical_cpuids; i++) { + if (cpuid_to_apicid[i] == apicid) + return i; + } + + /* Allocate a new cpuid. */ + if (nr_logical_cpuids >= nr_cpu_ids) { + WARN_ONCE(1, "Only %d processors supported." + "Processor %d/0x%x and the rest are ignored.\n", + nr_cpu_ids - 1, nr_logical_cpuids, apicid); + return -1; + } + + cpuid_to_apicid[nr_logical_cpuids] = apicid; + return nr_logical_cpuids++; +} + +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, @@ -2096,8 +2142,16 @@ static int __generic_processor_info(int apicid, int version, bool enabled) * for BSP. */ cpu = 0; - } else - cpu = cpumask_next_zero(-1, cpu_present_mask); + + /* Logical cpuid 0 is reserved for BSP. */ + cpuid_to_apicid[0] = apicid; + } else { + cpu = allocate_logical_cpuid(apicid); + if (cpu < 0) { + disabled_cpus++; + return -EINVAL; + } + } /* * This can happen on physical hotplug. The sanity check at boot time -- 2.20.1