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 <guz.fnst@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
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 <tglx@linutronix.de>

diff --git a/arch/x86/include/asm/mpspec.h b/arch/x86/include/asm/mpspec.h
index c2f94dc..3200704 100644 (file)
--- 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 0447e31..7d668d1 100644 (file)
--- 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 a8c94bb..2dc01c3 100644 (file)
--- 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