diff options
Diffstat (limited to 'arch/x86/kernel/apic/x2apic_cluster.c')
| -rw-r--r-- | arch/x86/kernel/apic/x2apic_cluster.c | 27 |
1 files changed, 21 insertions, 6 deletions
diff --git a/arch/x86/kernel/apic/x2apic_cluster.c b/arch/x86/kernel/apic/x2apic_cluster.c index f4da9bb69a88..e696e22d0531 100644 --- a/arch/x86/kernel/apic/x2apic_cluster.c +++ b/arch/x86/kernel/apic/x2apic_cluster.c @@ -15,9 +15,15 @@ struct cluster_mask { struct cpumask mask; }; -static DEFINE_PER_CPU(u32, x86_cpu_to_logical_apicid); +/* + * __x2apic_send_IPI_mask() possibly needs to read + * x86_cpu_to_logical_apicid for all online cpus in a sequential way. + * Using per cpu variable would cost one cache line per cpu. + */ +static u32 *x86_cpu_to_logical_apicid __read_mostly; + static DEFINE_PER_CPU(cpumask_var_t, ipi_mask); -static DEFINE_PER_CPU(struct cluster_mask *, cluster_masks); +static DEFINE_PER_CPU_READ_MOSTLY(struct cluster_mask *, cluster_masks); static struct cluster_mask *cluster_hotplug_mask; static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id) @@ -27,7 +33,7 @@ static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id) static void x2apic_send_IPI(int cpu, int vector) { - u32 dest = per_cpu(x86_cpu_to_logical_apicid, cpu); + u32 dest = x86_cpu_to_logical_apicid[cpu]; /* x2apic MSRs are special and need a special fence: */ weak_wrmsr_fence(); @@ -58,7 +64,7 @@ __x2apic_send_IPI_mask(const struct cpumask *mask, int vector, int apic_dest) dest = 0; for_each_cpu_and(clustercpu, tmpmsk, &cmsk->mask) - dest |= per_cpu(x86_cpu_to_logical_apicid, clustercpu); + dest |= x86_cpu_to_logical_apicid[clustercpu]; if (!dest) continue; @@ -94,7 +100,7 @@ static void x2apic_send_IPI_all(int vector) static u32 x2apic_calc_apicid(unsigned int cpu) { - return per_cpu(x86_cpu_to_logical_apicid, cpu); + return x86_cpu_to_logical_apicid[cpu]; } static void init_x2apic_ldr(void) @@ -103,7 +109,7 @@ static void init_x2apic_ldr(void) u32 cluster, apicid = apic_read(APIC_LDR); unsigned int cpu; - this_cpu_write(x86_cpu_to_logical_apicid, apicid); + x86_cpu_to_logical_apicid[smp_processor_id()] = apicid; if (cmsk) goto update; @@ -166,12 +172,21 @@ static int x2apic_dead_cpu(unsigned int dead_cpu) static int x2apic_cluster_probe(void) { + u32 slots; + if (!x2apic_mode) return 0; + slots = max_t(u32, L1_CACHE_BYTES/sizeof(u32), nr_cpu_ids); + x86_cpu_to_logical_apicid = kcalloc(slots, sizeof(u32), GFP_KERNEL); + if (!x86_cpu_to_logical_apicid) + return 0; + if (cpuhp_setup_state(CPUHP_X2APIC_PREPARE, "x86/x2apic:prepare", x2apic_prepare_cpu, x2apic_dead_cpu) < 0) { pr_err("Failed to register X2APIC_PREPARE\n"); + kfree(x86_cpu_to_logical_apicid); + x86_cpu_to_logical_apicid = NULL; return 0; } init_x2apic_ldr(); |