On Fri, 2006-09-22 at 22:00 +1000, Rusty Russell wrote: > This implements smp_processor_id() as a per-cpu variable. Updated for revised 5/7: we no longer need to avoid using smp_processor_id() in cpu_init. This implements smp_processor_id() as a per-cpu variable. The generic code expects it in thread_info still, so we can't remove it from there, but reducing smp_processor_id() from 9 bytes/3 insns to 6 bytes/1 insn is a nice micro-optimization. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> Index: ak-fresh/arch/i386/kernel/smpboot.c =================================================================== --- ak-fresh.orig/arch/i386/kernel/smpboot.c 2006-09-25 14:49:05.000000000 +1000 +++ ak-fresh/arch/i386/kernel/smpboot.c 2006-09-25 15:02:51.000000000 +1000 @@ -105,6 +105,9 @@ DEFINE_PER_CPU(unsigned long, this_cpu_off); EXPORT_PER_CPU_SYMBOL(this_cpu_off); +DEFINE_PER_CPU(u32, processor_id); +EXPORT_PER_CPU_SYMBOL(processor_id); + /* * Trampoline 80x86 program as an array. */ @@ -939,6 +942,7 @@ struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); per_cpu(this_cpu_off, cpu) = __per_cpu_offset[cpu]; + per_cpu(processor_id, cpu) = cpu; setup_percpu_descriptor(&gdt[GDT_ENTRY_PERCPU], __per_cpu_offset[cpu]); cpu_gdt_descr->address = (unsigned long)gdt; cpu_gdt_descr->size = GDT_SIZE - 1; @@ -1361,6 +1365,7 @@ struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); per_cpu(this_cpu_off, cpu) = __per_cpu_offset[cpu]; + per_cpu(processor_id, cpu) = cpu; setup_percpu_descriptor(&gdt[GDT_ENTRY_PERCPU], __per_cpu_offset[cpu]); cpu_gdt_descr->address = (unsigned long)gdt; cpu_gdt_descr->size = GDT_SIZE - 1; Index: ak-fresh/include/asm-i386/smp.h =================================================================== --- ak-fresh.orig/include/asm-i386/smp.h 2006-09-25 14:49:05.000000000 +1000 +++ ak-fresh/include/asm-i386/smp.h 2006-09-25 14:52:05.000000000 +1000 @@ -8,6 +8,7 @@ #include <linux/kernel.h> #include <linux/threads.h> #include <linux/cpumask.h> +#include <asm/percpu.h> #endif #ifdef CONFIG_X86_LOCAL_APIC @@ -56,7 +57,8 @@ * from the initial startup. We map APIC_BASE very early in page_setup(), * so this is correct in the x86 case. */ -#define raw_smp_processor_id() (current_thread_info()->cpu) +DECLARE_PER_CPU(u32, processor_id); +#define raw_smp_processor_id() x86_read_percpu(processor_id) extern cpumask_t cpu_callout_map; extern cpumask_t cpu_callin_map; -- Help! Save Australia from the worst of the DMCA: http://linux.org.au/law
