From 71fff5e6ca1b738ac4742580e4c0ff79d906f6c8 Mon Sep 17 00:00:00 2001 From: Mike Travis Date: Fri, 19 Oct 2007 20:35:03 +0200 Subject: x86: convert cpu_to_apicid to be a per cpu variable This patch converts the x86_cpu_to_apicid array to be a per cpu variable. This saves sizeof(apicid) * NR unused cpus. Access is mostly from startup and CPU HOTPLUG functions. MP_processor_info() is one of the functions that require access to the x86_cpu_to_apicid array before the per_cpu data area is setup. For this case, a pointer to the __initdata array is initialized in setup_arch() and removed in smp_prepare_cpus() after the per_cpu data area is initialized. A second change is included to change the initial array value of ARCH i386 from 0xff to BAD_APICID to be consistent with ARCH x86_64. Signed-off-by: Mike Travis Cc: Andi Kleen Cc: Christoph Lameter Cc: "Siddha, Suresh B" Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/kernel/mpparse_64.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/mpparse_64.c') diff --git a/arch/x86/kernel/mpparse_64.c b/arch/x86/kernel/mpparse_64.c index 8bf0ca03ac8e..4336c0fc3b81 100644 --- a/arch/x86/kernel/mpparse_64.c +++ b/arch/x86/kernel/mpparse_64.c @@ -86,7 +86,7 @@ static int __init mpf_checksum(unsigned char *mp, int len) return sum & 0xFF; } -static void __cpuinit MP_processor_info (struct mpc_config_processor *m) +static void __cpuinit MP_processor_info(struct mpc_config_processor *m) { int cpu; cpumask_t tmp_map; @@ -123,7 +123,18 @@ static void __cpuinit MP_processor_info (struct mpc_config_processor *m) cpu = 0; } bios_cpu_apicid[cpu] = m->mpc_apicid; - x86_cpu_to_apicid[cpu] = m->mpc_apicid; + /* + * We get called early in the the start_kernel initialization + * process when the per_cpu data area is not yet setup, so we + * use a static array that is removed after the per_cpu data + * area is created. + */ + if (x86_cpu_to_apicid_ptr) { + u8 *x86_cpu_to_apicid = (u8 *)x86_cpu_to_apicid_ptr; + x86_cpu_to_apicid[cpu] = m->mpc_apicid; + } else { + per_cpu(x86_cpu_to_apicid, cpu) = m->mpc_apicid; + } cpu_set(cpu, cpu_possible_map); cpu_set(cpu, cpu_present_map); -- cgit v1.2.2