[PATCH] [12/66] x86_64: cleanup allocating logical cpu numbers in x86_64

["Andi Kleen" <ak@xxxxxxx>]

From: Ashok Raj <ashok.raj@xxxxxxxxx>
Hi Andi

Iam working on physical hotplug support for x86_64 as well now. In the process
i found that logical cpu generation in mpparse.c isnt friendly for cpu hotplug
since it uses num_processors as an index to fill bios_* arrays to store 
apic ids.

Moreover the code earlier had this static stuff about found_bsp etc that 
looks very ugly.

I could wait to send the code until the entire physical hotplug is ready, but
thought this will be a minor change that we could consider now, and 
improves the code readability much better.

Let me know what you think.

-- 
Cheers,
Ashok Raj
- Open Source Technology Center


Minor cleanup to lend better for physical CPU hotplug.
Earlier way of using num_processors as index doesnt
fit if CPUs come and go. This makes the code little bit better
to read, and helps physical hotplug use the same functions as boot.

Reserving CPU0 for BSP is too late to be done in smp_prepare_boot_cpu().
Since logical assignments from MADT is already done via
setup_arch()->acpi_boot_init()->parse lapic

Signed-off-by: Ashok Raj <ashok.raj@xxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxx>

------------------------------------------------------
 arch/x86_64/kernel/mpparse.c |   19 ++++++++-----------
 arch/x86_64/kernel/setup.c   |    6 ++++++
 2 files changed, 14 insertions(+), 11 deletions(-)

Index: linux/arch/x86_64/kernel/mpparse.c
===================================================================
--- linux.orig/arch/x86_64/kernel/mpparse.c
+++ linux/arch/x86_64/kernel/mpparse.c
@@ -106,11 +106,11 @@ static int __init mpf_checksum(unsigned 
 	return sum & 0xFF;
 }
 
-static void __init MP_processor_info (struct mpc_config_processor *m)
+static void __cpuinit MP_processor_info (struct mpc_config_processor *m)
 {
 	int cpu;
 	unsigned char ver;
-	static int found_bsp=0;
+	cpumask_t tmp_map;
 
 	if (!(m->mpc_cpuflag & CPU_ENABLED)) {
 		disabled_cpus++;
@@ -133,8 +133,10 @@ static void __init MP_processor_info (st
 		return;
 	}
 
-	cpu = num_processors++;
-	
+	num_processors++;
+	cpus_complement(tmp_map, cpu_present_map);
+	cpu = first_cpu(tmp_map);
+
 #if MAX_APICS < 255	
 	if ((int)m->mpc_apicid > MAX_APICS) {
 		printk(KERN_ERR "Processor #%d INVALID. (Max ID: %d).\n",
@@ -160,12 +162,7 @@ static void __init MP_processor_info (st
  		 * entry is BSP, and so on.
  		 */
 		cpu = 0;
-
- 		bios_cpu_apicid[0] = m->mpc_apicid;
- 		x86_cpu_to_apicid[0] = m->mpc_apicid;
- 		found_bsp = 1;
- 	} else
-		cpu = num_processors - found_bsp;
+ 	}
 	bios_cpu_apicid[cpu] = m->mpc_apicid;
 	x86_cpu_to_apicid[cpu] = m->mpc_apicid;
 
@@ -691,7 +688,7 @@ void __init mp_register_lapic_address (
 }
 
 
-void __init mp_register_lapic (
+void __cpuinit mp_register_lapic (
 	u8			id, 
 	u8			enabled)
 {
Index: linux/arch/x86_64/kernel/setup.c
===================================================================
--- linux.orig/arch/x86_64/kernel/setup.c
+++ linux/arch/x86_64/kernel/setup.c
@@ -708,6 +708,12 @@ void __init setup_arch(char **cmdline_p)
 
 	check_ioapic();
 
+	/*
+	 * set this early, so we dont allocate cpu0
+	 * if MADT list doesnt list BSP first
+	 * mpparse.c/MP_processor_info() allocates logical cpu numbers.
+	 */
+	cpu_set(0, cpu_present_map);
 #ifdef CONFIG_ACPI
 	/*
 	 * Read APIC and some other early information from ACPI tables.
-
: send the line "unsubscribe linux-x86_64" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html