x86, apic: explain the purpose of max_physical_apicid

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2009-01-31 03:57:12 +01:00
parent 65a4e574d2
commit fdbecd9fd1

View File

@ -50,13 +50,26 @@
#include <asm/smp.h>
unsigned int num_processors;
unsigned disabled_cpus __cpuinitdata;
/* Processor that is doing the boot up */
unsigned int boot_cpu_physical_apicid = -1U;
EXPORT_SYMBOL(boot_cpu_physical_apicid);
/*
* The highest APIC ID seen during enumeration.
*
* This determines the messaging protocol we can use: if all APIC IDs
* are in the 0 ... 7 range, then we can use logical addressing which
* has some performance advantages (better broadcasting).
*
* If there's an APIC ID above 8, we use physical addressing.
*/
unsigned int max_physical_apicid;
/* Bitmask of physically existing CPUs */
/*
* Bitmask of physically existing CPUs:
*/
physid_mask_t phys_cpu_present_map;
/*