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[IA64] Add interface so modules can discover whether multithreading is on. 

Add is_multithreading_enabled() to check whether multi-threading
is enabled independently of which cpu is currently online

Signed-off-by: stephane eranian <eranian@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
Stephane Eranian 2006-09-21 10:35:44 -07:00 committed by Tony Luck
parent fd32cb3a9c
commit dd562c0541
2 changed files with 25 additions and 0 deletions
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24
arch/ia64/kernel/smpboot.c
View File

@ -879,3 +879,27 @@ identify_siblings(struct cpuinfo_ia64 *c)
c->core_id = info.log1_cid; c->core_id = info.log1_cid;
c->thread_id = info.log1_tid; c->thread_id = info.log1_tid;
} }
/*
* returns non zero, if multi-threading is enabled
* on at least one physical package. Due to hotplug cpu
* and (maxcpus=), all threads may not necessarily be enabled
* even though the processor supports multi-threading.
*/
int is_multithreading_enabled(void)
{
int i, j;
for_each_present_cpu(i) {
for_each_present_cpu(j) {
if (j == i)
continue;
if ((cpu_data(j)->socket_id == cpu_data(i)->socket_id)) {
if (cpu_data(j)->core_id == cpu_data(i)->core_id)
return 1;
}
}
}
return 0;
}
EXPORT_SYMBOL_GPL(is_multithreading_enabled);

1
include/asm-ia64/smp.h
View File

@ -128,6 +128,7 @@ extern void smp_send_reschedule (int cpu);
extern void lock_ipi_calllock(void); extern void lock_ipi_calllock(void);
extern void unlock_ipi_calllock(void); extern void unlock_ipi_calllock(void);
extern void identify_siblings (struct cpuinfo_ia64 *); extern void identify_siblings (struct cpuinfo_ia64 *);
extern int is_multithreading_enabled(void);
#else #else