Commit dd562c05 authored by Stephane Eranian's avatar Stephane Eranian Committed by Tony Luck
Browse files

[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: default avatarstephane eranian <eranian@hpl.hp.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent fd32cb3a

arch/ia64/kernel/smpboot.c

+24 −0
Original line number Diff line number Diff line
@@ -879,3 +879,27 @@ identify_siblings(struct cpuinfo_ia64 *c) 
	c->core_id = info.log1_cid;

	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);

include/asm-ia64/smp.h

+1 −0
Original line number Diff line number Diff line
@@ -128,6 +128,7 @@ extern void smp_send_reschedule (int cpu); 
extern void lock_ipi_calllock(void);

extern void unlock_ipi_calllock(void);

extern void identify_siblings (struct cpuinfo_ia64 *);

extern int is_multithreading_enabled(void);



#else