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authorStephane Eranian <eranian@hpl.hp.com>2006-09-21 10:35:44 -0700
committerTony Luck <tony.luck@intel.com>2006-09-26 11:39:38 -0700
commitdd562c05410e13e878a3ee0deb8ac06db2e132c7 (patch)
treeb99f2e8c4aae70a17a8caf7e3f72926c4dcdd7a4
parentfd32cb3a9c9f9399421408e8734cd8a6d9d1a09f (diff)
[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>
-rw-r--r--arch/ia64/kernel/smpboot.c24
-rw-r--r--include/asm-ia64/smp.h1
2 files changed, 25 insertions, 0 deletions
diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index 6203ed4ec8cf..f7d7f5668144 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -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);
diff --git a/include/asm-ia64/smp.h b/include/asm-ia64/smp.h
index 719ff309ce09..6533eb4e86ad 100644
--- a/include/asm-ia64/smp.h
+++ b/include/asm-ia64/smp.h
@@ -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