Thread (26 messages) 26 messages, 4 authors, 2023-10-20

Re: [PATCH v2 3/6] powerpc/smp: Move shared_processor static key to smp.h

From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2023-10-19 04:41:48
Also in: lkml, virtualization

Srikar Dronamraju [off-list ref] writes:
The ability to detect if the system is running in a shared processor
mode is helpful in few more generic cases not just in
paravirtualization.
For example: At boot time, different scheduler/ topology flags may be
set based on the processor mode. Hence move it to a more generic file.
I'd rather you just included paravirt.h in the few files where you need it.

cheers
quoted hunk ↗ jump to hunk
diff --git a/arch/powerpc/include/asm/paravirt.h b/arch/powerpc/include/asm/paravirt.h
index 0372b0093f72..cf83e837a571 100644
--- a/arch/powerpc/include/asm/paravirt.h
+++ b/arch/powerpc/include/asm/paravirt.h
@@ -15,13 +15,6 @@
 #include <asm/kvm_guest.h>
 #include <asm/cputhreads.h>
 
-DECLARE_STATIC_KEY_FALSE(shared_processor);
-
-static inline bool is_shared_processor(void)
-{
-	return static_branch_unlikely(&shared_processor);
-}
-
 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
 extern struct static_key paravirt_steal_enabled;
 extern struct static_key paravirt_steal_rq_enabled;
@@ -77,11 +70,6 @@ static inline bool is_vcpu_idle(int vcpu)
 	return lppaca_of(vcpu).idle;
 }
 #else
-static inline bool is_shared_processor(void)
-{
-	return false;
-}
-
 static inline u32 yield_count_of(int cpu)
 {
 	return 0;
diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index aaaa576d0e15..08631b2a4528 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -34,6 +34,20 @@ extern bool coregroup_enabled;
 extern int cpu_to_chip_id(int cpu);
 extern int *chip_id_lookup_table;
 
+#ifdef CONFIG_PPC_SPLPAR
+DECLARE_STATIC_KEY_FALSE(shared_processor);
+
+static inline bool is_shared_processor(void)
+{
+	return static_branch_unlikely(&shared_processor);
+}
+#else
+static inline bool is_shared_processor(void)
+{
+	return false;
+}
+#endif
+
 DECLARE_PER_CPU(cpumask_var_t, thread_group_l1_cache_map);
 DECLARE_PER_CPU(cpumask_var_t, thread_group_l2_cache_map);
 DECLARE_PER_CPU(cpumask_var_t, thread_group_l3_cache_map);
-- 
2.31.1
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