[PATCH v1 2/2] perf/x86: Reduce is_hybrid calls and aid ellision of BUG_ON in hybrid_pmu

[Ian Rogers]

Use the capabilities of the PMU rather than the global variable
perf_is_hybrid to determine if a hybrid pmu has been passed to the
main accessors. As the pmu capabilities check mirrors that in
is_x86_pmu, the BUG_ON(!is_x86_pmu...) in hybrid_pmu can be elided as
it is provably always false (with sufficient function inlining, common
sub-expression elimination, etc.) in its most common uses.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
Only build tested.
---
 arch/x86/events/perf_event.h | 52 +++++++++++++++++++-----------------
 1 file changed, 28 insertions(+), 24 deletions(-)

diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index f1123c95d174..7990d86ef233 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -802,34 +802,38 @@ static __always_inline struct x86_hybrid_pmu *hybrid_pmu(struct pmu *pmu)
 extern struct static_key_false perf_is_hybrid;
 #define is_hybrid()		static_branch_unlikely(&perf_is_hybrid)
 
-#define hybrid(_pmu, _field)				\
-(*({							\
-	typeof(&x86_pmu._field) __Fp = &x86_pmu._field;	\
-							\
-	if (is_hybrid() && (_pmu))			\
-		__Fp = &hybrid_pmu(_pmu)->_field;	\
-							\
-	__Fp;						\
+
+#define hybrid(_pmu, _field)						\
+(*({									\
+	typeof(&x86_pmu._field) __Fp = &x86_pmu._field;			\
+	struct pmu *__pmu = _pmu;					\
+									\
+	if (__pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE)	\
+		__Fp = &hybrid_pmu(__pmu)->_field;			\
+									\
+	__Fp;								\
 }))
 
-#define hybrid_var(_pmu, _var)				\
-(*({							\
-	typeof(&_var) __Fp = &_var;			\
-							\
-	if (is_hybrid() && (_pmu))			\
-		__Fp = &hybrid_pmu(_pmu)->_var;		\
-							\
-	__Fp;						\
+#define hybrid_var(_pmu, _var)						\
+(*({									\
+	typeof(&_var) __Fp = &_var;					\
+	struct pmu *__pmu = _pmu;					\
+									\
+	if (__pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE)	\
+		__Fp = &hybrid_pmu(__pmu)->_var;			\
+									\
+	__Fp;								\
 }))
 
-#define hybrid_bit(_pmu, _field)			\
-({							\
-	bool __Fp = x86_pmu._field;			\
-							\
-	if (is_hybrid() && (_pmu))			\
-		__Fp = hybrid_pmu(_pmu)->_field;	\
-							\
-	__Fp;						\
+#define hybrid_bit(_pmu, _field)					\
+({									\
+	bool __Fp = x86_pmu._field;					\
+	struct pmu *__pmu = _pmu;					\
+									\
+	if (__pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE)	\
+		__Fp = hybrid_pmu(__pmu)->_field;			\
+									\
+	__Fp;								\
 })
 
 /*
-- 
2.53.0.851.ga537e3e6e9-goog