From e84df04f2a4cd8fb392c12804ecf5e0b18e6d5c6 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Fri, 29 Jan 2010 13:25:12 +0100
Subject: [PATCH] --- yaml --- r: 182456 b: refs/heads/master c:
 fce877e3a429940a986e085a41e8b57f2d922e36 h: refs/heads/master v: v3

---
 [refs]                                 |  2 +-
 trunk/arch/x86/kernel/cpu/perf_event.c | 10 +++++---
 trunk/include/linux/bitops.h           | 33 +++++++++++++++++---------
 3 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/[refs] b/[refs]
index 6eb50065b6c6..f386ade63e96 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8c48e444191de0ff84e85d41180d7bc3e74f14ef
+refs/heads/master: fce877e3a429940a986e085a41e8b57f2d922e36
diff --git a/trunk/arch/x86/kernel/cpu/perf_event.c b/trunk/arch/x86/kernel/cpu/perf_event.c
index 5b91992b6b25..96cfc1a4fe9f 100644
--- a/trunk/arch/x86/kernel/cpu/perf_event.c
+++ b/trunk/arch/x86/kernel/cpu/perf_event.c
@@ -93,13 +93,16 @@ struct cpu_hw_events {
 	struct perf_event	*event_list[X86_PMC_IDX_MAX]; /* in enabled order */
 };
 
-#define EVENT_CONSTRAINT(c, n, m) {	\
+#define __EVENT_CONSTRAINT(c, n, m, w) {\
 	{ .idxmsk64[0] = (n) },		\
 	.code = (c),			\
 	.cmask = (m),			\
-	.weight = HWEIGHT64((u64)(n)),	\
+	.weight = (w),			\
 }
 
+#define EVENT_CONSTRAINT(c, n, m)	\
+	__EVENT_CONSTRAINT(c, n, m, HWEIGHT(n))
+
 #define INTEL_EVENT_CONSTRAINT(c, n)	\
 	EVENT_CONSTRAINT(c, n, INTEL_ARCH_EVTSEL_MASK)
 
@@ -2622,7 +2625,8 @@ void __init init_hw_perf_events(void)
 	register_die_notifier(&perf_event_nmi_notifier);
 
 	unconstrained = (struct event_constraint)
-		EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_events) - 1, 0);
+		__EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_events) - 1,
+				   0, x86_pmu.num_events);
 
 	pr_info("... version:                %d\n",     x86_pmu.version);
 	pr_info("... bit width:              %d\n",     x86_pmu.event_bits);
diff --git a/trunk/include/linux/bitops.h b/trunk/include/linux/bitops.h
index ba0fd1eb4af7..25b8b2f33ae9 100644
--- a/trunk/include/linux/bitops.h
+++ b/trunk/include/linux/bitops.h
@@ -45,19 +45,30 @@ static inline unsigned long hweight_long(unsigned long w)
 	return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
 }
 
-#define HWEIGHT8(w)			\
-      (	(!!((w) & (1ULL << 0))) +	\
-	(!!((w) & (1ULL << 1))) +	\
-	(!!((w) & (1ULL << 2))) +	\
-	(!!((w) & (1ULL << 3))) +	\
-	(!!((w) & (1ULL << 4))) +	\
-	(!!((w) & (1ULL << 5))) +	\
-	(!!((w) & (1ULL << 6))) +	\
+/*
+ * Clearly slow versions of the hweightN() functions, their benefit is
+ * of course compile time evaluation of constant arguments.
+ */
+#define HWEIGHT8(w)					\
+      (	BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) +	\
+	(!!((w) & (1ULL << 0))) +			\
+	(!!((w) & (1ULL << 1))) +			\
+	(!!((w) & (1ULL << 2))) +			\
+	(!!((w) & (1ULL << 3))) +			\
+	(!!((w) & (1ULL << 4))) +			\
+	(!!((w) & (1ULL << 5))) +			\
+	(!!((w) & (1ULL << 6))) +			\
 	(!!((w) & (1ULL << 7)))	)
 
-#define HWEIGHT16(w) (HWEIGHT8(w)  + HWEIGHT8(w >> 8))
-#define HWEIGHT32(w) (HWEIGHT16(w) + HWEIGHT16(w >> 16))
-#define HWEIGHT64(w) (HWEIGHT32(w) + HWEIGHT32(w >> 32))
+#define HWEIGHT16(w) (HWEIGHT8(w)  + HWEIGHT8((w) >> 8))
+#define HWEIGHT32(w) (HWEIGHT16(w) + HWEIGHT16((w) >> 16))
+#define HWEIGHT64(w) (HWEIGHT32(w) + HWEIGHT32((w) >> 32))
+
+/*
+ * Type invariant version that simply casts things to the
+ * largest type.
+ */
+#define HWEIGHT(w)   HWEIGHT64((u64)(w))
 
 /**
  * rol32 - rotate a 32-bit value left