Enable prefetching on P4/PIII class machines with CONFIG_X86_PREFETCH

arch/i386/Kconfig

@@ -283,6 +283,11 @@ config X86_OOSTORE
 	depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6
 	default y
 
+config X86_PREFETCH
+	bool
+	depends on MPENTIUMIII || MP4
+	default y
+
 config HUGETLB_PAGE
 	bool "Huge TLB Page Support"
 	help

include/asm-i386/processor.h

@@ -486,7 +486,7 @@ static inline void rep_nop(void)
 #define cpu_relax()	rep_nop()
 
 /* Prefetch instructions for Pentium III and AMD Athlon */
-#ifdef 	CONFIG_MPENTIUMIII
+#ifdef 	CONFIG_X86_PREFETCH
 
 #define ARCH_HAS_PREFETCH
 extern inline void prefetch(const void *x)