On Tue, 31 May 2011, H. Peter Anvin wrote: > On 05/31/2011 09:53 AM, Christoph Lameter wrote: > > Index: linux-2.6/arch/x86/Kconfig.cpu > > =================================================================== > > --- linux-2.6.orig/arch/x86/Kconfig.cpu 2011-05-31 11:28:24.202948792 -0500 > > +++ linux-2.6/arch/x86/Kconfig.cpu 2011-05-31 11:29:36.742948327 -0500 > > @@ -312,6 +312,16 @@ config X86_CMPXCHG > > config CMPXCHG_LOCAL > > def_bool X86_64 || (X86_32 && !M386) > > > > +# > > +# CMPXCHG_DOUBLE needs to be set to enable the kernel to use cmpxchg16/8b > > +# for cmpxchg_double if it find processor flags that indicate that the > > +# capabilities are available. CMPXCHG_DOUBLE only compiles in > > +# detection support. It needs to be set if there is a chance that processor > > +# supports these instructions. > > +# > > +config CMPXCHG_DOUBLE > > + def_bool GENERIC_CPU || X86_GENERIC || !M386 > > + > > config X86_L1_CACHE_SHIFT > > int > > default "7" if MPENTIUM4 || MPSC > > Per previous discussion: > > - Drop this Kconfig option (it is irrelevant.) CONFIG_CMPXCHG_LOCAL is > different: it indicates that CMPXCHG is *guaranteed* to exist. Right but this is for cmpxchg16b which means that we need to check a bit in the processor flags. Isnt this what you suggested? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>