On 05/31/2011 04:49 PM, Christoph Lameter wrote: >>> >>> +# >>> +# 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? > Per your own description: "CMPXCHG_DOUBLE only compiles in detection support. It needs to be set if there is a chance that processor supports these instructions." That condition is always TRUE, so no Kconfig is needed. -hpa -- 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>