On Tue, Jan 06, 2009 at 10:27:41AM -0600, Dimitri Sivanich wrote: > Turn on CONFIG_HAVE_UNSTABLE_SCHED_CLOCK for SGI_SN. > > SGI Altix has unsynchronized itc clocks. This results in rq->clock > occasionally being set to a time in the past by a remote cpu. > > Note that it is possible that this problem may exist for other ia64 > machines as well, based on the following comment for sched_clock() in > arch/ia64/kernel/head.S: > > * Return a CPU-local timestamp in nano-seconds. This timestamp is > * NOT synchronized across CPUs its return value must never be > * compared against the values returned on another CPU. The usage in > * kernel/sched.c ensures that. > > > Signed-off-by: Dimitri Sivanich <sivanich@xxxxxxx> > > --- > > Greg, if everyone is OK with this patch, this should also be applied > to all stable trees starting with 2.6.26. That's fine (but 2.6.26 is no longer getting -stable releases). Just let stable@xxxxxxxxxx know when this patch is applied in Linus's tree. You can do this automatically by adding a: Cc: stable <stable@xxxxxxxxxx> to the signed-off-by: area of the patch, and the stable team will be automatically notified when it goes into Linus's tree. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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