From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> Date: Sun, 31 Aug 2008 10:33:49 -0700 > Make sparc64 refrain from clearing a given to-be-offlined CPU's bit in the > cpu_online_mask until it has processed pending irqs. This change > prevents other CPUs from being blindsided by an apparently offline CPU > nevertheless changing globally visible state. > > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> I wonder what the 'call_lock' thing protects :-) That lock is a cobweb from the sparc64 code before I switched it over to use the generic smp_call_function() code in kernel/smp.c So this lock doesn't protect anything any more. kernel/smp.c has a call_function_lock, which isn't marked static but isn't declared in any header file. My instinct is that the intention is that I could use this lock for the synchronization previously provided by sparc64's local "call_lock", and it even seems the author of kernel/smp.c intended this kind of usage. Anyways, if this code is still using the worthless call_lock, it isn't protecting against anything. So I'd like to hold off on this patch until this locking issue is resolved. -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
