Re: [PATCH][2.5] Protect smp_call_function_data w/ spinlocks on Alpha

[Richard Henderson]

On Fri, Feb 14, 2003 at 12:16:12PM -0500, Zwane Mwaikambo wrote:
> Ok the reason being is that the lock not only protects the 
> smp_call_function_data pointer but also acts as a lock for that critical 
> section. Without it you'll constantly be overwriting the pointer halfway 
> through IPI acceptance (or even worse whilst a remote CPU is assigning the 
> data members).

Really.  Show me the sequence there? 

I happen to like the pointer_lock a lot, and think we should
make more use of it on systems known to have cmpxchg.  It
saves on the number of cache lines that have to get bounced
between processors.

r~