On Fri 23-01-09 23:49:12, Andrew Morton wrote: > On Fri, 16 Jan 2009 19:08:09 +0100 Jan Kara <jack@xxxxxxx> wrote: > > > static DEFINE_SPINLOCK(dq_list_lock); > > +static DEFINE_SPINLOCK(dq_state_lock); > > DEFINE_SPINLOCK(dq_data_lock); > > The chances are very good that two or even three of these locks will > all get placed into the same cacheline in main memory. The effects > will be quite bad if different CPUs (or, worse, different nodes) are > taking these locks. > > For single, kernel-wide locks like these I think we should almost > always pad out to a cacheline. I never thought about this. Thanks for the idea. > With __cacheline_aligned_in_smp, rather than __cacheline_aligned. > Because spinlocks do take space even in uniprocessor builds. I've added this to my list of quota cleanups. Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
