On Wed, 2011-03-30 at 09:41 +0800, Andrew Morton wrote:
> On Wed, 30 Mar 2011 09:36:40 +0800 Shaohua Li <shaohua.li@xxxxxxxxx> wrote:
>
> > > how is it that this improves things?
> > Hmm, it actually is:
> > struct percpu_counter {
> > spinlock_t lock;
> > s64 count;
> > #ifdef CONFIG_HOTPLUG_CPU
> > struct list_head list; /* All percpu_counters are on a list */
> > #endif
> > s32 __percpu *counters;
> > } __attribute__((__aligned__(1 << (INTERNODE_CACHE_SHIFT))))
> > so lock and count are in one cache line.
>
> ____cacheline_aligned_in_smp would achieve that?
____cacheline_aligned_in_smp can't guarantee the cache alignment for
multiple nodes, because the variable can be updated by multiple
nodes/cpus.
Thanks,
Shaohua
--
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>