On Wed, Feb 03, 2016 at 06:11:56PM -0500, Waiman Long wrote: > On 01/31/2016 07:47 PM, Dave Chinner wrote: > >So at what point does simply replacing the list_head with a list_lru > >become more efficient than this batch processing (i.e. > >https://lkml.org/lkml/2015/3/10/660)? The list_lru isn't a great > >fit for the inode list (doesn't need any of the special LRU/memcg > >stuff https://lkml.org/lkml/2015/3/16/261) but it will tell us if, > >like Ingo suggested, moving more towards a generic per-cpu list > >would provide better overall performance... > > I will take a look at the list_lru patch to see if that help. As for > the per-cpu list, I tried that and it didn't quite work out. OK, see my last email as to why Andi's patch didn't change anything. The list_lru implementation has a list per node, a lock per node, and each item is placed on the list for the node it is physically allocated from. Hence for local workloads, the list/lock that is accessed for add/remove should be local to the node and hence should reduce cache line contention mostly to within a single node. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- 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
