On Fri 25-05-12 13:57:38, Kent Overstreet wrote: > Right now, users of the rb tree code have to open code their own search and > insert functions. This provides generic versions that you pass a comparison > function to. > > I highly doubt the extra function calls are going to have a measurable > performance impact in practice - the pointer chasing is going to dominate. I > did provide inline versions just in case, though - it's modelled after the > spinlock code. > > The inline version of rb_search() is important for another reason, though - you > have to pass rb_search a pointer to your struct for it to compare against, > which has to be allocated on the stack. For most users I think that'll be fine, > but for the elevator code struct rb_node is embedded in struct request, which > is rather large. By using the inline version that stack allocation goes away. > > (I looked at the generated assembly of elv_rb_find() before and after, and if > I'm reading it right it's not using any extra stack. Code is a bit worse, but > IMO removing code duplication is worth it). > > Kent Overstreet (3): > rbtree: Add rb_insert(), rb_search(), etc. > timerqueue: convert to generic rb tree code > block: convert elevator to generic rb tree code Hum, are you aware of another generic rb-tree attempt - https://lkml.org/lkml/2012/4/30/132 ? Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
