On Mon, Oct 01, 2012 at 10:26:43PM +0000, Brad Walker wrote: > Kent Overstreet <koverstreet@...> writes: > > > > I was just browsing around the code, and I bet I know what it is - > > btree_insert_check_key() is failing because the btree node is full. > > > > But, we should confirm this really is what's going on... Can you apply > > this patch and rerun to test my theory? See if the number of times the > > printk fires lines up with the number of cache misses. > > > > > I applied this change and I see a LOT of the messages. > > And the rate seems to be increasing.
Sweet, we know what it is then. So, like I mentioned this won't be an issue on any workload with mixed read/writes, so if that's what your production workloads are then this may not matter to you. For warming up the cache, doing a few random writes (just enough that you hit all the btree nodes - and there aren't many btree nodes, cat internel/btree_nodes) will fix it. A real fix for this shouldn't be too hard, but it's not exactly trivial and it'll be a pain to test... not quite sure when I'll get to it, but it would be good to have it fixed. -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
