On 20/03/15 20:31, Matthew Wilcox wrote: > Ah! I've looked at that a couple of times as well. I asked our database > performance team what impact freeing up the memmap would have on their > performance. They told me that doubling the amount of memory generally > resulted in approximately a 40% performance improvement. So freeing up > 1.5% additional memory would result in about 0.6% performance improvement, > which I thought was probably too small a return on investment to justify > turning memmap into a two-level data structure. Don't get me started on databases! This is very much a relational problem, other databases don't suffer like this. (imho relational theory is totally inappropriate for an engineering problem, like designing a database engine ...) Cheers, Wol -- 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