On Tue, May 21, 2019 at 01:04:10AM +0000, Roman Gushchin wrote: > On Mon, May 20, 2019 at 03:40:14PM +1000, Tobin C. Harding wrote: > > We have just implemented Slab Movable Objects (SMO). On NUMA systems > > slabs can become unbalanced i.e. many slabs on one node while other > > nodes have few slabs. Using SMO we can balance the slabs across all > > the nodes. > > > > The algorithm used is as follows: > > > > 1. Move all objects to node 0 (this has the effect of defragmenting the > > cache). > > This already sounds dangerous (or costly). Can't it be done without > cross-node data moves? > > > > > 2. Calculate the desired number of slabs for each node (this is done > > using the approximation nr_slabs / nr_nodes). > > So that on this step only (actual data size - desired data size) has > to be moved? This is just the most braindead algorithm I could come up with. Surely there are a bunch of things that could be improved. Since I don't know the exact use case it seemed best not to optimize for any one use case. I'll review, comment on, and test any algorithm you come up with! thanks, Tobin.
