On Thu, Nov 29, 2012 at 11:02:24AM -0800, Andi Kleen wrote: > Dave Chinner <david@xxxxxxxxxxxxx> writes: > > > > Comments, thoughts and flames all welcome. > > Doing the reclaim per CPU sounds like a big change in the VM balance. It's per node, not per CPU. And AFAICT, it hasn't changed the balance of page cache vs inode/dentry caches under general, global workloads at all. > Doesn't this invalidate some zone reclaim mode settings? No, because zone reclaim is per-node and the shrinkers now can reclaim just from a single node. i.e. the behaviour is now better suited to the aims of zone reclaim which is to free memory from a single, targetted node. Indeed, I removed a hack in the zone reclaim code that sprayed slab reclaim across the entire machine until sufficient objects had been freed from the target node.... > How did you validate all this? fakenuma setups, various workloads that generate even dentry/slab cache loadings across all nodes, adding page cache pressure on a single node, watching slab reclaim from a single node. that sort of thing. I haven't really done any performance testing other than "not obviously slower". There's no point optimising anything before there's any sort of agreement as to whether this is the right approach to take or not.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>