On Tue, Feb 22, 2011 at 05:43:31PM +0100, Andrea Arcangeli wrote: > On Tue, Feb 22, 2011 at 08:36:26AM -0800, Dave Hansen wrote: > > On Mon, 2011-02-21 at 11:07 -0800, Andi Kleen wrote: > > > From: Andi Kleen <ak@xxxxxxxxxxxxxxx> > > > > > > I found it difficult to make sense of transparent huge pages without > > > having any counters for its actions. Add some counters to vmstat > > > for allocation of transparent hugepages and fallback to smaller > > > pages. > > > > > > Optional patch, but useful for development and understanding the system. > > > > Very nice. I did the same thing, splits-only. I also found this stuff > > a must-have for trying to do any work with transparent hugepages. It's > > just impossible otherwise. > > This patch is good too. 1 and 8 I think can go in, patch 1 is high > priority. > > Patches 2-5 I've an hard time to see how they're not hurting > performance instead of improving it, especially patch 3 looks dead Well right now THP destroys memory locality and that is a quite bad regression. Destroying memory locality hurts performance significantly. In general the assumption that you can get the full policy from the vma only is wrong: for local you always have to look at the node of the existing page too. I haven't had any reports of KSM doing so, but it seems better to fix it in the same way. Don't feel very strongly about KSM for this though, i guess these parts could be dropped too. I guess you're right and KSM is a bit of a lost cause for NUMA anyways. Also in my experience KSM is very little memory usually anyways so it shouldn't matter too much. I guess I can drop that part if it's controversal. -Andi -- ak@xxxxxxxxxxxxxxx -- Speaking for myself only. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>