We find it useful for GPU compute applications (APU I suppose, with GPU access via IOMMUv2) working on large datasets.

I wouldn't have expected THP to find much use for databases -- those seem to be more like graphics stacks where you have enough hints about future usage to justify explicit management of pages. I thought of THP as "the solution for everything else".

From: James Hartshorn
Sent: Monday, August 24, 2015 3:12 PM
To: linux-mm@kvack.org
Subject: Can we disable transparent hugepages for lack of a legitimate use case please?



Hi,


I've been struggling with transparent hugepage performance issues, and can't seem to find anyone who actually uses it intentionally.  Virtually every database that runs on linux however recommends disabling it or setting it to madvise.  I'm referring to:


/sys/kernel/mm/transparent_hugepage/enabled


I asked on the internet http://unix.stackexchange.com/questions/201906/does-anyone-actually-use-and-benefit-from-transparent-huge-pages and got no responses there.



Independently I noticed


"sysctl: The scan_unevictable_pages sysctl/node-interface has been disabled for lack of a legitimate use case.  If you have one, please send an email to linux-mm@kvack.org."


And thought wow that's exactly what should be done to transparent hugepages.


Thoughts?