Re: [RFC PATCH 2/3] Add tunable to control THP behavior

2013-12-12 Thread Alex Thorlton
On Thu, Dec 12, 2013 at 04:37:11PM -0500, Rik van Riel wrote: > On 12/12/2013 01:00 PM, Alex Thorlton wrote: > >This part of the patch adds a tunable to > >/sys/kernel/mm/transparent_hugepage called threshold. This threshold > >determines how many pages a user must fault in from a single node befo

Re: [RFC PATCH 2/3] Add tunable to control THP behavior

2013-12-12 Thread Rik van Riel
On 12/12/2013 01:00 PM, Alex Thorlton wrote: This part of the patch adds a tunable to /sys/kernel/mm/transparent_hugepage called threshold. This threshold determines how many pages a user must fault in from a single node before a temporary compound page is turned into a THP. +++ b/mm/huge_mem

Re: [RFC PATCH 2/3] Add tunable to control THP behavior

2013-12-12 Thread Alex Thorlton
> Right. I like that behavior for my workload. (Although I currently > allocate huge pages -- when I wrote that code, THP interacted so badly > with pagecache that it was a non-starter. I think it's fixed now, > though.) In that case, it's probably best to just stick with current behavior, and

Re: [RFC PATCH 2/3] Add tunable to control THP behavior

2013-12-12 Thread Andy Lutomirski
On Thu, Dec 12, 2013 at 12:49 PM, Alex Thorlton wrote: > > > Is there a setting that will turn off the must-be-the-same-node > > behavior? There are workloads where TLB matters more than cross-node > > traffic (or where all the pages are hopelessly shared between nodes, > > but hugepages are stil

Re: [RFC PATCH 2/3] Add tunable to control THP behavior

2013-12-12 Thread Alex Thorlton
> Is there a setting that will turn off the must-be-the-same-node > behavior? There are workloads where TLB matters more than cross-node > traffic (or where all the pages are hopelessly shared between nodes, > but hugepages are still useful). That's pretty much how THPs already behave in the kern

Re: [RFC PATCH 2/3] Add tunable to control THP behavior

2013-12-12 Thread Andy Lutomirski
On Thu, Dec 12, 2013 at 10:00 AM, Alex Thorlton wrote: > This part of the patch adds a tunable to > /sys/kernel/mm/transparent_hugepage called threshold. This threshold > determines how many pages a user must fault in from a single node before > a temporary compound page is turned into a THP. Is

[RFC PATCH 2/3] Add tunable to control THP behavior

2013-12-12 Thread Alex Thorlton
This part of the patch adds a tunable to /sys/kernel/mm/transparent_hugepage called threshold. This threshold determines how many pages a user must fault in from a single node before a temporary compound page is turned into a THP. Signed-off-by: Alex Thorlton Cc: Andrew Morton Cc: Nate Zimmer