Messages in this thread | | | Date | Mon, 19 Mar 2012 10:31:47 -0500 (CDT) | From | Christoph Lameter <> | Subject | Re: [RFC][PATCH 10/26] mm, mpol: Make mempolicy home-node aware |
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On Mon, 19 Mar 2012, Peter Zijlstra wrote:
> > No they wont work the same way as before. Applications may be relying on > > MPOL_DEFAULT behavior now expecting node local allocations. The home-node > > functionality would cause a difference in behavior because it would > > perform remote node allocs when a thread has been moved to a different > > socket. The changes also cause migrations that may cause additional > > latencies as well as change the location of memory in surprising ways for > > the applications > > Still not sure what you're suggesting though, you argue to keep the > default what it is, this is in direct conflict with making the default > do something saner for most of the time.
MPOL_DEFAULT is a certain type of behavior right now that applications rely on. If you change that then these applications will no longer work as expected.
MPOL_DEFAULT is currently set to be the default policy on bootup. You can change that of course and allow setting MPOL_DEFAULT manually for applications that rely on old behavor. Instead set the default behavior on bootup for MPOL_HOME_NODE.
So the default system behavior would be MPOL_HOME_NODE but it could be overriding by numactl to allow old apps to run as they are used to run.
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