On Mon, Jan 27, 2014 at 05:03:44PM -0500, r...@redhat.com wrote: > From: Rik van Riel <r...@redhat.com> > > Use the active_nodes nodemask to make smarter decisions on NUMA migrations. > > In order to maximize performance of workloads that do not fit in one NUMA > node, we want to satisfy the following criteria: > 1) keep private memory local to each thread > 2) avoid excessive NUMA migration of pages > 3) distribute shared memory across the active nodes, to > maximize memory bandwidth available to the workload > > This patch accomplishes that by implementing the following policy for > NUMA migrations: > 1) always migrate on a private fault > 2) never migrate to a node that is not in the set of active nodes > for the numa_group > 3) always migrate from a node outside of the set of active nodes, > to a node that is in that set > 4) within the set of active nodes in the numa_group, only migrate > from a node with more NUMA page faults, to a node with fewer > NUMA page faults, with a 25% margin to avoid ping-ponging > > This results in most pages of a workload ending up on the actively > used nodes, with reduced ping-ponging of pages between those nodes. > > Cc: Peter Zijlstra <pet...@infradead.org> > Cc: Mel Gorman <mgor...@suse.de> > Cc: Ingo Molnar <mi...@redhat.com> > Cc: Chegu Vinod <chegu_vi...@hp.com> > Signed-off-by: Rik van Riel <r...@redhat.com>
Acked-by: Mel Gorman <mgor...@suse.de> -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
