* Benjamin Herrenschmidt (benh@kernel.crashing.org) wrote:

On Tue, 2013-07-23 at 07:33 -0500, Robert Jennings wrote:

quoted

When an associativity level change is found for one thread, the
siblings threads need to be updated as well.  This is done today
for PRRN in stage_topology_update() but is missing for VPHN in
update_cpu_associativity_changes_mask().

All threads should be updated to move to the new node.  Without this
patch, a single thread may be flagged for a topology change, leaving it
in a different node from its siblings, which is incorrect.  This causes
problems for the scheduler where overlapping scheduler groups are created
and a loop is formed in those groups.

Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Robert Jennings <redacted>
Cc: <redacted>

Patch breaks the UP build ...

Cheers,
Ben.

Very sorry about that, a fix is on the way.