Commit 9de05d48 authored by Rik van Riel's avatar Rik van Riel Committed by Ingo Molnar

sched/numa: Check all nodes when placing a pseudo-interleaved group

In pseudo-interleaved numa_groups, all tasks try to relocate to
the group's preferred_nid.  When a group is spread across multiple
NUMA nodes, this can lead to tasks swapping their location with
other tasks inside the same group, instead of swapping location with
tasks from other NUMA groups. This can keep NUMA groups from converging.

Examining all nodes, when dealing with a task in a pseudo-interleaved
NUMA group, avoids this problem. Note that only CPUs in nodes that
improve the task or group score are examined, so the loop isn't too
bad.
Tested-by: default avatarVinod Chegu <chegu_vinod@hp.com>
Signed-off-by: default avatarRik van Riel <riel@redhat.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Vinod Chegu" <chegu_vinod@hp.com>
Cc: mgorman@suse.de
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20141009172747.0d97c38c@annuminas.surriel.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 54009416
...@@ -1436,8 +1436,15 @@ static int task_numa_migrate(struct task_struct *p) ...@@ -1436,8 +1436,15 @@ static int task_numa_migrate(struct task_struct *p)
/* Try to find a spot on the preferred nid. */ /* Try to find a spot on the preferred nid. */
task_numa_find_cpu(&env, taskimp, groupimp); task_numa_find_cpu(&env, taskimp, groupimp);
/* No space available on the preferred nid. Look elsewhere. */ /*
if (env.best_cpu == -1) { * Look at other nodes in these cases:
* - there is no space available on the preferred_nid
* - the task is part of a numa_group that is interleaved across
* multiple NUMA nodes; in order to better consolidate the group,
* we need to check other locations.
*/
if (env.best_cpu == -1 || (p->numa_group &&
nodes_weight(p->numa_group->active_nodes) > 1)) {
for_each_online_node(nid) { for_each_online_node(nid) {
if (nid == env.src_nid || nid == p->numa_preferred_nid) if (nid == env.src_nid || nid == p->numa_preferred_nid)
continue; continue;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment