Commit-ID: 5085e2a328849bdee6650b32d52c87c3788ab01c
Gitweb: http://git.kernel.org/tip/5085e2a328849bdee6650b32d52c87c3788ab01c
Author: Rik van Riel <riel@xxxxxxxxxx>
AuthorDate: Fri, 11 Apr 2014 13:00:28 -0400
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 7 May 2014 13:33:46 +0200
sched/numa: Retry placement more frequently when misplaced
When tasks have not converged on their preferred nodes yet, we want
to retry fairly often, to make sure we do not migrate a task's memory
to an undesirable location, only to have to move it again later.
This patch reduces the interval at which migration is retried,
when the task's numa_scan_period is small.
Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>
Tested-by: Vinod Chegu <chegu_vinod@xxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1397235629-16328-3-git-send-email-riel@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/fair.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index f6457b6..ecea8d9 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1326,12 +1326,15 @@ static int task_numa_migrate(struct task_struct *p)
/* Attempt to migrate a task to a CPU on the preferred node. */
static void numa_migrate_preferred(struct task_struct *p)
{
+ unsigned long interval = HZ;
+
/* This task has no NUMA fault statistics yet */
if (unlikely(p->numa_preferred_nid == -1 || !p->numa_faults_memory))
return;
/* Periodically retry migrating the task to the preferred node */
- p->numa_migrate_retry = jiffies + HZ;
+ interval = min(interval, msecs_to_jiffies(p->numa_scan_period) / 16);
+ p->numa_migrate_retry = jiffies + interval;
/* Success if task is already running on preferred CPU */
if (task_node(p) == p->numa_preferred_nid)
--
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