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authorBen Segall <bsegall@google.com>2014-05-15 15:59:20 -0700
committerIngo Molnar <mingo@kernel.org>2014-05-22 11:16:25 +0200
commit3944a9274ef6cda0cc282daf0739832f661670f7 (patch)
tree915704002a970ef8e8f359734355a0784d935088 /kernel/sched
parent6669dc89078da020241e78e5589489e494203332 (diff)
downloadlinux-3944a9274ef6cda0cc282daf0739832f661670f7.tar.bz2
sched: Fix exec_start/task_hot on migrated tasks
task_hot checks exec_start on any runnable task, but if it has been migrated since the it last ran, then exec_start is a clock_task from another cpu. If the old cpu's clock_task was sufficiently far ahead of this cpu's then the task will not be considered for another migration until it has run. Instead reset exec_start whenever a task is migrated, since it is presumably no longer hot anyway. Signed-off-by: Ben Segall <bsegall@google.com> [ Made it compile. ] Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140515225920.7179.13924.stgit@sword-of-the-dawn.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/fair.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 28ccf502c63c..dd3fa14a2998 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4544,6 +4544,9 @@ migrate_task_rq_fair(struct task_struct *p, int next_cpu)
atomic_long_add(se->avg.load_avg_contrib,
&cfs_rq->removed_load);
}
+
+ /* We have migrated, no longer consider this task hot */
+ se->exec_start = 0;
}
#endif /* CONFIG_SMP */