Messages in this thread Patch in this message | | | Date | Thu, 22 May 2014 05:26:37 -0700 | From | tip-bot for Ben Segall <> | Subject | [tip:sched/core] sched: Fix exec_start/task_hot on migrated tasks |
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Commit-ID: 3944a9274ef6cda0cc282daf0739832f661670f7 Gitweb: http://git.kernel.org/tip/3944a9274ef6cda0cc282daf0739832f661670f7 Author: Ben Segall <bsegall@google.com> AuthorDate: Thu, 15 May 2014 15:59:20 -0700 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Thu, 22 May 2014 11:16:25 +0200
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> --- kernel/sched/fair.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 28ccf50..dd3fa14 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 */
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