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| author |   Vincent Guittot <vincent.guittot@linaro.org> | 2022-08-25 14:27:23 +0200 |
|---|---|---|
| committer |   Peter Zijlstra <peterz@infradead.org> | 2022-09-15 16:13:51 +0200 |
| commit | b0defa7ae03ecf91b8bfd10ede430cff12fcbd06 (patch) | |
| tree | d590d068e868d7ce347e237d7e04095a65193388 | |
| parent | sched: Show PF_flag holes (diff) | |
| download | linux-dev-b0defa7ae03ecf91b8bfd10ede430cff12fcbd06.tar.xz linux-dev-b0defa7ae03ecf91b8bfd10ede430cff12fcbd06.zip | |
sched/fair: Make sure to try to detach at least one movable task
During load balance, we try at most env->loop_max time to move a task.
But it can happen that the loop_max LRU tasks (ie tail of
the cfs_tasks list) can't be moved to dst_cpu because of affinity.
In this case, loop in the list until we found at least one.
The maximum of detached tasks remained the same as before.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220825122726.20819-2-vincent.guittot@linaro.org
| -rw-r--r-- | kernel/sched/fair.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 4e5b171b1171..dae3bfae1bc0 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8049,8 +8049,12 @@ static int detach_tasks(struct lb_env *env) p = list_last_entry(tasks, struct task_struct, se.group_node); env->loop++; - /* We've more or less seen every task there is, call it quits */ - if (env->loop > env->loop_max) + /* + * We've more or less seen every task there is, call it quits + * unless we haven't found any movable task yet. + */ + if (env->loop > env->loop_max && + !(env->flags & LBF_ALL_PINNED)) break; /* take a breather every nr_migrate tasks */ @@ -10179,7 +10183,9 @@ more_balance: if (env.flags & LBF_NEED_BREAK) { env.flags &= ~LBF_NEED_BREAK; - goto more_balance; + /* Stop if we tried all running tasks */ + if (env.loop < busiest->nr_running) + goto more_balance; } /* |