[RFC][PATCH 03/10] sched/fair: Cleanup pick_task_fair() vs throttle

Peter Zijlstra
2024-04-05T11:04:04Z

Per 54d27365cae8 ("sched/fair: Prevent throttling in early
pick_next_task_fair()") the reason check_cfs_rq_runtime() is under the
'if (curr)' check is to ensure the (downward) traversal does not
result in an empty cfs_rq.

But then the pick_task_fair() 'copy' of all this made it restart the
traversal anyway, so that seems to solve the issue too.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/sched/fair.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8435,11 +8435,11 @@ static struct task_struct *pick_task_fai
update_curr(cfs_rq);
else
curr = NULL;
-
- if (unlikely(check_cfs_rq_runtime(cfs_rq)))
- goto again;
}

+ if (unlikely(check_cfs_rq_runtime(cfs_rq)))
+ goto again;
+
se = pick_next_entity(cfs_rq);
cfs_rq = group_cfs_rq(se);
} while (cfs_rq);