sched/fair: Use cfs_rq->h_curr in distribute_cfs_runtime()

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distribute_cfs_runtime() refreshes the rq clock and accounts elapsed
runtime with update_curr() before redistributing bandwidth, but gates
this on cfs_rq->curr. Since commit 85570f10a4 ("sched/eevdf: Move to
a single runqueue") cfs_rq->curr is only maintained on the root
cfs_rq, so for the cgroup cfs_rqs it walks, the check never fires and
the refresh is dead code.

Use cfs_rq->h_curr, the per-level current entity, restoring the
intended behaviour: only refresh when something is actually running at
the throttled level, i.e. within the deferred throttle window.
Without this, runtime consumed by a still-running task of the
throttled hierarchy is not docked before redistribution;
unthrottle_cfs_rq() catches up unconditionally since
commit 28ad542768 ("sched/fair: Call update_curr() before
unthrottling the hierarchy"), so this is not a correctness hole today,
but the refresh the check was written for is gone.

Fixes: 85570f10a4 ("sched/eevdf: Move to a single runqueue")
Signed-off-by: Wanwu Li <liwanwu@kylinos.cn>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Aaron Lu <ziqianlu@bytedance.com>
Tested-by: Aaron Lu <ziqianlu@bytedance.com>
Link: https://patch.msgid.link/20260831101141.391382-3-liwanwu@kylinos.cn

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Wanwu Li 2026-08-31 18:11:41 +08:00 • committed by Peter Zijlstra

parent f8610c57f4

commit b038383526

1 changed files with 1 additions and 1 deletions

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kernel/sched/fair.c

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