sched_ext: scx_qmap: Fix pending partition work handoff

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qmap can leave partition work pending with no runner. The effective-cap
callback publishes its request after failing to acquire part_busy, while
redistribute() checks for pending work before releasing it. Either ordering
can miss a request arriving as the current runner finishes, delaying the
update until the round-robin timer runs.

Publish requests before trying to become the runner and release part_busy
before checking for more work. Have all holders drain pending requests after
releasing it, including the stats flush. Distinguish mask refreshes from
repartitions so an effective-cap update only rebuilds the partition when a
repartition was also requested.

Fixes: e9151ed5c9 ("tools/sched_ext: scx_qmap - Expand hierarchical sub-scheduling")
Reported-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

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Tejun Heo 2026-09-05 12:53:44 -10:00

parent 63b4ff6222

commit 89ff16f071

1 changed files with 40 additions and 35 deletions

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tools/sched_ext/scx_qmap.bpf.c

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