From: Tejun Heo <tj@kernel.org>
To: sashiko-bot@kernel.org
Cc: sched-ext@lists.linux.dev
Subject: Re: [PATCH sched_ext/for-7.3 21/32] sched_ext: Add reject DSQ for cap-rejected dispatches
Date: Fri, 03 Jul 2026 14:54:31 -1000 [thread overview]
Message-ID: <b15777e5dae5fbc21e411d574908bad0@kernel.org> (raw)
In-Reply-To: <20260703125746.0D8371F000E9@smtp.kernel.org>
> [High] Infinite loop of deferred requeues for exiting tasks or tasks
> on offline CPUs when the sub-scheduler lacks capabilities.
This is intended - re-rejection is unbounded by design and a capless
sub is ejected by the stall watchdog, as the function comment notes.
> [High] Tasks undergoing migration (with p->migration_pending set) are
> incorrectly rejected to reject_dsq and then skipped during
> reenqueuing, leaving them stranded indefinitely.
The WARN is an assertion. The migration stopper clears migration_pending
before the re-enqueue, and queued tasks are skipped by
scx_reenq_local(), so it shouldn't reach here. If it turns out it can,
force-admitting it like migration-disabled is a straightforward
follow-up.
Thanks.
next prev parent reply other threads:[~2026-07-04 0:54 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-03 8:01 [PATCHSET sched_ext/for-7.3] sched_ext: Capability-based CPU delegation for sub-schedulers Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 01/32] sched_ext: Fix premature ops->priv publication in scx_alloc_and_add_sched() Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 02/32] tools/sched_ext: scx - Fix cmask_subset(), cmask_equal() and cmask_weight() Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 03/32] sched_ext: Use READ_ONCE/WRITE_ONCE in cmask word ops and drop _RACY variants Tejun Heo
2026-07-03 8:33 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 04/32] tools/sched_ext: scx_qmap - Use bare u64/u32/s32 integer types Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 05/32] sched_ext: Reject direct slice and dsq_vtime writes for cid-form schedulers Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 06/32] sched_ext: Make scx_bpf_kick_cid() return void Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 07/32] sched_ext: Make the kick machinery per-sched Tejun Heo
2026-07-03 9:02 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 08/32] sched_ext: Add ops.init_cids() to finalize the cid layout before init Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 09/32] sched_ext: Add CID sharding Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 10/32] sched_ext: Add shard boundaries to scx_bpf_cid_override() Tejun Heo
2026-07-03 9:51 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 11/32] sched_ext: Defer scx_sched kobj sysfs add into the enable workfns Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 12/32] sched_ext: Add per-shard scx_sched storage scaffolding Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 13/32] sched_ext: Add scx_cmask_ref for validated arena cmask access Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 14/32] sched_ext: RCU-protect the sub-sched tree's children/sibling lists Tejun Heo
2026-07-03 10:49 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 15/32] sched_ext: Add scx_skip_subtree_pre() Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 16/32] sched_ext: Add per-shard cap delegation for sub-schedulers Tejun Heo
2026-07-03 11:17 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 17/32] sched_ext: Add coalescing sub_caps_updated() notifier " Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 18/32] sched_ext: Maintain per-cpu effective cap copies for single-read checks Tejun Heo
2026-07-03 12:05 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 19/32] sched_ext: Add sub_ecaps_updated() effective-cap change notifier Tejun Heo
2026-07-03 12:25 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 20/32] sched_ext: Generalize local-DSQ handling to rq-owned DSQs Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 21/32] sched_ext: Add reject DSQ for cap-rejected dispatches Tejun Heo
2026-07-03 12:57 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo [this message]
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 22/32] sched_ext: Add the SCX_CAP_ENQ_IMMED cap Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 23/32] sched_ext: Assign a unique id to each scheduler instance Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 24/32] sched_ext: Route task slice writes through set_task_slice() Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 25/32] sched_ext: Tie cpu occupancy to SCX_CAP_BASE through the task slice Tejun Heo
2026-07-03 13:34 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 26/32] sched_ext: Add the SCX_CAP_ENQ cap Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 27/32] sched_ext: Gate kicks on SCX_CAP_BASE and preemption on SCX_CAP_PREEMPT Tejun Heo
2026-07-03 14:01 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 28/32] sched_ext: Route ops.update_idle() to sub-schedulers and re-notify owed scheds Tejun Heo
2026-07-03 14:14 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 29/32] sched_ext: Replay ecaps notifications suppressed by bypass Tejun Heo
2026-07-03 14:28 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 30/32] sched_ext: Add scx_bpf_sub_kill() to evict a child sub-scheduler Tejun Heo
2026-07-03 14:45 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 31/32] tools/sched_ext: scx_qmap - Expand hierarchical sub-scheduling Tejun Heo
2026-07-03 14:57 ` sashiko-bot
2026-07-04 0:54 ` Tejun Heo
2026-07-03 8:01 ` [PATCH sched_ext/for-7.3 32/32] tools/sched_ext: scx_qmap - Add sub-sched cap fault injection Tejun Heo
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