From: Tejun Heo <tj@kernel.org>
To: sashiko-reviews@lists.linux.dev
Cc: sashiko-bot@kernel.org, sched-ext@lists.linux.dev
Subject: Re: [PATCH 10/14] sched_ext: Fix bypassed tasks stalling when the host lacks SCX_CAP_BASE
Date: Thu, 22 Oct 2026 14:03:33 -1000 [thread overview]
Message-ID: <e89a3bde1785fd3609635c463e382318@kernel.org> (raw)
In-Reply-To: <sashiko-outbox-182098@kernel.org>
Hello,
On Thu, Oct 22, 2026 at 10:09:43PM +0000, sashiko-bot@kernel.org wrote:
> [Severity: High]
> Should the initial slice check in dispatch_one() also allow a task with
> scx_task_has_kernel_slice(prev) to keep running while its scheduler is
> bypassing, matching put_prev_task_scx()?
Yes, it should keep the rescuee. The next version adds a patch ahead of
this one. It expires a bypassing prev's slice in dispatch_one() before
the keep test and drops the bypass test from the keep test. A kernel
slice survives the expiry, so a bypassed rescuee keeps the CPU. The
post-dispatch test in scx_dispatch_sched() also can no longer keep a
prev that dispatch_one() declined.
Thanks.
--
tejun
next prev parent reply other threads:[~2026-10-23 0:03 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-22 21:38 [PATCHSET sched_ext/for-7.4] sched_ext: Fix bypassed sub-scheduler tasks stalling when the host lacks caps Tejun Heo
2026-10-22 21:38 ` [PATCH 01/14] sched_ext: Pack scx_ent_flags' multi-bit fields at the top Tejun Heo
2026-10-22 21:38 ` [PATCH 02/14] sched_ext: Clear holding_cpu where the claim is confirmed Tejun Heo
2026-10-22 21:38 ` [PATCH 03/14] sched_ext: Fix bypassed tasks looping on a host without SCX_CAP_ENQ Tejun Heo
2026-10-22 22:04 ` sashiko-bot
2026-10-23 0:03 ` Tejun Heo
2026-10-22 21:38 ` [PATCH 04/14] sched_ext: Move refill_task_slice_dfl() below apply_slice_vtime() Tejun Heo
2026-10-22 21:38 ` [PATCH 05/14] sched_ext: Restore a rescuee's slice after ops.stopping() Tejun Heo
2026-10-22 21:38 ` [PATCH 06/14] sched_ext: Fix a cpu idling with a runnable rescuee Tejun Heo
2026-10-22 21:56 ` sashiko-bot
2026-10-23 0:03 ` Tejun Heo
2026-10-22 21:38 ` [PATCH 07/14] sched_ext: Mark the rescue grant as a kernel slice with SCX_TASK_KERNEL_SLICE Tejun Heo
2026-10-22 21:38 ` [PATCH 08/14] sched_ext: Refuse extending a kernel slice Tejun Heo
2026-10-22 21:38 ` [PATCH 09/14] sched_ext: Fix a cpu idling after put_prev_task_scx() queues its task on the local DSQ Tejun Heo
2026-10-22 21:38 ` [PATCH 10/14] sched_ext: Fix bypassed tasks stalling when the host lacks SCX_CAP_BASE Tejun Heo
2026-10-22 22:09 ` sashiko-bot
2026-10-23 0:03 ` Tejun Heo [this message]
2026-10-22 21:38 ` [PATCH 11/14] sched_ext: Fix the bypass load balancer stranding tasks on cpus where " Tejun Heo
2026-10-22 21:38 ` [PATCH 12/14] sched_ext: Factor out bypass_lb_move() and insert with the donor DSQ unlocked Tejun Heo
2026-10-22 21:38 ` [PATCH 13/14] sched_ext: Let the bypass load balancer move tasks homed on other cpus Tejun Heo
2026-10-22 21:38 ` [PATCH 14/14] sched_ext: Fix queued bypassed tasks stalling when the host loses SCX_CAP_BASE Tejun Heo
2026-10-22 22:04 ` sashiko-bot
2026-10-23 0:03 ` Tejun Heo
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