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From: Tejun Heo <tj@kernel.org>
To: Tao Cui <cui.tao@linux.dev>
Cc: void@manifault.com, arighi@nvidia.com, changwoo@igalia.com,
	liwanwu@kylinos.cn, usama.arif@linux.dev,
	sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org,
	bpf@vger.kernel.org, Tao Cui <cuitao@kylinos.cn>
Subject: Re: [PATCH 3/6] sched_ext: Return -EBUSY from a pre-init scx_bpf_sub_caps() read
Date: Thu, 12 Nov 2026 07:34:35 -1000	[thread overview]
Message-ID: <b2c95831800d2cd21fd28ec66f84cd9c@kernel.org> (raw)
In-Reply-To: <20261112130934.563321-4-cui.tao@linux.dev>

Hello, Tao.

On Thu, Nov 12, 2026 at 09:09:31PM +0800, Tao Cui wrote:
> Return -EBUSY instead: the caller sees a retryable "not ready yet"
> and the comment's expected scenario stays survivable. This mirrors
> how the cid path already handles the same class of pre-init window:
> reads before the tables are published test the table pointer and
> return -EINVAL instead of killing the scheduler.

Why is this useful? ops.init_cids() is documented to run before caps and
shards are finalized, so there's nothing for a scheduler to query or retry
from there.

Thanks.

--
tejun

  reply	other threads:[~2026-11-12 17:34 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-12 13:09 [PATCH 0/6] sched_ext: fix kfunc, sub-sched, flatcg and idle-mask issues Tao Cui
2026-11-12 13:09 ` [PATCH 1/6] sched_ext: Reject DSQ iterator kfuncs in tracing programs Tao Cui
2026-11-12 17:34   ` Tejun Heo
2026-11-12 13:09 ` [PATCH 2/6] sched_ext: Make scx_bpf_cid_node() a benign lookup for invalid cids Tao Cui
2026-11-12 17:34   ` Tejun Heo
2026-11-12 13:09 ` [PATCH 3/6] sched_ext: Return -EBUSY from a pre-init scx_bpf_sub_caps() read Tao Cui
2026-11-12 17:34   ` Tejun Heo [this message]
2026-11-12 13:09 ` [PATCH 4/6] sched_ext: Reject cid_online/cid_offline on sub-schedulers Tao Cui
2026-11-12 17:34   ` Tejun Heo
2026-11-12 13:09 ` [PATCH 5/6] tools/sched_ext: scx_flatcg: Don't strand a cgroup on the ENQ_RACE path Tao Cui
2026-11-12 17:34   ` Tejun Heo
2026-11-12 13:09 ` [PATCH 6/6] sched_ext: Clear the built-in idle masks on CPU hotplug transitions Tao Cui
2026-11-12 17:34   ` Tejun Heo
2026-11-12 17:34 ` [PATCH 0/6] sched_ext: fix kfunc, sub-sched, flatcg and idle-mask issues Tejun Heo

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