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Date: Wed, 29 Apr 2026 07:06:52 -1000
Message-ID: <f94a79fcbc4fa07c470c2b6f0fd2e6c9@kernel.org>
From: Tejun Heo <tj@kernel.org>
To: Andrea Righi <arighi@nvidia.com>
Cc: David Vernet <void@manifault.com>,
 Changwoo Min <changwoo@igalia.com>,
 sched-ext@lists.linux.dev,
 Emil Tsalapatis <emil@etsalapatis.com>,
 linux-kernel@vger.kernel.org
Subject: Re: [PATCHSET v3 sched_ext/for-7.2] sched_ext: Topological CPU IDs and cid-form struct_ops
In-Reply-To: <afIHuXXJWHEJnzaO@gpd4>
References: <20260428203545.181052-1-tj@kernel.org>
 <afIHuXXJWHEJnzaO@gpd4>
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Hello,

Yeah. Expanding the in-kernel idle selector to be sub-sched-aware is
hard - it has to respect each sub-sched's cid window, partition
constraints, etc. Cmask in arena makes the same logic a lot easier
to express on the BPF side, so I think the right path is building
that infra in BPF rather than extending ext_idle.c.

Thanks.

--
tejun