From nobody Thu Apr 9 17:15:45 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 388D333E37B; Fri, 6 Mar 2026 10:31:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772793077; cv=none; b=emBdsgs30RuslE71o0n4A+m4cobp3ATZlh+syN32LrjUkmO31L0K5u5G7NHJl4TNnBMgK2PXi2YshL44cBL7Bdy2sFfjlvBNSVAyp5mUTerTMq5iEFCDO+OxIdwxHt6OkjJt5Uj6/osD3EbnjYFXQ6gJb2Hro9v+TsUpLo41+7o= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772793077; c=relaxed/simple; bh=kw2XtYZN3Kr84aIBUsDMUgvLsYNsSuOOpGAKDmubLBU=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=CWYarJECCgxLFA2uiDUh6Dj0I1Ao9Sf4gjbFIXJt2XNZG0Q83lqeSg+If/YI5rLSknQu9/wysxMeqZ8MStgaFXwveKBrZ9xCF69RQTUvGAmWHgNmuKMK6Z2mQ+LoF1JaOETcjO2A9t5WAmGhrJ48el62ZLVHvfx1jUSFGUMVCVw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 15A30497; Fri, 6 Mar 2026 02:31:09 -0800 (PST) Received: from e127648.cambridge.arm.com (e127648.arm.com [10.1.27.43]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 1764A3F694; Fri, 6 Mar 2026 02:31:13 -0800 (PST) From: Christian Loehle To: tj@kernel.org, corbet@lwn.net, linux-kernel@vger.kernel.org Cc: arighi@nvidia.com, linux-doc@vger.kernel.org, Christian Loehle Subject: [PATCH] sched_ext: Documentation: Mention scheduling class precedence Date: Fri, 6 Mar 2026 10:30:51 +0000 Message-Id: <20260306103051.1038604-1-christian.loehle@arm.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Mention the scheduling class precedence of fair and sched_ext to clear up how sched_ext partial mode works. Signed-off-by: Christian Loehle Acked-by: Andrea Righi --- Documentation/scheduler/sched-ext.rst | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/Documentation/scheduler/sched-ext.rst b/Documentation/schedule= r/sched-ext.rst index 9e2882d937b4..100d45963781 100644 --- a/Documentation/scheduler/sched-ext.rst +++ b/Documentation/scheduler/sched-ext.rst @@ -58,7 +58,8 @@ in ``ops->flags``, all ``SCHED_NORMAL``, ``SCHED_BATCH``,= ``SCHED_IDLE``, and However, when the BPF scheduler is loaded and ``SCX_OPS_SWITCH_PARTIAL`` is set in ``ops->flags``, only tasks with the ``SCHED_EXT`` policy are schedu= led by sched_ext, while tasks with ``SCHED_NORMAL``, ``SCHED_BATCH`` and -``SCHED_IDLE`` policies are scheduled by the fair-class scheduler. +``SCHED_IDLE`` policies are scheduled by the fair-class scheduler which has +higher sched_class precedence than ``SCHED_EXT``. =20 Terminating the sched_ext scheduler program, triggering `SysRq-S`, or detection of any internal error including stalled runnable tasks aborts the --=20 2.34.1