From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E7D3D3C8704 for ; Fri, 20 Mar 2026 16:47:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774025243; cv=none; b=hI6ZWsze2Msr+76Q7BuH1CAXpji3T+VlYRbuF2DLXsrqDvSNb8gJdzIv1Ofrxxf5KMx9Eecog3UwQ7RkFaIdOg5BLFJQbtKvKd04fhkDDneGk2NmvG3vYhy5NQxu0p1lAi36/aC83pzfMW4onn5SnCz23qxKFVX+NqZeDX9gesQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774025243; c=relaxed/simple; bh=zW8GrpQDlgm5g2KgQWwbmI7hUPlq2kkNd1LKt0TyYlQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=tqpVxvyrNbuGmQizzj3dZVf+V+v64taSkYLkvUPVOi5QX/4BHGMyB/jZWnxvEBRWR5FqpTERp1CAbJ8SCI69sG9DlInj8fqQKfz18xVagydCvWoQ/2PLLan/uTgcI5cg1+wD74APey5baHzL9zKkV+Oms9GvshTeZOzvFIJ69uM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jpiecuch.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=ZoOV21YK; arc=none smtp.client-ip=209.85.128.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jpiecuch.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ZoOV21YK" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-48535f4d5e1so21116835e9.0 for ; Fri, 20 Mar 2026 09:47:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1774025240; x=1774630040; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=zW8GrpQDlgm5g2KgQWwbmI7hUPlq2kkNd1LKt0TyYlQ=; b=ZoOV21YKKV28rkzmW2rG8zxktZTgXZUfFxvgZrWzHUrGEccv8T8CgI+bNYM1mR1Wqs 1us7mQhdsX4nUe//PV8ONyNBZj5zJPzP3Pdfy4gLOPkz7l1ZHK+LadA252wAfjDd5V/d laW9qwHhtfG+75hbrpFhZXIBbwr+zwSzIRm9ztwZHZ0MIcoJs2pdY+LUFPwC8WmsBVUU tYKlmqI0CNgyUm0UBXQaBc9JoEEbT1Ci8QFidWnT87Z1XW7+lMI63N1IFPqIZT5crPhu 60037LX7oSOZCgWAmSGfGI2Fu/3IOdFkFLcap+GSu/lcr99BPUPMM2rfQnr6894l+Txo VU6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774025240; x=1774630040; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=zW8GrpQDlgm5g2KgQWwbmI7hUPlq2kkNd1LKt0TyYlQ=; b=F2pl9XW9dStsDsz4DLGwvisICgLzXNcz4w/0m1t5qmVz36IQf14DK/miJsY3ngF8kU SQr29lobjH88f32rnZV0xQOw/PQvfd9VIEJw2kDbxHjxQRUnL4mUoyWQlTSNyrlCL4tw ut+AjBYH5AF5r8vBOpKek8XXvMVJGq12L5NdcRkC3RGUIeCwZvFRwUF/oceOjRJr5s8H Fh5lawhk1tEFkRSn4xmJDFCmy8/cn+qljvWguFHwl3gS3Cv6XEyR4ClZfT9ALUQR902l 92Wwsi1WysvR+a+jskiOocKXg+EzL4+Sa/0Qy2TeHBdRPsV1rEdFqfg0YJD214h3hGjo VMEg== X-Forwarded-Encrypted: i=1; AJvYcCUOjXx9kIUkaVon0s645u4WBi+a5cNiBLQNBhWBP5N8jJORg8jQ2EUzd4BjSWsyvOW5bSMqJJpVIJJhvOY=@vger.kernel.org X-Gm-Message-State: AOJu0YzzGcrRN/SJluHj5ZaGnGmMmLfRjjaHN0Jzscc9A9Y6hJYr4uUm 6Tpp00BkzTyDG6xkSJ9hN0JQLZAZAtbolZhwKayuI+1/cD0fMcoOfdQxSvoJUJq5m8j9d7RQ0dp TqeoB9LFJSfC8UA== X-Received: from wmbjs7.prod.google.com ([2002:a05:600c:5647:b0:477:9c96:9fb9]) (user=jpiecuch job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:4707:b0:480:20f1:7aa6 with SMTP id 5b1f17b1804b1-486fee231cdmr52691015e9.21.1774025240258; Fri, 20 Mar 2026 09:47:20 -0700 (PDT) Date: Fri, 20 Mar 2026 16:47:19 +0000 In-Reply-To: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260305062900.43450-1-arighi@nvidia.com> X-Mailer: aerc 0.21.0-0-g5549850facc2 Message-ID: Subject: Re: [PATCH v2] sched_ext: Document task ownership state machine From: Kuba Piecuch To: Kuba Piecuch , Andrea Righi , Tejun Heo , David Vernet , Changwoo Min Cc: Emil Tsalapatis , Daniel Hodges , , Content-Type: text/plain; charset="UTF-8" On Fri Mar 20, 2026 at 1:56 PM UTC, Kuba Piecuch wrote: > This prompted me to have a look at the logic around SCX_OPSS_QUEUED and I can't > convince myself that it's correct in the case of direct dispatches to > non-builtin DSQs. > > The only place where ops_state is set to QUEUED is at the end of > do_enqueue_task(). Notably, this assignment is skipped in the case of direct > dispatch. > > direct_dispatch() will then call dispatch_enqueue() with SCX_ENQ_CLEAR_OPSS, > causing ops_state to be reset to NONE. We end up in a state where the task > is enqueued on a user DSQ, its ops_state is NONE and p->scx.flags has > SCX_TASK_IN_CUSTODY, which doesn't look like a consistent state to me. > > Am I missing something here? I just saw the comment in ops_dequeue() introduced by your ops.dequeue() patchset, so I guess this is WAI. Please disregard this comment.