From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BBF5115746F; Sun, 19 Apr 2026 16:04:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776614680; cv=none; b=hWqnVtWqziPRk5OM2Kv2JOdYYN2ElRBbniJg0TLpi4Aep17R6z4u7tXqVuME/fGT72fXKxS4upQ/9ZvP9g5wmxHqj1HmzMrOWBYn2arOP4QCtZ3J/mYO5ClMq658MbsK3ymzBl60Pgpl4pne4aRhQzKAYvR5/aYgt+kXsjTf/AI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776614680; c=relaxed/simple; bh=rXB26XJY32PxczzTk4m8oATwG9lQdNPWIZad/b92lzY=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References; b=BIfd+/GtTTsAk85K21xgp2u6W4acKSffrGxXULqs4AUnIp/GJLWEnR3bCtTPH5nP3n8fx+a8fdbies6gWNMuFL6ixafPLwU0AFuBOjUFbzRXgs9nbKbyqqncX8hocwWHqy9q5x+UF1gaTx5nRZ6q0MVgNzSj2uGsiT/QdYG832c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=q8ZWI8al; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="q8ZWI8al" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4EF76C2BCAF; Sun, 19 Apr 2026 16:04:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776614680; bh=rXB26XJY32PxczzTk4m8oATwG9lQdNPWIZad/b92lzY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=q8ZWI8al5ypgs+Z0Y27QxLyP7q/6DHbmpt6P/ArF3TRs79g+x2+1LSL2AsEMPNA6i bFeQjpRiCdb0YrjoIwyQkseoIeCYYwgrQWoKGrUZreXRkdgJzUHp3056MSuk1sZsF1 DJH/PVQ+YfG5srxWMu33gpWELg8ejPvOQkxP4OqO5pqcA4K6Kn9zDyiEC1kKqPceFJ ycpOk84nzllColByzYRAyNaHux/kbX++2rlCZBnTJcqeK7VPcbcmbfx/3rXy/oy6p5 uiDGga+Jvp+VUk/bZgYGDxxzgF1ennjNTzK5CRhhMmmtshn1oQodXNGgPJHcBtKRgd XLFZGy718tl7A== Date: Sun, 19 Apr 2026 06:04:39 -1000 Message-ID: <8f403734b8b8f9da6b71dc1804960f9c@kernel.org> From: Tejun Heo To: Cheng-Yang Chou , sched-ext@lists.linux.dev, David Vernet , Andrea Righi , Changwoo Min Cc: Ching-Chun Huang , Chia-Ping Tsai , Emil Tsalapatis , linux-kernel@vger.kernel.org Subject: Re: [PATCH sched_ext/for-7.2] sched_ext: Documentation: update scx_qmap description for BPF arena In-Reply-To: <20260418120058.1555036-1-yphbchou0911@gmail.com> References: <20260418120058.1555036-1-yphbchou0911@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Hello, Thanks for catching this, but the proposed phrasing is a bit misleading. BPF_MAP_TYPE_ARENA isn't a queue-map replacement for BPF_MAP_TYPE_QUEUE - the arena is just memory; the queueing now happens through intrusive doubly-linked lists in arena with per-queue bpf_res_spin_lock. How about matching the file-level description in scx_qmap.bpf.c? For Documentation/scheduler/sched-ext.rst: * ``scx_qmap[.bpf].c``: A multi-level FIFO scheduler supporting five levels of priority implemented with arena-backed doubly-linked lists. For tools/sched_ext/README.md: Another simple, yet slightly more complex scheduler that provides an example of a basic weighted FIFO queuing policy. It also provides examples of some common useful BPF features, such as arena-backed doubly-linked lists threaded through per-task context and `bpf_res_spin_lock` for per-queue synchronization. It also illustrates how core-sched support could be implemented. Thanks. -- tejun