From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794599461; b=0+3xwWXSUbTXAQfWHd+K2ALM3o6s2mrfZMbGIc3sWDhVQhbtIWbCUzKA7+7IVMUPBf8a lWFkBoJT69BuUngdAeW8TtVAsHxewlzM4GFtlBzz4Ke847hdAxafRRR0Vpmr+hjPCx4hP xk7VWb7zVadw2ZQOEHbuKJmvoHpwPR89nlc+hUHEqofmqGKbRoWQQ8OICQm2F0+uubEyB wyqt3HW8ilDUizJfvwUf3lWUI2GCp/4GY/ArZFUb8pz6pAuKpmquCtZlgVAPp67RKvWej q0GqKQd/U0st+8vhWVYRhT2gks+zli7X9nsN6NuUbFu6WTOkALgPKUvhrgEQNeRzhIQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794599461; h=Received:DKIM-Signature:Date:Message-ID:From:To:Cc:Subject: In-Reply-To:References:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=1RViC7k9xKhgymEU03e/S7bNs6re40TdTRhXbj9cDgQ=; b=ETsv9RWpg2tNEQdBI5X9i1KaSur6fIQChtTyik3E/0SazZimj5ioiHyJMaeuw5Qim5tt b9isJO7LVB58P4H8TSgRyqDdf4NykkpBzB66VwCkHzpxxsdShzCUsXTx/RzIQ3nyQ1v0Z aVMsZAzxJs4O9KhNMTCdpp+BzaxQspoWHo2fGOnUmjMTMXSDX4JrfWGqn6LrycMc2Eo9l DwFaLAX9FMe8BoK3ChQVWDbIUVmO9gYh2hJKM1fzji839rdyDdZzrHyLmES+2fOwGKTQa ymG4QDj7ZOG82yY3q6jqq3N0BqjwuHndrW4dLrkfUgzK45tqxyudv2qfwKX1Sl8/m1w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=leDAC8+b; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3034C606A32D; Fri, 13 Nov 2026 19:51:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=leDAC8+b Received: by smtp.kernel.org (Postfix) with ESMTPSA id CADD01F000C4; Fri, 13 Nov 2026 19:51:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794599461; bh=1RViC7k9xKhgymEU03e/S7bNs6re40TdTRhXbj9cDgQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=leDAC8+bQloJn/mEZ9sZ1efIwIAqUVa3id0mx/Y2OlOs9fVnjj4oKZ29696nzFK7x 1t3oPt5lQr76cPiw4ip5HYWAvsgSXaTDaTQcGcc7/SbdwTnhLZlwHfXEDeMIeo4oex UCIi9I6eKG9DHyTLmaaFcBNaxalsgJUx2BfwooQyGyHqdUaxpvsCEp+G/+P+XwmAfb W00+IFZOB6APS+IUJf/aTxiV3RBzfSKM3UASuw7sW7HSSX8x/N9iQP3xUFSd2PQvAj LE6BlN9cwi8CQv6dsiTR4u8t/swVJSgNoIbEj1j/rw2FNvHrjGkS7ogepXaeMr5pOU mbuO9/v3iQu+w== Date: Fri, 13 Nov 2026 09:50:59 -1000 Message-ID: <2a1f54ec70384b99add9987a462b2052@kernel.org> From: Tejun Heo To: Kang Chen Cc: David Vernet , Andrea Righi , Changwoo Min , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org, bpf@vger.kernel.org Subject: Re: [PATCH sched_ext v2 1/2] sched_ext: make DSQ iterator stay drained after NULL In-Reply-To: <20261113024505.922854-1-k.chen@smail.nju.edu.cn> References: <20261110125113.2935742-1-k.chen@smail.nju.edu.cn> <20261113024505.922854-1-k.chen@smail.nju.edu.cn> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hello, Kang. v1 is already applied to sched_ext/for-7.4-fixes. The selftest doesn't catch the bug reliably. Every ops.dequeue() invocation overwrites next_after_drain and the test reads it once at the end. If the last invocation saw an empty DSQ, the restarted walk returns NULL too and the test passes on a kernel without the fix. Here, it passed about half of the runs on an idle VM without the fix. Also, I don't think the selftest is all that useful. Thanks. -- tejun