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 5514E191F98; Sat, 7 Mar 2026 00:28:19 +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=1772843299; cv=none; b=NuceJ59NGJtRA4w7cj7WfeNkjUN5Od+WqXzTr28uxSHEwCqMJ14XrW04mJRfX58Kr8ieBvOFidq44bF0PU3Gz/mhrpA/7xaY8ZKDZgfMJ674Wb2E6YNB5GkgEj74esayvxDVdKsM8JhadOoo6eE2ztctJqmLafvPh1byhA3xJqU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772843299; c=relaxed/simple; bh=62J/+zN5REtrjq/LC1pIqtJ8l/XjaLyxLvF7fwry5jU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=bYQNIm1iqi4h2i2mr7O5DAXTEgOnkd2glBaZJaU9LVoYdedojReRiEk+mXhTjkw01HYH6nLR80wLUh7/bkh1bK8r0x6MmSD0UU7TY18nLe61yK+ulVl5v8++95AAfMEb7VIuOcIx5Nb4rnhxpOFQThxygpgSN/apKphb87oAkng= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kjSdZEaX; 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="kjSdZEaX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CA090C4CEF7; Sat, 7 Mar 2026 00:28:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772843299; bh=62J/+zN5REtrjq/LC1pIqtJ8l/XjaLyxLvF7fwry5jU=; h=From:To:Cc:Subject:Date:From; b=kjSdZEaXeYwuVvbcx02bKdYFcPUcA3lJU1l7CZJuQIljsL3FosmvlAlLjHS/n8CTi FMD0OwKT4GnFfottFglrtkR/rlKAlnDgyz+fcH5OyIlulEkzGZ5rTsvx8OK9ovgS1+ QB00Uw0fFfz2aL/j9VlwCRb0t0Hq27egGTm0zdtOGFSFhlL2UArDaCuFazh4/jDFcF sFo2Rjwtu1pkI0GrihNUT6jEHGGuqTpcCshSp/vkHQ82uQsaMM0xcT5xY0QZkb5VDF 9dOMfZoHeWBcGT2Zgi7hBFaub7y/IBTCLE6OXLqMzkE/XljHQG0yo66SdZ6vyGDxqf yZH5HW6aKDuFQ== From: Tejun Heo To: David Vernet , Andrea Righi , Changwoo Min Cc: sched-ext@lists.linux.dev, Emil Tsalapatis , linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCHSET sched_ext/for-7.1] sched_ext: Implement SCX_ENQ_IMMED Date: Fri, 6 Mar 2026 14:28:14 -1000 Message-ID: <20260307002817.1298341-1-tj@kernel.org> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: sched-ext@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hello, SCX_ENQ_IMMED makes enqueue to local DSQs succeed only if the task can start running immediately - the current task is done and no other tasks are waiting. If the condition isn't met, the task is re-enqueued through ops.enqueue(). This gives the BPF scheduler tighter control over when tasks actually land on a CPU. - Patch 1 disallows setting slice to zero via scx_bpf_task_set_slice() as zero slice is used by ENQ_IMMED to detect whether the current task is done. - Patch 2 implements SCX_ENQ_IMMED with reenqueue support and loop detection. - Patch 3 adds SCX_OPS_ALWAYS_ENQ_IMMED ops flag to automatically apply IMMED to all local DSQ enqueues. This patchset depends on: - "sched_ext: Overhaul DSQ reenqueue infrastructure" http://lkml.kernel.org/r/20260306190623.1076074-1-tj@kernel.org Based on sched_ext/for-7.1 (4f8b122848db) + scx-reenq (a41719e6ae12). 0001-sched_ext-Disallow-setting-slice-to-zero-via-scx_bpf.patch 0002-sched_ext-Implement-SCX_ENQ_IMMED.patch 0003-sched_ext-Add-SCX_OPS_ALWAYS_ENQ_IMMED-ops-flag.patch Git tree: git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext.git scx-enq-immed include/linux/sched/ext.h | 3 + kernel/sched/ext.c | 208 +++++++++++++++++++++++++++++++---- kernel/sched/ext_internal.h | 43 ++++++++ kernel/sched/sched.h | 2 + tools/sched_ext/include/scx/compat.h | 1 + tools/sched_ext/scx_qmap.bpf.c | 7 +- tools/sched_ext/scx_qmap.c | 9 +- 7 files changed, 250 insertions(+), 23 deletions(-) -- tejun