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=1792705119; b=S1gUAZLb7Ne8lD7yW3YR8oT9syPZwo94a3eA3/VKT4pTLTtRctQ+hMyXyGTHwfubH937 /OwtUzGijYpT6RaCGCgeWYV4kyUwQK6A7Wbq/4v1+37A39ZTv7iL4fazm6jy5TPBBfUFo cLBQSwrkjE58th9nkTOSY7/KS/g8iq8DJ5E9IxbLMFqmTFQPSuIKFqNKziZKnwR6jJtEl AT7k6ZrBb5WegF6LPcOXyv+JM6X+M752PL23vUy/ySCJvp9HI41sbujk/gfrJhwyJgG/u IKrK6v+C1Pw/ZCTnV2Mtjg0Ki46dg0+xdaZbqtsn0IHMS953BIh7XeZlA6IrqC/VgPQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792705119; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=OuFRntLsKWVkhln7NLPq021dG4sakpiOgmRybSJ2J70=; b=QKHWirsxi9e3VQjgrrFX3GpV6d4Azq6bNnZ+CnNhs/pa521xbyLWug2W86yj4lVHKLsR XzZA9XmvwpDjADeefWRjgGtoWtpbxyVkzO82vK+skhJa04OCTXsL+FSx5WiHk1QpNs28y z8+yEiAOiol1pMPTMkZI+3LxZHuRic15wXS4JQBuaU8u/PMgDlgY4IwrsbJuOh/i9NVXQ WzdjRlopcd0A9Mlx/XjVdrRFqTv16rDAu6Aiyb9v3kUJ9uSfHUTqEqvjseVbpTaR5FIHG 4Du0RZ7gfIjHRwnMOVBiTZvj/Vp0VpwSQB85S/N0a0XjR74TqE5WIQvWI2QbT79UFkA== 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=kSD39q6u; 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 A6E4C606A321; Thu, 22 Oct 2026 21:38:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=kSD39q6u Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D5131F01825; Thu, 22 Oct 2026 21:38:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792705118; bh=OuFRntLsKWVkhln7NLPq021dG4sakpiOgmRybSJ2J70=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kSD39q6uEYfGJjrFFV9LOsddZmhafa0ynYmA70IHa3zJeHfjW/VhTDwWwuLa1b34M WRYkoqqoHq+hIEN09nwjSNiLoJHAQ9BNj9smlKq/o4Gvb6IJkgjctMJjKng0nmCU3R etOecexHOer0S7ujdhpjhqQahZtL746OgxnBOXxjmnWlvr0hSD8IoysVTTH+3rxRoG cKLlCUD9yfpzQrFaoGlgn8koFz/fF4tb05AmBH5fNyhbs0/dAIYOSCJg1GqNdIJbBk t4lTCdDfBxhxRO121OaPnYDXF+MpmFpI/nsUZkUMo/0B1O5W3dYVYLWaBFu5XlaZL3 uOKUY/nD9fuxg== From: Tejun Heo To: sched-ext@lists.linux.dev Cc: David Vernet , Andrea Righi , Changwoo Min , Emil Tsalapatis , David Dai , linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 01/14] sched_ext: Pack scx_ent_flags' multi-bit fields at the top Date: Thu, 22 Oct 2026 11:38:23 -1000 Message-ID: <20261022213836.2259069-2-tj@kernel.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261022213836.2259069-1-tj@kernel.org> References: <20261022213836.2259069-1-tj@kernel.org> 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-Transfer-Encoding: 8bit The following patches add a flag for a kernel-owned slice to scx_ent_flags. The two 3-bit fields, the task state at bits 8 to 10 and the reenqueue reason at bits 12 to 14, sit right above the single-bit flags, so the new flag would have to take bit 11 or 15, out of sequence with the rest. Pack the fields at the top of the word, below SCX_TASK_CURSOR, the state at bits 25 to 27 and the reason at bits 28 to 30, so that the single-bit flags continue from bit 8. The renumbering changes the values a BPF scheduler reads from p->scx.flags. Nothing in the kernel or the in-tree schedulers hardcodes the numbers. The enum ABI table in tools/sched_ext/include/scx/enums_abi.autogen.h, kept for repairing enum values that a kernel's BTF truncates, is regenerated for the two fields. In the scx repository, scx_eevdf tests SCX_TASK_REENQ_IMMED and SCX_TASK_REENQ_PREEMPTED against SCX_TASK_REENQ_REASON_MASK. Those three names belong in its load-time enum table, so that they follow the running kernel. No behavior change. Signed-off-by: Tejun Heo --- include/linux/sched/ext.h | 11 +++++--- .../sched_ext/include/scx/enums_abi.autogen.h | 28 +++++++++---------- 2 files changed, 21 insertions(+), 18 deletions(-) diff --git a/include/linux/sched/ext.h b/include/linux/sched/ext.h index efd635a99309..b341c328948e 100644 --- a/include/linux/sched/ext.h +++ b/include/linux/sched/ext.h @@ -107,7 +107,10 @@ enum scx_ent_flags { SCX_TASK_RUN_TRACKED = 1 << 7, /* task is in an ops.running()/stopping() session */ /* - * Bits 8 to 10 are used to carry task state: + * The multi-bit fields are packed at the top, below SCX_TASK_CURSOR, so + * that the single-bit flags stay contiguous from bit 0. + * + * Bits 25 to 27 are used to carry task state: * * NONE ops.init_task() not called yet * INIT_BEGIN ops.init_task() in flight; see sched_ext_dead() @@ -116,7 +119,7 @@ enum scx_ent_flags { * ENABLED fully initialized and in sched_ext * DEAD terminal state set by sched_ext_dead() */ - SCX_TASK_STATE_SHIFT = 8, + SCX_TASK_STATE_SHIFT = 25, SCX_TASK_STATE_BITS = 3, SCX_TASK_STATE_MASK = ((1 << SCX_TASK_STATE_BITS) - 1) << SCX_TASK_STATE_SHIFT, @@ -128,7 +131,7 @@ enum scx_ent_flags { SCX_TASK_DEAD = 5 << SCX_TASK_STATE_SHIFT, /* - * Bits 12 to 14 are used to carry reenqueue reason. In addition to + * Bits 28 to 30 are used to carry reenqueue reason. In addition to * %SCX_ENQ_REENQ flag, ops.enqueue() can also test for * %SCX_TASK_REENQ_REASON_NONE to distinguish reenqueues. * @@ -139,7 +142,7 @@ enum scx_ent_flags { * CAP sub-sched cap miss, see p->scx.reenq_reason_* * PROXY proxy state prevented a remote DSQ transfer */ - SCX_TASK_REENQ_REASON_SHIFT = 12, + SCX_TASK_REENQ_REASON_SHIFT = 28, SCX_TASK_REENQ_REASON_BITS = 3, SCX_TASK_REENQ_REASON_MASK = ((1 << SCX_TASK_REENQ_REASON_BITS) - 1) << SCX_TASK_REENQ_REASON_SHIFT, diff --git a/tools/sched_ext/include/scx/enums_abi.autogen.h b/tools/sched_ext/include/scx/enums_abi.autogen.h index 1186daa9cb14..05a460611c4d 100644 --- a/tools/sched_ext/include/scx/enums_abi.autogen.h +++ b/tools/sched_ext/include/scx/enums_abi.autogen.h @@ -120,24 +120,24 @@ static const struct __scx_enum_abi_val __scx_enum_abi_vals[] { "scx_ent_flags", "SCX_TASK_IMMED", 0x20LLU }, { "scx_ent_flags", "SCX_TASK_PROTECTED", 0x40LLU }, { "scx_ent_flags", "SCX_TASK_RUN_TRACKED", 0x80LLU }, - { "scx_ent_flags", "SCX_TASK_STATE_SHIFT", 0x8LLU }, + { "scx_ent_flags", "SCX_TASK_STATE_SHIFT", 0x19LLU }, { "scx_ent_flags", "SCX_TASK_STATE_BITS", 0x3LLU }, - { "scx_ent_flags", "SCX_TASK_STATE_MASK", 0x700LLU }, + { "scx_ent_flags", "SCX_TASK_STATE_MASK", 0xe000000LLU }, { "scx_ent_flags", "SCX_TASK_NONE", 0x0LLU }, - { "scx_ent_flags", "SCX_TASK_INIT_BEGIN", 0x100LLU }, - { "scx_ent_flags", "SCX_TASK_INIT", 0x200LLU }, - { "scx_ent_flags", "SCX_TASK_READY", 0x300LLU }, - { "scx_ent_flags", "SCX_TASK_ENABLED", 0x400LLU }, - { "scx_ent_flags", "SCX_TASK_DEAD", 0x500LLU }, - { "scx_ent_flags", "SCX_TASK_REENQ_REASON_SHIFT", 0xcLLU }, + { "scx_ent_flags", "SCX_TASK_INIT_BEGIN", 0x2000000LLU }, + { "scx_ent_flags", "SCX_TASK_INIT", 0x4000000LLU }, + { "scx_ent_flags", "SCX_TASK_READY", 0x6000000LLU }, + { "scx_ent_flags", "SCX_TASK_ENABLED", 0x8000000LLU }, + { "scx_ent_flags", "SCX_TASK_DEAD", 0xa000000LLU }, + { "scx_ent_flags", "SCX_TASK_REENQ_REASON_SHIFT", 0x1cLLU }, { "scx_ent_flags", "SCX_TASK_REENQ_REASON_BITS", 0x3LLU }, - { "scx_ent_flags", "SCX_TASK_REENQ_REASON_MASK", 0x7000LLU }, + { "scx_ent_flags", "SCX_TASK_REENQ_REASON_MASK", 0x70000000LLU }, { "scx_ent_flags", "SCX_TASK_REENQ_NONE", 0x0LLU }, - { "scx_ent_flags", "SCX_TASK_REENQ_KFUNC", 0x1000LLU }, - { "scx_ent_flags", "SCX_TASK_REENQ_IMMED", 0x2000LLU }, - { "scx_ent_flags", "SCX_TASK_REENQ_PREEMPTED", 0x3000LLU }, - { "scx_ent_flags", "SCX_TASK_REENQ_CAP", 0x4000LLU }, - { "scx_ent_flags", "SCX_TASK_REENQ_PROXY", 0x5000LLU }, + { "scx_ent_flags", "SCX_TASK_REENQ_KFUNC", 0x10000000LLU }, + { "scx_ent_flags", "SCX_TASK_REENQ_IMMED", 0x20000000LLU }, + { "scx_ent_flags", "SCX_TASK_REENQ_PREEMPTED", 0x30000000LLU }, + { "scx_ent_flags", "SCX_TASK_REENQ_CAP", 0x40000000LLU }, + { "scx_ent_flags", "SCX_TASK_REENQ_PROXY", 0x50000000LLU }, { "scx_ent_flags", "SCX_TASK_CURSOR", 0xffffffff80000000LLU }, { "scx_exit_code", "SCX_ECODE_RSN_HOTPLUG", 0x100000000LLU }, { "scx_exit_code", "SCX_ECODE_RSN_CGROUP_OFFLINE", 0x200000000LLU }, -- 2.56.0