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=1793060271; b=jbYNtTcvWcLJ1S3PQ05MGMmtDoWOc8lcJLO4ekUr1M7DrdKAwh1utdLku4yMImY4ELRp K0bwxKzdntKgRv4MMiC7z4x5eku2ayxIEWlQywLd8ucGLwVLRlyarV7wnceyl2Xw/YlgH ZwoM57SUsz81dE3GYMBJxv3MPu1Zerzjz5aC2v+91iwTMjD2Hi2vjGUx9IJXblUnC1MF9 MHUlbllesGZwtwjcLTMXDtAMckd1XOhYMA8nvCP2Hg9smhB3wzFTO+xT02bT4hPGuvZFH JYNyRTPRsBy8K6NYEIktccJ7oyhUB3ljbjuk4QtH07c9MJzYHsHB+E9G049A4eY5UXw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793060271; 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=fHrLRHIe6SFAB9C/mOQRVN4w+yPjFiWqDASBk+JqESDUASAaif0QASWkIOIfMApj2bpA XO6YKNVkpYhS27mJsgaoxCN6DG45JMsCoHTVhpoIK+zFlEc712WIlRk+upBLiwx0b+25x BihYPERtGu9CKn+6RM98st3f15H6m7MHgsnusIcgMi7zOlczdQFcIlhbDcs/+irpvRTCg j70RKj3pMCK50DXBj6jr+afjor11ICGIjL1a1M3YMO8bfZXpitKg4D6XdW7bDZZwHymB2 NDMLzCohd3elJHTjTtrplloXtYihTxWugle6RufL2M9kX5kBxv/6OAPcz2XKOgHmxCw== 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=ZSh0ZDTQ; 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 76264606A321; Tue, 27 Oct 2026 00:17:51 +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=ZSh0ZDTQ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0A21C1F01825; Tue, 27 Oct 2026 00:17:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793060271; bh=OuFRntLsKWVkhln7NLPq021dG4sakpiOgmRybSJ2J70=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ZSh0ZDTQAO4uQw/uFtLs3ILMR6ju8DhUgm5Ail4VGtq9haKGbrERtjCxgS7Agd2zP a1f/w5+U308vOK74oz1w7owYzMrAjYeCwvMf5EoRgaXMjBu5VI2CvDAqCY4GRNjv3v BHeIEySRykIqi5N3i7dlEyUOaTriQ+4S1ww0GJHwN8JaJnp1cX6vMvrxYrt6KuB6ge PhRjvMKNnCqIY/500k+hVnXNj5AU8uEFdeU6vB7QhsYgN0rKuZP082nx0yH+fHyWYn bt7CvQ0f+U9uB4yiI+0wPKekPvxPE+KcGrdAzuK+vJ58YNEwmBZcZI1WitA6V1s+il nYNppI0Txq79A== 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 01/18] sched_ext: Pack scx_ent_flags' multi-bit fields at the top Date: Mon, 26 Oct 2026 14:17:32 -1000 Message-ID: <20261027001749.1821379-2-tj@kernel.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261027001749.1821379-1-tj@kernel.org> References: <20261027001749.1821379-1-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