From nobody Wed Nov 27 14:30:00 2024 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 2A9671E0DC5; Wed, 9 Oct 2024 18:00:46 +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=1728496847; cv=none; b=PX5jnZHLxWHWPOyAZH5Xrh9HQiCXlFi5xAAWecKZG895u/PnQPO/lxtHKQWfOvo8zoEP2235znLs6GfYHWVvLbPLQ9kvAACvwNG3uDvEgm+X2vtHHLdXJgstv+TTIKBuhyBzGu0UVDlIOx5k18hcitRX9gBbd2WKm1Ant7Mc2Ak= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728496847; c=relaxed/simple; bh=vpuIgx5kDOrF1tvN1wFdkRmFqkJZGZwsKVqT4sAsn8E=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=pXx1OyqytY0LolwZDHuxL5t/a4q8Ar8hmMTKEGrDk5JMxNFvfk8dofv460W23Ntdt2rpbB7wNFJK4fEiu/6+FWgXlj4jQhEhPgC8t7c6dMDu5AIGD1s8XLfa+pHs9+lWOhqCMQ3hbczQhLvPJS2soNKM7qEIrLR4hKsmLGqgK04= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=vGcpGRHG; 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="vGcpGRHG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C9ACCC4CECF; Wed, 9 Oct 2024 18:00:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728496846; bh=vpuIgx5kDOrF1tvN1wFdkRmFqkJZGZwsKVqT4sAsn8E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vGcpGRHGEXMF9dLRiTMFtMsfpal65nz3iH4dwnTOVDbZNXp/l/8IUf8yG85J/dJhb 7yWJY/K1pFKDQP97xf56Q36xSVy8JoHnCkO0bVKr0OAkePB9PsqzjXHZ5WAL1mZIRm 9SM5fTxx1D1P6aI4F0Bd0KHYOHmlgQGBnhNKd9sY0RG/REnBmW9sBY+3ifs6bCpkrb IEkBXd2wuq0d5dD5ZpI7CSq2OZYk8tq6F0sZQDvdJhC3RoXi1X05DbUBxoRJmPcz3U ivpP8uopy1/dpgXilpKAnjqMTE1wsXCUBVCBG7G8TT2tj7dmAaH3YKzz0En8KrkiJD ThTBKgT2m1efA== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 6E7C8CE0BB1; Wed, 9 Oct 2024 11:00:46 -0700 (PDT) From: "Paul E. McKenney" To: frederic@kernel.org, rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, "Paul E. McKenney" , Peter Zijlstra , Neeraj Upadhyay Subject: [PATCH rcu 3/7] rcu: Allow short-circuiting of synchronize_rcu_tasks_rude() Date: Wed, 9 Oct 2024 11:00:41 -0700 Message-Id: <20241009180045.777721-3-paulmck@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <2dc6de07-374d-44da-82e9-fa9d9c516b46@paulmck-laptop> References: <2dc6de07-374d-44da-82e9-fa9d9c516b46@paulmck-laptop> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" There are now architectures for which all deep-idle and entry-exit functions are properly inlined or marked noinstr. Such architectures do not need synchronize_rcu_tasks_rude(), or will not once RCU Tasks has been modified to pay attention to idle tasks. This commit therefore allows a CONFIG_ARCH_HAS_NOINSTR_MARKINGS Kconfig option to turn synchronize_rcu_tasks_rude() into a no-op. To facilitate testing, kernels built by rcutorture scripting will enable RCU Tasks Trace even on systems that do not need it. [ paulmck: Apply Peter Zijlstra feedback. ] Signed-off-by: Paul E. McKenney Cc: Peter Zijlstra Signed-off-by: Neeraj Upadhyay --- kernel/rcu/tasks.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 6333f4ccf024b..dd9730fd44fbe 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1398,7 +1398,8 @@ static void call_rcu_tasks_rude(struct rcu_head *rhp,= rcu_callback_t func) */ void synchronize_rcu_tasks_rude(void) { - synchronize_rcu_tasks_generic(&rcu_tasks_rude); + if (!IS_ENABLED(CONFIG_ARCH_WANTS_NO_INSTR) || IS_ENABLED(CONFIG_FORCE_TA= SKS_RUDE_RCU)) + synchronize_rcu_tasks_generic(&rcu_tasks_rude); } EXPORT_SYMBOL_GPL(synchronize_rcu_tasks_rude); =20 --=20 2.40.1