From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 08DFEC2BB48 for ; Tue, 15 Dec 2020 14:17:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C358D224D2 for ; Tue, 15 Dec 2020 14:17:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728591AbgLOORm (ORCPT ); Tue, 15 Dec 2020 09:17:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727876AbgLOORj (ORCPT ); Tue, 15 Dec 2020 09:17:39 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D081C0617A7 for ; Tue, 15 Dec 2020 06:16:59 -0800 (PST) From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1608041817; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ULkU1PcbpU2l78G0960G5T5ULxU0eHA7I68Bh4WAkAs=; b=2N8vwfNesIbjMsnaZv1Pa641cJW2CutAPno9ssCZehFw+hU283saN7357z/MisfuQ7l5pE WQzvh5NdNg9GJWJYhHWJf5BvO79E3HaXbEEHxq8geZZdLLI98UYc40r27CQevc/g1skPCw Aupd//h+OcNCKdE6u+Ok+/XQg93Bf4jukka7B4Vlniu5oPvDWAoWJwNUZGvzdCx7jqUOw2 JzyRALXGL07ohgS0vl92SNtrsmV4AqM2lgcbeWzd55SiF3N1zUo/ZJ7AzSQHUrcgOg4YaA kizra7Cg2RmDoKYHeLk4fEim0Wz4jxPv59Ta+5qpdlNFiC9UZCcXacwESQBBUw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1608041817; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ULkU1PcbpU2l78G0960G5T5ULxU0eHA7I68Bh4WAkAs=; b=Vx+awOVGxDrnLs+DfoOVhaaSmR3a3nOBWx5XeOeHG6FT5LyMn1T2SIN2XWzKMNG654USX0 kGZFF6uveYUiIhCQ== To: rcu@vger.kernel.org Cc: "Paul E. McKenney" , Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , Scott Wood , Thomas Gleixner , Sebastian Andrzej Siewior Subject: [PATCH 1/5] rcu: make RCU_BOOST default on CONFIG_PREEMPT_RT Date: Tue, 15 Dec 2020 15:16:45 +0100 Message-Id: <20201215141649.796472-2-bigeasy@linutronix.de> In-Reply-To: <20201215141649.796472-1-bigeasy@linutronix.de> References: <20201215141649.796472-1-bigeasy@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org With RCU callbacks deferred to the `rcuc' thread it is more likely that people run into OOM if the RCU reader or the thread is stalled for too long and RCU can't continue its work. On PREEMPT_RT this is more likely because the amount of RT tasks is higher and the general workload involves more RT tasks. Make RCU_BOOST default on PREEMPT_RT to ease the configuration. It can be still disabled if someone knows better. Signed-off-by: Sebastian Andrzej Siewior --- kernel/rcu/Kconfig | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig index cdc57b4f6d48a..aa8cc8c977e78 100644 --- a/kernel/rcu/Kconfig +++ b/kernel/rcu/Kconfig @@ -188,8 +188,8 @@ config RCU_FAST_NO_HZ =20 config RCU_BOOST bool "Enable RCU priority boosting" - depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT - default n + depends on (RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT) || PREEMPT_RT + default y if PREEMPT_RT help This option boosts the priority of preempted RCU readers that block the current preemptible RCU grace period for too long. --=20 2.29.2