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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF30CC433F5 for ; Wed, 12 Jan 2022 01:03:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344870AbiALBDJ (ORCPT ); Tue, 11 Jan 2022 20:03:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344077AbiALBDG (ORCPT ); Tue, 11 Jan 2022 20:03:06 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 88A53C06173F for ; Tue, 11 Jan 2022 17:03:06 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 0A393CE1BBB for ; Wed, 12 Jan 2022 01:03:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B244C36AE3; Wed, 12 Jan 2022 01:03:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1641949383; bh=175gygNvX/igOQyHqyBDa6ice4DXkW9ovpC1HV7NYf8=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=qPbVAd37NkIJ4rKHTPYTMlgNUGKVsXrwBbVC+iJhiX9euf2gI9U1KaPjHk3Ek9hdC tvxWdAa2mpx/b654GnISkJNBgNvzm0lJees8WJ2bT95CKq6fDoWP+3hgfcEgGbuEPc 1/C5ew0aLceZfcLxj7bF5GswGypm0TAPrAPk9m3VMYvtCmL6ABRKU0nXCbZpMO+uAd +UMz47e6ZTKQ3EAAeUiv6eb9GDDpR6aIIMG+WeJxy7ZfkNd49fiXrsOD6bB4KllpRi wPOwjTzUgwVgqg7djrPd5vj6A/24TRfYBN3wPxy7P2UERQle16d2A9V8CW24XOrDwn w1OcXL8WpLAxA== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id BA94D5C0DA1; Tue, 11 Jan 2022 17:03:02 -0800 (PST) Date: Tue, 11 Jan 2022 17:03:02 -0800 From: "Paul E. McKenney" To: Alison Chaiken Cc: tglx@linutronix.de, peterz@infradead.org, valentin.schneider@arm.com, frederic@kernel.org, linux-kernel@vger.kernel.org, glenn@aurora.tech, alison@she-devel.com Subject: Re: [PATCH 0/5] handle kthread_prio kernel cmdline parameter consistently Message-ID: <20220112010302.GL947480@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org References: <20220111233253.21692-1-achaiken@aurora.tech> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220111233253.21692-1-achaiken@aurora.tech> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 11, 2022 at 03:32:49PM -0800, Alison Chaiken wrote: > When CONFIG_PREEMPT_RT=y, RCU_SOFTIRQ work is moved to dedicated rcuc > per-core threads. The rcutree.kthread_prio kernel cmdline parameter > controls the priority of those threads. > > A provided kthread_prio kernel cmdline parameter also elevates the > priority of rcuog threads, but only if they are launched from > rcu_spawn_gp_kthread(), not if they are launched from > rcu_spawn_one_nocb_kthread(). Fix this inconsistency. > > When CONFIG_RCU_NOCB_CPU=y, an rcu_nocbs command-line parameter > offloads the work of rcuc on designated cores to new rcuop threads > that are not pinned to the cores whose expired grace-period timer > callbacks they run. While rcuop threads have the same function as > rcuc threads, their priority is not controlled by the kthread_prio > parameter. Add this feature and update the documentation accordingly. > > Alison Chaiken (4): > RCU: move kthread_prio bounds-check to a separate function > RCU: make priority of grace-period thread consistent > RCU: elevate priority of offloaded callback threads > RCU: update documentation regarding kthread_prio cmdline parameter I have queued these for review and testing, thank you! 2/4 appears to have been produced against a pre-merge-window mainline, so I had to adjust it a bit to queue it on -rcu. Please check to make sure that I did not mess anything up. Thanx, Paul