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 2CB08C433EF for ; Tue, 3 May 2022 11:42:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234811AbiECLqC (ORCPT ); Tue, 3 May 2022 07:46:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51204 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234783AbiECLqB (ORCPT ); Tue, 3 May 2022 07:46:01 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 86A42E33 for ; Tue, 3 May 2022 04:42:29 -0700 (PDT) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 2137F61615 for ; Tue, 3 May 2022 11:42:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27C84C385A9; Tue, 3 May 2022 11:42:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1651578148; bh=hGA2Groz7gQQ/kmnt+I9Tr5rbZd9MlrRBpWEWxGepXA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KpGxvh0d20K/6UtArbCuUzhFAq7fYvm+TbmiBKBTpGEict/if0lxkTx8lzAVqO4H6 bLNQ7Y7NQprxCAEaY4NxExedCdhS9uEWeyvJpIevEVbKfmeaaPGIre1LFfy65rY51c T5PGdtroK63XI2Y32FfK8XsuUHIlcJGsU18i/qD3NsLGT1KpknOI4jGC3bkyrAHq6A pX4bxTU0DQBefHSl3PaVz8VYy4rcYVsz29kegmPJWe8zu7ZbfGGOGnpOWjQOBvjBU4 I9t/N6xkADnRRG5mEDTXe2WP605jTVs+Ot1Ic3/oPCk3WoLMS1urUdBT8TnJ93kMjM 3CRv9m0gejEOw== Date: Tue, 3 May 2022 13:42:25 +0200 From: Frederic Weisbecker To: Mark Rutland Cc: LKML , Peter Zijlstra , Phil Auld , Alex Belits , Nicolas Saenz Julienne , Xiongfeng Wang , Neeraj Upadhyay , Thomas Gleixner , Yu Liao , Boqun Feng , "Paul E . McKenney" , Marcelo Tosatti , Paul Gortmaker , Uladzislau Rezki , Joel Fernandes Subject: Re: [PATCH 10/21] context_tracking: Take idle eqs entrypoints over RCU Message-ID: <20220503114225.GA2799075@lothringen> References: <20220503100051.2799723-1-frederic@kernel.org> <20220503100051.2799723-11-frederic@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 03, 2022 at 12:02:51PM +0100, Mark Rutland wrote: > Hi Frederic, > > On Tue, May 03, 2022 at 12:00:40PM +0200, Frederic Weisbecker wrote: > > The RCU dynticks counter is going to be merged into the context tracking > > subsystem. Start with moving the idle extended quiescent states > > entrypoints to context tracking. For now those are dumb redirections to > > existing RCU calls. > > I was a bit confused looking at this, because that redirection only exists for > CONFIG_CONTEXT_TRACKING, and is empty otherwise. > > I see this patch makes TREE_RCU select CONTEXT_TRACKING, which means that > works. Since that also means building the rest of the context tracking code, I > think it'd be worth mentioning that in the commit message. Not exactly, it only builds a minimal version of CONTEXT_TRACKING, which maps to roughly the vanilla RCU-idle code. The user tracking part (which is the vanilla CONTEXT_TRACKING) now becomes CONFIG_CONTEXT_TRACKING_USER > Do all architectures which can use TREE_RCU today already support context > tracking? If not, do those work by default? No need to, the old context tracking becomes CONFIG_CONTEXT_TRACKING_USER which is not needed by TREE_RCU. Ok you're right, this is all very confusing :o) Let's clarify this, I'm going to do the following on the next version: * The current CONFIG_CONTEXT_TRACKING becomes CONFIG_CONTEXT_TRACKING_USER. This part needs support from the architecture. * The RCU-idle functions that have been moved to context tracking will become CONFIG_CONTEXT_TRACKING_IDLE. This part doesn't need support from the architecture and will be set by TREE_RCU. Would that look clearer? Thanks.