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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6C618C433F5 for ; Wed, 29 Sep 2021 19:18:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4821B61505 for ; Wed, 29 Sep 2021 19:18:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245386AbhI2TUO (ORCPT ); Wed, 29 Sep 2021 15:20:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245131AbhI2TUN (ORCPT ); Wed, 29 Sep 2021 15:20:13 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59BBEC06161C; Wed, 29 Sep 2021 12:18:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=rDlIUYjTm39b2Z8IS0wdVZ3JLOJjy6yOyLpknJOI2Nk=; b=lGmQZw71exQWPBnjdWDupYTtpl D8qQqLKPHK023bQNN4tNkbfBTffbADEjCZunnGWQjBOwSS4aH9ij8l17t7tgIHwTbWcOhMh4MIr3E 31ancIfRMc6e+1OsxQ7gr9KDO+NX5DZv1+ra8fgd0SHhILuuYvmrRsDLqbXKJiTv/cHM/Ji+qNpLX T7dT5w11uy0lerIvt9/KXJ5F47+TRayB+rvQoKngfgfKIB/YgASU0ULQT871sOocBWjQUwdK9R9my /NdHjyGL3C0S16BTc7GW1p7Xtu9+tO7VkULafumTPIxUNOsmvXXqHwyJ0WfNTsGl1PkYYUtwspuYI z/HXk/+Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mVf1D-00C9dK-Am; Wed, 29 Sep 2021 19:14:09 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id D1E8A981431; Wed, 29 Sep 2021 21:13:26 +0200 (CEST) Date: Wed, 29 Sep 2021 21:13:26 +0200 From: Peter Zijlstra To: "Paul E. McKenney" Cc: gor@linux.ibm.com, jpoimboe@redhat.com, jikos@kernel.org, mbenes@suse.cz, pmladek@suse.com, mingo@kernel.org, linux-kernel@vger.kernel.org, joe.lawrence@redhat.com, fweisbec@gmail.com, tglx@linutronix.de, hca@linux.ibm.com, svens@linux.ibm.com, sumanthk@linux.ibm.com, live-patching@vger.kernel.org, rostedt@goodmis.org, x86@kernel.org Subject: Re: [RFC][PATCH v2 08/11] context_tracking,rcu: Replace RCU dynticks counter with context_tracking Message-ID: <20210929191326.GZ4323@worktop.programming.kicks-ass.net> References: <20210929151723.162004989@infradead.org> <20210929152429.007420590@infradead.org> <20210929183701.GY880162@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210929183701.GY880162@paulmck-ThinkPad-P17-Gen-1> Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org On Wed, Sep 29, 2021 at 11:37:01AM -0700, Paul E. McKenney wrote: > And what happens to all of this in !CONFIG_CONTEXT_TRACKING kernels? > Of course, RCU needs it unconditionally. (There appear to be at least > parts of it that are unconditionally available, but I figured that I > should ask. Especially given the !CONFIG_CONTEXT_TRACKING definition > of the __context_tracking_cpu_seq() function.) For !CONFIG_CONTEXT_TRACKING it goes *poof*. Since the thing was called dynticks, I presumed it was actually dynticks only, silly me (also, I didn't see any obvious !context_tracking usage of it, i'll go audit it more carefully.