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=-11.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 2C960C55179 for ; Tue, 3 Nov 2020 15:07:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E0ABD221FB for ; Tue, 3 Nov 2020 15:07:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="NSZmoJN8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728277AbgKCPHq (ORCPT ); Tue, 3 Nov 2020 10:07:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53208 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728192AbgKCPHk (ORCPT ); Tue, 3 Nov 2020 10:07:40 -0500 Received: from mail-qv1-xf42.google.com (mail-qv1-xf42.google.com [IPv6:2607:f8b0:4864:20::f42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5CC19C0617A6 for ; Tue, 3 Nov 2020 07:07:40 -0800 (PST) Received: by mail-qv1-xf42.google.com with SMTP id i17so5808180qvp.11 for ; Tue, 03 Nov 2020 07:07:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=4n4eKbeBF029LZEVM8Tx6GsjHib9jcrVPlcNT/Y/Yx0=; b=NSZmoJN8BVndRdwEMQQd1+hTP/RRmifn9wf265YZzYwbSlBwPLhY/7F+PPW8+Y/68Z WhaRUJ9ki+KpWXZMu3+oEIcJ3fB2Gebdj/gTiMHYKlV8qP+I6Q7s1tqR8f9p+oMu9ftV 5LSvV7PyTDq2NTyClPrKeEVZGckDJ2mmhvauo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=4n4eKbeBF029LZEVM8Tx6GsjHib9jcrVPlcNT/Y/Yx0=; b=Ikkil5UmRD1O65DARgxMC5Pv85pEhrsfad0/wyv2mowa9a/6LQ6GMKRC7Iltz1rb7l p2V5Z0a8cImtBHcauW9vxUtNIySM5uo4NUXkzT0YyItwYz7kBp2l8MDTrQGwsIRdwFp2 /TtP2r6RKRWL6KXff7dGGdlwl+4gOo70Jt05wEUwt4MSbhi1doiitz/nIAsa576PANGZ fO8yAecNE7BGSI4wIkgYz2Q5HuN+gGEjSlhFQGm4lW6PfT7CdQ9K4kPofyVMXjT/pZFu QzXxXr0WYMhoBg38EU3BwZUhuoeXbL7iMUcd22On64dR9Oe6kH5mt0D1vNBCeEXRIdgQ Nl2g== X-Gm-Message-State: AOAM530Wh7kIQAFJWK+CIXakjXUj7f4/BFbhtQU67i7iFqrlx6OImdPw o6uPFxeAnAdR04Qb7Gw7Flmu8IVIy8uJpA== X-Google-Smtp-Source: ABdhPJzzlcDLLdFjM34pMHGZgTdfKu/8EkQtfR2uV18EK3dvw/pyiibGX7BzyhFs4My2qNIiqkFtUA== X-Received: by 2002:ad4:4985:: with SMTP id t5mr25591422qvx.27.1604416059573; Tue, 03 Nov 2020 07:07:39 -0800 (PST) Received: from localhost ([2620:15c:6:411:cad3:ffff:feb3:bd59]) by smtp.gmail.com with ESMTPSA id c6sm4857206qke.35.2020.11.03.07.07.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Nov 2020 07:07:38 -0800 (PST) Date: Tue, 3 Nov 2020 10:07:38 -0500 From: Joel Fernandes To: Frederic Weisbecker Cc: linux-kernel@vger.kernel.org, Josh Triplett , Lai Jiangshan , Marco Elver , Mathieu Desnoyers , "Paul E. McKenney" , rcu@vger.kernel.org, Steven Rostedt , "Uladzislau Rezki (Sony)" , fweisbec@gmail.com, neeraj.iitr10@gmail.com Subject: Re: [PATCH v9 3/7] srcu: Fix invoke_rcu_callbacks() segcb length adjustment Message-ID: <20201103150738.GB1304393@google.com> References: <20201103142603.1302207-1-joel@joelfernandes.org> <20201103142603.1302207-4-joel@joelfernandes.org> <20201103144714.GA432431@lothringen> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201103144714.GA432431@lothringen> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 03, 2020 at 03:47:14PM +0100, Frederic Weisbecker wrote: > On Tue, Nov 03, 2020 at 09:25:59AM -0500, Joel Fernandes (Google) wrote: > > With earlier patches, the negative counting of the unsegmented list > > cannot be used to adjust the segmented one. To fix this, sample the > > unsegmented length in advance, and use it after CB execution to adjust > > the segmented list's length. > > > > Reviewed-by: Frederic Weisbecker > > Suggested-by: Frederic Weisbecker > > Signed-off-by: Joel Fernandes (Google) > > This breaks bisection, you need to either fix up the previous patch > by adding this diff inside or better yet: expand what you did > in "rcu/tree: Make rcu_do_batch count how many callbacks were executed" > to also handle srcu before introducing the segcb count. Since doing the latter is a lot more tedious and I want to get reviewing other's RCU patches today :) , I just squashed the suggestion into the counters patch to fix bissection: https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git/commit/?h=rcu/segcb-counts&id=595e3a65eeef109cb8fcbfcc114fd3ea2064b873 Hope that's Ok. Also, so that I don't have to resend everything, here is the final branch if Paul wants to take it: git://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git (branch rcu/segcb-counts) Thank you for your time, Frederick! - Joel