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=-17.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PULL_REQUEST,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 AF719C4363D for ; Tue, 22 Sep 2020 16:25:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6407723A34 for ; Tue, 22 Sep 2020 16:25:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600791947; bh=Zy3XcAZEuXN9x3ObhUD0OY7DYKY3IewXpXT4gnrZLFk=; h=Date:From:To:Cc:Subject:Reply-To:List-ID:From; b=dOKtahKYQoY6BeB/y5oCcw6ZFfhRvDmKxVirJd2RqqYfowvxFVBNpF0gzAWOFKgkZ ppe02bgaW8wTWguthzNN9EfPSUtVqaL1Q1kOJRZ0+SECUzxi/0MgKktiWDvDqIVio9 0xMc6rhOODOUEaXnhZ+RDpSZTOFtH1HrC7UBS4tY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726661AbgIVQZq (ORCPT ); Tue, 22 Sep 2020 12:25:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:52518 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726563AbgIVQZn (ORCPT ); Tue, 22 Sep 2020 12:25:43 -0400 Received: from paulmck-ThinkPad-P72.home (unknown [50.45.173.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D5C5E2395C; Tue, 22 Sep 2020 16:25:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600791942; bh=Zy3XcAZEuXN9x3ObhUD0OY7DYKY3IewXpXT4gnrZLFk=; h=Date:From:To:Cc:Subject:Reply-To:From; b=ri3+yqDmAouwXMzNVoMrn+apPOU3KeYF+QJwAGX4CFY0tK6fLjZnliX2qVuTYM+l+ eX8iUz9BYmB0JRbdWuGpjlnMDG4T2cidrq+lSDwhddV5cH8+DpliLu8c/fngYKbGTk T7TCMB4MkGqM/q0BnfAYqr6ecXYK2zASoeE8ei0c= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 7B79B35227BD; Tue, 22 Sep 2020 09:25:42 -0700 (PDT) Date: Tue, 22 Sep 2020 09:25:42 -0700 From: "Paul E. McKenney" To: ast@kernel.org Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@kernel.org, tglx@linutronix.de, daniel@iogearbox.net, jolsa@redhat.com, bpf@vger.kernel.org, kernel-team@fb.com Subject: [GIT PULL rcu-tasks-trace] 50x speedup for synchronize_rcu_tasks_trace() Message-ID: <20200922162542.GA18664@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Hello, Alexei, This pull request contains eight commits that speed up RCU Tasks Trace grace periods by a factor of 50, fix a few race conditions exposed by this speedup, and clean up a couple of minor issues. These have been exposed to 0day and -next testing, and have passed well over 1,000 hours of rcutorture testing, some of which has contained ad-hoc changes to further increase race probabilities. So they should be solid! (Famous last words...) I would normally have sent this series up through -tip, but as we discussed, going up through the BFP and networking trees provides the needed exposure to real-world testing of these changes. Please note that the first patch is already in mainline, but given identical SHA-1 commit IDs, git should have no problem figuring this out. I will also be retaining these commits in -rcu in order to continue exposing them to rcutorture testing, but again the identical SHA-1 commit IDs will make everything work out. The fact that these commits will reside in multiple trees is of course what motivates inclusion of the otherwise unrelated minor-issue cleanups. Including these cleanups allows all the various trees to keep synchronized SHA-1 commit IDs. And so, without further ado: The following changes since commit 9123e3a74ec7b934a4a099e98af6a61c2f80bbf5: Linux 5.9-rc1 (2020-08-16 13:04:57 -0700) are available in the git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git rtt-speedup.2020.09.16a for you to fetch changes up to f747c7e15d7bc71a967a94ceda686cf2460b69e8: rcu-tasks: Enclose task-list scan in rcu_read_lock() (2020-09-16 16:32:38 -0700) ---------------------------------------------------------------- Paul E. McKenney (8): rcu-tasks: Prevent complaints of unused show_rcu_tasks_classic_gp_kthread() rcu-tasks: Mark variables static rcu-tasks: Use more aggressive polling for RCU Tasks Trace rcu-tasks: Selectively enable more RCU Tasks Trace IPIs rcu-tasks: Shorten per-grace-period sleep for RCU Tasks Trace rcu-tasks: Fix grace-period/unlock race in RCU Tasks Trace rcu-tasks: Fix low-probability task_struct leak rcu-tasks: Enclose task-list scan in rcu_read_lock() include/linux/rcupdate_trace.h | 4 +++ kernel/rcu/tasks.h | 55 ++++++++++++++++++++++++++++++++---------- 2 files changed, 46 insertions(+), 13 deletions(-)