From patchwork Wed Nov 30 18:13:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Paul E. McKenney" X-Patchwork-Id: 13060204 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 9BFD0C433FE for ; Wed, 30 Nov 2022 18:13:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229636AbiK3SNi (ORCPT ); Wed, 30 Nov 2022 13:13:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230070AbiK3SNX (ORCPT ); Wed, 30 Nov 2022 13:13:23 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 973922A717; Wed, 30 Nov 2022 10:13:19 -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 ams.source.kernel.org (Postfix) with ESMTPS id 54695B81C9C; Wed, 30 Nov 2022 18:13:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 12907C433C1; Wed, 30 Nov 2022 18:13:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669831997; bh=jEXYy2sRGOMTywAVi6nSyBZ4IPniFAdcqehMf/7xaAA=; h=Date:From:To:Cc:Subject:Reply-To:From; b=KoBp+JJFP9XX5vMmouLEgYef2BeT9hv2NqucWpaDWpTSiioISbDM++dWYySNUo8hB fRw2iYavo5MoxOiP6JKZ220PJ196ad070E6/5UDjCGHFiE4AqVCPahzxvgqXzIpCdC HN3Z/V4/JgNb3mEFChv/XK/H9n70ZpvPlUbX9xRk4OawQIkVoQGxsDMP3wr2Jq4xLT mwDpZY5IBnVWFTx4SJXpJvUnBcc7mnEIOkIAqZM8CVDkpkDZT32GMct2GwtEAUOU3y HcTSeLUib4HXLAwfsc9HUe8HJ1j3Ygg82cyCEkkJmIrxFTxO5JLRmo36RedW429lvk r7HI/YlKG9DZQ== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id B268F5C051C; Wed, 30 Nov 2022 10:13:16 -0800 (PST) Date: Wed, 30 Nov 2022 10:13:16 -0800 From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org Subject: [PATCH v3 rcu 0/16] Lazy call_rcu() updates for v6.2 Message-ID: <20221130181316.GA1012431@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org Hello! This series provides energy efficiency for nearly-idle systems by making call_rcu() more lazy. Several NOCB changes come along for the ride: 1. Simplify rcu_init_nohz() cpumask handling, courtesy of Zhen Lei. 2. Fix late wakeup when flush of bypass cblist happens, courtesy of "Joel Fernandes (Google)". 3. Fix missing nocb gp wake on rcu_barrier(), courtesy of Frederic Weisbecker. 4. Make call_rcu() lazy to save power, courtesy of "Joel Fernandes (Google)". 5. Refactor code a bit in rcu_nocb_do_flush_bypass(), courtesy of "Joel Fernandes (Google)". 6. Shrinker for lazy rcu, courtesy of Vineeth Pillai. 7. Add laziness and kfree tests, courtesy of "Joel Fernandes (Google)". 8. Use call_rcu_hurry() instead of call_rcu, courtesy of "Joel Fernandes (Google)". 9. Use call_rcu_hurry() for async reader test, courtesy of "Joel Fernandes (Google)". 10. Use call_rcu_hurry() where needed, courtesy of "Joel Fernandes (Google)". 11. scsi/scsi_error: Use call_rcu_hurry() instead of call_rcu(), courtesy of Uladzislau Rezki. 12. percpu-refcount: Use call_rcu_hurry() for atomic switch, courtesy of "Joel Fernandes (Google)". 13. Make queue_rcu_work() use call_rcu_hurry(), courtesy of Uladzislau Rezki. 14. Use call_rcu_hurry() instead of call_rcu(), courtesy of "Joel Fernandes (Google)". 15. Use call_rcu_hurry() for dst_release(), courtesy of "Joel Fernandes (Google)". 16. devinet: Reduce refcount before grace period, courtesy of Eric Dumazet. Changes since v2: o Rename call_rcu_flush() to call_rcu_hurry() to avoid naming conflicts in workqueues as suggested by Tejun Heo. o Apply acks and reviews. https://lore.kernel.org/all/20221122010408.GA3799268@paulmck-ThinkPad-P17-Gen-1/ Changes since v1: o Add more adjustments to avoid excessive laziness (#15 and #16 above). o Get appropriate Cc lines onto non-RCU patches. https://lore.kernel.org/all/20221019225138.GA2499943@paulmck-ThinkPad-P17-Gen-1/ Thanx, Paul ------------------------------------------------------------------------ b/drivers/scsi/scsi_error.c | 2 b/include/linux/rcupdate.h | 9 + b/kernel/rcu/Kconfig | 8 + b/kernel/rcu/rcu.h | 8 + b/kernel/rcu/rcuscale.c | 67 +++++++++++- b/kernel/rcu/rcutorture.c | 16 +- b/kernel/rcu/sync.c | 2 b/kernel/rcu/tiny.c | 2 b/kernel/rcu/tree.c | 11 + b/kernel/rcu/tree.h | 1 b/kernel/rcu/tree_exp.h | 2 b/kernel/rcu/tree_nocb.h | 34 +----- b/kernel/workqueue.c | 2 b/lib/percpu-refcount.c | 3 b/net/core/dst.c | 2 b/net/ipv4/devinet.c | 19 +-- b/net/rxrpc/conn_object.c | 2 kernel/rcu/rcuscale.c | 2 kernel/rcu/tree.c | 129 +++++++++++++++-------- kernel/rcu/tree.h | 11 + kernel/rcu/tree_nocb.h | 243 ++++++++++++++++++++++++++++++++++++-------- 21 files changed, 434 insertions(+), 141 deletions(-)