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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 2B34BC433F5 for ; Wed, 15 Sep 2021 23:34:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1696561242 for ; Wed, 15 Sep 2021 23:34:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232977AbhIOXfV (ORCPT ); Wed, 15 Sep 2021 19:35:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:60460 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232934AbhIOXfE (ORCPT ); Wed, 15 Sep 2021 19:35:04 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3C2FE611CE; Wed, 15 Sep 2021 23:33:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631748825; bh=gO1MMFnm1zCJjS/gCVvB0Xfe7BwmJf6Jg0wu6mIXWAw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k5LfraBiX/Y1Drs5JcY3RnY9JStA8qh7UOabyHv15hBoMFOq9526N56VL0ieYZFuL WfnyTQ/5DK25J0/RB37Yl+W5SdEOqi9pTHQfeEqB4IcilVqXBqN6Zw9frUwofSAP6o SYjKYzcrzww9irevbCNRYWOAWA0lidRc0LMuXAj+3M0LQcId9XSFPvsIL/E7pAGNPx 1R6J2w5r/zFoMZJrWrj1PyIqrSfXiMM9SyFmsUbFTQ8gdSDbww5jZXunIgKlbc6G+h XyDXojajoqk6TPPW6NuN4te1kvI5rx8IUmSXl82GyXDSQBYyyKmvOeQlx8Pd6K0qol 950V1VIsCGSGw== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id C543A5C0954; Wed, 15 Sep 2021 16:33:44 -0700 (PDT) From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, Zhouyi Zhou , "Paul E . McKenney" Subject: [PATCH rcu 06/14] rcu: Fix undefined Kconfig macros Date: Wed, 15 Sep 2021 16:33:35 -0700 Message-Id: <20210915233343.3906738-6-paulmck@kernel.org> X-Mailer: git-send-email 2.31.1.189.g2e36527f23 In-Reply-To: <20210915233305.GA3906641@paulmck-ThinkPad-P17-Gen-1> References: <20210915233305.GA3906641@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zhouyi Zhou Invoking scripts/checkkconfigsymbols.py in the Linux-kernel source tree located the following issues: 1. TREE_PREEMPT_RCU Referencing files: arch/sh/configs/sdk7786_defconfig It should now be CONFIG_PREEMPT_RCU. Except that the CONFIG_PREEMPT=y in that same file implies CONFIG_PREEMPT_RCU=y. Therefore, delete the CONFIG_TREE_PREEMPT_RCU=y line. The reason is as follows: In kernel/rcu/Kconfig, we have config PREEMPT_RCU bool default y if PREEMPTION https://www.kernel.org/doc/Documentation/kbuild/kconfig-language.txt says, "The default value is only assigned to the config symbol if no other value was set by the user (via the input prompt above)." there is no prompt in config PREEMPT_RCU entry, so we are guaranteed to get CONFIG_PREEMPT_RCU=y when CONFIG_PREEMPT is present. 2. RCU_CPU_STALL_INFO Referencing files: arch/xtensa/configs/nommu_kc705_defconfig The old Kconfig option RCU_CPU_STALL_INFO was removed by commit 75c27f119b64 ("rcu: Remove CONFIG_RCU_CPU_STALL_INFO"), and the kernel now acts as if this Kconfig option was unconditionally enabled. 3. RCU_NOCB_CPU_ALL Referencing files: Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst This is an old snapshot of the code. I update this from the real rcu_prepare_for_idle() function in kernel/rcu/tree_plugin.h. This change was tested by invoking "make htmldocs". 4. RCU_TORTURE_TESTS Referencing files: kernel/rcu/rcutorture.c Forward-progress checking conflicts with CPU-stall testing, so we should complain at "modprobe rcutorture" when both are enabled. Signed-off-by: Zhouyi Zhou Signed-off-by: Paul E. McKenney --- .../Tree-RCU-Memory-Ordering.rst | 69 +++++++++---------- arch/sh/configs/sdk7786_defconfig | 1 - arch/xtensa/configs/nommu_kc705_defconfig | 1 - kernel/rcu/rcutorture.c | 2 +- 4 files changed, 33 insertions(+), 40 deletions(-) diff --git a/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst b/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst index eeb351296df1..7fdf151a8680 100644 --- a/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst +++ b/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst @@ -202,49 +202,44 @@ newly arrived RCU callbacks against future grace periods: 1 static void rcu_prepare_for_idle(void) 2 { 3 bool needwake; - 4 struct rcu_data *rdp; - 5 struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks); - 6 struct rcu_node *rnp; - 7 struct rcu_state *rsp; - 8 int tne; - 9 - 10 if (IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL) || - 11 rcu_is_nocb_cpu(smp_processor_id())) - 12 return; + 4 struct rcu_data *rdp = this_cpu_ptr(&rcu_data); + 5 struct rcu_node *rnp; + 6 int tne; + 7 + 8 lockdep_assert_irqs_disabled(); + 9 if (rcu_rdp_is_offloaded(rdp)) + 10 return; + 11 + 12 /* Handle nohz enablement switches conservatively. */ 13 tne = READ_ONCE(tick_nohz_active); - 14 if (tne != rdtp->tick_nohz_enabled_snap) { - 15 if (rcu_cpu_has_callbacks(NULL)) - 16 invoke_rcu_core(); - 17 rdtp->tick_nohz_enabled_snap = tne; + 14 if (tne != rdp->tick_nohz_enabled_snap) { + 15 if (!rcu_segcblist_empty(&rdp->cblist)) + 16 invoke_rcu_core(); /* force nohz to see update. */ + 17 rdp->tick_nohz_enabled_snap = tne; 18 return; - 19 } + 19 } 20 if (!tne) 21 return; - 22 if (rdtp->all_lazy && - 23 rdtp->nonlazy_posted != rdtp->nonlazy_posted_snap) { - 24 rdtp->all_lazy = false; - 25 rdtp->nonlazy_posted_snap = rdtp->nonlazy_posted; - 26 invoke_rcu_core(); - 27 return; - 28 } - 29 if (rdtp->last_accelerate == jiffies) - 30 return; - 31 rdtp->last_accelerate = jiffies; - 32 for_each_rcu_flavor(rsp) { - 33 rdp = this_cpu_ptr(rsp->rda); - 34 if (rcu_segcblist_pend_cbs(&rdp->cblist)) - 35 continue; - 36 rnp = rdp->mynode; - 37 raw_spin_lock_rcu_node(rnp); - 38 needwake = rcu_accelerate_cbs(rsp, rnp, rdp); - 39 raw_spin_unlock_rcu_node(rnp); - 40 if (needwake) - 41 rcu_gp_kthread_wake(rsp); - 42 } - 43 } + 22 + 23 /* + 24 * If we have not yet accelerated this jiffy, accelerate all + 25 * callbacks on this CPU. + 26 */ + 27 if (rdp->last_accelerate == jiffies) + 28 return; + 29 rdp->last_accelerate = jiffies; + 30 if (rcu_segcblist_pend_cbs(&rdp->cblist)) { + 31 rnp = rdp->mynode; + 32 raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */ + 33 needwake = rcu_accelerate_cbs(rnp, rdp); + 34 raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */ + 35 if (needwake) + 36 rcu_gp_kthread_wake(); + 37 } + 38 } But the only part of ``rcu_prepare_for_idle()`` that really matters for -this discussion are lines 37–39. We will therefore abbreviate this +this discussion are lines 32–34. We will therefore abbreviate this function as follows: .. kernel-figure:: rcu_node-lock.svg diff --git a/arch/sh/configs/sdk7786_defconfig b/arch/sh/configs/sdk7786_defconfig index f776a1d0d277..a8662b6927ec 100644 --- a/arch/sh/configs/sdk7786_defconfig +++ b/arch/sh/configs/sdk7786_defconfig @@ -5,7 +5,6 @@ CONFIG_BSD_PROCESS_ACCT=y CONFIG_BSD_PROCESS_ACCT_V3=y CONFIG_AUDIT=y CONFIG_AUDITSYSCALL=y -CONFIG_TREE_PREEMPT_RCU=y CONFIG_RCU_TRACE=y CONFIG_IKCONFIG=y CONFIG_IKCONFIG_PROC=y diff --git a/arch/xtensa/configs/nommu_kc705_defconfig b/arch/xtensa/configs/nommu_kc705_defconfig index 88b2e222d4bf..fcb620ef3799 100644 --- a/arch/xtensa/configs/nommu_kc705_defconfig +++ b/arch/xtensa/configs/nommu_kc705_defconfig @@ -119,7 +119,6 @@ CONFIG_DEBUG_SPINLOCK=y CONFIG_DEBUG_MUTEXES=y CONFIG_DEBUG_ATOMIC_SLEEP=y CONFIG_STACKTRACE=y -# CONFIG_RCU_CPU_STALL_INFO is not set CONFIG_RCU_TRACE=y # CONFIG_FTRACE is not set # CONFIG_LD_NO_RELAX is not set diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index ab4215266ebe..f640cbd9262c 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -2449,7 +2449,7 @@ static int __init rcu_torture_fwd_prog_init(void) } if (stall_cpu > 0) { VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing"); - if (IS_MODULE(CONFIG_RCU_TORTURE_TESTS)) + if (IS_MODULE(CONFIG_RCU_TORTURE_TEST)) return -EINVAL; /* In module, can fail back to user. */ WARN_ON(1); /* Make sure rcutorture notices conflict. */ return 0; -- 2.31.1.189.g2e36527f23