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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 55854C433E3 for ; Wed, 24 Jun 2020 20:13:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3812720823 for ; Wed, 24 Jun 2020 20:13:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593029599; bh=44gkBO60VbhtMZnAT43mBNScWOy3QmO50MmjS6JrwAY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=g/fTHKp+W1ww0rDDv6yC96nAhm5Um3ujqV/0eEksLvzh5WGa6oF624D0JYPaZE7wm cWUdj5UVa+LXjhEgGc/tljTFQ23nt4mc2q7uwjAVZhPDMyTMkZNHBHzcXrdt7+SnH4 /5B43Wz3RNQ2JduqYe12cAF7Q/oUAIaLI0+mt/lc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406503AbgFXUNS (ORCPT ); Wed, 24 Jun 2020 16:13:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:52574 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406384AbgFXUMa (ORCPT ); Wed, 24 Jun 2020 16:12:30 -0400 Received: from paulmck-ThinkPad-P72.home (50-39-105-78.bvtn.or.frontiernet.net [50.39.105.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A60492145D; Wed, 24 Jun 2020 20:12:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593029549; bh=44gkBO60VbhtMZnAT43mBNScWOy3QmO50MmjS6JrwAY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NjUXTYy1d/vRtJWGxtMlrgZjNhZ44hinrl1EsJ0yEgFGKKrIw+FiHmb+SklHpPQ89 KXK73u+my5voVh8v9EeyE/WLYVzvi51E0bjM1a3G1NPGmLZzpLr3sON2KARyCRJOFi ZHErrPXtmBngMcmOX+f4GD7cEsBsqhWj4e3h7LR8= From: paulmck@kernel.org To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.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, Sebastian Andrzej Siewior , Uladzislau Rezki , "Paul E . McKenney" Subject: [PATCH tip/core/rcu 08/17] rcu/tree: Use static initializer for krc.lock Date: Wed, 24 Jun 2020 13:12:17 -0700 Message-Id: <20200624201226.21197-8-paulmck@kernel.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20200624201200.GA28901@paulmck-ThinkPad-P72> References: <20200624201200.GA28901@paulmck-ThinkPad-P72> Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Sebastian Andrzej Siewior The per-CPU variable is initialized at runtime in kfree_rcu_batch_init(). This function is invoked before 'rcu_scheduler_active' is set to 'RCU_SCHEDULER_RUNNING'. After the initialisation, '->initialized' is to true. The raw_spin_lock is only acquired if '->initialized' is set to true. The worqueue item is only used if 'rcu_scheduler_active' set to RCU_SCHEDULER_RUNNING which happens after initialisation. Use a static initializer for krc.lock and remove the runtime initialisation of the lock. Since the lock can now be always acquired, remove the '->initialized' check. Cc: Sebastian Andrzej Siewior Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Uladzislau Rezki (Sony) Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index edc512e..4fba1e9 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2984,7 +2984,7 @@ struct kfree_rcu_cpu_work { * @lock: Synchronize access to this structure * @monitor_work: Promote @head to @head_free after KFREE_DRAIN_JIFFIES * @monitor_todo: Tracks whether a @monitor_work delayed work is pending - * @initialized: The @lock and @rcu_work fields have been initialized + * @initialized: The @rcu_work fields have been initialized * @count: Number of objects for which GP not started * * This is a per-CPU structure. The reason that it is not included in @@ -3004,7 +3004,9 @@ struct kfree_rcu_cpu { int count; }; -static DEFINE_PER_CPU(struct kfree_rcu_cpu, krc); +static DEFINE_PER_CPU(struct kfree_rcu_cpu, krc) = { + .lock = __RAW_SPIN_LOCK_UNLOCKED(krc.lock), +}; static __always_inline void debug_rcu_bhead_unqueue(struct kfree_rcu_bulk_data *bhead) @@ -3024,8 +3026,7 @@ krc_this_cpu_lock(unsigned long *flags) local_irq_save(*flags); // For safely calling this_cpu_ptr(). krcp = this_cpu_ptr(&krc); - if (likely(krcp->initialized)) - raw_spin_lock(&krcp->lock); + raw_spin_lock(&krcp->lock); return krcp; } @@ -3033,8 +3034,7 @@ krc_this_cpu_lock(unsigned long *flags) static inline void krc_this_cpu_unlock(struct kfree_rcu_cpu *krcp, unsigned long flags) { - if (likely(krcp->initialized)) - raw_spin_unlock(&krcp->lock); + raw_spin_unlock(&krcp->lock); local_irq_restore(flags); } @@ -4260,7 +4260,6 @@ static void __init kfree_rcu_batch_init(void) for_each_possible_cpu(cpu) { struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu); - raw_spin_lock_init(&krcp->lock); for (i = 0; i < KFREE_N_BATCHES; i++) { INIT_RCU_WORK(&krcp->krw_arr[i].rcu_work, kfree_rcu_work); krcp->krw_arr[i].krcp = krcp; -- 2.9.5