From patchwork Fri Mar 24 00:19:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Paul E. McKenney" X-Patchwork-Id: 13186194 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 DD1C0C761AF for ; Fri, 24 Mar 2023 00:20:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231217AbjCXAUA (ORCPT ); Thu, 23 Mar 2023 20:20:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58000 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231278AbjCXATw (ORCPT ); Thu, 23 Mar 2023 20:19:52 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 822D52E0C5; Thu, 23 Mar 2023 17:19:45 -0700 (PDT) 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 sin.source.kernel.org (Postfix) with ESMTPS id 43C2FCE23F2; Fri, 24 Mar 2023 00:19:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 587A2C433A0; Fri, 24 Mar 2023 00:19:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1679617181; bh=1zZMbnj6wCHzqV26Ik2U3pZ5xQ0e/amfS4bQebuVTDo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o7EV7iCLpr0TJDTZJ4avWQJqOKyCa7BhzDmRu1B4UgeeQUswVdFBXUU0tYiizhpGH pViUmMTWcGtxz6RvMn/WIq4bQYfvwJOwOxxYl5htEUlPzWznd//kbNyjSYkEaWy0jQ 73HeQloSXoSOcpgViMPrQRS7+QvJh6X5HtL7z69Iq6K7Xi3jyncu+KR5DiJKtSW8YB xVW3mQ39iPBbaeqdnF0H7TYpuUZylGnXHxwuJj0S3wYSTbthNuFhWvIQibdFcZoe1i Brum04832rhsxlvlwWT2YlxcadWbSL0Nqmw4HZ7R6lX0Fqj0OgPuPrtU0N/5hFWk9d gYMF/FQxTzUlA== Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 9BE43154039F; Thu, 23 Mar 2023 17:19:40 -0700 (PDT) From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, hch@lst.de, "Paul E. McKenney" Subject: [PATCH RFC rcu 06/19] srcu: Move ->srcu_cb_mutex from srcu_struct to srcu_usage Date: Thu, 23 Mar 2023 17:19:25 -0700 Message-Id: <20230324001938.3443499-6-paulmck@kernel.org> X-Mailer: git-send-email 2.40.0.rc2 In-Reply-To: <3db82572-f156-4a5d-b711-841aa28bd996@paulmck-laptop> References: <3db82572-f156-4a5d-b711-841aa28bd996@paulmck-laptop> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org This commit moves the ->srcu_cb_mutex field from the srcu_struct structure to the srcu_usage structure to reduce the size of the former in order to improve cache locality. Suggested-by: Christoph Hellwig Signed-off-by: Paul E. McKenney --- include/linux/srcutree.h | 2 +- kernel/rcu/srcutree.c | 6 +++--- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h index 72fb01fb2eb5..69d49de87b67 100644 --- a/include/linux/srcutree.h +++ b/include/linux/srcutree.h @@ -65,13 +65,13 @@ struct srcu_usage { struct srcu_node *level[RCU_NUM_LVLS + 1]; /* First node at each level. */ int srcu_size_state; /* Small-to-big transition state. */ + struct mutex srcu_cb_mutex; /* Serialize CB preparation. */ }; /* * Per-SRCU-domain structure, similar in function to rcu_state. */ struct srcu_struct { - struct mutex srcu_cb_mutex; /* Serialize CB preparation. */ spinlock_t __private lock; /* Protect counters and size state. */ struct mutex srcu_gp_mutex; /* Serialize GP work. */ unsigned int srcu_idx; /* Current rdr array element. */ diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 2717217de136..6b6d92fe41cf 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -242,7 +242,7 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static) return -ENOMEM; ssp->srcu_sup->srcu_size_state = SRCU_SIZE_SMALL; ssp->srcu_sup->node = NULL; - mutex_init(&ssp->srcu_cb_mutex); + mutex_init(&ssp->srcu_sup->srcu_cb_mutex); mutex_init(&ssp->srcu_gp_mutex); ssp->srcu_idx = 0; ssp->srcu_gp_seq = 0; @@ -861,7 +861,7 @@ static void srcu_gp_end(struct srcu_struct *ssp) int ss_state; /* Prevent more than one additional grace period. */ - mutex_lock(&ssp->srcu_cb_mutex); + mutex_lock(&ssp->srcu_sup->srcu_cb_mutex); /* End the current grace period. */ spin_lock_irq_rcu_node(ssp); @@ -921,7 +921,7 @@ static void srcu_gp_end(struct srcu_struct *ssp) } /* Callback initiation done, allow grace periods after next. */ - mutex_unlock(&ssp->srcu_cb_mutex); + mutex_unlock(&ssp->srcu_sup->srcu_cb_mutex); /* Start a new grace period if needed. */ spin_lock_irq_rcu_node(ssp);