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=-19.7 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 EEDC3C433ED for ; Tue, 11 May 2021 23:09:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D2F9D61919 for ; Tue, 11 May 2021 23:09:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230367AbhEKXJE (ORCPT ); Tue, 11 May 2021 19:09:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:45636 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230023AbhEKXIz (ORCPT ); Tue, 11 May 2021 19:08:55 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8523061939; Tue, 11 May 2021 23:07:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1620774468; bh=dCeesBPD8EQLQ5NTaAbs0FYY7oV3gGlAfJXafP/iE/U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L25Lg3jh7hOSF0jNM51XuL216lJeC+lmJRNEk3BqlafqUqiCC7Plkg4sW2e1MIi90 sZWonatKKiEh3ejh6W/UAWMjFD2rMAzDmzOJtUzh3TF/FFF8lXyS1HSHWEVlKahUXu oLhFPtjsIZHar8krNVHNIxwh7H/qMro0AtEZ1PyrDDuWRDZz8er1nPHLP21Lqvvzxy 5AeipXmjr81N8QQUNvZFd8bnyl7Vuks5jW8O5KP0hTIQ3DJBbvaim1+ihzls3H9caf OOqjPa+ykooEqbF1XujQQarzJnNqkEEMUS6AmVEmEPVKMAig8u/DtGogdcWE+qqpwq 9IYvrY7C9fO0Q== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id E58995C0DB3; Tue, 11 May 2021 16:07:47 -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, Frederic Weisbecker , Boqun Feng , Neeraj Upadhyay , Uladzislau Rezki , "Paul E . McKenney" Subject: [PATCH tip/core/rcu 6/6] srcu: Early test SRCU polling start Date: Tue, 11 May 2021 16:07:45 -0700 Message-Id: <20210511230745.2894650-6-paulmck@kernel.org> X-Mailer: git-send-email 2.31.1.189.g2e36527f23 In-Reply-To: <20210511230720.GA2894512@paulmck-ThinkPad-P17-Gen-1> References: <20210511230720.GA2894512@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Frederic Weisbecker Place an early call to start_poll_synchronize_srcu() before the the invocation of call_srcu() on the same srcu_struct structure. After the later call to srcu_barrier(), the completion of the first grace period should be visible to a subsequent invocation of poll_state_synchronize_srcu(), and if not, warn. Signed-off-by: Frederic Weisbecker Cc: Boqun Feng Cc: Lai Jiangshan Cc: Neeraj Upadhyay Cc: Josh Triplett Cc: Joel Fernandes Cc: Uladzislau Rezki Signed-off-by: Paul E. McKenney --- kernel/rcu/update.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index b95ae86c40a7..0aa118ac37ba 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -524,6 +524,7 @@ static void test_callback(struct rcu_head *r) } DEFINE_STATIC_SRCU(early_srcu); +static unsigned long early_srcu_cookie; struct early_boot_kfree_rcu { struct rcu_head rh; @@ -536,8 +537,10 @@ static void early_boot_test_call_rcu(void) struct early_boot_kfree_rcu *rhp; call_rcu(&head, test_callback); - if (IS_ENABLED(CONFIG_SRCU)) + if (IS_ENABLED(CONFIG_SRCU)) { + early_srcu_cookie = start_poll_synchronize_srcu(&early_srcu); call_srcu(&early_srcu, &shead, test_callback); + } rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); if (!WARN_ON_ONCE(!rhp)) kfree_rcu(rhp, rh); @@ -563,6 +566,7 @@ static int rcu_verify_early_boot_tests(void) if (IS_ENABLED(CONFIG_SRCU)) { early_boot_test_counter++; srcu_barrier(&early_srcu); + WARN_ON_ONCE(!poll_state_synchronize_srcu(&early_srcu, early_srcu_cookie)); } } if (rcu_self_test_counter != early_boot_test_counter) { -- 2.31.1.189.g2e36527f23