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=-19.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 A76EBC43216 for ; Thu, 29 Jul 2021 14:08:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 93BF06054E for ; Thu, 29 Jul 2021 14:08:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239029AbhG2OIW (ORCPT ); Thu, 29 Jul 2021 10:08:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:49148 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238226AbhG2OA3 (ORCPT ); Thu, 29 Jul 2021 10:00:29 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id DA43F6108C; Thu, 29 Jul 2021 13:59:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1627567185; bh=ehVN1lUmJP5gTZ3vI5IQKKSPb1DWaFucAs0vsktFrAg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fhvLuVkKGLhXJjumFnTY/RhT1AfWIrozlzTQ5d86QY/wogTpqmHjRPp4koOd9TVLh FT7AqTIOypF+RCwdc8T4gEAb0z3J58YP8MKqosfZrrz+oGgRBLiqaQAKMFFXScxdtO rRQHt5f7uDHZSUUMZN5QvnKi/S+0H/7GwhIrlcMI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Xu, Yanfei" , "Paul E. McKenney" , Sasha Levin Subject: [PATCH 5.13 09/22] rcu-tasks: Dont delete holdouts within trc_wait_for_one_reader() Date: Thu, 29 Jul 2021 15:54:40 +0200 Message-Id: <20210729135137.632633169@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210729135137.336097792@linuxfoundation.org> References: <20210729135137.336097792@linuxfoundation.org> User-Agent: quilt/0.66 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: Paul E. McKenney [ Upstream commit a9ab9cce9367a2cc02a3c7eb57a004dc0b8f380d ] Invoking trc_del_holdout() from within trc_wait_for_one_reader() is only a performance optimization because the RCU Tasks Trace grace-period kthread will eventually do this within check_all_holdout_tasks_trace(). But it is not a particularly important performance optimization because it only applies to the grace-period kthread, of which there is but one. This commit therefore removes this invocation of trc_del_holdout() in favor of the one in check_all_holdout_tasks_trace() in the grace-period kthread. Reported-by: "Xu, Yanfei" Signed-off-by: Paul E. McKenney Signed-off-by: Sasha Levin --- kernel/rcu/tasks.h | 1 - 1 file changed, 1 deletion(-) diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 71e9d625371a..fcef5f0c60b8 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -937,7 +937,6 @@ static void trc_wait_for_one_reader(struct task_struct *t, // The current task had better be in a quiescent state. if (t == current) { t->trc_reader_checked = true; - trc_del_holdout(t); WARN_ON_ONCE(t->trc_reader_nesting); return; } -- 2.30.2