From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 57ABE2DEA7B; Fri, 31 Jul 2026 01:01:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785459717; cv=none; b=Gc4CW2oNSb2n7PIFhm1Fj76KyUUuNQ/91mHhkjM1+3H3co5wbBCuthAPJjsZOrnJRevGVGfVl0JyE0sx0uwRSvCJBk0zz5I7Fmy4riiC0XrloddWNC134QKbbVoeJHbeV9VaUh+pNzLptMChdLryr+IjAo1OXJcrvBvkw9oJ0KQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785459717; c=relaxed/simple; bh=pCRX8+l1IN+X5y8V4I17znb7He/4+TOcNXkyr+OWpN8=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=nnxyF4nFugOjAi2XovV35Ze3DYoMWnhNaq4Ald2KMbNyLNQEuBI6I5QAS7omtRqbJqJdwuLEALaZda3CbUd6K2v7pYCXtpzDGK3QRx5D8oloR8HqmW8qQEk1g9AYFJoMBq3xQ+ccZalK8ua4HzXlSppa518M7w0jX6eSLGYQSOc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XpL0Fkl4; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XpL0Fkl4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 324101F01558; Fri, 31 Jul 2026 01:01:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785459715; bh=CbTCQ1g3TRtR5B10oGb8BErMIh3Q8zsIuXKRGr+KqM0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=XpL0Fkl4WUWPPNFJN7KdODAGnIaj7fsUdfx+nbmxTrB0UZ8ld/saHw3WFsyKNr/2A J6xerWoAjFrZTtxkVrodt/kviMiwndzlgDZ2+fiFgqp9x3JbARlDpk3IWTB0sVujzh u4SjYqwvZ7F7N+wpM7f/K24CA33h4hucGDK2KHdPo4Nxx02e6b48DU0ksueDctp9s5 DvJ9BIu0soDjgBTa9e4N+ZJkS2VBuJPbX2czupbTfM80+oxkSQ4altU6U7WE70BX4F ssnQk5xa+Y77uSL+OIj2DrHfHJG7wHphSczK9CNfM0QFzY7gl+IHq49MaJAFd9Llr5 R4wce8Jw7h/+w== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id B774FCE14D9; Thu, 30 Jul 2026 18:01:54 -0700 (PDT) From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, Joel Fernandes , "Paul E . McKenney" Subject: [PATCH RFC 09/16] rcu: Remove unused expedited_need_qs field from rcu_state Date: Thu, 30 Jul 2026 18:01:46 -0700 Message-Id: <20260731010153.3531313-9-paulmck@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <9de287bc-e565-4f21-bd3c-5c17792e6abc@paulmck-laptop> References: <9de287bc-e565-4f21-bd3c-5c17792e6abc@paulmck-laptop> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Joel Fernandes The ->expedited_need_qs counter was part of the old expedited grace-period machinery that spun waiting for each CPU to check in. The current implementation instead tracks holdout CPUs via the rcu_node structures' ->expmask fields and waits on the ->exp_wq[] wait queues, so nothing reads or writes ->expedited_need_qs any longer. Remove the field to avoid wasting space in rcu_state and to keep readers of the expedited code from searching for nonexistent users. Signed-off-by: Joel Fernandes Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.h | 1 - 1 file changed, 1 deletion(-) diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 4069132f9d4446..587bd71396eaa3 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -391,7 +391,6 @@ struct rcu_state { struct mutex exp_mutex; /* Serialize expedited GP. */ struct mutex exp_wake_mutex; /* Serialize wakeup. */ unsigned long expedited_sequence; /* Take a ticket. */ - atomic_t expedited_need_qs; /* # CPUs left to check in. */ struct swait_queue_head expedited_wq; /* Wait for check-ins. */ int ncpus_snap; /* # CPUs seen last time. */ u8 cbovld; /* Callback overload now? */ -- 2.40.1