From patchwork Fri Oct 11 17:39:20 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Paul E. McKenney" X-Patchwork-Id: 13832858 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5A5D61BE86E; Fri, 11 Oct 2024 17:39:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728668373; cv=none; b=VE7sbfkFiZXatFItYEYDTHBvHf2A6rbrxpwpKTCsPWG/e1oSH2daQhV6T6zxWcfxdOvIBG4FcJK+930B+KycSVs4pKv2rCFRcpHOum3drvp3QYuroFqaKSy0WLqggD0gVRQp8/vQB3s1np/yWwee2Yy2TtDgt7GEdhV9j1gLZUk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728668373; c=relaxed/simple; bh=wmL8nD35K+D183HPbTxmWpox+7fCqVw7eRDQh/aakYc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=CjoP/cqx4o8EzUiXXPfc6oluqWs4MDLTDPwRUTzDI7BNUw+eGnjy3s+ASYOWaPS0TYBDcKHxhooG2h013HVzU9JwuL9GhFcs/byCbxMydvjzaKoN2NBuMr5vIoeatxeR50w3jFQZ4qn6RRdmYhAAjHQsVmj8wHKjN517D0vE0cc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CnyJ0mPn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CnyJ0mPn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 01CE3C4CECE; Fri, 11 Oct 2024 17:39:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728668373; bh=wmL8nD35K+D183HPbTxmWpox+7fCqVw7eRDQh/aakYc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CnyJ0mPn2Mju9oCnyXhNKnku/qSFeWAAZ6DUyXDP0ok1IcZsp2GZrj7eR6/Gq32Sc 9rlDtu66GRN/b4PC31YGdIuOK1bp7mKJlxlRyWBlL77A5T312HTNK3mDgbVTit4WZo RBKnW7vJkrT+y0cd/fYsPLddZjLN9ZksJOhmFmKtYSTdfXKapP40q3REtQTtnVOazn MpEu4vZ3G9xnmhfsn4bFJlVTBezcpggpyRzNCEHzYUp9cgIGCggNrQLW2Agadt8xWa Tf4/AfEVolX/7k0gRmZ2B3qw73nD+sW8egkB0Jl3PZM3cMfWfX0+9FSoqg0YU+d2QW TEi51Dk/1bN6A== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 9C27DCE0BB3; Fri, 11 Oct 2024 10:39:32 -0700 (PDT) From: "Paul E. McKenney" To: frederic@kernel.org, rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, "Paul E. McKenney" , Alexei Starovoitov , Andrii Nakryiko , Peter Zijlstra , Kent Overstreet , bpf@vger.kernel.org Subject: [PATCH v2 rcu 02/13] srcu: Introduce srcu_gp_is_expedited() helper function Date: Fri, 11 Oct 2024 10:39:20 -0700 Message-Id: <20241011173931.2050422-2-paulmck@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <3b82ac1a-8786-4a27-8eff-ecc67b50dfb6@paulmck-laptop> References: <3b82ac1a-8786-4a27-8eff-ecc67b50dfb6@paulmck-laptop> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Even though the open-coded expressions usually fit on one line, this commit replaces them with a call to a new srcu_gp_is_expedited() helper function in order to improve readability. Signed-off-by: Paul E. McKenney Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Kent Overstreet Cc: --- kernel/rcu/srcutree.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 9ff4ded609ba5..e29c6cbffbcb0 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -418,6 +418,16 @@ static void check_init_srcu_struct(struct srcu_struct *ssp) spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags); } +/* + * Is the current or any upcoming grace period to be expedited? + */ +static bool srcu_gp_is_expedited(struct srcu_struct *ssp) +{ + struct srcu_usage *sup = ssp->srcu_sup; + + return ULONG_CMP_LT(READ_ONCE(sup->srcu_gp_seq), READ_ONCE(sup->srcu_gp_seq_needed_exp)); +} + /* * Returns approximate total of the readers' ->srcu_lock_count[] values * for the rank of per-CPU counters specified by idx. @@ -622,7 +632,7 @@ static unsigned long srcu_get_delay(struct srcu_struct *ssp) unsigned long jbase = SRCU_INTERVAL; struct srcu_usage *sup = ssp->srcu_sup; - if (ULONG_CMP_LT(READ_ONCE(sup->srcu_gp_seq), READ_ONCE(sup->srcu_gp_seq_needed_exp))) + if (srcu_gp_is_expedited(ssp)) jbase = 0; if (rcu_seq_state(READ_ONCE(sup->srcu_gp_seq))) { j = jiffies - 1; @@ -867,7 +877,7 @@ static void srcu_gp_end(struct srcu_struct *ssp) spin_lock_irq_rcu_node(sup); idx = rcu_seq_state(sup->srcu_gp_seq); WARN_ON_ONCE(idx != SRCU_STATE_SCAN2); - if (ULONG_CMP_LT(READ_ONCE(sup->srcu_gp_seq), READ_ONCE(sup->srcu_gp_seq_needed_exp))) + if (srcu_gp_is_expedited(ssp)) cbdelay = 0; WRITE_ONCE(sup->srcu_last_gp_end, ktime_get_mono_fast_ns());