From patchwork Wed Oct 9 18:07:09 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: 13828955 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 C54A71E1A17; Wed, 9 Oct 2024 18:07:21 +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=1728497241; cv=none; b=d8H4oSnFFHWUp+4XXFaKjth7RPAjndCBq0Rfe/T5pzwU7lt4eccPnaBtJKVWt8hch/KJd/XB8tguEgqdpYMYSfYvTWB4rmnmK56rkIls/ffY1xA9BcnWADIvouw9wJwIG56W0tEHBTy4rrv555rEf7n4vDmn4SkmT5su5UeBSYI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728497241; c=relaxed/simple; bh=wmL8nD35K+D183HPbTxmWpox+7fCqVw7eRDQh/aakYc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=ZkmrwZVzXMHBOW5J/bYW6BFjFa5t4GlNV2pSHAxKB70Hyrq7VWhphW2HZH1Ud+fXYIrbfIV/NFv3Bq5Kt0s3QjgGwBK6TWZ6CxQF2MGPMVJIh69VK2fR0eWgLJot84P+BrXoZIbFZ9ULO7z3bPIyZBCAktxkVKWNKddZCyo5WFw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZtHyMAzi; 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="ZtHyMAzi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5F0ADC4CECC; Wed, 9 Oct 2024 18:07:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728497241; bh=wmL8nD35K+D183HPbTxmWpox+7fCqVw7eRDQh/aakYc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZtHyMAzi5pzVy2FO6NdbHf1NjpkLld39dm+aDhUmCMhDih/CCOF+vcj1qNUlAzVo3 xzXk7hkxptMPUO5Vc4t5wsewui8Asg2VYaVHbgjmTGIFo21rY9g0Ne9o94tm3N/Vme LNlMYqjC57KmIhE93FHAFTiEXXrkHZofwQg8WwL9JRw4yuOv64sdlRXgt+eHE5ZMQM flCE8cJE3SG0LKmBI5MR0zMDMchsgvPqltBhy7Ist8vZqvPHA0pwHEraTjLbzWc+y2 Vhk0GMe4zwynZfTAO85mD9DulKtNzWXiA3Rt19UDSR/INKkd8fZLYPtvr/MS5eXhAW 9WvJ/OS5cqAwA== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 12413CE0B68; Wed, 9 Oct 2024 11:07:21 -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 rcu 02/12] srcu: Introduce srcu_gp_is_expedited() helper function Date: Wed, 9 Oct 2024 11:07:09 -0700 Message-Id: <20241009180719.778285-2-paulmck@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: bpf@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: Reviewed-by: Neeraj Upadhyay --- 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());