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 960F841A914; Wed, 7 Oct 2026 20:59:27 +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=1791406769; cv=none; b=cZipPU4vAGVmuAHNdeIAQEcW9rdvvrXKvYKWZMrx8Su0IALMLBcj0/rkAzjf8VcteK4QIvrltXoxP/OCRyMOb00AMotfwcq/8ts+Ecklvd6eUKp3clAMY+fVSwVSzQHLuF2Banp+zJC6DWx4MSOd5Lr3Y8yXceTC1Fpc/yPATHQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791406769; c=relaxed/simple; bh=nk0VT+ejcehvauCAbLgwNiiYkA6XlZRRiQia10amOo0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=NWq+ZW82XLn81eeTDE3I0NWf9QNIaUXo3FEsbcSgGYsTNfzducsmU95Hiz9i0NexDFXc0bb3UQWJDQF/z7iUGYMSUMy7iFOIZpGrFLGQYfNtjl9s04ttyAi8WSsxFduSPQ55/AFcBlT/xiQ7Gudvc/xM8a0DCDL8F3/dRrfXNNg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AR2Kgucs; 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="AR2Kgucs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C2F801F008A5; Wed, 7 Oct 2026 20:59:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791406765; bh=V+EAgTthBzAiXqoGwZhj5RXRbqmhseyxwF20ilJu5OM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=AR2KgucsCTD/Hbw3kp4hat/aOsVLVuSJk6TKSuIvIpyLSD/oDRLcCREmJ1vuHXX3t OuSt6TYgMsLwfaqcYSlu7/Jm/KRppgQ15xIwOd33zPUXQYVObEjcxGJWyX0luu3sjo tWdQaKS/7NAN8bYi3jk1YeQ4rq14xS44Os5jLxuWTMqmXvsiJU2Uf7NQIsRnNlhhmk jfMwNHzUdU4IkHuNNcuaWik8zS783Ods6Rq/KaRGvwXfN1TjMhJGacT3hozphjtQKN 0ZvPGF0+NmupH2GdiOMN6Z510zQ2aRBk2xrlGIK/YiLi2JZuVo4iKCpTOHT+s0VaYr EtjFVcNEjwzjg== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 30A7ECE3991; Wed, 7 Oct 2026 13:59:25 -0700 (PDT) From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, Kunwu Chan , "Paul E . McKenney" Subject: [PATCH v2 13/21] srcutree: Skip callback scheduling for atomic SRCU grace periods Date: Wed, 7 Oct 2026 13:59:16 -0700 Message-Id: <20261007205924.1983367-13-paulmck@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <546c81a7-f677-4d8e-a304-746b227058b0@paulmck-laptop> References: <546c81a7-f677-4d8e-a304-746b227058b0@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: Kunwu Chan call_srcu() is forbidden on atomic srcu_struct, so srcu_gp_end() never has callbacks to invoke for them. Yet it schedules callback invocation, which for atomic SRCU's SRCU_SIZE_SMALL state arms the boot CPU's ->delay_work timer every grace period, only for srcu_invoke_callbacks() to find nothing to do. Skip this for atomic SRCU. Signed-off-by: Kunwu Chan Signed-off-by: Paul E. McKenney --- kernel/rcu/srcutree.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 93b8d1088abe8..0954486880c7d 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -1016,10 +1016,10 @@ static void srcu_gp_end(struct srcu_struct *ssp, bool is_atomic) /* Initiate callback invocation as needed. */ ss_state = smp_load_acquire(&sup->srcu_size_state); - if (ss_state < SRCU_SIZE_WAIT_BARRIER) { + if (!is_atomic && ss_state < SRCU_SIZE_WAIT_BARRIER) { srcu_schedule_cbs_sdp(per_cpu_ptr(ssp->sda, get_boot_cpu_id()), cbdelay); - } else { + } else if (!is_atomic) { idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs); srcu_for_each_node_breadth_first(ssp, snp) { raw_spin_lock_irq_rcu_node(snp); -- 2.40.1