From mboxrd@z Thu Jan 1 00:00:00 1970 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 125D54BAB1; Mon, 8 Jan 2024 15:13:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Z/il3M1C" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46873C433C8; Mon, 8 Jan 2024 15:13:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1704726791; bh=9h4QNBY+ydhVERcGkUAdQGtsJ9+LiU5R2dfsP5PoPxo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z/il3M1CEAPK9PAISx2jvCLUk26GjU8He18TMI6HTeT+jzyx8RwRSRiwokbV8ZU56 opXiPAO8n3JWI0bdr2+kpthxDpS57faEB0MG6q2ZO2FCF6JFNqQZhzWNlmpKH4lkVC gNeAJbxF58ZEmYp7QpdB+H2u4L0dTumxkWvkgve8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Peter Zijlstra (Intel)" , Frederic Weisbecker , Sasha Levin Subject: [PATCH 6.6 079/124] rcu: Introduce rcu_cpu_online() Date: Mon, 8 Jan 2024 16:08:25 +0100 Message-ID: <20240108150606.603987829@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240108150602.976232871@linuxfoundation.org> References: <20240108150602.976232871@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Frederic Weisbecker [ Upstream commit 2be4686d866ad5896f2bb94d82fe892197aea9c7 ] Export the RCU point of view as to when a CPU is considered offline (ie: when does RCU consider that a CPU is sufficiently down in the hotplug process to not feature any possible read side). This will be used by RCU-tasks whose vision of an offline CPU should reasonably match the one of RCU core. Fixes: cff9b2332ab7 ("kernel/sched: Modify initial boot task idle setup") Acked-by: Peter Zijlstra (Intel) Signed-off-by: Frederic Weisbecker Signed-off-by: Sasha Levin --- kernel/rcu/rcu.h | 2 ++ kernel/rcu/tree.c | 7 +++++++ 2 files changed, 9 insertions(+) diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index 98e13be411afd..3d1851f82dbb6 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -493,6 +493,7 @@ static inline void rcu_expedite_gp(void) { } static inline void rcu_unexpedite_gp(void) { } static inline void rcu_async_hurry(void) { } static inline void rcu_async_relax(void) { } +static inline bool rcu_cpu_online(int cpu) { return true; } #else /* #ifdef CONFIG_TINY_RCU */ bool rcu_gp_is_normal(void); /* Internal RCU use. */ bool rcu_gp_is_expedited(void); /* Internal RCU use. */ @@ -502,6 +503,7 @@ void rcu_unexpedite_gp(void); void rcu_async_hurry(void); void rcu_async_relax(void); void rcupdate_announce_bootup_oddness(void); +bool rcu_cpu_online(int cpu); #ifdef CONFIG_TASKS_RCU_GENERIC void show_rcu_tasks_gp_kthreads(void); #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */ diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 92a090e161865..9af42eae1ba38 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -4139,6 +4139,13 @@ static bool rcu_rdp_cpu_online(struct rcu_data *rdp) return !!(rdp->grpmask & rcu_rnp_online_cpus(rdp->mynode)); } +bool rcu_cpu_online(int cpu) +{ + struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); + + return rcu_rdp_cpu_online(rdp); +} + #if defined(CONFIG_PROVE_RCU) && defined(CONFIG_HOTPLUG_CPU) /* -- 2.43.0