From patchwork Tue Apr 30 09:17:18 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Valentin Schneider X-Patchwork-Id: 13648590 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 3BEF31A38CD for ; Tue, 30 Apr 2024 09:18:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714468733; cv=none; b=hQ7Z58xftQz6MVIQm9gegizuhAU3tKGycJyor5bNOELPiLI2pv2rqn6tTRA6BV28fgAEQHf5kFtBrJWiysjXpNBV7ddwiUC5gU3kV5pmzOZJjPk5R4KyV1wJADYepFmQU2bjQtYXw2zGJVlATJTiQtzG9bxkMXlscZvZU8ivULM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714468733; c=relaxed/simple; bh=rdwNE4TivoWSLkLZ0FAD1O9FFZJKd8QQYOGbXyhpCkg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Mz8efxGKJpScxuaBqkYWDEwkyzdRUSLmrbPNM6mxfdiPOBHrER7CyHXi9KuZnN1OA6TI2bo5R/GuU7V1ootPldExpPFqUQuBNPYgJWNksmJamUaU37ptJ3VcWiqFNxsXY1uSDuFIAaaTv9HtMcpw2pV27gHxQ4bsQMDafQa+1Vk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Tm7rNQHG; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Tm7rNQHG" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1714468731; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=yFvEhpDaXmg9BXMihL4YArPI3eFmOuObqd6gNO/1dYU=; b=Tm7rNQHGv5zu/i3CwhpdABH0dAdb70IetIAkGGQ2+zUWTtVTAedrmfWsBYl/QZeiaN3CMO BKuP020eiYLJKDGnNi6Ke6LmREs1V5Cn6uSiw/2YSoixxxFPPrwCqyAkmpiFOTMVJJZW0g 6gj/c9FIHgVaUOehEc/ZYmVrK7pEDJk= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-593-bIDlG8WmPRyFIlnRIz9QIw-1; Tue, 30 Apr 2024 05:18:45 -0400 X-MC-Unique: bIDlG8WmPRyFIlnRIz9QIw-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 20437800CA2; Tue, 30 Apr 2024 09:18:45 +0000 (UTC) Received: from vschneid-thinkpadt14sgen2i.remote.csb (unknown [10.39.193.247]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9823D477F81; Tue, 30 Apr 2024 09:18:42 +0000 (UTC) From: Valentin Schneider To: rcu@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Frederic Weisbecker , "Paul E. McKenney" , Peter Zijlstra , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang Subject: [PATCH v2 14/27] context_tracking, rcu: Rename rcu_dynticks_curr_cpu_in_eqs() into rcu_watching_curr_cpu() Date: Tue, 30 Apr 2024 11:17:18 +0200 Message-ID: <20240430091740.1826862-15-vschneid@redhat.com> In-Reply-To: <20240430091740.1826862-1-vschneid@redhat.com> References: <20240430091740.1826862-1-vschneid@redhat.com> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.10 The context_tracking.state RCU_DYNTICKS subvariable has been renamed to RCU_WATCHING, reflect that change in the related helpers. Note that "watching" is the opposite of "in EQS", so the negation is lifted out of the helper and into the callsites. Signed-off-by: Valentin Schneider Reviewed-by: Frederic Weisbecker --- include/linux/context_tracking.h | 12 ++++++++---- kernel/context_tracking.c | 6 +++--- kernel/rcu/tree.c | 6 +++--- 3 files changed, 14 insertions(+), 10 deletions(-) diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h index a6c36780cc3bd..d53092ffa9dba 100644 --- a/include/linux/context_tracking.h +++ b/include/linux/context_tracking.h @@ -113,13 +113,17 @@ extern void ct_idle_enter(void); extern void ct_idle_exit(void); /* - * Is the current CPU in an extended quiescent state? + * Is RCU watching the current CPU (IOW, it is not in an extended quiescent state)? + * + * Note that this returns the actual boolean data (watching / not watching), + * whereas ct_rcu_watching() returns the RCU_WATCHING subvariable of + * context_tracking.state. * * No ordering, as we are sampling CPU-local information. */ -static __always_inline bool rcu_dynticks_curr_cpu_in_eqs(void) +static __always_inline bool rcu_is_watching_curr_cpu(void) { - return !(raw_atomic_read(this_cpu_ptr(&context_tracking.state)) & CT_RCU_WATCHING); + return raw_atomic_read(this_cpu_ptr(&context_tracking.state)) & CT_RCU_WATCHING; } /* @@ -140,7 +144,7 @@ static __always_inline bool warn_rcu_enter(void) * lots of the actual reporting also relies on RCU. */ preempt_disable_notrace(); - if (rcu_dynticks_curr_cpu_in_eqs()) { + if (!rcu_is_watching_curr_cpu()) { ret = true; ct_state_inc(CT_RCU_WATCHING); } diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 9c8f7b9191cd4..e82f19bab9ed9 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -212,7 +212,7 @@ void noinstr ct_nmi_exit(void) * to us!) */ WARN_ON_ONCE(ct_nmi_nesting() <= 0); - WARN_ON_ONCE(rcu_dynticks_curr_cpu_in_eqs()); + WARN_ON_ONCE(!rcu_is_watching_curr_cpu()); /* * If the nesting level is not 1, the CPU wasn't RCU-idle, so @@ -271,7 +271,7 @@ void noinstr ct_nmi_enter(void) * to be in the outermost NMI handler that interrupted an RCU-idle * period (observation due to Andy Lutomirski). */ - if (rcu_dynticks_curr_cpu_in_eqs()) { + if (!rcu_is_watching_curr_cpu()) { if (!in_nmi()) rcu_task_exit(); @@ -281,7 +281,7 @@ void noinstr ct_nmi_enter(void) // ... but is watching here. instrumentation_begin(); - // instrumentation for the noinstr rcu_dynticks_curr_cpu_in_eqs() + // instrumentation for the noinstr rcu_is_watching_curr_cpu() instrument_atomic_read(&ct->state, sizeof(ct->state)); // instrumentation for the noinstr ct_kernel_enter_state() instrument_atomic_write(&ct->state, sizeof(ct->state)); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index d8f89bc573448..bb0d9dd8b6d3a 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -600,7 +600,7 @@ void rcu_irq_exit_check_preempt(void) RCU_LOCKDEP_WARN(ct_nmi_nesting() != CT_NESTING_IRQ_NONIDLE, "Bad RCU nmi_nesting counter\n"); - RCU_LOCKDEP_WARN(rcu_dynticks_curr_cpu_in_eqs(), + RCU_LOCKDEP_WARN(!rcu_is_watching_curr_cpu(), "RCU in extended quiescent state!"); } #endif /* #ifdef CONFIG_PROVE_RCU */ @@ -640,7 +640,7 @@ void __rcu_irq_enter_check_tick(void) if (in_nmi()) return; - RCU_LOCKDEP_WARN(rcu_dynticks_curr_cpu_in_eqs(), + RCU_LOCKDEP_WARN(!rcu_is_watching_curr_cpu(), "Illegal rcu_irq_enter_check_tick() from extended quiescent state"); if (!tick_nohz_full_cpu(rdp->cpu) || @@ -722,7 +722,7 @@ notrace bool rcu_is_watching(void) bool ret; preempt_disable_notrace(); - ret = !rcu_dynticks_curr_cpu_in_eqs(); + ret = rcu_is_watching_curr_cpu(); preempt_enable_notrace(); return ret; }