From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E7292C433F5 for ; Wed, 2 Mar 2022 15:49:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241516AbiCBPuj (ORCPT ); Wed, 2 Mar 2022 10:50:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242197AbiCBPuK (ORCPT ); Wed, 2 Mar 2022 10:50:10 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA6E340E44 for ; Wed, 2 Mar 2022 07:48:59 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 4D22BB8207F for ; Wed, 2 Mar 2022 15:48:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BAD50C340F6; Wed, 2 Mar 2022 15:48:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646236138; bh=LEEbg/tTkNBYhQGsXaeUmRgAChHsIDSgUV6Twd2J88E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fHbAze20whdP/pPGI9gRVSPjG8dxF2UCwEBpdQl0zh2mNMDpmW+Vh4XlZtnZiBjj5 4i3kgoKDCdf0zewx68YHGx6Tc9lM/jkj2V3oM/+d2LSfvb1ij6OBhUEIVFFm3fCqU/ 5tF+0SBL/nIwCXgj7fUibZ6WrZsobmVJz9XHLTToUlzGEQfB41n8xM+zXUZFLxBXG8 W8VJZmh70GBX8slwF45Vr4YjS14GCW+daAaDTB+YV4bBO0Uxc/WEnwwcBCgiCHChXF ChyN3QXsz3JQEOvp7D4/tLofiT97SW7p+ao1i/4n7BrbURUczFHb1FnIL3XB2C1kPf fEBte/UX9D18g== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Peter Zijlstra , Phil Auld , Alex Belits , Nicolas Saenz Julienne , Xiongfeng Wang , Neeraj Upadhyay , Thomas Gleixner , Yu Liao , Boqun Feng , "Paul E . McKenney" , Marcelo Tosatti , Paul Gortmaker , Uladzislau Rezki , Joel Fernandes Subject: [PATCH 11/19] rcu/context_tracking: Move dynticks_nesting to context tracking Date: Wed, 2 Mar 2022 16:48:02 +0100 Message-Id: <20220302154810.42308-12-frederic@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220302154810.42308-1-frederic@kernel.org> References: <20220302154810.42308-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The RCU eqs tracking is going to be performed by the context tracking subsystem. The related nesting counters thus need to be moved to the context tracking structure. Signed-off-by: Frederic Weisbecker Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Neeraj Upadhyay Cc: Uladzislau Rezki Cc: Joel Fernandes Cc: Boqun Feng Cc: Nicolas Saenz Julienne Cc: Marcelo Tosatti Cc: Xiongfeng Wang Cc: Yu Liao Cc: Phil Auld Cc: Paul Gortmaker Cc: Alex Belits --- include/linux/context_tracking_state.h | 1 + kernel/context_tracking.c | 1 + kernel/rcu/tree.c | 31 +++++++++++++------------- kernel/rcu/tree.h | 1 - kernel/rcu/tree_stall.h | 3 ++- 5 files changed, 20 insertions(+), 17 deletions(-) diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h index 5ad0e481c5a3..bcb942945265 100644 --- a/include/linux/context_tracking_state.h +++ b/include/linux/context_tracking_state.h @@ -24,6 +24,7 @@ struct context_tracking { } state; #endif atomic_t dynticks; /* Even value for idle, else odd. */ + long dynticks_nesting; /* Track process nesting level. */ }; #ifdef CONFIG_CONTEXT_TRACKING diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 77b61a7c9890..09a77884a4e3 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -234,6 +234,7 @@ void __init context_tracking_init(void) #endif /* #ifdef CONFIG_CONTEXT_TRACKING_USER */ DEFINE_PER_CPU(struct context_tracking, context_tracking) = { + .dynticks_nesting = 1, .dynticks = ATOMIC_INIT(1), }; EXPORT_SYMBOL_GPL(context_tracking); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 96eb8503f28e..8708d1a99565 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -75,7 +75,6 @@ /* Data structures. */ static DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_data, rcu_data) = { - .dynticks_nesting = 1, .dynticks_nmi_nesting = DYNTICK_IRQ_NONIDLE, #ifdef CONFIG_RCU_NOCB_CPU .cblist.flags = SEGCBLIST_RCU_CORE, @@ -441,7 +440,7 @@ static int rcu_is_cpu_rrupt_from_idle(void) lockdep_assert_irqs_disabled(); /* Check for counter underflows */ - RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nesting) < 0, + RCU_LOCKDEP_WARN(__this_cpu_read(context_tracking.dynticks_nesting) < 0, "RCU dynticks_nesting counter underflow!"); RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nmi_nesting) <= 0, "RCU dynticks_nmi_nesting counter underflow/zero!"); @@ -457,7 +456,7 @@ static int rcu_is_cpu_rrupt_from_idle(void) WARN_ON_ONCE(!nesting && !is_idle_task(current)); /* Does CPU appear to be idle from an RCU standpoint? */ - return __this_cpu_read(rcu_data.dynticks_nesting) == 0; + return __this_cpu_read(context_tracking.dynticks_nesting) == 0; } #define DEFAULT_RCU_BLIMIT (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD) ? 1000 : 10) @@ -624,16 +623,16 @@ static noinstr void rcu_eqs_enter(bool user) WARN_ON_ONCE(rdp->dynticks_nmi_nesting != DYNTICK_IRQ_NONIDLE); WRITE_ONCE(rdp->dynticks_nmi_nesting, 0); WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && - rdp->dynticks_nesting == 0); - if (rdp->dynticks_nesting != 1) { + ct->dynticks_nesting == 0); + if (ct->dynticks_nesting != 1) { // RCU will still be watching, so just do accounting and leave. - rdp->dynticks_nesting--; + ct->dynticks_nesting--; return; } lockdep_assert_irqs_disabled(); instrumentation_begin(); - trace_rcu_dyntick(TPS("Start"), rdp->dynticks_nesting, 0, atomic_read(&ct->dynticks)); + trace_rcu_dyntick(TPS("Start"), ct->dynticks_nesting, 0, atomic_read(&ct->dynticks)); WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user && !is_idle_task(current)); rcu_preempt_deferred_qs(current); @@ -641,7 +640,7 @@ static noinstr void rcu_eqs_enter(bool user) instrument_atomic_write(&ct->dynticks, sizeof(ct->dynticks)); instrumentation_end(); - WRITE_ONCE(rdp->dynticks_nesting, 0); /* Avoid irq-access tearing. */ + WRITE_ONCE(ct->dynticks_nesting, 0); /* Avoid irq-access tearing. */ // RCU is watching here ... rcu_dynticks_eqs_enter(); // ... but is no longer watching here. @@ -798,7 +797,7 @@ void rcu_irq_exit_check_preempt(void) { lockdep_assert_irqs_disabled(); - RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nesting) <= 0, + RCU_LOCKDEP_WARN(__this_cpu_read(context_tracking.dynticks_nesting) <= 0, "RCU dynticks_nesting counter underflow/zero!"); RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nmi_nesting) != DYNTICK_IRQ_NONIDLE, @@ -824,11 +823,11 @@ static void noinstr rcu_eqs_exit(bool user) lockdep_assert_irqs_disabled(); rdp = this_cpu_ptr(&rcu_data); - oldval = rdp->dynticks_nesting; + oldval = ct->dynticks_nesting; WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && oldval < 0); if (oldval) { // RCU was already watching, so just do accounting and leave. - rdp->dynticks_nesting++; + ct->dynticks_nesting++; return; } rcu_dynticks_task_exit(); @@ -840,9 +839,9 @@ static void noinstr rcu_eqs_exit(bool user) // instrumentation for the noinstr rcu_dynticks_eqs_exit() instrument_atomic_write(&ct->dynticks, sizeof(ct->dynticks)); - trace_rcu_dyntick(TPS("End"), rdp->dynticks_nesting, 1, atomic_read(&ct->dynticks)); + trace_rcu_dyntick(TPS("End"), ct->dynticks_nesting, 1, atomic_read(&ct->dynticks)); WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user && !is_idle_task(current)); - WRITE_ONCE(rdp->dynticks_nesting, 1); + WRITE_ONCE(ct->dynticks_nesting, 1); WARN_ON_ONCE(rdp->dynticks_nmi_nesting); WRITE_ONCE(rdp->dynticks_nmi_nesting, DYNTICK_IRQ_NONIDLE); instrumentation_end(); @@ -4122,12 +4121,13 @@ static void rcu_init_new_rnp(struct rcu_node *rnp_leaf) static void __init rcu_boot_init_percpu_data(int cpu) { + struct context_tracking *ct = this_cpu_ptr(&context_tracking); struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); /* Set up local state, ensuring consistent view of global state. */ rdp->grpmask = leaf_node_cpu_bit(rdp->mynode, cpu); INIT_WORK(&rdp->strict_work, strict_work_handler); - WARN_ON_ONCE(rdp->dynticks_nesting != 1); + WARN_ON_ONCE(ct->dynticks_nesting != 1); WARN_ON_ONCE(rcu_dynticks_in_eqs(rcu_dynticks_snap(cpu))); rdp->barrier_seq_snap = rcu_state.barrier_sequence; rdp->rcu_ofl_gp_seq = rcu_state.gp_seq; @@ -4152,6 +4152,7 @@ rcu_boot_init_percpu_data(int cpu) int rcutree_prepare_cpu(unsigned int cpu) { unsigned long flags; + struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu); struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); struct rcu_node *rnp = rcu_get_root(); @@ -4160,7 +4161,7 @@ int rcutree_prepare_cpu(unsigned int cpu) rdp->qlen_last_fqs_check = 0; rdp->n_force_qs_snap = READ_ONCE(rcu_state.n_force_qs); rdp->blimit = blimit; - rdp->dynticks_nesting = 1; /* CPU not up, no tearing. */ + ct->dynticks_nesting = 1; /* CPU not up, no tearing. */ raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */ /* diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 15246a3f0734..8050bab08f39 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -186,7 +186,6 @@ struct rcu_data { /* 3) dynticks interface. */ int dynticks_snap; /* Per-GP tracking for dynticks. */ - long dynticks_nesting; /* Track process nesting level. */ long dynticks_nmi_nesting; /* Track irq/NMI nesting level. */ bool rcu_need_heavy_qs; /* GP old, so heavy quiescent state! */ bool rcu_urgent_qs; /* GP old need light quiescent state. */ diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 202129b1c7e4..30a5e0a8ddb3 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -429,6 +429,7 @@ static void print_cpu_stall_info(int cpu) { unsigned long delta; bool falsepositive; + struct context_tracking *ct = this_cpu_ptr(&context_tracking); struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); char *ticks_title; unsigned long ticks_value; @@ -459,7 +460,7 @@ static void print_cpu_stall_info(int cpu) "!."[!delta], ticks_value, ticks_title, rcu_dynticks_snap(cpu) & 0xfff, - rdp->dynticks_nesting, rdp->dynticks_nmi_nesting, + ct->dynticks_nesting, rdp->dynticks_nmi_nesting, rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu), data_race(rcu_state.n_force_qs) - rcu_state.n_force_qs_gpstart, falsepositive ? " (false positive?)" : ""); -- 2.25.1