Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 13/20] rcu/context_tracking: Move dynticks_nesting to context tracking | Date | Wed, 8 Jun 2022 16:40:30 +0200 |
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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.
Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao<liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> --- include/linux/context_tracking_state.h | 12 ++++++++++ kernel/context_tracking.c | 1 + kernel/rcu/tree.c | 31 +++++++++++++------------- kernel/rcu/tree.h | 1 - kernel/rcu/tree_stall.h | 2 +- 5 files changed, 30 insertions(+), 17 deletions(-)
diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h index 651bb9c353f0..164f4673ee74 100644 --- a/include/linux/context_tracking_state.h +++ b/include/linux/context_tracking_state.h @@ -25,6 +25,7 @@ struct context_tracking { #endif #ifdef CONFIG_CONTEXT_TRACKING_IDLE atomic_t dynticks; /* Even value for idle, else odd. */ + long dynticks_nesting; /* Track process nesting level. */ #endif }; @@ -49,6 +50,17 @@ static __always_inline int ct_dynticks_cpu_acquire(int cpu) struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu); return atomic_read_acquire(&ct->dynticks); } + +static __always_inline long ct_dynticks_nesting(void) +{ + return __this_cpu_read(context_tracking.dynticks_nesting); +} + +static __always_inline long ct_dynticks_nesting_cpu(int cpu) +{ + struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu); + return ct->dynticks_nesting; +} #endif /* #ifdef CONFIG_CONTEXT_TRACKING_IDLE */ #ifdef CONFIG_CONTEXT_TRACKING_USER diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 3475dbfa4d73..d5ff1de1a24a 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -25,6 +25,7 @@ DEFINE_PER_CPU(struct context_tracking, context_tracking) = { #ifdef CONFIG_CONTEXT_TRACKING_IDLE + .dynticks_nesting = 1, .dynticks = ATOMIC_INIT(1), #endif }; diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 5c9ca5900540..5e7771c78162 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, @@ -440,7 +439,7 @@ 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(ct_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!"); @@ -456,7 +455,7 @@ 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 ct_dynticks_nesting() == 0; } #define DEFAULT_RCU_BLIMIT (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD) ? 1000 : 10) @@ -623,16 +622,16 @@ 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; } instrumentation_begin(); lockdep_assert_irqs_disabled(); - trace_rcu_dyntick(TPS("Start"), rdp->dynticks_nesting, 0, ct_dynticks()); + trace_rcu_dyntick(TPS("Start"), ct_dynticks_nesting(), 0, ct_dynticks()); WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user && !is_idle_task(current)); rcu_preempt_deferred_qs(current); @@ -640,7 +639,7 @@ 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. @@ -797,7 +796,7 @@ 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(ct_dynticks_nesting() <= 0, "RCU dynticks_nesting counter underflow/zero!"); RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nmi_nesting) != DYNTICK_IRQ_NONIDLE, @@ -823,11 +822,11 @@ static void noinstr rcu_eqs_exit(bool user) WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !raw_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(); @@ -839,9 +838,9 @@ 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, ct_dynticks()); + trace_rcu_dyntick(TPS("End"), ct_dynticks_nesting(), 1, 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(); @@ -4229,12 +4228,13 @@ 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; @@ -4259,6 +4259,7 @@ 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(); @@ -4267,7 +4268,7 @@ 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 2e46ee108d13..642b11cd8027 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -191,7 +191,6 @@ 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 594a3c5aded1..b5195bbd9ebc 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -479,7 +479,7 @@ 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_cpu(cpu), 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, rcuc_starved ? buf : "", -- 2.25.1
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