Messages in this thread Patch in this message |  | | Date | Sun, 13 Mar 2022 00:23:07 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 11/19] rcu/context_tracking: Move dynticks_nesting to context tracking |
| |
On Wed, Mar 02, 2022 at 04:48:02PM +0100, Frederic Weisbecker wrote:
> @@ -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)
> @@ -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,
Would it make sense to create __ct_wrappers() to access the dynticks_{nmi_,}_nesting counters ?
> @@ -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(); >
> 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?)" : "");
And perhaps helpers here too? RCU grubbing in the context_tracking internals seems a bit yuck.
|  |