Currently rdp->defer_qs_pending transitions from DEFER_QS_PENDING to DEFER_QS_IDLE at two sites: rcu_preempt_deferred_qs_irqrestore() and rcu_preempt_deferred_qs_handler() (depth>0 reset). Both write the IDLE value directly.
Introduce a single inline helper rcu_defer_qs_clear() in tree.h and route both sites through it. This becomes the single PENDING->IDLE transition point for upcoming work. Signed-off-by: Joel Fernandes <[email protected]> --- kernel/rcu/tree.h | 5 +++++ kernel/rcu/tree_plugin.h | 4 ++-- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 7dfc57e9adb1..4069132f9d44 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -296,6 +296,11 @@ struct rcu_data { int cpu; }; +static inline void rcu_defer_qs_clear(struct rcu_data *rdp) +{ + WRITE_ONCE(rdp->defer_qs_pending, DEFER_QS_IDLE); +} + /* Values for nocb_defer_wakeup field in struct rcu_data. */ #define RCU_NOCB_WAKE_NOT 0 #define RCU_NOCB_WAKE_BYPASS 1 diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 95ad967adcf3..8637f405cb47 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -488,7 +488,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) rdp = this_cpu_ptr(&rcu_data); if (rdp->defer_qs_pending == DEFER_QS_PENDING) - rdp->defer_qs_pending = DEFER_QS_IDLE; + rcu_defer_qs_clear(rdp); /* * If RCU core is waiting for this CPU to exit its critical section, @@ -645,7 +645,7 @@ static void rcu_preempt_deferred_qs_handler(struct irq_work *iwp) * 5. Deferred QS reporting does not happen. */ if (rcu_preempt_depth() > 0) - WRITE_ONCE(rdp->defer_qs_pending, DEFER_QS_IDLE); + rcu_defer_qs_clear(rdp); } /* -- 2.34.1
