From 38200cf24702e5d79ce6c8f4c62036c41845c62d Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 21 Oct 2014 12:50:04 -0700 Subject: [PATCH] rcu: Remove "cpu" argument to rcu_note_context_switch() The "cpu" argument to rcu_note_context_switch() is always the current CPU, so drop it. This in turn allows the "cpu" argument to rcu_preempt_note_context_switch() to be removed, which allows the sole use of "cpu" in both functions to be replaced with a this_cpu_ptr(). Again, the anticipated cross-CPU uses of these functions has been replaced by NO_HZ_FULL. Signed-off-by: Paul E. McKenney Reviewed-by: Pranith Kumar --- include/linux/rcutiny.h | 2 +- include/linux/rcutree.h | 4 ++-- kernel/rcu/tree.c | 4 ++-- kernel/rcu/tree.h | 2 +- kernel/rcu/tree_plugin.h | 6 +++--- kernel/sched/core.c | 2 +- kernel/softirq.c | 2 +- 7 files changed, 11 insertions(+), 11 deletions(-) diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 38cc5b1e252d..0e5366200154 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -78,7 +78,7 @@ static inline void kfree_call_rcu(struct rcu_head *head, call_rcu(head, func); } -static inline void rcu_note_context_switch(int cpu) +static inline void rcu_note_context_switch(void) { rcu_sched_qs(); } diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 3e2f5d432743..7b5484db1857 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -30,7 +30,7 @@ #ifndef __LINUX_RCUTREE_H #define __LINUX_RCUTREE_H -void rcu_note_context_switch(int cpu); +void rcu_note_context_switch(void); #ifndef CONFIG_RCU_NOCB_CPU_ALL int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies); #endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */ @@ -43,7 +43,7 @@ void rcu_cpu_stall_reset(void); */ static inline void rcu_virt_note_context_switch(int cpu) { - rcu_note_context_switch(cpu); + rcu_note_context_switch(); } void synchronize_rcu_bh(void); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 1af5e2cdcbeb..b591f1459240 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -286,11 +286,11 @@ static void rcu_momentary_dyntick_idle(void) * and requires special handling for preemptible RCU. * The caller must have disabled preemption. */ -void rcu_note_context_switch(int cpu) +void rcu_note_context_switch(void) { trace_rcu_utilization(TPS("Start context switch")); rcu_sched_qs(); - rcu_preempt_note_context_switch(cpu); + rcu_preempt_note_context_switch(); if (unlikely(raw_cpu_read(rcu_sched_qs_mask))) rcu_momentary_dyntick_idle(); trace_rcu_utilization(TPS("End context switch")); diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 94a26e330c1b..238ac39053fc 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -547,7 +547,7 @@ DECLARE_PER_CPU(char, rcu_cpu_has_work); /* Forward declarations for rcutree_plugin.h */ static void rcu_bootup_announce(void); long rcu_batches_completed(void); -static void rcu_preempt_note_context_switch(int cpu); +static void rcu_preempt_note_context_switch(void); static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp); #ifdef CONFIG_HOTPLUG_CPU static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 7158814b7b4a..495d4cce47a7 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -156,7 +156,7 @@ static void rcu_preempt_qs(void) * * Caller must disable preemption. */ -static void rcu_preempt_note_context_switch(int cpu) +static void rcu_preempt_note_context_switch(void) { struct task_struct *t = current; unsigned long flags; @@ -167,7 +167,7 @@ static void rcu_preempt_note_context_switch(int cpu) !t->rcu_read_unlock_special.b.blocked) { /* Possibly blocking in an RCU read-side critical section. */ - rdp = per_cpu_ptr(rcu_preempt_state.rda, cpu); + rdp = this_cpu_ptr(rcu_preempt_state.rda); rnp = rdp->mynode; raw_spin_lock_irqsave(&rnp->lock, flags); smp_mb__after_unlock_lock(); @@ -945,7 +945,7 @@ EXPORT_SYMBOL_GPL(rcu_batches_completed); * Because preemptible RCU does not exist, we never have to check for * CPUs being in quiescent states. */ -static void rcu_preempt_note_context_switch(int cpu) +static void rcu_preempt_note_context_switch(void) { } diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 44999505e1bf..cc186945296d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2802,7 +2802,7 @@ need_resched: preempt_disable(); cpu = smp_processor_id(); rq = cpu_rq(cpu); - rcu_note_context_switch(cpu); + rcu_note_context_switch(); prev = rq->curr; schedule_debug(prev); diff --git a/kernel/softirq.c b/kernel/softirq.c index 0699add19164..501baa9ac1be 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -656,7 +656,7 @@ static void run_ksoftirqd(unsigned int cpu) * in the task stack here. */ __do_softirq(); - rcu_note_context_switch(cpu); + rcu_note_context_switch(); local_irq_enable(); cond_resched(); return; -- 2.20.1