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Commit 38200cf2 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

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Again, the anticipated cross-CPU uses of these functions has been
replaced by NO_HZ_FULL.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: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarPranith Kumar <bobby.prani@gmail.com>
parent 86aea0e6

include/linux/rcutiny.h

+1 −1
Original line number Diff line number Diff line
@@ -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();

}

include/linux/rcutree.h

+2 −2
Original line number Diff line number Diff line
@@ -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);

kernel/rcu/tree.c

+2 −2
Original line number Diff line number Diff line
@@ -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"));

kernel/rcu/tree.h

+1 −1
Original line number Diff line number Diff line
@@ -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,

kernel/rcu/tree_plugin.h

+3 −3
Original line number Diff line number Diff line
@@ -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)

{

}