Commit edd6f78b authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Frederic Weisbecker
Browse files

refscale: Add local_irq_disable() and local_irq_save() readers 



This commit adds refscale readers based on local_irq_disable() and
local_irq_enable() ("refscale.scale_type=irq") and on local_irq_save()
and local_irq_restore ("refscale.scale_type=irqsave").  On my x86 laptop,
these are about 2.8ns and 7.5ns per enable/disable pair, respectively.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Signed-off-by: default avatarFrederic Weisbecker <frederic@kernel.org>
parent 3a866087

kernel/rcu/refscale.c

+65 −1
Original line number Diff line number Diff line
@@ -629,6 +629,70 @@ static const struct ref_scale_ops jiffies_ops = { 
	.name		= "jiffies"

};



static void ref_irq_section(const int nloops)

{

	int i;



	preempt_disable();

	for (i = nloops; i >= 0; i--) {

		local_irq_disable();

		local_irq_enable();

	}

	preempt_enable();

}



static void ref_irq_delay_section(const int nloops, const int udl, const int ndl)

{

	int i;



	preempt_disable();

	for (i = nloops; i >= 0; i--) {

		local_irq_disable();

		un_delay(udl, ndl);

		local_irq_enable();

	}

	preempt_enable();

}



static const struct ref_scale_ops irq_ops = {

	.readsection	= ref_irq_section,

	.delaysection	= ref_irq_delay_section,

	.name		= "irq"

};



static void ref_irqsave_section(const int nloops)

{

	unsigned long flags;

	int i;



	preempt_disable();

	for (i = nloops; i >= 0; i--) {

		local_irq_save(flags);

		local_irq_restore(flags);

	}

	preempt_enable();

}



static void ref_irqsave_delay_section(const int nloops, const int udl, const int ndl)

{

	unsigned long flags;

	int i;



	preempt_disable();

	for (i = nloops; i >= 0; i--) {

		local_irq_save(flags);

		un_delay(udl, ndl);

		local_irq_restore(flags);

	}

	preempt_enable();

}



static const struct ref_scale_ops irqsave_ops = {

	.readsection	= ref_irqsave_section,

	.delaysection	= ref_irqsave_delay_section,

	.name		= "irqsave"

};



////////////////////////////////////////////////////////////////////////

//

// Methods leveraging SLAB_TYPESAFE_BY_RCU.
@@ -1165,7 +1229,7 @@ ref_scale_init(void) 
	static const struct ref_scale_ops *scale_ops[] = {

		&rcu_ops, &srcu_ops, &srcu_fast_ops, RCU_TRACE_OPS RCU_TASKS_OPS

		&refcnt_ops, &rwlock_ops, &rwsem_ops, &lock_ops, &lock_irq_ops,

		&acqrel_ops, &sched_clock_ops, &clock_ops, &jiffies_ops,

		&acqrel_ops, &sched_clock_ops, &clock_ops, &jiffies_ops, &irq_ops, &irqsave_ops,

		&typesafe_ref_ops, &typesafe_lock_ops, &typesafe_seqlock_ops,

	};