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refscale: Add local_irq_disable() and local_irq_save() readers

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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: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This commit is contained in:
Paul E. McKenney 2025-11-02 14:49:42 -08:00 committed by Frederic Weisbecker
parent 3a86608788
commit edd6f78b75
1 changed files with 65 additions and 1 deletions
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66
kernel/rcu/refscale.c
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@ -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,
};