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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Fri, 16 Aug 2019 12:49:36 +0200
Subject: [PATCH 4/4] cgroup: Acquire cgroup_rstat_lock with enabled interrupts
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.4/older/patches-5.4.17-rt8.tar.xz
There is no need to disable interrupts while cgroup_rstat_lock is
acquired. The lock is never used in-IRQ context so a simple spin_lock()
is enough for synchronisation purpose.
Acquire cgroup_rstat_lock without disabling interrupts and ensure that
cgroup_rstat_cpu_lock is acquired with disabled interrupts (this one is
acquired in-IRQ context).
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/cgroup/rstat.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -161,17 +161,17 @@ static void cgroup_rstat_flush_locked(st
cpu);
struct cgroup *pos = NULL;
- raw_spin_lock(cpu_lock);
+ raw_spin_lock_irq(cpu_lock);
while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu)))
cgroup_base_stat_flush(pos, cpu);
- raw_spin_unlock(cpu_lock);
+ raw_spin_unlock_irq(cpu_lock);
if (need_resched() || spin_needbreak(&cgroup_rstat_lock)) {
- spin_unlock_irq(&cgroup_rstat_lock);
+ spin_unlock(&cgroup_rstat_lock);
if (!cond_resched())
cpu_relax();
- spin_lock_irq(&cgroup_rstat_lock);
+ spin_lock(&cgroup_rstat_lock);
}
}
}
@@ -193,9 +193,9 @@ void cgroup_rstat_flush(struct cgroup *c
{
might_sleep();
- spin_lock_irq(&cgroup_rstat_lock);
+ spin_lock(&cgroup_rstat_lock);
cgroup_rstat_flush_locked(cgrp);
- spin_unlock_irq(&cgroup_rstat_lock);
+ spin_unlock(&cgroup_rstat_lock);
}
/**
@@ -211,7 +211,7 @@ static void cgroup_rstat_flush_hold(stru
__acquires(&cgroup_rstat_lock)
{
might_sleep();
- spin_lock_irq(&cgroup_rstat_lock);
+ spin_lock(&cgroup_rstat_lock);
cgroup_rstat_flush_locked(cgrp);
}
@@ -221,7 +221,7 @@ static void cgroup_rstat_flush_hold(stru
static void cgroup_rstat_flush_release(void)
__releases(&cgroup_rstat_lock)
{
- spin_unlock_irq(&cgroup_rstat_lock);
+ spin_unlock(&cgroup_rstat_lock);
}
int cgroup_rstat_init(struct cgroup *cgrp)
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