linux-stable/include/linux/bottom_half.h
Thomas Gleixner 47c218dcae tick/sched: Prevent false positive softirq pending warnings on RT
On RT a task which has soft interrupts disabled can block on a lock and
schedule out to idle while soft interrupts are pending. This triggers the
warning in the NOHZ idle code which complains about going idle with pending
soft interrupts. But as the task is blocked soft interrupt processing is
temporarily blocked as well which means that such a warning is a false
positive.

To prevent that check the per CPU state which indicates that a scheduled
out task has soft interrupts disabled.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210309085727.527563866@linutronix.de
2021-03-17 16:34:11 +01:00

41 lines
974 B
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_BH_H
#define _LINUX_BH_H
#include <linux/preempt.h>
#if defined(CONFIG_PREEMPT_RT) || defined(CONFIG_TRACE_IRQFLAGS)
extern void __local_bh_disable_ip(unsigned long ip, unsigned int cnt);
#else
static __always_inline void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
{
preempt_count_add(cnt);
barrier();
}
#endif
static inline void local_bh_disable(void)
{
__local_bh_disable_ip(_THIS_IP_, SOFTIRQ_DISABLE_OFFSET);
}
extern void _local_bh_enable(void);
extern void __local_bh_enable_ip(unsigned long ip, unsigned int cnt);
static inline void local_bh_enable_ip(unsigned long ip)
{
__local_bh_enable_ip(ip, SOFTIRQ_DISABLE_OFFSET);
}
static inline void local_bh_enable(void)
{
__local_bh_enable_ip(_THIS_IP_, SOFTIRQ_DISABLE_OFFSET);
}
#ifdef CONFIG_PREEMPT_RT
extern bool local_bh_blocked(void);
#else
static inline bool local_bh_blocked(void) { return false; }
#endif
#endif /* _LINUX_BH_H */