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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2018-04-23 18:10:23 +0200
committerThomas Gleixner <tglx@linutronix.de>2018-04-27 14:34:51 +0200
commit02acc80d19edb0d5684c997b2004ad19f9f5236e (patch)
tree068ff4bf66e2bf13dc73e56d858e8f7f4994dfda /kernel/delayacct.c
parent3bea9adc96842b8a7345c7fb202c16ae9c8d5b25 (diff)
downloadlinux-02acc80d19edb0d5684c997b2004ad19f9f5236e.tar.bz2
delayacct: Use raw_spinlocks
try_to_wake_up() might invoke delayacct_blkio_end() while holding the pi_lock (which is a raw_spinlock_t). delayacct_blkio_end() acquires task_delay_info.lock which is a spinlock_t. This causes a might sleep splat on -RT where non raw spinlocks are converted to 'sleeping' spinlocks. task_delay_info.lock is only held for a short amount of time so it's not a problem latency wise to make convert it to a raw spinlock. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Balbir Singh <bsingharora@gmail.com> Link: https://lkml.kernel.org/r/20180423161024.6710-1-bigeasy@linutronix.de
Diffstat (limited to 'kernel/delayacct.c')
-rw-r--r--kernel/delayacct.c17
1 files changed, 9 insertions, 8 deletions
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
index e2764d767f18..ca8ac2824f0b 100644
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -44,23 +44,24 @@ void __delayacct_tsk_init(struct task_struct *tsk)
{
tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
if (tsk->delays)
- spin_lock_init(&tsk->delays->lock);
+ raw_spin_lock_init(&tsk->delays->lock);
}
/*
* Finish delay accounting for a statistic using its timestamps (@start),
* accumalator (@total) and @count
*/
-static void delayacct_end(spinlock_t *lock, u64 *start, u64 *total, u32 *count)
+static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total,
+ u32 *count)
{
s64 ns = ktime_get_ns() - *start;
unsigned long flags;
if (ns > 0) {
- spin_lock_irqsave(lock, flags);
+ raw_spin_lock_irqsave(lock, flags);
*total += ns;
(*count)++;
- spin_unlock_irqrestore(lock, flags);
+ raw_spin_unlock_irqrestore(lock, flags);
}
}
@@ -127,7 +128,7 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
/* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
- spin_lock_irqsave(&tsk->delays->lock, flags);
+ raw_spin_lock_irqsave(&tsk->delays->lock, flags);
tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
@@ -137,7 +138,7 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
d->blkio_count += tsk->delays->blkio_count;
d->swapin_count += tsk->delays->swapin_count;
d->freepages_count += tsk->delays->freepages_count;
- spin_unlock_irqrestore(&tsk->delays->lock, flags);
+ raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
return 0;
}
@@ -147,10 +148,10 @@ __u64 __delayacct_blkio_ticks(struct task_struct *tsk)
__u64 ret;
unsigned long flags;
- spin_lock_irqsave(&tsk->delays->lock, flags);
+ raw_spin_lock_irqsave(&tsk->delays->lock, flags);
ret = nsec_to_clock_t(tsk->delays->blkio_delay +
tsk->delays->swapin_delay);
- spin_unlock_irqrestore(&tsk->delays->lock, flags);
+ raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
return ret;
}