Commit 02acc80d authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Thomas Gleixner

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: 's avatarSebastian Andrzej Siewior <>
Signed-off-by: 's avatarThomas Gleixner <>
Cc: Balbir Singh <>
parent 3bea9adc
......@@ -29,7 +29,7 @@
struct task_delay_info {
spinlock_t lock;
raw_spinlock_t lock;
unsigned int flags; /* Private per-task flags */
/* For each stat XXX, add following, aligned appropriately
......@@ -44,23 +44,24 @@ void __delayacct_tsk_init(struct task_struct *tsk)
tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
if (tsk->delays)
* 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;
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 +
spin_unlock_irqrestore(&tsk->delays->lock, flags);
raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
return ret;
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