diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2018-04-23 18:10:23 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-04-27 14:34:51 +0200 |
| commit | 02acc80d19edb0d5684c997b2004ad19f9f5236e (patch) | |
| tree | 068ff4bf66e2bf13dc73e56d858e8f7f4994dfda | |
| parent | 3bea9adc96842b8a7345c7fb202c16ae9c8d5b25 (diff) | |
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
| -rw-r--r-- | include/linux/delayacct.h | 2 | ||||
| -rw-r--r-- | kernel/delayacct.c | 17 |
2 files changed, 10 insertions, 9 deletions
diff --git a/include/linux/delayacct.h b/include/linux/delayacct.h index 5e335b6203f4..e6c0448ebcc7 100644 --- a/include/linux/delayacct.h +++ b/include/linux/delayacct.h @@ -29,7 +29,7 @@ #ifdef CONFIG_TASK_DELAY_ACCT 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 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; } |