lkml.org 
[lkml]   [2018]   [Apr]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] delayacct: use raw_spinlocks
Date
try_to_wake_up() might invoke delayacct_blkio_end() while holding the
pi_lock (which is a raw_spinlock_t). The lock is only held for a short
amount of time so it should be safe to make it raw.
Make struct task_delay_info.lock a raw_spinlock_t.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
include/linux/delayacct.h | 2 +-
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;
}

--
2.17.0
\
 
 \ /
  Last update: 2018-04-23 18:11    [W:0.082 / U:0.896 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site