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authorLinus Torvalds <torvalds@linux-foundation.org>2018-01-17 12:28:22 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-01-17 12:28:22 -0800
commit9a4ba2ab08a2cefd8fa2b6829219093fbed4df75 (patch)
treefb8393a8641c9ed5bb707dd12936527f904d0809 /kernel
parent7dfda84d1699c2ae2fbd82f3ce611af2ed7b18b3 (diff)
parentc96f5471ce7d2aefd0dda560cc23f08ab00bc65d (diff)
downloadlinux-9a4ba2ab08a2cefd8fa2b6829219093fbed4df75.tar.bz2
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Ingo Molnar: "A delayacct statistics correctness fix" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: delayacct: Account blkio completion on the correct task
Diffstat (limited to 'kernel')
-rw-r--r--kernel/delayacct.c42
-rw-r--r--kernel/sched/core.c6
2 files changed, 29 insertions, 19 deletions
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
index 4a1c33416b6a..e2764d767f18 100644
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -51,16 +51,16 @@ void __delayacct_tsk_init(struct task_struct *tsk)
* Finish delay accounting for a statistic using its timestamps (@start),
* accumalator (@total) and @count
*/
-static void delayacct_end(u64 *start, u64 *total, u32 *count)
+static void delayacct_end(spinlock_t *lock, u64 *start, u64 *total, u32 *count)
{
s64 ns = ktime_get_ns() - *start;
unsigned long flags;
if (ns > 0) {
- spin_lock_irqsave(&current->delays->lock, flags);
+ spin_lock_irqsave(lock, flags);
*total += ns;
(*count)++;
- spin_unlock_irqrestore(&current->delays->lock, flags);
+ spin_unlock_irqrestore(lock, flags);
}
}
@@ -69,17 +69,25 @@ void __delayacct_blkio_start(void)
current->delays->blkio_start = ktime_get_ns();
}
-void __delayacct_blkio_end(void)
+/*
+ * We cannot rely on the `current` macro, as we haven't yet switched back to
+ * the process being woken.
+ */
+void __delayacct_blkio_end(struct task_struct *p)
{
- if (current->delays->flags & DELAYACCT_PF_SWAPIN)
- /* Swapin block I/O */
- delayacct_end(&current->delays->blkio_start,
- &current->delays->swapin_delay,
- &current->delays->swapin_count);
- else /* Other block I/O */
- delayacct_end(&current->delays->blkio_start,
- &current->delays->blkio_delay,
- &current->delays->blkio_count);
+ struct task_delay_info *delays = p->delays;
+ u64 *total;
+ u32 *count;
+
+ if (p->delays->flags & DELAYACCT_PF_SWAPIN) {
+ total = &delays->swapin_delay;
+ count = &delays->swapin_count;
+ } else {
+ total = &delays->blkio_delay;
+ count = &delays->blkio_count;
+ }
+
+ delayacct_end(&delays->lock, &delays->blkio_start, total, count);
}
int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
@@ -153,8 +161,10 @@ void __delayacct_freepages_start(void)
void __delayacct_freepages_end(void)
{
- delayacct_end(&current->delays->freepages_start,
- &current->delays->freepages_delay,
- &current->delays->freepages_count);
+ delayacct_end(
+ &current->delays->lock,
+ &current->delays->freepages_start,
+ &current->delays->freepages_delay,
+ &current->delays->freepages_count);
}
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 644fa2e3d993..a7bf32aabfda 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2056,7 +2056,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
p->state = TASK_WAKING;
if (p->in_iowait) {
- delayacct_blkio_end();
+ delayacct_blkio_end(p);
atomic_dec(&task_rq(p)->nr_iowait);
}
@@ -2069,7 +2069,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
#else /* CONFIG_SMP */
if (p->in_iowait) {
- delayacct_blkio_end();
+ delayacct_blkio_end(p);
atomic_dec(&task_rq(p)->nr_iowait);
}
@@ -2122,7 +2122,7 @@ static void try_to_wake_up_local(struct task_struct *p, struct rq_flags *rf)
if (!task_on_rq_queued(p)) {
if (p->in_iowait) {
- delayacct_blkio_end();
+ delayacct_blkio_end(p);
atomic_dec(&rq->nr_iowait);
}
ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_NOCLOCK);