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Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull scheduler fixes from Ingo Molnar:
 "Misc fixlets"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/cputime: Fix accounting on multi-threaded processes
  sched/debug: Fix sd->*_idx limit range avoiding overflow
  sched_clock: Prevent 64bit inatomicity on 32bit systems
  sched: Convert BUG_ON()s in try_to_wake_up_local() to WARN_ON_ONCE()s
This commit is contained in:
Linus Torvalds 2013-04-14 11:12:17 -07:00
commit af788e35bf
3 changed files with 32 additions and 4 deletions
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26
kernel/sched/clock.c
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@ -176,10 +176,36 @@ static u64 sched_clock_remote(struct sched_clock_data *scd)
u64 this_clock, remote_clock;
u64 *ptr, old_val, val;
#if BITS_PER_LONG != 64
again:
/*
* Careful here: The local and the remote clock values need to
* be read out atomic as we need to compare the values and
* then update either the local or the remote side. So the
* cmpxchg64 below only protects one readout.
*
* We must reread via sched_clock_local() in the retry case on
* 32bit as an NMI could use sched_clock_local() via the
* tracer and hit between the readout of
* the low32bit and the high 32bit portion.
*/
this_clock = sched_clock_local(my_scd);
/*
* We must enforce atomic readout on 32bit, otherwise the
* update on the remote cpu can hit inbetween the readout of
* the low32bit and the high 32bit portion.
*/
remote_clock = cmpxchg64(&scd->clock, 0, 0);
#else
/*
* On 64bit the read of [my]scd->clock is atomic versus the
* update, so we can avoid the above 32bit dance.
*/
sched_clock_local(my_scd);
again:
this_clock = my_scd->clock;
remote_clock = scd->clock;
#endif
/*
* Use the opportunity that we have both locks

8
kernel/sched/core.c
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@ -1498,8 +1498,10 @@ static void try_to_wake_up_local(struct task_struct *p)
{
struct rq *rq = task_rq(p);
BUG_ON(rq != this_rq());
BUG_ON(p == current);
if (WARN_ON_ONCE(rq != this_rq()) ||
WARN_ON_ONCE(p == current))
return;
lockdep_assert_held(&rq->lock);
if (!raw_spin_trylock(&p->pi_lock)) {
@ -4999,7 +5001,7 @@ static void sd_free_ctl_entry(struct ctl_table **tablep)
}
static int min_load_idx = 0;
static int max_load_idx = CPU_LOAD_IDX_MAX;
static int max_load_idx = CPU_LOAD_IDX_MAX-1;
static void
set_table_entry(struct ctl_table *entry,

2
kernel/sched/cputime.c
View File

@ -310,7 +310,7 @@ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
t = tsk;
do {
task_cputime(tsk, &utime, &stime);
task_cputime(t, &utime, &stime);
times->utime += utime;
times->stime += stime;
times->sum_exec_runtime += task_sched_runtime(t);