Messages in this thread | | | Date | Mon, 6 Nov 2017 17:06:21 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 2/4] sched: Account per task_group nr_iowait |
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On Mon, Nov 06, 2017 at 05:40:32PM +0300, Kirill Tkhai wrote: > The patch makes number of task_group's tasks in iowait state > be tracked separately. This may be useful for containers to > check nr_iowait state of a single one. > > Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> > --- > kernel/sched/core.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ > kernel/sched/sched.h | 5 +++++ > 2 files changed, 50 insertions(+) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 712ee54edaa1..86d1ad5f49bd 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -796,12 +796,32 @@ void deactivate_task(struct rq *rq, struct task_struct *p, int flags) > > static void task_iowait_start(struct rq *rq, struct task_struct *p) > { > +#ifdef CONFIG_CGROUP_SCHED > + struct task_group *tg = task_group(p); > + > + /* Task's sched_task_group is changed under both of the below locks */ > + BUG_ON(!raw_spin_is_locked(&p->pi_lock) && !raw_spin_is_locked(&rq->lock));
We have lockdep_assert_held for that.
> + while (task_group_is_autogroup(tg)) > + tg = tg->parent; > + atomic_inc(&tg->stat[rq->cpu].nr_iowait);
You're joking right, more atomic ops on the fast paths..
> +#endif > + > atomic_inc(&rq->nr_iowait); > delayacct_blkio_start();
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