lkml.org 
[lkml]   [2011]   [Apr]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [patch 12/15] sched: maintain throttled rqs as a list
    Hi Paul,

    (2011/03/23 12:03), Paul Turner wrote:
    > @@ -1434,7 +1435,11 @@ static void throttle_cfs_rq(struct cfs_r
    > if (!se)
    > rq->nr_running += task_delta;
    >
    > + raw_spin_lock(&cfs_b->lock);
    > cfs_rq->throttled = 1;
    > + list_add_tail_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq);
    > + raw_spin_unlock(&cfs_b->lock);
    > +
    > cfs_rq->throttled_timestamp = rq_of(cfs_rq)->clock;
    > }
    >

    Though I'm looking forward to see your updates soon, just FYI,
    I found that somehow throttle_cfs_rq() was called with already
    throttled cfs_rq.

    So it breaks list throttled_cfs_rq by repeating list_add_tail_rcu()
    and results in lockups like that Bharata and Xiao already reported.

    There should be better fix, but following first aid to put_prev_entity()
    worked for me:

    - if (!within_bandwidth(cfs_rq))
    + if (!within_bandwidth(cfs_rq) && !cfs_rq->throttled)
    throttle_cfs_rq(cfs_rq);
    else
    return_cfs_rq_quota(cfs_rq);

    I believe you can do better next time.


    Thanks,
    H.Seto



    \
     
     \ /
      Last update: 2011-04-22 04:53    [W:0.035 / U:0.764 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site