lkml.org 
[lkml]   [2010]   [Oct]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [RFC/RFT PATCH] sched: automated per tty task groups
    * Mike Galbraith (efault@gmx.de) wrote:
    [...]
    > +static void
    > +autogroup_attach_tty(struct task_struct *p, struct task_group **tg)
    > +{
    > + struct tty_struct *tty = p->signal->tty;
    > +
    > + if (!tty)
    > + return;
    > +
    > + *tg = p->signal->tty->tg;
    > +}
    > +
    > +static inline void
    > +autogroup_check_attach(struct task_struct *p, struct task_group **tg)
    > +{
    > + if (!sysctl_sched_autogroup_enabled || *tg != &root_task_group ||
    > + p->sched_class != &fair_sched_class)
    > + return;
    > +
    > + rcu_read_lock();
    > +
    > + autogroup_attach_tty(p, tg);
    > +
    > + rcu_read_unlock();
    > +}
    > +

    Hi Mike,

    This per-tty task grouping approach looks very promising. I'll give it a spin
    when I find the time. Meanwhile, a little question about locking here: how is
    the read lock supposed to protect from p->signal (and p->signal->tty)
    modifications ? What's the locking scheme here ? So maybe just simple
    rcu_dereference are missing, or maybe the tsk->sighand->siglock might be
    required. In all cases, I feel something is missing there.

    Thanks!

    Mathieu

    --
    Mathieu Desnoyers
    Operating System Efficiency R&D Consultant
    EfficiOS Inc.
    http://www.efficios.com


    \
     
     \ /
      Last update: 2010-10-21 12:53    [W:0.021 / U:1.496 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site