lkml.org 
[lkml]   [2008]   [Jan]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: Hang in work_resched
    On Jan 29, 2008 11:30 PM, Guillaume Chazarain <guichaz@gmail.com> wrote:
    > =======================
    > gnome-termina S 00000027 0 2201 1
    > f6711fb0 00200082 cb330d62 00000027 f664105c 00000b1e 00000000 cb331880
    > 00000027 f660d780 009e3840 080ab7d8 080ab298 f6711000 c0103e7e 009e3840
    > 000e0002 00000002 080ab7d8 080ab298 bfb41be8 080ab7d8 0000007b c010007b
    > Call Trace:
    > [<c0103e7e>] work_resched+0x5/0x16
    > =======================
    >
    > This corresponds to the cli instruction:
    > c0103e7e: fa cli

    I bisected it, and the resulting commit is appended. Rerverting this
    commit applies cleanly on today's git
    (dd430ca20c40ecccd6954a7efd13d4398f507728) and makes the hang go away
    -:)


    commit 37bb6cb4097e29ffee970065b74499cbf10603a3
    Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Date: Fri Jan 25 21:08:32 2008 +0100

    hrtimer: unlock hrtimer_wakeup

    hrtimer_wakeup creates a

    base->lock
    rq->lock

    lock dependancy. Avoid this by switching to HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
    which doesn't hold base->lock.

    This fully untangles hrtimer locks from the scheduler locks, and allows
    hrtimer usage in the scheduler proper.

    Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Signed-off-by: Ingo Molnar <mingo@elte.hu>

    diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
    index 061ae28..bd5d6b5 100644
    --- a/kernel/hrtimer.c
    +++ b/kernel/hrtimer.c
    @@ -1293,7 +1293,7 @@ void hrtimer_init_sleeper(struct hrtimer_sleeper
    *sl, struct task_struct *task)
    sl->timer.function = hrtimer_wakeup;
    sl->task = task;
    #ifdef CONFIG_HIGH_RES_TIMERS
    - sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_RESTART;
    + sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
    #endif
    }

    @@ -1304,6 +1304,8 @@ static int __sched do_nanosleep(struct
    hrtimer_sleeper *t, enum hrtimer_mode mod
    do {
    set_current_state(TASK_INTERRUPTIBLE);
    hrtimer_start(&t->timer, t->timer.expires, mode);
    + if (!hrtimer_active(&t->timer))
    + t->task = NULL;

    if (likely(t->task))
    schedule();

    --
    Guillaume


    \
     
     \ /
      Last update: 2008-01-30 23:57    [W:0.042 / U:91.652 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site