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fix deadlock in load_balancing

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Stefan Lankes 2012-02-24 06:47:41 +01:00
parent 5b5139c283
commit 8ec1d0e817
1 changed files with 22 additions and 9 deletions
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31
kernel/tasks.c
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@ -1155,17 +1155,16 @@ void load_balancing(void)
uint32_t prio;
task_t* task;
spinlock_irqsave_lock(&runqueues[core_id].lock);
for(i=0; (i<atomic_int32_read(&cpu_online)) && (runqueues[core_id].balance_counter <= 0); i++)
{
if (i == core_id)
continue;
spinlock_irqsave_lock(&runqueues[i].lock);
if ((runqueues[i].load[0] >> (FSHIFT-1)) > (runqueues[core_id].load[0] >> (FSHIFT-1))) {
//kprintf("Try to steal a task from core %u (load %u) to %u (load %u)\n", i, runqueues[i].load[0], core_id, runqueues[core_id].load[0]);
//kprintf("Task on core %u: %u, core %u, %u\n", i, runqueues[i].nr_tasks, core_id, runqueues[i].nr_tasks);
spinlock_irqsave_lock(&runqueues[i].lock);
prio = lsb(runqueues[i].prio_bitmap);
if (prio < sizeof(size_t)*8) {
// steal a ready task
@ -1180,7 +1179,12 @@ void load_balancing(void)
runqueues[i].prio_bitmap &= ~(1 << prio);
} else runqueues[i].queue[prio-1].last = task->prev;
// update task counters
runqueues[i].nr_tasks--;
spinlock_irqsave_unlock(&runqueues[i].lock);
// add task at the end of queue core_id
spinlock_irqsave_lock(&runqueues[core_id].lock);
if (!runqueues[core_id].queue[prio-1].last) {
runqueues[core_id].queue[prio-1].first = runqueues[core_id].queue[prio-1].last = task;
task->next = task->prev = NULL;
@ -1194,15 +1198,20 @@ void load_balancing(void)
// update task counters
runqueues[core_id].nr_tasks++;
runqueues[i].nr_tasks--;
runqueues[core_id].balance_counter = TIMER_FREQ/2;
} /*else {
spinlock_irqsave_unlock(&runqueues[core_id].lock);
} else {
#if 1
spinlock_irqsave_unlock(&runqueues[i].lock);
#else
task_t* tmp;
// steal a blocked task
task = runqueues[i].timers.first;
if (!task) // Ups, found no valid task to steal
if (!task) { // Ups, found no valid task to steal
spinlock_irqsave_unlock(&runqueues[i].lock);
goto no_task_found;
}
kprintf("Core %u steals the blocked task %d from %u with prio %u\n", core_id, task->id, i, task->prio);
@ -1212,6 +1221,10 @@ void load_balancing(void)
else
runqueues[i].timers.first = runqueues[i].timers.first->next;
spinlock_irqsave_unlock(&runqueues[i].lock);
spinlock_irqsave_lock(&runqueues[core_id].lock);
// add timer to queue core_id
tmp = runqueues[core_id].timers.first;
while(tmp && (task->timeout >= tmp->timeout))
@ -1240,16 +1253,16 @@ void load_balancing(void)
// update task counters
runqueues[core_id].balance_counter = TIMER_FREQ/2;
}*/
spinlock_irqsave_lock(&runqueues[core_id].lock);
#endif
}
}
//no_task_found:
spinlock_irqsave_unlock(&runqueues[i].lock);
}
if (runqueues[core_id].balance_counter <= 0)
runqueues[core_id].balance_counter = TIMER_FREQ/2;
spinlock_irqsave_unlock(&runqueues[core_id].lock);
#endif
}
#endif