Paul Menage wrote:
> On 11/23/06, Pavel Emelianov <xemul@xxxxxxxxxx> wrote:
>> You mean moving is like this:
>>
>> old_bc = task->real_bc;
>> task->real_bc = new_bc;
>> cmpxchg(&tsk->exec_bc, old_bc, new_bc);
>>
>> ? Then this won't work:
>>
>> Initialisation:
>> current->exec_bc = init_bc;
>> current->real_bc = init_bc;
>> ...
>> IRQ:
>> current->exec_bc = init_bc;
>> ...
>> old_bc = tsk->real_bc; /* init_bc */
>> tsk->real_bc = bc1;
>> cx(tsk->exec_bc, init_bc, bc1); /* ok */
>> ...
>> Here at the middle of an interrupt
>> we have bc1 set as exec_bc on task
>> which IS wrong!
>
> You could get round that by having a separate "irq_bc" that's never
> valid for a task not in an interrupt.
No no no. This is not what is needed. You see, we do have to
set exec_bc as temporary (and atomic) context. Having temporary
context is 1. flexible 2. needed by beancounters' network accountig.
Maybe we can make smth similar to wait_task_inactive and change
it's beancounter before unlocking the runqueue?