On 11/23/06, Pavel Emelianov <[EMAIL PROTECTED]> wrote: > Paul Menage wrote: > > On 11/23/06, Pavel Emelianov <[EMAIL PROTECTED]> 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.
I don't see why having an irq_bc wouldn't solve this. At the start of the interrupt handler, set current->exec_bc to &irq_bc; at the end set it to current->real_bc; use the cmpxchg() that I suggested to ensure that you never update task->exec_bc from another task if it's not equal to task->real_bc; use RCU to ensure that a beancounter is never freed while someone might be accessing it. > > Maybe we can make smth similar to wait_task_inactive and change > it's beancounter before unlocking the runqueue? That could work too. Paul ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ ckrm-tech mailing list https://lists.sourceforge.net/lists/listinfo/ckrm-tech
