On 1/2/07, Anand H. Krishnan <[EMAIL PROTECTED]> wrote:
Hi, I had a couple of doubts when I was going through 6.1 freebsd code. * First one is in the wakeup() code. After a series of calls wakeup() lands in maybe_preempt() and if preemption is enabled maybe_preempt() switches to a new thread (if a high priority thread has been made runnable). That means that an interrupt handler which calls wakeup() will not return immediately. (I'm looking @ ULE scheduler). So is there a problem when wakeup() is called from high priority (fast interr upt) handlers ? * Second one is in spinlock code. Can anyone say why critical_enter is called from spinlock_enter() ? The only thing that critical_enter seems to be doing is to increment td_critnest which probably helps in finding out whether a thread can be pre-empted or not. But spinlock_enter() disables interrupts and I fail to understand how can any thread become runnable and get scheduled in between. I've one more.. * msleep() allows a thread to change it's priority when it gets woken up and in many places they gets woken up with very high priority indeed. Is there any convincing reason as to why it should be ? Thanks, Anand
Anand, If I remember correctly a significant amount of the ULE scheduler code from 6.1 (and 7-CUR at that time) has been overhauled. In fact, the scheduler was taken off the list of "working" due to a bunch of problems. You may want to review the versions of the scheduler code from the latest -CURRENT or 6.2-RELEASE and then re-ask... -- Coleman Kane _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
