Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: preemption when running in the kernel | From | Robert Love <> | Date | Sun, 09 Nov 2003 12:56:40 -0500 |
| |
On Sun, 2003-11-09 at 05:04, Frank Cusack wrote:
> Thank you for the clarification.
No problem.
> That leads me to 2 followup questions. > > If a task in the kernel is preempted, is a membar issued? (I believe > so -- running another task means that the scheduler must have run, > which will grab and release various locks thus giving us the membars.)
Yes, a memory barrier is definitely issued.
> When the preempted task resumes, is it guaranteed to run on the same CPU? > (I wouldn't expect so, unless the task was specifically told to do that > via hard affinity. But maybe a task preempted in the kernel is different > then a task preempted in userland.)
No. A preempted task can reschedule on any processor.
Robert Love
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| ![\](/images/icornerr.gif) |