On Mon, 16 Feb 2015 17:32:23 +0800 Xunlei Pang <xlp...@126.com> wrote:
> From: Xunlei Pang <pang.xun...@linaro.org> > > Currently, SMP RT scheduler has some trouble in dealing with > equal prio cases. > > For example, in check_preempt_equal_prio(): > When RT1(current task) gets preempted by RT2, if there is a > migratable RT3 with same prio, RT3 will be pushed away instead > of RT1 afterwards, because RT1 will be enqueued to the tail of > the pushable list when going through succeeding put_prev_task_rt() > triggered by resched. This broke FIFO. > > Furthermore, this is also problematic for normal preempted cases > if there're some rt tasks queued with the same prio as current, > because current will be put behind these tasks in the pushable > queue. > > So, if a task is running and gets preempted by a higher priority > task (or even with same priority for migrating), this patch ensures > that it is put before any existing task with the same priority in > the pushable queue. > > Signed-off-by: Xunlei Pang <pang.xun...@linaro.org> I'd love to review this now, but unfortunately I need to get ready for my trip to Linux Collab. I'll get back to this next week. Feel free to ping me then. If I have time, I might review this while at the conference, but don't place any bets that I will. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
