On 07/06/2016 13:50, Wanpeng Li wrote: >> > I'm not sure this patch is necessary. Instead you could just revert >> > commit e9532e69b8d1. The previous patch obviously makes it unnecessary >> > to reset rq->prev_steal_time and rq->prev_steal_time_rq, and the reset >> > of rq->prev_irq_time looks like a no-op to me. > The reason why I'm not just simple revert it is that commit mentioned > "steal is smaller than rq->prev_steal_time we end up with an insane > large value which then gets added to rq->prev_steal_time, resulting in > a permanent wreckage of the accounting."
With this patch, you go back to having underflow if steal is smaller than rq->prev_steal_time. The point is that it should never be smaller; it was only smaller because of the bug that you are fixing in patch 1. Thanks, Paolo Though I didn't meet such > scenario. So I just do what that commit really want to do.
