lkml.org 
[lkml]   [2018]   [Aug]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] sched/fair: vruntime should normalize when switching from fair
> > On 08/17/2018 11:27 AM, Steve Muckle wrote:

> > > When rt_mutex_setprio changes a task's scheduling class to RT,
> > > we're seeing cases where the task's vruntime is not updated
> > > correctly upon return to the fair class.

> > > Specifically, the following is being observed:
> > > - task is deactivated while still in the fair class
> > > - task is boosted to RT via rt_mutex_setprio, which changes
> > > the task to RT and calls check_class_changed.
> > > - check_class_changed leads to detach_task_cfs_rq, at which point
> > > the vruntime_normalized check sees that the task's state is TASK_WAKING,
> > > which results in skipping the subtraction of the rq's min_vruntime
> > > from the task's vruntime
> > > - later, when the prio is deboosted and the task is moved back
> > > to the fair class, the fair rq's min_vruntime is added to
> > > the task's vruntime, even though it wasn't subtracted earlier.

I'm thinking that is an incomplete scenario; where do we get to
TASK_WAKING.

\
 
 \ /
  Last update: 2018-08-24 12:02    [W:2.408 / U:1.760 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site