Re: [PATCH v2] sched/fair: sanitize vruntime of entity being migrated

[Peter Zijlstra]

On Fri, Mar 17, 2023 at 05:08:10PM +0100, Vincent Guittot wrote:
> Commit 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed")
> fixes an overflowing bug, but ignore a case that se->exec_start is reset
> after a migration.
> 
> For fixing this case, we delay the reset of se->exec_start after
> placing the entity which se->exec_start to detect long sleeping task.
> 
> In order to take into account a possible divergence between the clock_task
> of 2 rqs, we increase the threshold to around 104 days.
> 
> 
> Fixes: 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed")
> Signed-off-by: Zhang Qiao <zhangqiao22@xxxxxxxxxx>
> Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
> ---

Blergh, this just isn't going to be nice. I'll go queue this for
sched/urgent and then we can forget about this for a little while.

Thanks!