Re: [PATCHv4] psi: fix possible trigger missing in the window

From: Peter Zijlstra
Date: Mon Feb 14 2022 - 10:10:14 EST


On Mon, Feb 14, 2022 at 10:05:37AM -0500, Johannes Weiner wrote:
> On Tue, Jan 25, 2022 at 02:56:58PM +0800, Huangzhaoyang wrote:
> > From: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
> >
> > When a new threshold breaching stall happens after a psi event was
> > generated and within the window duration, the new event is not
> > generated because the events are rate-limited to one per window. If
> > after that no new stall is recorded then the event will not be
> > generated even after rate-limiting duration has passed. This is
> > happening because with no new stall, window_update will not be called
> > even though threshold was previously breached. To fix this, record
> > threshold breaching occurrence and generate the event once window
> > duration is passed.
> >
> > Suggested-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
> > Signed-off-by: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
>
> Hey Peter, would you mind taking this through the scheduler tree? It's
> got my and Suren's acks. It's not a recent regression so I'm thinking
> for 5.18 is fine. Thanks!

Sorry, missed it, got it now. Thanks!