Re: [PATCH 3/3] sched/core: Indicate a sched_delayed task was migrated before wakeup

[K Prateek Nayak]

Hello Johannes,

On 10/14/2024 8:13 PM, Johannes Weiner wrote:
> On Fri, Oct 11, 2024 at 12:39:58PM +0200, Peter Zijlstra wrote:
> > On Fri, Oct 11, 2024 at 06:08:03AM -0400, Johannes Weiner wrote:
> > > Completely untested. But if it looks good, I'll send a proper patch.
> >
> > Sure. Thanks for doing this.
>
> Ok here goes. Built, booted and runtime-tested.
>
> ---
>
>  From 91f230caa0119877cb861047e1af1371bf00d908 Mon Sep 17 00:00:00 2001
> From: Johannes Weiner <hannes@xxxxxxxxxxx>
> Date: Fri, 11 Oct 2024 06:18:07 -0400
> Subject: [PATCH] sched: psi: pass enqueue/dequeue flags to psi callbacks
>   directly
>
> What psi needs to do on each enqueue and dequeue has gotten more
> subtle, and the generic sched code trying to distill this into a bool
> for the callbacks is awkward.
>
> Pass the flags directly and let psi parse them. For that to work, the
> #include "stats.h" (which has the psi callback implementations) needs
> to be below the flag definitions in "sched.h". Move that section
> further down, next to some of the other accounting stuff.
>
> This also puts the ENQUEUE_SAVE/RESTORE branch behind the psi jump
> label, slightly reducing overhead when PSI=y but runtime disabled.
>
> Link: https://lore.kernel.org/lkml/20241011083323.GL17263@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
> Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>

I tested this series on top of tip:sched/urgent at commit cd9626e9ebc7
("sched/fair: Fix external p->on_rq users") and did not observe any
splats related to PSI or otherwise. Please feel free to add:

Tested-by: K Prateek Nayak <kprateek.nayak@xxxxxxx>

--
Thanks and Regards,
Prateek

> ---
>   kernel/sched/core.c  | 12 +++++-----
>   kernel/sched/sched.h | 56 ++++++++++++++++++++++----------------------
>   kernel/sched/stats.h | 29 +++++++++++++++--------
>   3 files changed, 53 insertions(+), 44 deletions(-)
>
> [..snip..]