Re: [PATCHSET sched_ext/for-7.3] sched_ext: Sub-scheduler follow-ups

[Andrea Righi]

Hi Tejun,

On Tue, Jul 14, 2026 at 01:09:13PM -1000, Tejun Heo wrote:
> Hello,
> 
> Follow-ups to the sub-scheduler capability series, addressing two things
> Andrea raised while reviewing v5[1]: sched teardown drained queued ecaps
> syncs with an msleep() poll loop, and with CONFIG_EXT_SUB_SCHED=y hot paths
> keep paying for sub-sched bookkeeping even when no sub-scheduler exists.
> 
> Patch 0001 replaces the teardown poll loop with direct removal from the
> llist. Patches 0002-0003 are prep and 0004 adds the scx_has_subs static key
> and gates the sub-sched portions of hot paths on it.

Thanks for addressing the issues! For the whole series:

Reviewed-by: Andrea Righi <arighi@xxxxxxxxxx>

-Andrea

> 
> [1] https://lore.kernel.org/r/20260709225041.1695495-1-tj@xxxxxxxxxx
> 
> Based on sched_ext/for-7.3 (35f9cbbacb67).
> 
> This patchset contains the following 4 patches.
> 
>  0001 sched_ext: Remove queued ecaps syncs directly on sched teardown
>  0002 sched_ext: Move scx_dispatch_sched() from sub.h to internal.h
>  0003 sched_ext: Gate sub_dispatch_prev with CONFIG_EXT_SUB_SCHED
>  0004 sched_ext: Add the scx_has_subs static key and gate sub-sched hot paths
> 
> The patchset is also available in the following git branch:
> 
>  git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext.git scx-sub-followups
> 
> diffstat follows. Thanks.
> 
>  kernel/sched/ext/ext.c      |   6 +-
>  kernel/sched/ext/idle.c     |  10 ++++
>  kernel/sched/ext/internal.h | 133 +++++++++++++++++++++++++++++++++++++++++++-
>  kernel/sched/ext/sub.c      |  88 ++++++++++++++++++++---------
>  kernel/sched/ext/sub.h      | 124 +++++------------------------------------
>  kernel/sched/sched.h        |   3 +-
>  6 files changed, 223 insertions(+), 141 deletions(-)
> 
> --
> tejun