[RFC 0/4] DRM scheduler fixes, or not, or incorrect kind

[Matthew Brost]

On Fri, Sep 06, 2024 at 07:06:14PM +0100, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
> 
> In a recent conversation with Christian there was a thought that
> drm_sched_entity_modify_sched() should start using the entity->rq_lock to be
> safe against job submission and simultaneous priority changes.
> 
> The kerneldoc accompanying that function however is a bit unclear to me. For
> instance is amdgpu simply doing it wrongly by not serializing the two in the
> driver? Or is the comment referring to some other race condition than which is
> of concern in this series?
> 
> To cut the long story short, first three patches try to fix this race in three
> places I *think* can manifest in different ways.
> 
> Last patch is a trivial optimisation I spotted can be easily done.
> 
> Cc: Christian König <christian.koenig at amd.com>
> Cc: Alex Deucher <alexander.deucher at amd.com>
> Cc: Luben Tuikov <ltuikov89 at gmail.com>
> Cc: Matthew Brost <matthew.brost at intel.com>

It seems like the series is getting traction on reviews so don't have
much to add series looks sane enough to me. Consider series acked by me
on whatever you hash out in reviews.

Matt

> 
> Tvrtko Ursulin (4):
>   drm/sched: Add locking to drm_sched_entity_modify_sched
>   drm/sched: Always wake up correct scheduler in
>     drm_sched_entity_push_job
>   drm/sched: Always increment correct scheduler score
>   drm/sched: Optimise drm_sched_entity_push_job
> 
>  drivers/gpu/drm/scheduler/sched_entity.c | 17 ++++++++++++-----
>  drivers/gpu/drm/scheduler/sched_main.c   | 21 ++++++++++++++-------
>  include/drm/gpu_scheduler.h              |  1 +
>  3 files changed, 27 insertions(+), 12 deletions(-)
> 
> -- 
> 2.46.0
>