[Intel-gfx] [PATCH] i915/guc/reset: Make __guc_reset_context aware of guilty engines
Teres Alexis, Alan Previn
alan.previn.teres.alexis at intel.com
Wed May 4 21:01:46 UTC 2022
Thanks Umesh for clarifying that question. With that, here is my rvb and apologies for the tardiness.
Reviewed-by: Alan Previn <alan.previn.teres.alexis at intel.com>
On Mon, 2022-05-02 at 13:07 -0700, Umesh Nerlige Ramappa wrote:
> On Thu, Apr 28, 2022 at 09:13:57AM -0700, Teres Alexis, Alan Previn wrote:
> > At a high level, this change looks good and simple.
> > However, inside __guc_reset_context, i think there might be
> > an observed change in behavior for parallel submission.
> > (or perhaps this change is part the intent?):
> >
> > Unless my understanding is incorrect, assuming a
> > parallel submission comes in with virtual engines that
> > repeat the same kinds of workloads across multiple
> > physical engines (which i assume would be the typical
> > end-user usage of this UAPI feature), we would end up
> > marking the parent content (and other children contexts
> > that use the same engine) as guilty but not children
> > contexts that are running on a different engine.
> > I'm not sure if this would be an expected UAPI response
> > for parallel submission. (i.e. one or more children
> > get a re-run on other engines? I havent checked if
> > the replay is revoked later if the parent's or sibling's
> > 'request' was reset and marked as -EIO ... this marking
> > of req->force_error as -EIO or -EAGAIN is part of the
> > call to __i915_request_reset where the guilty param
> > value sees this change i am referring to).
> >
> > Is this intended / expected?
>
> Expectation: For virtual engine, only the virtual context must be marked
> guilty. For parallel engines, parent/child contexts must be marked as
> guilty.
>
> Looking into the code, I see the expected behavior is already taken care
> of.
>
> For virtual engines, only one context is created with a mask of engines
> that can be used by GuC. This context is registered with GuC and the
> workloads are run on any one of these engines. When a reset occurs, the
> G2H notification points to this context. When the __guc_reset_context
> executes, it will only mark this context as guilty.
>
> fwiu, for parallel submission, if N engines can run in parallel, then N
> contexts are submitted. If there are no siblings, then there is only one
> parent and the below reset logic works fine because G2H has only the
> parent context.
>
> If there are more than 1 siblings in parallel submission, then the
> execution between siblings is just treated like virtual engines where
> the parent has the mask of engines used. In this case, G2H points to
> parent context and parent has a mask of all sibling engines, so this
> works as expected too (in __guc_reset_context).
>
> Thanks,
> Umesh
>
> > ...alan
> >
> >
> > On Mon, 2022-04-25 at 17:30 -0700, Umesh Nerlige Ramappa wrote:
> > > There are 2 ways an engine can get reset in i915 and the method of reset
> > > affects how KMD labels a context as guilty/innocent.
> > >
> > > (1) GuC initiated engine-reset: GuC resets a hung engine and notifies
> > > KMD. The context that hung on the engine is marked guilty and all other
> > > contexts are innocent. The innocent contexts are resubmitted.
> > >
> > > (2) GT based reset: When an engine heartbeat fails to tick, KMD
> > > initiates a gt/chip reset. All active contexts are marked as guilty and
> > > discarded.
> > >
> > > In order to correctly mark the contexts as guilty/innocent, pass a mask
> > > of engines that were reset to __guc_reset_context.
> > >
> > > Fixes: eb5e7da736f3 ("drm/i915/guc: Reset implementation for new GuC interface")
> > > Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
> > > ---
> > > drivers/gpu/drm/i915/gt/intel_reset.c | 2 +-
> > > drivers/gpu/drm/i915/gt/uc/intel_guc.h | 2 +-
> > > .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 16 ++++++++--------
> > > drivers/gpu/drm/i915/gt/uc/intel_uc.c | 2 +-
> > > drivers/gpu/drm/i915/gt/uc/intel_uc.h | 2 +-
> > > 5 files changed, 12 insertions(+), 12 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/gt/intel_reset.c b/drivers/gpu/drm/i915/gt/intel_reset.c
> > > index 5422a3b84bd4..a5338c3fde7a 100644
> > > --- a/drivers/gpu/drm/i915/gt/intel_reset.c
> > > +++ b/drivers/gpu/drm/i915/gt/intel_reset.c
> > > @@ -808,7 +808,7 @@ static int gt_reset(struct intel_gt *gt, intel_engine_mask_t stalled_mask)
> > > __intel_engine_reset(engine, stalled_mask & engine->mask);
> > > local_bh_enable();
> > >
> > > - intel_uc_reset(>->uc, true);
> > > + intel_uc_reset(>->uc, ALL_ENGINES);
> > >
> > > intel_ggtt_restore_fences(gt->ggtt);
> > >
> > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> > > index 3f3373f68123..966e69a8b1c1 100644
> > > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> > > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> > > @@ -443,7 +443,7 @@ int intel_guc_global_policies_update(struct intel_guc *guc);
> > > void intel_guc_context_ban(struct intel_context *ce, struct i915_request *rq);
> > >
> > > void intel_guc_submission_reset_prepare(struct intel_guc *guc);
> > > -void intel_guc_submission_reset(struct intel_guc *guc, bool stalled);
> > > +void intel_guc_submission_reset(struct intel_guc *guc, intel_engine_mask_t stalled);
> > > void intel_guc_submission_reset_finish(struct intel_guc *guc);
> > > void intel_guc_submission_cancel_requests(struct intel_guc *guc);
> > >
> > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > > index 61a6f2424e24..1fbf7b6c2740 100644
> > > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > > @@ -1667,9 +1667,9 @@ __unwind_incomplete_requests(struct intel_context *ce)
> > > spin_unlock_irqrestore(&sched_engine->lock, flags);
> > > }
> > >
> > > -static void __guc_reset_context(struct intel_context *ce, bool stalled)
> > > +static void __guc_reset_context(struct intel_context *ce, intel_engine_mask_t stalled)
> > > {
> > > - bool local_stalled;
> > > + bool guilty;
> > > struct i915_request *rq;
> > > unsigned long flags;
> > > u32 head;
> > > @@ -1697,7 +1697,7 @@ static void __guc_reset_context(struct intel_context *ce, bool stalled)
> > > if (!intel_context_is_pinned(ce))
> > > goto next_context;
> > >
> > > - local_stalled = false;
> > > + guilty = false;
> > > rq = intel_context_find_active_request(ce);
> > > if (!rq) {
> > > head = ce->ring->tail;
> > > @@ -1705,14 +1705,14 @@ static void __guc_reset_context(struct intel_context *ce, bool stalled)
> > > }
> > >
> > > if (i915_request_started(rq))
> > > - local_stalled = true;
> > > + guilty = stalled & ce->engine->mask;
> > >
> > > GEM_BUG_ON(i915_active_is_idle(&ce->active));
> > > head = intel_ring_wrap(ce->ring, rq->head);
> > >
> > > - __i915_request_reset(rq, local_stalled && stalled);
> > > + __i915_request_reset(rq, guilty);
> > > out_replay:
> > > - guc_reset_state(ce, head, local_stalled && stalled);
> > > + guc_reset_state(ce, head, guilty);
> > > next_context:
> > > if (i != number_children)
> > > ce = list_next_entry(ce, parallel.child_link);
> > > @@ -1722,7 +1722,7 @@ static void __guc_reset_context(struct intel_context *ce, bool stalled)
> > > intel_context_put(parent);
> > > }
> > >
> > > -void intel_guc_submission_reset(struct intel_guc *guc, bool stalled)
> > > +void intel_guc_submission_reset(struct intel_guc *guc, intel_engine_mask_t stalled)
> > > {
> > > struct intel_context *ce;
> > > unsigned long index;
> > > @@ -4217,7 +4217,7 @@ static void guc_context_replay(struct intel_context *ce)
> > > {
> > > struct i915_sched_engine *sched_engine = ce->engine->sched_engine;
> > >
> > > - __guc_reset_context(ce, true);
> > > + __guc_reset_context(ce, ce->engine->mask);
> > > tasklet_hi_schedule(&sched_engine->tasklet);
> > > }
> > >
> > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> > > index 8c9ef690ac9d..e8f099360e01 100644
> > > --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> > > +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> > > @@ -595,7 +595,7 @@ void intel_uc_reset_prepare(struct intel_uc *uc)
> > > __uc_sanitize(uc);
> > > }
> > >
> > > -void intel_uc_reset(struct intel_uc *uc, bool stalled)
> > > +void intel_uc_reset(struct intel_uc *uc, intel_engine_mask_t stalled)
> > > {
> > > struct intel_guc *guc = &uc->guc;
> > >
> > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.h b/drivers/gpu/drm/i915/gt/uc/intel_uc.h
> > > index 866b462821c0..a8f38c2c60e2 100644
> > > --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.h
> > > +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.h
> > > @@ -42,7 +42,7 @@ void intel_uc_driver_late_release(struct intel_uc *uc);
> > > void intel_uc_driver_remove(struct intel_uc *uc);
> > > void intel_uc_init_mmio(struct intel_uc *uc);
> > > void intel_uc_reset_prepare(struct intel_uc *uc);
> > > -void intel_uc_reset(struct intel_uc *uc, bool stalled);
> > > +void intel_uc_reset(struct intel_uc *uc, intel_engine_mask_t stalled);
> > > void intel_uc_reset_finish(struct intel_uc *uc);
> > > void intel_uc_cancel_requests(struct intel_uc *uc);
> > > void intel_uc_suspend(struct intel_uc *uc);
> > > --
> > > 2.35.1
> > >
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