| Message ID | 20210820224446.30620-14-matthew.brost@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Parallel submission aka multi-bb execbuf | expand |
On 8/20/2021 15:44, Matthew Brost wrote: > In GuC parent-child contexts the parent context controls the scheduling, > ensure only the parent does the scheduling operations. > > Signed-off-by: Matthew Brost <matthew.brost@intel.com> > --- > .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 24 ++++++++++++++----- > 1 file changed, 18 insertions(+), 6 deletions(-) > > 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 dbcb9ab28a9a..00d54bb00bfb 100644 > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > @@ -320,6 +320,12 @@ static void decr_context_committed_requests(struct intel_context *ce) > GEM_BUG_ON(ce->guc_state.number_committed_requests < 0); > } > > +static struct intel_context * > +request_to_scheduling_context(struct i915_request *rq) > +{ > + return intel_context_to_parent(rq->context); > +} > + > static bool context_guc_id_invalid(struct intel_context *ce) > { > return ce->guc_id.id == GUC_INVALID_LRC_ID; > @@ -1684,6 +1690,7 @@ static void __guc_context_sched_disable(struct intel_guc *guc, > > GEM_BUG_ON(guc_id == GUC_INVALID_LRC_ID); > > + GEM_BUG_ON(intel_context_is_child(ce)); > trace_intel_context_sched_disable(ce); > > guc_submission_send_busy_loop(guc, action, ARRAY_SIZE(action), > @@ -1898,6 +1905,8 @@ static void guc_context_sched_disable(struct intel_context *ce) > u16 guc_id; > bool enabled; > > + GEM_BUG_ON(intel_context_is_child(ce)); > + > if (submission_disabled(guc) || context_guc_id_invalid(ce) || > !lrc_desc_registered(guc, ce->guc_id.id)) { > spin_lock_irqsave(&ce->guc_state.lock, flags); > @@ -2286,6 +2295,8 @@ static void guc_signal_context_fence(struct intel_context *ce) > { > unsigned long flags; > > + GEM_BUG_ON(intel_context_is_child(ce)); > + > spin_lock_irqsave(&ce->guc_state.lock, flags); > clr_context_wait_for_deregister_to_register(ce); > __guc_signal_context_fence(ce); > @@ -2315,7 +2326,7 @@ static void guc_context_init(struct intel_context *ce) > > static int guc_request_alloc(struct i915_request *rq) > { > - struct intel_context *ce = rq->context; > + struct intel_context *ce = request_to_scheduling_context(rq); > struct intel_guc *guc = ce_to_guc(ce); > unsigned long flags; > int ret; > @@ -2358,11 +2369,12 @@ static int guc_request_alloc(struct i915_request *rq) > * exhausted and return -EAGAIN to the user indicating that they can try > * again in the future. > * > - * There is no need for a lock here as the timeline mutex ensures at > - * most one context can be executing this code path at once. The > - * guc_id_ref is incremented once for every request in flight and > - * decremented on each retire. When it is zero, a lock around the > - * increment (in pin_guc_id) is needed to seal a race with unpin_guc_id. > + * There is no need for a lock here as the timeline mutex (or > + * parallel_submit mutex in the case of multi-lrc) ensures at most one > + * context can be executing this code path at once. The guc_id_ref is Isn't that now two? One uni-LRC holding the timeline mutex and one multi-LRC holding the parallel submit mutex? John. > + * incremented once for every request in flight and decremented on each > + * retire. When it is zero, a lock around the increment (in pin_guc_id) > + * is needed to seal a race with unpin_guc_id. > */ > if (atomic_add_unless(&ce->guc_id.ref, 1, 0)) > goto out;
On Wed, Sep 15, 2021 at 12:24:41PM -0700, John Harrison wrote: > On 8/20/2021 15:44, Matthew Brost wrote: > > In GuC parent-child contexts the parent context controls the scheduling, > > ensure only the parent does the scheduling operations. > > > > Signed-off-by: Matthew Brost <matthew.brost@intel.com> > > --- > > .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 24 ++++++++++++++----- > > 1 file changed, 18 insertions(+), 6 deletions(-) > > > > 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 dbcb9ab28a9a..00d54bb00bfb 100644 > > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > > @@ -320,6 +320,12 @@ static void decr_context_committed_requests(struct intel_context *ce) > > GEM_BUG_ON(ce->guc_state.number_committed_requests < 0); > > } > > +static struct intel_context * > > +request_to_scheduling_context(struct i915_request *rq) > > +{ > > + return intel_context_to_parent(rq->context); > > +} > > + > > static bool context_guc_id_invalid(struct intel_context *ce) > > { > > return ce->guc_id.id == GUC_INVALID_LRC_ID; > > @@ -1684,6 +1690,7 @@ static void __guc_context_sched_disable(struct intel_guc *guc, > > GEM_BUG_ON(guc_id == GUC_INVALID_LRC_ID); > > + GEM_BUG_ON(intel_context_is_child(ce)); > > trace_intel_context_sched_disable(ce); > > guc_submission_send_busy_loop(guc, action, ARRAY_SIZE(action), > > @@ -1898,6 +1905,8 @@ static void guc_context_sched_disable(struct intel_context *ce) > > u16 guc_id; > > bool enabled; > > + GEM_BUG_ON(intel_context_is_child(ce)); > > + > > if (submission_disabled(guc) || context_guc_id_invalid(ce) || > > !lrc_desc_registered(guc, ce->guc_id.id)) { > > spin_lock_irqsave(&ce->guc_state.lock, flags); > > @@ -2286,6 +2295,8 @@ static void guc_signal_context_fence(struct intel_context *ce) > > { > > unsigned long flags; > > + GEM_BUG_ON(intel_context_is_child(ce)); > > + > > spin_lock_irqsave(&ce->guc_state.lock, flags); > > clr_context_wait_for_deregister_to_register(ce); > > __guc_signal_context_fence(ce); > > @@ -2315,7 +2326,7 @@ static void guc_context_init(struct intel_context *ce) > > static int guc_request_alloc(struct i915_request *rq) > > { > > - struct intel_context *ce = rq->context; > > + struct intel_context *ce = request_to_scheduling_context(rq); > > struct intel_guc *guc = ce_to_guc(ce); > > unsigned long flags; > > int ret; > > @@ -2358,11 +2369,12 @@ static int guc_request_alloc(struct i915_request *rq) > > * exhausted and return -EAGAIN to the user indicating that they can try > > * again in the future. > > * > > - * There is no need for a lock here as the timeline mutex ensures at > > - * most one context can be executing this code path at once. The > > - * guc_id_ref is incremented once for every request in flight and > > - * decremented on each retire. When it is zero, a lock around the > > - * increment (in pin_guc_id) is needed to seal a race with unpin_guc_id. > > + * There is no need for a lock here as the timeline mutex (or > > + * parallel_submit mutex in the case of multi-lrc) ensures at most one > > + * context can be executing this code path at once. The guc_id_ref is > Isn't that now two? One uni-LRC holding the timeline mutex and one multi-LRC > holding the parallel submit mutex? > This is actually a stale comment and need scrub this. The parallel_submit mutex is gone, now we grab the ce->timeline locks starting at the parent and then all children in a loop. I think the original comment is sufficient. Matt > John. > > > + * incremented once for every request in flight and decremented on each > > + * retire. When it is zero, a lock around the increment (in pin_guc_id) > > + * is needed to seal a race with unpin_guc_id. > > */ > > if (atomic_add_unless(&ce->guc_id.ref, 1, 0)) > > goto out; >
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 dbcb9ab28a9a..00d54bb00bfb 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -320,6 +320,12 @@ static void decr_context_committed_requests(struct intel_context *ce) GEM_BUG_ON(ce->guc_state.number_committed_requests < 0); } +static struct intel_context * +request_to_scheduling_context(struct i915_request *rq) +{ + return intel_context_to_parent(rq->context); +} + static bool context_guc_id_invalid(struct intel_context *ce) { return ce->guc_id.id == GUC_INVALID_LRC_ID; @@ -1684,6 +1690,7 @@ static void __guc_context_sched_disable(struct intel_guc *guc, GEM_BUG_ON(guc_id == GUC_INVALID_LRC_ID); + GEM_BUG_ON(intel_context_is_child(ce)); trace_intel_context_sched_disable(ce); guc_submission_send_busy_loop(guc, action, ARRAY_SIZE(action), @@ -1898,6 +1905,8 @@ static void guc_context_sched_disable(struct intel_context *ce) u16 guc_id; bool enabled; + GEM_BUG_ON(intel_context_is_child(ce)); + if (submission_disabled(guc) || context_guc_id_invalid(ce) || !lrc_desc_registered(guc, ce->guc_id.id)) { spin_lock_irqsave(&ce->guc_state.lock, flags); @@ -2286,6 +2295,8 @@ static void guc_signal_context_fence(struct intel_context *ce) { unsigned long flags; + GEM_BUG_ON(intel_context_is_child(ce)); + spin_lock_irqsave(&ce->guc_state.lock, flags); clr_context_wait_for_deregister_to_register(ce); __guc_signal_context_fence(ce); @@ -2315,7 +2326,7 @@ static void guc_context_init(struct intel_context *ce) static int guc_request_alloc(struct i915_request *rq) { - struct intel_context *ce = rq->context; + struct intel_context *ce = request_to_scheduling_context(rq); struct intel_guc *guc = ce_to_guc(ce); unsigned long flags; int ret; @@ -2358,11 +2369,12 @@ static int guc_request_alloc(struct i915_request *rq) * exhausted and return -EAGAIN to the user indicating that they can try * again in the future. * - * There is no need for a lock here as the timeline mutex ensures at - * most one context can be executing this code path at once. The - * guc_id_ref is incremented once for every request in flight and - * decremented on each retire. When it is zero, a lock around the - * increment (in pin_guc_id) is needed to seal a race with unpin_guc_id. + * There is no need for a lock here as the timeline mutex (or + * parallel_submit mutex in the case of multi-lrc) ensures at most one + * context can be executing this code path at once. The guc_id_ref is + * incremented once for every request in flight and decremented on each + * retire. When it is zero, a lock around the increment (in pin_guc_id) + * is needed to seal a race with unpin_guc_id. */ if (atomic_add_unless(&ce->guc_id.ref, 1, 0)) goto out;
In GuC parent-child contexts the parent context controls the scheduling, ensure only the parent does the scheduling operations. Signed-off-by: Matthew Brost <matthew.brost@intel.com> --- .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 24 ++++++++++++++----- 1 file changed, 18 insertions(+), 6 deletions(-)