Taking a PM reference to prevent intel_gt_wait_for_idle from short circuiting while a deregister context H2G is in flight. To do this must issue the deregister H2G from a worker as context can be destroyed from an atomic context and taking GT PM ref blows up. Previously we took a runtime PM from this atomic context which worked but will stop working once runtime pm autosuspend in enabled.
So this patch is two fold, stop intel_gt_wait_for_idle from short circuting and fix runtime pm autosuspend.
v2: (John Harrison) - Split structure changes out in different patch (Tvrtko) - Don't drop lock in deregister_destroyed_contexts v3: (John Harrison) - Flush destroyed contexts before destroying context reg pool
Signed-off-by: Matthew Brost matthew.brost@intel.com Reviewed-by: John Harrison John.C.Harrison@Intel.com --- drivers/gpu/drm/i915/gt/intel_context.c | 2 + drivers/gpu/drm/i915/gt/intel_context_types.h | 7 + drivers/gpu/drm/i915/gt/intel_engine_pm.h | 5 + drivers/gpu/drm/i915/gt/intel_gt_pm.h | 4 + drivers/gpu/drm/i915/gt/uc/intel_guc.h | 11 ++ .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 146 +++++++++++------- 6 files changed, 121 insertions(+), 54 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c index 35babd02ddfe..d008ef8623ce 100644 --- a/drivers/gpu/drm/i915/gt/intel_context.c +++ b/drivers/gpu/drm/i915/gt/intel_context.c @@ -400,6 +400,8 @@ intel_context_init(struct intel_context *ce, struct intel_engine_cs *engine) ce->guc_id.id = GUC_INVALID_LRC_ID; INIT_LIST_HEAD(&ce->guc_id.link);
+ INIT_LIST_HEAD(&ce->destroyed_link); + /* * Initialize fence to be complete as this is expected to be complete * unless there is a pending schedule disable outstanding. diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h index e7e3984aab78..4613d027cbc3 100644 --- a/drivers/gpu/drm/i915/gt/intel_context_types.h +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h @@ -213,6 +213,13 @@ struct intel_context { struct list_head link; } guc_id;
+ /** + * @destroyed_link: link in guc->submission_state.destroyed_contexts, in + * list when context is pending to be destroyed (deregistered with the + * GuC), protected by guc->submission_state.lock + */ + struct list_head destroyed_link; + #ifdef CONFIG_DRM_I915_SELFTEST /** * @drop_schedule_enable: Force drop of schedule enable G2H for selftest diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.h b/drivers/gpu/drm/i915/gt/intel_engine_pm.h index 8520c595f5e1..6fdeae668e6e 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_pm.h +++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.h @@ -16,6 +16,11 @@ intel_engine_pm_is_awake(const struct intel_engine_cs *engine) return intel_wakeref_is_active(&engine->wakeref); }
+static inline void __intel_engine_pm_get(struct intel_engine_cs *engine) +{ + __intel_wakeref_get(&engine->wakeref); +} + static inline void intel_engine_pm_get(struct intel_engine_cs *engine) { intel_wakeref_get(&engine->wakeref); diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.h b/drivers/gpu/drm/i915/gt/intel_gt_pm.h index d0588d8aaa44..05de6c1af25b 100644 --- a/drivers/gpu/drm/i915/gt/intel_gt_pm.h +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.h @@ -41,6 +41,10 @@ static inline void intel_gt_pm_put_async(struct intel_gt *gt) intel_wakeref_put_async(>->wakeref); }
+#define with_intel_gt_pm(gt, tmp) \ + for (tmp = 1, intel_gt_pm_get(gt); tmp; \ + intel_gt_pm_put(gt), tmp = 0) + static inline int intel_gt_pm_wait_for_idle(struct intel_gt *gt) { return intel_wakeref_wait_for_idle(>->wakeref); diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h index 82e248c2290c..74f071a0b6d5 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h @@ -90,6 +90,17 @@ struct intel_guc { * refs */ struct list_head guc_id_list; + /** + * @destroyed_contexts: list of contexts waiting to be destroyed + * (deregistered with the GuC) + */ + struct list_head destroyed_contexts; + /** + * @destroyed_worker: worker to deregister contexts, need as we + * need to take a GT PM reference and can't from destroy + * function as it might be in an atomic context (no sleeping) + */ + struct work_struct destroyed_worker; } submission_state;
/** 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 48bdcdb823b3..5c53428032b5 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -90,8 +90,8 @@ * used for all of GuC submission but that could change in the future. * * guc->submission_state.lock - * Protects guc_id allocation for the given GuC, i.e. only one context can be - * doing guc_id allocation operations at a time for each GuC in the system. + * Global lock for GuC submission state. Protects guc_ids and destroyed contexts + * list. * * ce->guc_state.lock * Protects everything under ce->guc_state. Ensures that a context is in the @@ -719,6 +719,7 @@ static void scrub_guc_desc_for_outstanding_g2h(struct intel_guc *guc) if (deregister) guc_signal_context_fence(ce); if (destroyed) { + intel_gt_pm_put_async(guc_to_gt(guc)); release_guc_id(guc, ce); __guc_context_destroy(ce); } @@ -797,6 +798,8 @@ static void guc_flush_submissions(struct intel_guc *guc) spin_unlock_irqrestore(&sched_engine->lock, flags); }
+static void guc_flush_destroyed_contexts(struct intel_guc *guc); + void intel_guc_submission_reset_prepare(struct intel_guc *guc) { int i; @@ -815,6 +818,7 @@ void intel_guc_submission_reset_prepare(struct intel_guc *guc) spin_unlock_irq(&guc_to_gt(guc)->irq_lock);
guc_flush_submissions(guc); + guc_flush_destroyed_contexts(guc);
/* * Handle any outstanding G2Hs before reset. Call IRQ handler directly @@ -1126,6 +1130,8 @@ void intel_guc_submission_reset_finish(struct intel_guc *guc) intel_gt_unpark_heartbeats(guc_to_gt(guc)); }
+static void destroyed_worker_func(struct work_struct *w); + /* * Set up the memory resources to be shared with the GuC (via the GGTT) * at firmware loading time. @@ -1151,6 +1157,9 @@ int intel_guc_submission_init(struct intel_guc *guc) spin_lock_init(&guc->submission_state.lock); INIT_LIST_HEAD(&guc->submission_state.guc_id_list); ida_init(&guc->submission_state.guc_ids); + INIT_LIST_HEAD(&guc->submission_state.destroyed_contexts); + INIT_WORK(&guc->submission_state.destroyed_worker, + destroyed_worker_func);
return 0; } @@ -1160,6 +1169,7 @@ void intel_guc_submission_fini(struct intel_guc *guc) if (!guc->lrc_desc_pool) return;
+ guc_flush_destroyed_contexts(guc); guc_lrc_desc_pool_destroy(guc); i915_sched_engine_put(guc->sched_engine); } @@ -1859,11 +1869,30 @@ static void guc_context_sched_disable(struct intel_context *ce) static inline void guc_lrc_desc_unpin(struct intel_context *ce) { struct intel_guc *guc = ce_to_guc(ce); + struct intel_gt *gt = guc_to_gt(guc); + unsigned long flags; + bool disabled;
+ GEM_BUG_ON(!intel_gt_pm_is_awake(gt)); GEM_BUG_ON(!lrc_desc_registered(guc, ce->guc_id.id)); GEM_BUG_ON(ce != __get_context(guc, ce->guc_id.id)); GEM_BUG_ON(context_enabled(ce));
+ /* Seal race with Reset */ + spin_lock_irqsave(&ce->guc_state.lock, flags); + disabled = submission_disabled(guc); + if (likely(!disabled)) { + __intel_gt_pm_get(gt); + set_context_destroyed(ce); + clr_context_registered(ce); + } + spin_unlock_irqrestore(&ce->guc_state.lock, flags); + if (unlikely(disabled)) { + release_guc_id(guc, ce); + __guc_context_destroy(ce); + return; + } + deregister_context(ce, ce->guc_id.id); }
@@ -1891,78 +1920,86 @@ static void __guc_context_destroy(struct intel_context *ce) } }
+static void guc_flush_destroyed_contexts(struct intel_guc *guc) +{ + struct intel_context *ce, *cn; + unsigned long flags; + + GEM_BUG_ON(!submission_disabled(guc) && + guc_submission_initialized(guc)); + + spin_lock_irqsave(&guc->submission_state.lock, flags); + list_for_each_entry_safe(ce, cn, + &guc->submission_state.destroyed_contexts, + destroyed_link) { + list_del_init(&ce->destroyed_link); + __release_guc_id(guc, ce); + __guc_context_destroy(ce); + } + spin_unlock_irqrestore(&guc->submission_state.lock, flags); +} + +static void deregister_destroyed_contexts(struct intel_guc *guc) +{ + struct intel_context *ce, *cn; + unsigned long flags; + + spin_lock_irqsave(&guc->submission_state.lock, flags); + list_for_each_entry_safe(ce, cn, + &guc->submission_state.destroyed_contexts, + destroyed_link) { + list_del_init(&ce->destroyed_link); + guc_lrc_desc_unpin(ce); + } + spin_unlock_irqrestore(&guc->submission_state.lock, flags); +} + +static void destroyed_worker_func(struct work_struct *w) +{ + struct intel_guc *guc = container_of(w, struct intel_guc, + submission_state.destroyed_worker); + struct intel_gt *gt = guc_to_gt(guc); + int tmp; + + with_intel_gt_pm(gt, tmp) + deregister_destroyed_contexts(guc); +} + static void guc_context_destroy(struct kref *kref) { struct intel_context *ce = container_of(kref, typeof(*ce), ref); - struct intel_runtime_pm *runtime_pm = ce->engine->uncore->rpm; struct intel_guc *guc = ce_to_guc(ce); - intel_wakeref_t wakeref; unsigned long flags; - bool disabled; + bool destroy;
/* * If the guc_id is invalid this context has been stolen and we can free * it immediately. Also can be freed immediately if the context is not * registered with the GuC or the GuC is in the middle of a reset. */ - if (context_guc_id_invalid(ce)) { - __guc_context_destroy(ce); - return; - } else if (submission_disabled(guc) || - !lrc_desc_registered(guc, ce->guc_id.id)) { - release_guc_id(guc, ce); - __guc_context_destroy(ce); - return; - } - - /* - * We have to acquire the context spinlock and check guc_id again, if it - * is valid it hasn't been stolen and needs to be deregistered. We - * delete this context from the list of unpinned guc_id available to - * steal to seal a race with guc_lrc_desc_pin(). When the G2H CTB - * returns indicating this context has been deregistered the guc_id is - * returned to the pool of available guc_id. - */ spin_lock_irqsave(&guc->submission_state.lock, flags); - if (context_guc_id_invalid(ce)) { - spin_unlock_irqrestore(&guc->submission_state.lock, flags); - __guc_context_destroy(ce); - return; + destroy = submission_disabled(guc) || context_guc_id_invalid(ce) || + !lrc_desc_registered(guc, ce->guc_id.id); + if (likely(!destroy)) { + if (!list_empty(&ce->guc_id.link)) + list_del_init(&ce->guc_id.link); + list_add_tail(&ce->destroyed_link, + &guc->submission_state.destroyed_contexts); + } else { + __release_guc_id(guc, ce); } - - if (!list_empty(&ce->guc_id.link)) - list_del_init(&ce->guc_id.link); spin_unlock_irqrestore(&guc->submission_state.lock, flags); - - /* Seal race with Reset */ - spin_lock_irqsave(&ce->guc_state.lock, flags); - disabled = submission_disabled(guc); - if (likely(!disabled)) { - set_context_destroyed(ce); - clr_context_registered(ce); - } - spin_unlock_irqrestore(&ce->guc_state.lock, flags); - if (unlikely(disabled)) { - release_guc_id(guc, ce); + if (unlikely(destroy)) { __guc_context_destroy(ce); return; }
/* - * We defer GuC context deregistration until the context is destroyed - * in order to save on CTBs. With this optimization ideally we only need - * 1 CTB to register the context during the first pin and 1 CTB to - * deregister the context when the context is destroyed. Without this - * optimization, a CTB would be needed every pin & unpin. - * - * XXX: Need to acqiure the runtime wakeref as this can be triggered - * from context_free_worker when runtime wakeref is not held. - * guc_lrc_desc_unpin requires the runtime as a GuC register is written - * in H2G CTB to deregister the context. A future patch may defer this - * H2G CTB if the runtime wakeref is zero. + * We use a worker to issue the H2G to deregister the context as we can + * take the GT PM for the first time which isn't allowed from an atomic + * context. */ - with_intel_runtime_pm(runtime_pm, wakeref) - guc_lrc_desc_unpin(ce); + queue_work(system_unbound_wq, &guc->submission_state.destroyed_worker); }
static int guc_context_alloc(struct intel_context *ce) @@ -2798,6 +2835,7 @@ int intel_guc_deregister_done_process_msg(struct intel_guc *guc, intel_context_put(ce); } else if (context_destroyed(ce)) { /* Context has been destroyed */ + intel_gt_pm_put_async(guc_to_gt(guc)); release_guc_id(guc, ce); __guc_context_destroy(ce); }