Introduce context parent-child relationship. Once this relationship is created all pinning / unpinning operations are directed to the parent context. The parent context is responsible for pinning all of its' children and itself.
This is a precursor to the full GuC multi-lrc implementation but aligns to how GuC mutli-lrc interface is defined - a single H2G is used register / deregister all of the contexts simultaneously.
Subsequent patches in the series will implement the pinning / unpinning operations for parent / child contexts.
v2: (Daniel Vetter) - Add kernel doc, add wrapper to access parent to ensure safety v3: (John Harrison) - Fix comment explaing GEM_BUG_ON in to_parent() - Make variable names generic (non-GuC specific)
Signed-off-by: Matthew Brost matthew.brost@intel.com --- drivers/gpu/drm/i915/gt/intel_context.c | 29 +++++++++++++ drivers/gpu/drm/i915/gt/intel_context.h | 41 +++++++++++++++++++ drivers/gpu/drm/i915/gt/intel_context_types.h | 21 ++++++++++ 3 files changed, 91 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c index f601323b939f..c5bb7ccfb3f8 100644 --- a/drivers/gpu/drm/i915/gt/intel_context.c +++ b/drivers/gpu/drm/i915/gt/intel_context.c @@ -403,6 +403,8 @@ intel_context_init(struct intel_context *ce, struct intel_engine_cs *engine)
INIT_LIST_HEAD(&ce->destroyed_link);
+ INIT_LIST_HEAD(&ce->parallel.child_list); + /* * Initialize fence to be complete as this is expected to be complete * unless there is a pending schedule disable outstanding. @@ -417,10 +419,17 @@ intel_context_init(struct intel_context *ce, struct intel_engine_cs *engine)
void intel_context_fini(struct intel_context *ce) { + struct intel_context *child, *next; + if (ce->timeline) intel_timeline_put(ce->timeline); i915_vm_put(ce->vm);
+ /* Need to put the creation ref for the children */ + if (intel_context_is_parent(ce)) + for_each_child_safe(ce, child, next) + intel_context_put(child); + mutex_destroy(&ce->pin_mutex); i915_active_fini(&ce->active); i915_sw_fence_fini(&ce->guc_state.blocked); @@ -537,6 +546,26 @@ struct i915_request *intel_context_find_active_request(struct intel_context *ce) return active; }
+void intel_context_bind_parent_child(struct intel_context *parent, + struct intel_context *child) +{ + /* + * Callers responsibility to validate that this function is used + * correctly but we use GEM_BUG_ON here ensure that they do. + */ + GEM_BUG_ON(!intel_engine_uses_guc(parent->engine)); + GEM_BUG_ON(intel_context_is_pinned(parent)); + GEM_BUG_ON(intel_context_is_child(parent)); + GEM_BUG_ON(intel_context_is_pinned(child)); + GEM_BUG_ON(intel_context_is_child(child)); + GEM_BUG_ON(intel_context_is_parent(child)); + + parent->parallel.number_children++; + list_add_tail(&child->parallel.child_link, + &parent->parallel.child_list); + child->parallel.parent = parent; +} + #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) #include "selftest_context.c" #endif diff --git a/drivers/gpu/drm/i915/gt/intel_context.h b/drivers/gpu/drm/i915/gt/intel_context.h index c41098950746..b63c10a144af 100644 --- a/drivers/gpu/drm/i915/gt/intel_context.h +++ b/drivers/gpu/drm/i915/gt/intel_context.h @@ -44,6 +44,47 @@ void intel_context_free(struct intel_context *ce); int intel_context_reconfigure_sseu(struct intel_context *ce, const struct intel_sseu sseu);
+static inline bool intel_context_is_child(struct intel_context *ce) +{ + return !!ce->parallel.parent; +} + +static inline bool intel_context_is_parent(struct intel_context *ce) +{ + return !!ce->parallel.number_children; +} + +static inline bool intel_context_is_pinned(struct intel_context *ce); + +static inline struct intel_context * +intel_context_to_parent(struct intel_context *ce) +{ + if (intel_context_is_child(ce)) { + /* + * The parent holds ref count to the child so it is always safe + * for the parent to access the child, but the child has a + * pointer to the parent without a ref. To ensure this is safe + * the child should only access the parent pointer while the + * parent is pinned. + */ + GEM_BUG_ON(!intel_context_is_pinned(ce->parallel.parent)); + + return ce->parallel.parent; + } else { + return ce; + } +} + +void intel_context_bind_parent_child(struct intel_context *parent, + struct intel_context *child); + +#define for_each_child(parent, ce)\ + list_for_each_entry(ce, &(parent)->parallel.child_list,\ + parallel.child_link) +#define for_each_child_safe(parent, ce, cn)\ + list_for_each_entry_safe(ce, cn, &(parent)->parallel.child_list,\ + parallel.child_link) + /** * intel_context_lock_pinned - Stablises the 'pinned' status of the HW context * @ce - the context diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h index 4613d027cbc3..76dfca57cb45 100644 --- a/drivers/gpu/drm/i915/gt/intel_context_types.h +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h @@ -220,6 +220,27 @@ struct intel_context { */ struct list_head destroyed_link;
+ /** @parallel: sub-structure for parallel submission members */ + struct { + union { + /** + * @child_list: parent's list of children + * contexts, no protection as immutable after context + * creation + */ + struct list_head child_list; + /** + * @child_link: child's link into parent's list of + * children + */ + struct list_head child_link; + }; + /** @parent: pointer to parent if child */ + struct intel_context *parent; + /** @number_children: number of children if parent */ + u8 number_children; + } parallel; + #ifdef CONFIG_DRM_I915_SELFTEST /** * @drop_schedule_enable: Force drop of schedule enable G2H for selftest