[Intel-gfx] [PATCH 15/46] drm/i915/guc: Introduce context parent-child relationship

Matthew Brost
2021-08-03T22:12:31Z

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.

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 | 18 ++++++++++++
drivers/gpu/drm/i915/gt/intel_context_types.h | 12 ++++++++
3 files changed, 59 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
index 745e84c72c90..8cb92b10b547 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.c
+++ b/drivers/gpu/drm/i915/gt/intel_context.c
@@ -395,6 +395,8 @@ intel_context_init(struct intel_context *ce, struct intel_engine_cs *engine)
spin_lock_init(&ce->guc_state.lock);
INIT_LIST_HEAD(&ce->guc_state.fences);

+ INIT_LIST_HEAD(&ce->guc_child_list);
+
spin_lock_init(&ce->guc_active.lock);
INIT_LIST_HEAD(&ce->guc_active.requests);

@@ -414,10 +416,17 @@ 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);
}
@@ -533,6 +542,26 @@ 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->guc_number_children++;
+ list_add_tail(&child->guc_child_link,
+ &parent->guc_child_list);
+ child->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..ad6ce5ac4824 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.h
+++ b/drivers/gpu/drm/i915/gt/intel_context.h
@@ -44,6 +44,24 @@ 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->parent;
+}
+
+static inline bool intel_context_is_parent(struct intel_context *ce)
+{
+ return !!ce->guc_number_children;
+}
+
+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)->guc_child_list, guc_child_link)
+#define for_each_child_safe(parent, ce, cn)\
+ list_for_each_entry_safe(ce, cn, &(parent)->guc_child_list, guc_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 2df79ba39867..66b22b370a72 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
@@ -202,6 +202,18 @@ struct intel_context {
/* GuC context blocked fence */
struct i915_sw_fence guc_blocked;

+ /* Head of children list or link in parent's children list */
+ union {
+ struct list_head guc_child_list; /* parent */
+ struct list_head guc_child_link; /* child */
+ };
+
+ /* Pointer to parent */
+ struct intel_context *parent;
+
+ /* Number of children if parent */
+ u8 guc_number_children;
+
/*
* GuC priority management
*/
--
2.28.0