Commit 3897df4c authored by Matthew Brost's avatar Matthew Brost Committed by John Harrison

drm/i915/guc: Introduce context parent-child relationship

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)
v4:
 (John Harrison)
  - s/its'/its/g
Signed-off-by: default avatarMatthew Brost <matthew.brost@intel.com>
Reviewed-by: default avatarJohn Harrison <John.C.Harrison@Intel.com>
Signed-off-by: default avatarJohn Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014172005.27155-8-matthew.brost@intel.com
parent 9409eb35
......@@ -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
......@@ -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
......
......@@ -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
......
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