Commit bc955204 authored by Matthew Brost's avatar Matthew Brost Committed by John Harrison

drm/i915/guc: Insert submit fences between requests in parent-child relationship

The GuC must receive requests in the order submitted for contexts in a
parent-child relationship to function correctly. To ensure this, insert
a submit fence between the current request and last request submitted
for requests / contexts in a parent child relationship. This is
conceptually similar to a single timeline.
Signed-off-by: default avatarMatthew Brost <matthew.brost@intel.com>
Cc: John Harrison <John.C.Harrison@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/20211014172005.27155-14-matthew.brost@intel.com
parent 6b540bf6
......@@ -77,6 +77,11 @@ intel_context_to_parent(struct intel_context *ce)
}
}
static inline bool intel_context_is_parallel(struct intel_context *ce)
{
return intel_context_is_child(ce) || intel_context_is_parent(ce);
}
void intel_context_bind_parent_child(struct intel_context *parent,
struct intel_context *child);
......
......@@ -237,6 +237,12 @@ struct intel_context {
};
/** @parent: pointer to parent if child */
struct intel_context *parent;
/**
* @last_rq: last request submitted on a parallel context, used
* to insert submit fences between requests in the parallel
* context
*/
struct i915_request *last_rq;
/** @number_children: number of children if parent */
u8 number_children;
/** @guc: GuC specific members for parallel submission */
......
......@@ -684,8 +684,7 @@ static inline int rq_prio(const struct i915_request *rq)
static bool is_multi_lrc_rq(struct i915_request *rq)
{
return intel_context_is_child(rq->context) ||
intel_context_is_parent(rq->context);
return intel_context_is_parallel(rq->context);
}
static bool can_merge_rq(struct i915_request *rq,
......@@ -2873,6 +2872,8 @@ static void guc_parent_context_unpin(struct intel_context *ce)
GEM_BUG_ON(!intel_context_is_parent(ce));
GEM_BUG_ON(!intel_engine_is_virtual(ce->engine));
if (ce->parallel.last_rq)
i915_request_put(ce->parallel.last_rq);
unpin_guc_id(guc, ce);
lrc_unpin(ce);
}
......
......@@ -1549,36 +1549,62 @@ i915_request_await_object(struct i915_request *to,
return ret;
}
static inline bool is_parallel_rq(struct i915_request *rq)
{
return intel_context_is_parallel(rq->context);
}
static inline struct intel_context *request_to_parent(struct i915_request *rq)
{
return intel_context_to_parent(rq->context);
}
static struct i915_request *
__i915_request_add_to_timeline(struct i915_request *rq)
__i915_request_ensure_parallel_ordering(struct i915_request *rq,
struct intel_timeline *timeline)
{
struct intel_timeline *timeline = i915_request_timeline(rq);
struct i915_request *prev;
/*
* Dependency tracking and request ordering along the timeline
* is special cased so that we can eliminate redundant ordering
* operations while building the request (we know that the timeline
* itself is ordered, and here we guarantee it).
*
* As we know we will need to emit tracking along the timeline,
* we embed the hooks into our request struct -- at the cost of
* having to have specialised no-allocation interfaces (which will
* be beneficial elsewhere).
*
* A second benefit to open-coding i915_request_await_request is
* that we can apply a slight variant of the rules specialised
* for timelines that jump between engines (such as virtual engines).
* If we consider the case of virtual engine, we must emit a dma-fence
* to prevent scheduling of the second request until the first is
* complete (to maximise our greedy late load balancing) and this
* precludes optimising to use semaphores serialisation of a single
* timeline across engines.
*/
GEM_BUG_ON(!is_parallel_rq(rq));
prev = request_to_parent(rq)->parallel.last_rq;
if (prev) {
if (!__i915_request_is_complete(prev)) {
i915_sw_fence_await_sw_fence(&rq->submit,
&prev->submit,
&rq->submitq);
if (rq->engine->sched_engine->schedule)
__i915_sched_node_add_dependency(&rq->sched,
&prev->sched,
&rq->dep,
0);
}
i915_request_put(prev);
}
request_to_parent(rq)->parallel.last_rq = i915_request_get(rq);
return to_request(__i915_active_fence_set(&timeline->last_request,
&rq->fence));
}
static struct i915_request *
__i915_request_ensure_ordering(struct i915_request *rq,
struct intel_timeline *timeline)
{
struct i915_request *prev;
GEM_BUG_ON(is_parallel_rq(rq));
prev = to_request(__i915_active_fence_set(&timeline->last_request,
&rq->fence));
if (prev && !__i915_request_is_complete(prev)) {
bool uses_guc = intel_engine_uses_guc(rq->engine);
bool pow2 = is_power_of_2(READ_ONCE(prev->engine)->mask |
rq->engine->mask);
bool same_context = prev->context == rq->context;
/*
* The requests are supposed to be kept in order. However,
......@@ -1586,13 +1612,11 @@ __i915_request_add_to_timeline(struct i915_request *rq)
* is used as a barrier for external modification to this
* context.
*/
GEM_BUG_ON(prev->context == rq->context &&
GEM_BUG_ON(same_context &&
i915_seqno_passed(prev->fence.seqno,
rq->fence.seqno));
if ((!uses_guc &&
is_power_of_2(READ_ONCE(prev->engine)->mask | rq->engine->mask)) ||
(uses_guc && prev->context == rq->context))
if ((same_context && uses_guc) || (!uses_guc && pow2))
i915_sw_fence_await_sw_fence(&rq->submit,
&prev->submit,
&rq->submitq);
......@@ -1607,6 +1631,50 @@ __i915_request_add_to_timeline(struct i915_request *rq)
0);
}
return prev;
}
static struct i915_request *
__i915_request_add_to_timeline(struct i915_request *rq)
{
struct intel_timeline *timeline = i915_request_timeline(rq);
struct i915_request *prev;
/*
* Dependency tracking and request ordering along the timeline
* is special cased so that we can eliminate redundant ordering
* operations while building the request (we know that the timeline
* itself is ordered, and here we guarantee it).
*
* As we know we will need to emit tracking along the timeline,
* we embed the hooks into our request struct -- at the cost of
* having to have specialised no-allocation interfaces (which will
* be beneficial elsewhere).
*
* A second benefit to open-coding i915_request_await_request is
* that we can apply a slight variant of the rules specialised
* for timelines that jump between engines (such as virtual engines).
* If we consider the case of virtual engine, we must emit a dma-fence
* to prevent scheduling of the second request until the first is
* complete (to maximise our greedy late load balancing) and this
* precludes optimising to use semaphores serialisation of a single
* timeline across engines.
*
* We do not order parallel submission requests on the timeline as each
* parallel submission context has its own timeline and the ordering
* rules for parallel requests are that they must be submitted in the
* order received from the execbuf IOCTL. So rather than using the
* timeline we store a pointer to last request submitted in the
* relationship in the gem context and insert a submission fence
* between that request and request passed into this function or
* alternatively we use completion fence if gem context has a single
* timeline and this is the first submission of an execbuf IOCTL.
*/
if (likely(!is_parallel_rq(rq)))
prev = __i915_request_ensure_ordering(rq, timeline);
else
prev = __i915_request_ensure_parallel_ordering(rq, timeline);
/*
* Make sure that no request gazumped us - if it was allocated after
* our i915_request_alloc() and called __i915_request_add() before
......
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