[PATCH] drm/i915: add infrastructure to hold off preemption on a request
Chris Wilson
chris at chris-wilson.co.uk
Tue Jul 9 14:40:21 UTC 2019
From: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
We want to set this flag in the next commit on requests containing
perf queries so that the result of the perf query can just be a delta
of global counters, rather than doing post processing of the OA
buffer.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/gt/intel_lrc.c | 6 +++++-
drivers/gpu/drm/i915/i915_priolist_types.h | 10 ++++++++++
drivers/gpu/drm/i915/i915_request.c | 4 ++--
drivers/gpu/drm/i915/i915_request.h | 15 ++++++++++++++-
drivers/gpu/drm/i915/intel_guc_submission.c | 13 ++++++++++++-
drivers/gpu/drm/i915/intel_pm.c | 5 +++--
6 files changed, 46 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index e1ae1399c72b..59a7a1d4e8d2 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -256,7 +256,11 @@ static inline int rq_prio(const struct i915_request *rq)
static int effective_prio(const struct i915_request *rq)
{
- int prio = rq_prio(rq);
+ int prio;
+
+ prio = rq_prio(rq);
+ if (i915_request_has_nopreempt(rq))
+ prio = I915_PRIORITY_NOPREEMPTION;
/*
* On unwinding the active request, we give it a priority bump
diff --git a/drivers/gpu/drm/i915/i915_priolist_types.h b/drivers/gpu/drm/i915/i915_priolist_types.h
index 49709de69875..bbfc0041d375 100644
--- a/drivers/gpu/drm/i915/i915_priolist_types.h
+++ b/drivers/gpu/drm/i915/i915_priolist_types.h
@@ -17,6 +17,16 @@ enum {
I915_PRIORITY_NORMAL = I915_CONTEXT_DEFAULT_PRIORITY,
I915_PRIORITY_MAX = I915_CONTEXT_MAX_USER_PRIORITY + 1,
+ /*
+ * Requests containing performance queries must not be preempted by
+ * another context. They get scheduled with their default priority and
+ * once they reach the execlist ports we ensure that they stick on the
+ * HW until finished by pretending that they have maximum priority,
+ * i.e. nothing can have higher priority and force us to usurp the
+ * active request.
+ */
+ I915_PRIORITY_NOPREEMPTION = INT_MAX,
+
I915_PRIORITY_INVALID = INT_MIN
};
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 5ff87c4a0cd5..222c9c56e9de 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -292,7 +292,7 @@ static bool i915_request_retire(struct i915_request *rq)
dma_fence_signal_locked(&rq->fence);
if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &rq->fence.flags))
i915_request_cancel_breadcrumb(rq);
- if (rq->waitboost) {
+ if (i915_request_has_waitboost(rq)) {
GEM_BUG_ON(!atomic_read(&rq->i915->gt_pm.rps.num_waiters));
atomic_dec(&rq->i915->gt_pm.rps.num_waiters);
}
@@ -684,7 +684,7 @@ __i915_request_create(struct intel_context *ce, gfp_t gfp)
rq->file_priv = NULL;
rq->batch = NULL;
rq->capture_list = NULL;
- rq->waitboost = false;
+ rq->flags = 0;
rq->execution_mask = ALL_ENGINES;
INIT_LIST_HEAD(&rq->active_list);
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index b58ceef92e20..6a44af40b899 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -216,7 +216,9 @@ struct i915_request {
/** Time at which this request was emitted, in jiffies. */
unsigned long emitted_jiffies;
- bool waitboost;
+#define I915_REQUEST_WAITBOOST BIT(0)
+#define I915_REQUEST_NOPREEMPT BIT(1)
+ u32 flags;
/** timeline->request entry for this request */
struct list_head link;
@@ -430,6 +432,17 @@ static inline void i915_request_mark_complete(struct i915_request *rq)
rq->hwsp_seqno = (u32 *)&rq->fence.seqno; /* decouple from HWSP */
}
+static inline bool i915_request_has_waitboost(const struct i915_request *rq)
+{
+ return rq->flags & I915_REQUEST_WAITBOOST;
+}
+
+static inline bool i915_request_has_nopreempt(const struct i915_request *rq)
+{
+ /* Preemption should only be disabled very rarely */
+ return unlikely(rq->flags & I915_REQUEST_NOPREEMPT);
+}
+
bool i915_retire_requests(struct drm_i915_private *i915);
#endif /* I915_REQUEST_H */
diff --git a/drivers/gpu/drm/i915/intel_guc_submission.c b/drivers/gpu/drm/i915/intel_guc_submission.c
index 12c22359fdac..017aaa9cb54a 100644
--- a/drivers/gpu/drm/i915/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/intel_guc_submission.c
@@ -707,6 +707,16 @@ static inline int rq_prio(const struct i915_request *rq)
return rq->sched.attr.priority | __NO_PREEMPTION;
}
+static inline int effective_prio(const struct i915_request *rq)
+{
+ int prio = rq_prio(rq);
+
+ if (i915_request_has_nopreempt(rq))
+ prio = I915_PRIORITY_NOPREEMPTION;
+
+ return prio;
+}
+
static struct i915_request *schedule_in(struct i915_request *rq, int idx)
{
trace_i915_request_in(rq, idx);
@@ -747,7 +757,8 @@ static void __guc_dequeue(struct intel_engine_cs *engine)
&engine->i915->guc.preempt_work[engine->id];
int prio = execlists->queue_priority_hint;
- if (i915_scheduler_need_preempt(prio, rq_prio(last))) {
+ if (i915_scheduler_need_preempt(prio,
+ effective_prio(last))) {
intel_write_status_page(engine,
I915_GEM_HWS_PREEMPT,
GUC_PREEMPT_INPROGRESS);
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 87244d8215a7..0cecea228546 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6876,9 +6876,10 @@ void gen6_rps_boost(struct i915_request *rq)
/* Serializes with i915_request_retire() */
boost = false;
spin_lock_irqsave(&rq->lock, flags);
- if (!rq->waitboost && !dma_fence_is_signaled_locked(&rq->fence)) {
+ if (!i915_request_has_waitboost(rq) &&
+ !dma_fence_is_signaled_locked(&rq->fence)) {
boost = !atomic_fetch_inc(&rps->num_waiters);
- rq->waitboost = true;
+ rq->flags |= I915_REQUEST_WAITBOOST;
}
spin_unlock_irqrestore(&rq->lock, flags);
if (!boost)
--
2.22.0
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