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-rw-r--r--drivers/gpu/drm/i915/i915_gem_execbuffer.c67
-rw-r--r--drivers/gpu/drm/i915/intel_ringbuffer.c13
-rw-r--r--drivers/gpu/drm/i915/intel_ringbuffer.h12
3 files changed, 79 insertions, 13 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 8eedf7cac493..02adcaf6ebea 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -753,6 +753,68 @@ static int eb_select_context(struct i915_execbuffer *eb)
return 0;
}
+static struct i915_request *__eb_wait_for_ring(struct intel_ring *ring)
+{
+ struct i915_request *rq;
+
+ /*
+ * Completely unscientific finger-in-the-air estimates for suitable
+ * maximum user request size (to avoid blocking) and then backoff.
+ */
+ if (intel_ring_update_space(ring) >= PAGE_SIZE)
+ return NULL;
+
+ /*
+ * Find a request that after waiting upon, there will be at least half
+ * the ring available. The hysteresis allows us to compete for the
+ * shared ring and should mean that we sleep less often prior to
+ * claiming our resources, but not so long that the ring completely
+ * drains before we can submit our next request.
+ */
+ list_for_each_entry(rq, &ring->request_list, ring_link) {
+ if (__intel_ring_space(rq->postfix,
+ ring->emit, ring->size) > ring->size / 2)
+ break;
+ }
+ if (&rq->ring_link == &ring->request_list)
+ return NULL; /* weird, we will check again later for real */
+
+ return i915_request_get(rq);
+}
+
+static int eb_wait_for_ring(const struct i915_execbuffer *eb)
+{
+ const struct intel_context *ce;
+ struct i915_request *rq;
+ int ret = 0;
+
+ /*
+ * Apply a light amount of backpressure to prevent excessive hogs
+ * from blocking waiting for space whilst holding struct_mutex and
+ * keeping all of their resources pinned.
+ */
+
+ ce = to_intel_context(eb->ctx, eb->engine);
+ if (!ce->ring) /* first use, assume empty! */
+ return 0;
+
+ rq = __eb_wait_for_ring(ce->ring);
+ if (rq) {
+ mutex_unlock(&eb->i915->drm.struct_mutex);
+
+ if (i915_request_wait(rq,
+ I915_WAIT_INTERRUPTIBLE,
+ MAX_SCHEDULE_TIMEOUT) < 0)
+ ret = -EINTR;
+
+ i915_request_put(rq);
+
+ mutex_lock(&eb->i915->drm.struct_mutex);
+ }
+
+ return ret;
+}
+
static int eb_lookup_vmas(struct i915_execbuffer *eb)
{
struct radix_tree_root *handles_vma = &eb->ctx->handles_vma;
@@ -2291,6 +2353,10 @@ i915_gem_do_execbuffer(struct drm_device *dev,
if (err)
goto err_rpm;
+ err = eb_wait_for_ring(&eb); /* may temporarily drop struct_mutex */
+ if (unlikely(err))
+ goto err_unlock;
+
err = eb_relocate(&eb);
if (err) {
/*
@@ -2435,6 +2501,7 @@ err_batch_unpin:
err_vma:
if (eb.exec)
eb_release_vmas(&eb);
+err_unlock:
mutex_unlock(&dev->struct_mutex);
err_rpm:
intel_runtime_pm_put(eb.i915, wakeref);
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index b889b27f8aeb..7f841dba87b3 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -49,19 +49,6 @@ static inline u32 intel_hws_seqno_address(struct intel_engine_cs *engine)
I915_GEM_HWS_INDEX_ADDR);
}
-static unsigned int __intel_ring_space(unsigned int head,
- unsigned int tail,
- unsigned int size)
-{
- /*
- * "If the Ring Buffer Head Pointer and the Tail Pointer are on the
- * same cacheline, the Head Pointer must not be greater than the Tail
- * Pointer."
- */
- GEM_BUG_ON(!is_power_of_2(size));
- return (head - tail - CACHELINE_BYTES) & (size - 1);
-}
-
unsigned int intel_ring_update_space(struct intel_ring *ring)
{
unsigned int space;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 4d4ea6963a72..710ffb221775 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -832,6 +832,18 @@ intel_ring_set_tail(struct intel_ring *ring, unsigned int tail)
return tail;
}
+static inline unsigned int
+__intel_ring_space(unsigned int head, unsigned int tail, unsigned int size)
+{
+ /*
+ * "If the Ring Buffer Head Pointer and the Tail Pointer are on the
+ * same cacheline, the Head Pointer must not be greater than the Tail
+ * Pointer."
+ */
+ GEM_BUG_ON(!is_power_of_2(size));
+ return (head - tail - CACHELINE_BYTES) & (size - 1);
+}
+
void intel_engine_write_global_seqno(struct intel_engine_cs *engine, u32 seqno);
int intel_engine_setup_common(struct intel_engine_cs *engine);