drm/i915: Only hold a process-local lock whilst throttling.
Avoid cause latencies in other clients by not taking the global struct
mutex and moving the per-client request manipulation a local per-client
mutex. For example, this allows a compositor to schedule a page-flip
(through X) whilst an OpenGL application is monopolising the GPU.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index dec7bbc..9185f09 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1592,17 +1592,17 @@
uint32_t
i915_add_request(struct drm_device *dev,
- struct drm_file *file_priv,
+ struct drm_file *file,
struct drm_i915_gem_request *request,
struct intel_ring_buffer *ring)
{
drm_i915_private_t *dev_priv = dev->dev_private;
- struct drm_i915_file_private *i915_file_priv = NULL;
+ struct drm_i915_file_private *file_priv = NULL;
uint32_t seqno;
int was_empty;
- if (file_priv != NULL)
- i915_file_priv = file_priv->driver_priv;
+ if (file != NULL)
+ file_priv = file->driver_priv;
if (request == NULL) {
request = kzalloc(sizeof(*request), GFP_KERNEL);
@@ -1610,7 +1610,7 @@
return 0;
}
- seqno = ring->add_request(dev, ring, file_priv, 0);
+ seqno = ring->add_request(dev, ring, 0);
request->seqno = seqno;
request->ring = ring;
@@ -1618,11 +1618,12 @@
was_empty = list_empty(&ring->request_list);
list_add_tail(&request->list, &ring->request_list);
- if (i915_file_priv) {
+ if (file_priv) {
+ mutex_lock(&file_priv->mutex);
+ request->file_priv = file_priv;
list_add_tail(&request->client_list,
- &i915_file_priv->mm.request_list);
- } else {
- INIT_LIST_HEAD(&request->client_list);
+ &file_priv->mm.request_list);
+ mutex_unlock(&file_priv->mutex);
}
if (!dev_priv->mm.suspended) {
@@ -1654,20 +1655,14 @@
I915_GEM_DOMAIN_COMMAND, flush_domains);
}
-/**
- * Returns true if seq1 is later than seq2.
- */
-bool
-i915_seqno_passed(uint32_t seq1, uint32_t seq2)
+static inline void
+i915_gem_request_remove_from_client(struct drm_i915_gem_request *request)
{
- return (int32_t)(seq1 - seq2) >= 0;
-}
-
-uint32_t
-i915_get_gem_seqno(struct drm_device *dev,
- struct intel_ring_buffer *ring)
-{
- return ring->get_gem_seqno(dev, ring);
+ if (request->file_priv) {
+ mutex_lock(&request->file_priv->mutex);
+ list_del(&request->client_list);
+ mutex_unlock(&request->file_priv->mutex);
+ }
}
static void i915_gem_reset_ring_lists(struct drm_i915_private *dev_priv,
@@ -1681,7 +1676,7 @@
list);
list_del(&request->list);
- list_del(&request->client_list);
+ i915_gem_request_remove_from_client(request);
kfree(request);
}
@@ -1746,7 +1741,7 @@
list_empty(&ring->request_list))
return;
- seqno = i915_get_gem_seqno(dev, ring);
+ seqno = ring->get_seqno(dev, ring);
while (!list_empty(&ring->request_list)) {
struct drm_i915_gem_request *request;
@@ -1760,7 +1755,7 @@
trace_i915_gem_request_retire(dev, request->seqno);
list_del(&request->list);
- list_del(&request->client_list);
+ i915_gem_request_remove_from_client(request);
kfree(request);
}
@@ -1862,7 +1857,7 @@
if (atomic_read(&dev_priv->mm.wedged))
return -EIO;
- if (!i915_seqno_passed(ring->get_gem_seqno(dev, ring), seqno)) {
+ if (!i915_seqno_passed(ring->get_seqno(dev, ring), seqno)) {
if (HAS_PCH_SPLIT(dev))
ier = I915_READ(DEIER) | I915_READ(GTIER);
else
@@ -1881,12 +1876,12 @@
if (interruptible)
ret = wait_event_interruptible(ring->irq_queue,
i915_seqno_passed(
- ring->get_gem_seqno(dev, ring), seqno)
+ ring->get_seqno(dev, ring), seqno)
|| atomic_read(&dev_priv->mm.wedged));
else
wait_event(ring->irq_queue,
i915_seqno_passed(
- ring->get_gem_seqno(dev, ring), seqno)
+ ring->get_seqno(dev, ring), seqno)
|| atomic_read(&dev_priv->mm.wedged));
ring->user_irq_put(dev, ring);
@@ -1899,7 +1894,7 @@
if (ret && ret != -ERESTARTSYS)
DRM_ERROR("%s returns %d (awaiting %d at %d, next %d)\n",
- __func__, ret, seqno, ring->get_gem_seqno(dev, ring),
+ __func__, ret, seqno, ring->get_seqno(dev, ring),
dev_priv->next_seqno);
/* Directly dispatch request retiring. While we have the work queue
@@ -3384,28 +3379,48 @@
* relatively low latency when blocking on a particular request to finish.
*/
static int
-i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file_priv)
+i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file)
{
- struct drm_i915_file_private *i915_file_priv = file_priv->driver_priv;
- int ret = 0;
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ struct drm_i915_file_private *file_priv = file->driver_priv;
unsigned long recent_enough = jiffies - msecs_to_jiffies(20);
+ struct drm_i915_gem_request *request;
+ struct intel_ring_buffer *ring = NULL;
+ u32 seqno = 0;
+ int ret;
- mutex_lock(&dev->struct_mutex);
- while (!list_empty(&i915_file_priv->mm.request_list)) {
- struct drm_i915_gem_request *request;
-
- request = list_first_entry(&i915_file_priv->mm.request_list,
- struct drm_i915_gem_request,
- client_list);
-
+ mutex_lock(&file_priv->mutex);
+ list_for_each_entry(request, &file_priv->mm.request_list, client_list) {
if (time_after_eq(request->emitted_jiffies, recent_enough))
break;
- ret = i915_wait_request(dev, request->seqno, request->ring);
- if (ret != 0)
- break;
+ ring = request->ring;
+ seqno = request->seqno;
}
- mutex_unlock(&dev->struct_mutex);
+ mutex_unlock(&file_priv->mutex);
+
+ if (seqno == 0)
+ return 0;
+
+ ret = 0;
+ if (!i915_seqno_passed(ring->get_seqno(dev, ring), seqno)) {
+ /* And wait for the seqno passing without holding any locks and
+ * causing extra latency for others. This is safe as the irq
+ * generation is designed to be run atomically and so is
+ * lockless.
+ */
+ ring->user_irq_get(dev, ring);
+ ret = wait_event_interruptible(ring->irq_queue,
+ i915_seqno_passed(ring->get_seqno(dev, ring), seqno)
+ || atomic_read(&dev_priv->mm.wedged));
+ ring->user_irq_put(dev, ring);
+
+ if (ret == 0 && atomic_read(&dev_priv->mm.wedged))
+ ret = -EIO;
+ }
+
+ if (ret == 0)
+ queue_delayed_work(dev_priv->wq, &dev_priv->mm.retire_work, 0);
return ret;
}
@@ -4857,17 +4872,26 @@
return 0;
}
-void i915_gem_release(struct drm_device * dev, struct drm_file *file_priv)
+void i915_gem_release(struct drm_device *dev, struct drm_file *file)
{
- struct drm_i915_file_private *i915_file_priv = file_priv->driver_priv;
+ struct drm_i915_file_private *file_priv = file->driver_priv;
/* Clean up our request list when the client is going away, so that
* later retire_requests won't dereference our soon-to-be-gone
* file_priv.
*/
mutex_lock(&dev->struct_mutex);
- while (!list_empty(&i915_file_priv->mm.request_list))
- list_del_init(i915_file_priv->mm.request_list.next);
+ mutex_lock(&file_priv->mutex);
+ while (!list_empty(&file_priv->mm.request_list)) {
+ struct drm_i915_gem_request *request;
+
+ request = list_first_entry(&file_priv->mm.request_list,
+ struct drm_i915_gem_request,
+ client_list);
+ list_del(&request->client_list);
+ request->file_priv = NULL;
+ }
+ mutex_unlock(&file_priv->mutex);
mutex_unlock(&dev->struct_mutex);
}