[PATCH 2/4] drm/vmwgfx: Defer fence irq processing to a tasklet
Thomas Hellstrom
thellstrom at vmware.com
Fri Oct 30 02:42:44 PDT 2015
Reduce the time in hardware irq context and hardware irq latency.
Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
Reviewed-by: Sinclair Yeh <syeh at vmware.com>
---
drivers/gpu/drm/vmwgfx/vmwgfx_fence.c | 108 ++++++++++++++++++++--------------
drivers/gpu/drm/vmwgfx/vmwgfx_fence.h | 2 +
drivers/gpu/drm/vmwgfx/vmwgfx_irq.c | 6 +-
3 files changed, 68 insertions(+), 48 deletions(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
index 8e689b4..f40c36e 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
@@ -47,6 +47,7 @@ struct vmw_fence_manager {
bool seqno_valid; /* Protected by @lock, and may not be set to true
without the @goal_irq_mutex held. */
unsigned ctx;
+ struct tasklet_struct tasklet;
};
struct vmw_user_fence {
@@ -81,6 +82,8 @@ struct vmw_event_fence_action {
uint32_t *tv_usec;
};
+static void vmw_fence_tasklet(unsigned long data);
+
static struct vmw_fence_manager *
fman_from_fence(struct vmw_fence_obj *fence)
{
@@ -115,12 +118,11 @@ static void vmw_fence_obj_destroy(struct fence *f)
container_of(f, struct vmw_fence_obj, base);
struct vmw_fence_manager *fman = fman_from_fence(fence);
- unsigned long irq_flags;
- spin_lock_irqsave(&fman->lock, irq_flags);
+ spin_lock_bh(&fman->lock);
list_del_init(&fence->head);
--fman->num_fence_objects;
- spin_unlock_irqrestore(&fman->lock, irq_flags);
+ spin_unlock_bh(&fman->lock);
fence->destroy(fence);
}
@@ -177,7 +179,6 @@ static long vmw_fence_wait(struct fence *f, bool intr, signed long timeout)
struct vmw_private *dev_priv = fman->dev_priv;
struct vmwgfx_wait_cb cb;
long ret = timeout;
- unsigned long irq_flags;
if (likely(vmw_fence_obj_signaled(fence)))
return timeout;
@@ -185,7 +186,7 @@ static long vmw_fence_wait(struct fence *f, bool intr, signed long timeout)
vmw_fifo_ping_host(dev_priv, SVGA_SYNC_GENERIC);
vmw_seqno_waiter_add(dev_priv);
- spin_lock_irqsave(f->lock, irq_flags);
+ spin_lock_bh(f->lock);
if (intr && signal_pending(current)) {
ret = -ERESTARTSYS;
@@ -205,11 +206,11 @@ static long vmw_fence_wait(struct fence *f, bool intr, signed long timeout)
__set_current_state(TASK_INTERRUPTIBLE);
else
__set_current_state(TASK_UNINTERRUPTIBLE);
- spin_unlock_irqrestore(f->lock, irq_flags);
+ spin_unlock_bh(f->lock);
ret = schedule_timeout(ret);
- spin_lock_irqsave(f->lock, irq_flags);
+ spin_lock_bh(f->lock);
if (ret > 0 && intr && signal_pending(current))
ret = -ERESTARTSYS;
}
@@ -219,7 +220,7 @@ static long vmw_fence_wait(struct fence *f, bool intr, signed long timeout)
__set_current_state(TASK_RUNNING);
out:
- spin_unlock_irqrestore(f->lock, irq_flags);
+ spin_unlock_bh(f->lock);
vmw_seqno_waiter_remove(dev_priv);
@@ -300,21 +301,22 @@ struct vmw_fence_manager *vmw_fence_manager_init(struct vmw_private *dev_priv)
ttm_round_pot(sizeof(struct vmw_event_fence_action));
mutex_init(&fman->goal_irq_mutex);
fman->ctx = fence_context_alloc(1);
+ tasklet_init(&fman->tasklet, vmw_fence_tasklet,
+ (unsigned long) fman);
return fman;
}
void vmw_fence_manager_takedown(struct vmw_fence_manager *fman)
{
- unsigned long irq_flags;
bool lists_empty;
(void) cancel_work_sync(&fman->work);
- spin_lock_irqsave(&fman->lock, irq_flags);
+ spin_lock_bh(&fman->lock);
lists_empty = list_empty(&fman->fence_list) &&
list_empty(&fman->cleanup_list);
- spin_unlock_irqrestore(&fman->lock, irq_flags);
+ spin_unlock_bh(&fman->lock);
BUG_ON(!lists_empty);
kfree(fman);
@@ -324,7 +326,6 @@ static int vmw_fence_obj_init(struct vmw_fence_manager *fman,
struct vmw_fence_obj *fence, u32 seqno,
void (*destroy) (struct vmw_fence_obj *fence))
{
- unsigned long irq_flags;
int ret = 0;
fence_init(&fence->base, &vmw_fence_ops, &fman->lock,
@@ -332,7 +333,7 @@ static int vmw_fence_obj_init(struct vmw_fence_manager *fman,
INIT_LIST_HEAD(&fence->seq_passed_actions);
fence->destroy = destroy;
- spin_lock_irqsave(&fman->lock, irq_flags);
+ spin_lock_bh(&fman->lock);
if (unlikely(fman->fifo_down)) {
ret = -EBUSY;
goto out_unlock;
@@ -341,7 +342,7 @@ static int vmw_fence_obj_init(struct vmw_fence_manager *fman,
++fman->num_fence_objects;
out_unlock:
- spin_unlock_irqrestore(&fman->lock, irq_flags);
+ spin_unlock_bh(&fman->lock);
return ret;
}
@@ -490,11 +491,9 @@ rerun:
void vmw_fences_update(struct vmw_fence_manager *fman)
{
- unsigned long irq_flags;
-
- spin_lock_irqsave(&fman->lock, irq_flags);
+ spin_lock_bh(&fman->lock);
__vmw_fences_update(fman);
- spin_unlock_irqrestore(&fman->lock, irq_flags);
+ spin_unlock_bh(&fman->lock);
}
bool vmw_fence_obj_signaled(struct vmw_fence_obj *fence)
@@ -694,11 +693,9 @@ void vmw_fence_fifo_down(struct vmw_fence_manager *fman)
void vmw_fence_fifo_up(struct vmw_fence_manager *fman)
{
- unsigned long irq_flags;
-
- spin_lock_irqsave(&fman->lock, irq_flags);
+ spin_lock_bh(&fman->lock);
fman->fifo_down = false;
- spin_unlock_irqrestore(&fman->lock, irq_flags);
+ spin_unlock_bh(&fman->lock);
}
@@ -825,10 +822,9 @@ void vmw_event_fence_fpriv_gone(struct vmw_fence_manager *fman,
{
struct vmw_event_fence_action *eaction;
struct drm_pending_event *event;
- unsigned long irq_flags;
while (1) {
- spin_lock_irqsave(&fman->lock, irq_flags);
+ spin_lock_bh(&fman->lock);
if (list_empty(event_list))
goto out_unlock;
eaction = list_first_entry(event_list,
@@ -837,11 +833,11 @@ void vmw_event_fence_fpriv_gone(struct vmw_fence_manager *fman,
list_del_init(&eaction->fpriv_head);
event = eaction->event;
eaction->event = NULL;
- spin_unlock_irqrestore(&fman->lock, irq_flags);
+ spin_unlock_bh(&fman->lock);
event->destroy(event);
}
out_unlock:
- spin_unlock_irqrestore(&fman->lock, irq_flags);
+ spin_unlock_bh(&fman->lock);
}
@@ -854,7 +850,7 @@ out_unlock:
* This function is called when the seqno of the fence where @action is
* attached has passed. It queues the event on the submitter's event list.
* This function is always called from atomic context, and may be called
- * from irq context.
+ * from tasklet context.
*/
static void vmw_event_fence_action_seq_passed(struct vmw_fence_action *action)
{
@@ -863,13 +859,12 @@ static void vmw_event_fence_action_seq_passed(struct vmw_fence_action *action)
struct drm_device *dev = eaction->dev;
struct drm_pending_event *event = eaction->event;
struct drm_file *file_priv;
- unsigned long irq_flags;
if (unlikely(event == NULL))
return;
file_priv = event->file_priv;
- spin_lock_irqsave(&dev->event_lock, irq_flags);
+ spin_lock_bh(&dev->event_lock);
if (likely(eaction->tv_sec != NULL)) {
struct timeval tv;
@@ -883,7 +878,7 @@ static void vmw_event_fence_action_seq_passed(struct vmw_fence_action *action)
list_add_tail(&eaction->event->link, &file_priv->event_list);
eaction->event = NULL;
wake_up_all(&file_priv->event_wait);
- spin_unlock_irqrestore(&dev->event_lock, irq_flags);
+ spin_unlock_bh(&dev->event_lock);
}
/**
@@ -900,11 +895,10 @@ static void vmw_event_fence_action_cleanup(struct vmw_fence_action *action)
struct vmw_event_fence_action *eaction =
container_of(action, struct vmw_event_fence_action, action);
struct vmw_fence_manager *fman = fman_from_fence(eaction->fence);
- unsigned long irq_flags;
- spin_lock_irqsave(&fman->lock, irq_flags);
+ spin_lock_bh(&fman->lock);
list_del(&eaction->fpriv_head);
- spin_unlock_irqrestore(&fman->lock, irq_flags);
+ spin_unlock_bh(&fman->lock);
vmw_fence_obj_unreference(&eaction->fence);
kfree(eaction);
@@ -924,11 +918,10 @@ static void vmw_fence_obj_add_action(struct vmw_fence_obj *fence,
struct vmw_fence_action *action)
{
struct vmw_fence_manager *fman = fman_from_fence(fence);
- unsigned long irq_flags;
bool run_update = false;
mutex_lock(&fman->goal_irq_mutex);
- spin_lock_irqsave(&fman->lock, irq_flags);
+ spin_lock_bh(&fman->lock);
fman->pending_actions[action->type]++;
if (fence_is_signaled_locked(&fence->base)) {
@@ -947,7 +940,7 @@ static void vmw_fence_obj_add_action(struct vmw_fence_obj *fence,
run_update = vmw_fence_goal_check_locked(fence);
}
- spin_unlock_irqrestore(&fman->lock, irq_flags);
+ spin_unlock_bh(&fman->lock);
if (run_update) {
if (!fman->goal_irq_on) {
@@ -985,7 +978,6 @@ int vmw_event_fence_action_queue(struct drm_file *file_priv,
struct vmw_event_fence_action *eaction;
struct vmw_fence_manager *fman = fman_from_fence(fence);
struct vmw_fpriv *vmw_fp = vmw_fpriv(file_priv);
- unsigned long irq_flags;
eaction = kzalloc(sizeof(*eaction), GFP_KERNEL);
if (unlikely(eaction == NULL))
@@ -1002,9 +994,9 @@ int vmw_event_fence_action_queue(struct drm_file *file_priv,
eaction->tv_sec = tv_sec;
eaction->tv_usec = tv_usec;
- spin_lock_irqsave(&fman->lock, irq_flags);
+ spin_lock_bh(&fman->lock);
list_add_tail(&eaction->fpriv_head, &vmw_fp->fence_events);
- spin_unlock_irqrestore(&fman->lock, irq_flags);
+ spin_unlock_bh(&fman->lock);
vmw_fence_obj_add_action(fence, &eaction->action);
@@ -1025,16 +1017,15 @@ static int vmw_event_fence_action_create(struct drm_file *file_priv,
struct vmw_event_fence_pending *event;
struct vmw_fence_manager *fman = fman_from_fence(fence);
struct drm_device *dev = fman->dev_priv->dev;
- unsigned long irq_flags;
int ret;
- spin_lock_irqsave(&dev->event_lock, irq_flags);
+ spin_lock_bh(&dev->event_lock);
ret = (file_priv->event_space < sizeof(event->event)) ? -EBUSY : 0;
if (likely(ret == 0))
file_priv->event_space -= sizeof(event->event);
- spin_unlock_irqrestore(&dev->event_lock, irq_flags);
+ spin_unlock_bh(&dev->event_lock);
if (unlikely(ret != 0)) {
DRM_ERROR("Failed to allocate event space for this file.\n");
@@ -1078,9 +1069,9 @@ static int vmw_event_fence_action_create(struct drm_file *file_priv,
out_no_queue:
event->base.destroy(&event->base);
out_no_event:
- spin_lock_irqsave(&dev->event_lock, irq_flags);
+ spin_lock_bh(&dev->event_lock);
file_priv->event_space += sizeof(*event);
- spin_unlock_irqrestore(&dev->event_lock, irq_flags);
+ spin_unlock_bh(&dev->event_lock);
out_no_space:
return ret;
}
@@ -1172,3 +1163,32 @@ out_no_ref_obj:
vmw_fence_obj_unreference(&fence);
return ret;
}
+
+/**
+ * vmw_fence_tasklet - Fence manager tasklet entry point
+ *
+ * @data: The tasklet closure - A pointer to the fence manager cast to an
+ * unsigned long.
+ */
+static void vmw_fence_tasklet(unsigned long data)
+{
+ struct vmw_fence_manager *fman = (struct vmw_fence_manager *) data;
+
+ spin_lock(&fman->lock);
+ __vmw_fences_update(fman);
+ spin_unlock(&fman->lock);
+ wake_up_all(&fman->dev_priv->fence_queue);
+}
+
+/**
+ * vmw_fence_tasklet_schedule - Schedule a fence manager tasklet run
+ *
+ * @fman: Pointer to a fence manager
+ */
+void vmw_fence_tasklet_schedule(struct vmw_fence_manager *fman)
+{
+ if (!fman)
+ return;
+
+ tasklet_schedule(&fman->tasklet);
+}
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.h b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.h
index 8be6c29..e55b2c9 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.h
@@ -124,4 +124,6 @@ extern int vmw_event_fence_action_queue(struct drm_file *filee_priv,
uint32_t *tv_sec,
uint32_t *tv_usec,
bool interruptible);
+extern void vmw_fence_tasklet_schedule(struct vmw_fence_manager *fman);
+
#endif /* _VMWGFX_FENCE_H_ */
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_irq.c b/drivers/gpu/drm/vmwgfx/vmwgfx_irq.c
index ac3eccd..b0a6e65 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_irq.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_irq.c
@@ -48,10 +48,8 @@ irqreturn_t vmw_irq_handler(int irq, void *arg)
return IRQ_NONE;
if (masked_status & (SVGA_IRQFLAG_ANY_FENCE |
- SVGA_IRQFLAG_FENCE_GOAL)) {
- vmw_fences_update(dev_priv->fman);
- wake_up_all(&dev_priv->fence_queue);
- }
+ SVGA_IRQFLAG_FENCE_GOAL))
+ vmw_fence_tasklet_schedule(dev_priv->fman);
if (masked_status & SVGA_IRQFLAG_FIFO_PROGRESS)
wake_up_all(&dev_priv->fifo_queue);
--
2.4.3
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