[PATCH 09/12] drm/i915/gvt: Stop waiting whilst holding struct_mutex

Chris Wilson
2016-10-19T10:12:05Z

For whatever reason, the gvt scheduler runs synchronously. At the very
least, lets run synchronously without holding the struct_mutex.

v2: cut'n'paste mutex_lock instead of unlock.
Replace long hold of struct_mutex with a mutex to serialise the worker
threads.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/gvt/scheduler.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index 310435498932..9957d8832c63 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -390,6 +390,8 @@ struct workload_thread_param {
int ring_id;
};

+static DEFINE_MUTEX(scheduler_mutex);
+
static int workload_thread(void *priv)
{
struct workload_thread_param *p = (struct workload_thread_param *)priv;
@@ -414,17 +416,14 @@ static int workload_thread(void *priv)
if (kthread_should_stop())
break;

+ mutex_lock(&scheduler_mutex);
+
gvt_dbg_sched("ring id %d next workload %p vgpu %d\n",
workload->ring_id, workload,
workload->vgpu->id);

intel_runtime_pm_get(gvt->dev_priv);

- /*
- * Always take i915 big lock first
- */
- mutex_lock(&gvt->dev_priv->drm.struct_mutex);
-
gvt_dbg_sched("ring id %d will dispatch workload %p\n",
workload->ring_id, workload);

@@ -432,7 +431,10 @@ static int workload_thread(void *priv)
intel_uncore_forcewake_get(gvt->dev_priv,
FORCEWAKE_ALL);

+ mutex_lock(&gvt->dev_priv->drm.struct_mutex);
ret = dispatch_workload(workload);
+ mutex_unlock(&gvt->dev_priv->drm.struct_mutex);
+
if (ret) {
gvt_err("fail to dispatch workload, skip\n");
goto complete;
@@ -442,8 +444,7 @@ static int workload_thread(void *priv)
workload->ring_id, workload);

workload->status = i915_wait_request(workload->req,
- I915_WAIT_LOCKED,
- NULL, NULL);
+ 0, NULL, NULL);
if (workload->status != 0)
gvt_err("fail to wait workload, skip\n");

@@ -451,7 +452,9 @@ static int workload_thread(void *priv)
gvt_dbg_sched("will complete workload %p\n, status: %d\n",
workload, workload->status);

+ mutex_lock(&gvt->dev_priv->drm.struct_mutex);
complete_current_workload(gvt, ring_id);
+ mutex_unlock(&gvt->dev_priv->drm.struct_mutex);

i915_gem_request_put(fetch_and_zero(&workload->req));

@@ -459,9 +462,10 @@ static int workload_thread(void *priv)
intel_uncore_forcewake_put(gvt->dev_priv,
FORCEWAKE_ALL);

- mutex_unlock(&gvt->dev_priv->drm.struct_mutex);
-
intel_runtime_pm_put(gvt->dev_priv);
+
+ mutex_unlock(&scheduler_mutex);
+
}
return 0;
}
--
2.9.3